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Particulate matter (PM2.5) containing polycyclic aromatic hydrocarbons (PAHs) is of considerable environmental importance worldwide due to its adverse effects on human health, which are associated with neurodegenerative diseases (NDDs). Areca catechu L. (AC) fruit is known to possess various pharmacological properties; however, the anti-neuroinflammatory roles of AC on the suppression of PAH-induced neuroinflammation are still limited. Thus, we focused on the effects and related signaling cascades of AC and its active compounds against anthracene-induced toxicity and inflammation in mouse microglial BV-2 cells. Phytochemicals in the ethanolic extract of AC (ACEE) were identified using LC-MS, and molecular docking was conducted to screen the interaction between compounds and target proteins. Significant bioactive compounds in ACEE such as arecoline, (−)-epicatechin, and syringic acid were evinced through the LC-MS spectrum. The docking study revealed that (−)-epicatechin showed the highest binding affinities against NF-κB. For cell-based approaches, anthracene induced intracellular ROS, mRNA levels of TNF-α, IL-1β, and IL-6, and the release of TNF-α through enhancing JNK, p38, and NF-κB signaling pathways. However, the co-treatment of cells with ACEE or (−)-epicatechin could reverse those anthracene-induced changes. The overall study suggested that ACEE-derived bioactive compounds such as (−)-epicatechin may be developed as a potential anti-neuroinflammatory agent by preventing inflammation-mediated NDDs. [ABSTRACT FROM AUTHOR]

Objective: The limited understanding of the molecular mechanism for oral submucosal fibrosis (OSF) poses challenges to the development of effective prevention and treatment strategies. The lack of suitable animal models is a major hindrance. Therefore, this study aimed to address this issue by comparing commonly used arecoline‐induced water drinking and injection mouse models. Materials and Methods: The mice were subjected to two protocols: receiving 2 mg/mL arecoline in drinking water and 4 mg/mL arecoline saline solution injections every other day. Tissues were collected at regular 4‐week intervals, with a final time point of 20 weeks. Stereo microscopy and histomorphological analysis were performed on live and harvested tissues, respectively. Results: During arecoline treatment, collagen deposition and myofibroblast proliferation progressively increased in both models. Changes in the collagen I/III ratio indicated that both models exhibited characteristics of the early and intermediate stages of OSF after 20 weeks of arecoline induction. The water‐drinking model also demonstrated multi‐organ fibrosis involving the tongue, lungs, and small intestine. Conclusion: Both the water drinking and injection mouse models effectively induced OSF, but the water‐drinking model better mirrored the observed pathogenesis in patients with OSF. These models provide valuable tools for investigating the mechanisms underlying OSF. [ABSTRACT FROM AUTHOR]

The betel nut is one of the most widely consumed addictive substances in the world after nicotine, ethanol, and caffeine. Arecoline is an active ingredient from the areca nut. It has many pharmacological effects and can affect the central nervous system. In this study, we found that arecoline can relieve fatigue behavior. Objective: This research aims to estimate the anti-fatigue effects of arecoline and explore its underlying mechanisms using a murine model of central fatigue precipitated by sleep deprivation (SD). Methods: Seventy-two male C57BL/6 mice were randomly assigned to six groups: a control group, an SD-induced fatigue model group, a group that received Rhodiola Rosea capsules (2.5 mg/kg), and three arecoline groups, which were administered at low, medium, and high doses (10, 20, and 40 mg/kg, respectively). Following 28 days of continuous administrations, the effects of arecoline on mouse fatigue-related behaviors were assessed by behavioral tests, including grip strength, rotarod performance, and weight-bearing swimming endurance. The release levels of the related biochemical markers were measured by enzyme-linked immunosorbent assays (ELISAs). Western blotting was employed to quantify the expression levels of nuclear factor erythroid 2-related factor (Nrf2), Kelch-like ECH-associated protein 1 (Keap1), heme oxygenase 1 (HO-1), sequestosome-1 (p62), and NADPH quinone oxidoreductase 1 (NQO1) in the gastrocnemius muscle. Results: Arecoline administration notably enhanced grip strength, delayed the onset of fatigue as evidenced by extended latencies in rotarod tests, and increased the duration of weight-bearing swimming in mice. In the elevated plus maze, arecoline obviously decreased both the number of entries and the total distance traveled in the open arms. Arecoline markedly decreased the contents of creatine kinase, blood urea nitrogen, lactate dehydrogenase, triglycerides, and cholesterol in the serum, while it elevated the levels of total testosterone, lactate dehydrogenase, and immunoglobulin G. Furthermore, it significantly increased the activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase in the gastrocnemius muscle, reduced malondialdehyde levels, augmented hippocampal SOD and CAT activity, and elevated glycogen stores in both liver and muscle tissues. Neurotransmitter levels showed significant increases, cytokine levels were markedly reduced, and the expressions of Nrf2, Keap1, NQO1, p62, and HO-1 in brain tissues were significantly upregulated. Conclusions: This study demonstrates that arecoline has anti-fatigue activity, and the specific mechanisms are associated with elevating glucose and lipid metabolism levels, relieving oxidative stress damage, inhibiting neuroinflammatory response, and regulating neurotransmitter levels and the Keap1/Nrf2/HO-1 signaling pathway. The research provides a new direction for arecoline's potential in preventing and improving fatigue. [ABSTRACT FROM AUTHOR]

As the areca nut market is expanding, there is a growing concern regarding areca nut toxicity. Areca nut alkaloids are the major risky components in betel nuts, and their toxic effects are not fully understood. Here, we investigated the parental and transgenerational toxicity of varied doses of areca nut alkaloids in Caenorhabditis elegans. The results showed that the minimal effective concentration of arecoline is 0.2–0.4 mM. First, arecoline exhibited transgenerational toxicity on the worms' longevity, oviposition, and reproduction. Second, the redox homeostasis of C. elegans was markedly altered under exposure to 0.2–0.4 mM arecoline. The mitochondrial membrane potential was thereafter impaired, which was also associated with the induction of apoptosis. Moreover, antioxidant treatments such as lycopene could significantly ameliorate the toxic effects caused by arecoline. In conclusion, arecoline enhances the ROS levels, inducing neurotoxicity, developmental toxicity, and reproductive toxicity in C. elegans through dysregulated oxidative stress, cell apoptosis, and DNA damage-related gene expression. Therefore, the drug-induced production of reactive oxygen species (ROS) may be crucial for its toxic effects, which could be mitigated by antioxidants. [ABSTRACT FROM AUTHOR]

Areca nut, the seed of Areca catechu L., is one of the most widely consumed addictive substances in the world after nicotine, ethanol, and caffeine. The major effective constituent of A. catechu, arecoline, has been reported to affect the central nervous system. Less is known if it may affect pain and its related emotional responses. In this study, we found that oral application of arecoline alleviated the inflammatory pain and its induced anxiolytic and anti-depressive-like behavior. Arecoline also increased the mechanical nociceptive threshold and alleviated depression-like behavior in naïve mice. In the anterior cingulate cortex (ACC), which acts as a hinge of nociception and its related anxiety and depression, by using the multi-electrode field potential recording and whole-cell patch-clamp recording, we found that the evoked postsynaptic transmission in the ACC of adult mice has been inhibited by the application of arecoline. The muscarinic receptor is the major receptor of the arecoline in the ACC. Our results suggest that arecoline alleviates pain, anxiety, and depression-like behavior in both physiological and pathological conditions, and this new mechanism may help to treat patients with chronic pain and its related anxiety and disorder in the future. [ABSTRACT FROM AUTHOR]

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Arecoline, the predominant bioactive substance extracted from areca nut (AN), is the world's fourth most frequently used psychoactive material. Research has revealed that chewing AN can affect the central nervous system (CNS) and may lead to neurocognitive deficits that are possibly linked to the action of arecoline. However, the mechanism behind the neurotoxicity caused by arecoline remains unclear. This study aimed to investigate the neurotoxic effects of arecoline and its underlying mechanism. The results showed that arecoline caused cytotoxicity against HT22 cells in a dose‐dependent manner and induced apoptosis by upregulating the expression of pro‐apoptotic caspase and Bcl‐2 family proteins. Furthermore, arecoline escalated intracellular reactive oxygen species (ROS) levels and Ca2+ concentration with increasing doses, thereby motivating endoplasmic reticulum stress (ERS) and ERS‐associated apoptotic protein expression. Additionally, the study found that arecoline attenuates intracellular antioxidant defense by inhibiting the translocation of NF‐E2‐related factor‐2 (Nrf2) into the nucleus and decreasing downstream Heme oxygenase‐1 (HO‐1) levels. The specific inhibitor Sodium 4‐phenylbutyrate (4‐PBA) can dramatically attenuate arecoline‐mediated cell apoptosis and ERS‐associated apoptotic pathway expression by blocking ERS. The antioxidant N‐Acetylcysteine (NAC) also effectively reverses the arecoline‐mediated increase of ERS‐related apoptotic pathway protein levels by scavenging intracellular ROS accumulation. In conclusion, this study suggests that arecoline induces neurotoxicity in HT22 cells via ERS mediated by oxidative stress‐ and Ca2+ disturbance, as well as by downregulation of the Nrf2/HO‐1 pathway. [ABSTRACT FROM AUTHOR]

Background: Areca Nut (AN) is the fourth most commonly abused drug after nicotine, ethanol, and caffeine, due to its psychoactive properties provided by bioactive substances. Although previous studies have demonstrated AN's anxiolytic-like activity and potential benefits in ameliorating symptoms of depression and schizophrenia, there remains limited awareness regarding its association with brief psychotic disorder. Case presentation: This case report presents the clinical profile of a 30-year-old male patient with a history of betel nut chewing for the past 2 years, who exhibited sudden onset delusions, hallucinations, and disorganized speech and behavior upon increasing the dosage of betel nut consumption. The patient displayed a positive response to antipsychotic treatment, and symptoms resolved upon discontinuation of betel nut consumption. However, one month after discharge, the patient experienced a recurrence of auditory hallucinations upon resuming betel nut chewing. Through counseling and support, the importance of abstaining from betel nut use and maintaining medication compliance was emphasized, resulting in no recurrence of psychotic symptoms during the six-month follow-up. Conclusions: This case report highlights the related role of betel nut with brief psychotic disorder, especially when the chewing dosage is abruptly increased. It underscores the importance of considering betel nut as a potential precipitant related to acute psychiatric disorders in clinical settings. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Pathophysiology is the property of Jinan University, School of Medicine and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Science & Technology of Food Industry is the property of Science & Technology of Food Industry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: Submucosal fibrosis (OSF) of the oral cavity is a chronic scarring disease. Arecoline (Are) is the driving factor for the occurrence and deterioration of OSF. Curcumin plays a vital anti‐inflammatory role in Are‐induced OSF development. However, its potential pharmacological mechanism needs to be elucidated. Methods: The relative molecular level was measured via qRT‐PCR or Western blot. MTT assay, transwell assay and flow cytometry detected cell proliferation, migration, and apoptosis. The correlation between hypoxia‐inducible factor‐1α (HIF‐1α) and LTBP2 promoter was confirmed through dual‐luciferase reporter assay. ELISA was performed to detect inflammatory cytokines levels. Results: Curcumin alleviated Are‐induced oral mucosal fibroblast cells fibrosis by reducing oral mucosa fibroblasts viability, promoting cell apoptosis, suppressing cell migration, and down‐regulating the levels of fibrosis markers and inflammatory factors. Curcumin relieved Are‐induced OSF via inhibiting HIF‐1α. Mechanically, HIF‐1α bound to the promoter of LTBP2 to transcriptionally activated LTBP2. LTBP2 knockdown relieved Are‐induced OSF, and curcumin down‐regulated LTBP2 via inhibiting HIF‐1α to relieve Are‐induced OSF. Moreover, curcumin decreased NF‐κB signal associated proteins via inhibiting LTBP2 to relieve Are‐induced OSF. Conclusion: Curcumin reduced the transcription level of LTBP2 by inhibiting HIF‐1α, thereby inactivating NF‐κB pathway to alleviate Are‐induced OSF. [ABSTRACT FROM AUTHOR]

Aerobic glycolysis is a typical metabolic rearrangement for tumorigenesis. Arecoline is of explicit carcinogenicity, numerous works demonstrate its mutagenicity, genotoxicity, and cytotoxicity. However, the effects of arecoline on aerobic glycolysis of esophageal epithelial cells remain unclear. In the present study, 5 μM arecoline efficiently increased HK2 expression to induce aerobic glycolysis in Het‐1A‐Are and NE2‐Are cells. The mechanistic analysis showed that arecoline activated the Akt‐c‐Myc signaling pathway and reduced the GSK3β‐mediated phosphorylation of c‐Myc on Thr58 to prevent its ubiquitination and destruction, subsequently promoting HK2 transcription and expression. Taken together, these results suggest that arecoline can induce aerobic glycolysis of esophageal epithelial cells and further confirm that arecoline is a carcinogen harmful to human health. [ABSTRACT FROM AUTHOR]

A series of arecoline derivatives with amino acid moieties were designed and synthesised using an acylamide condensation strategy, taking arecoline as the foundational structure. The insecticidal efficacy of these compounds against Aphis craccivora and Tetranychus cinnabarinus was evaluated. Notably, derivatives 3h and 3i demonstrated superior insecticidal activity compared with arecoline. Additionally, 3h and 3i showed good fungicidal effectiveness against two types of plant fungi. Moreover, molecular docking analyses suggested that 3h and 3i could affect the nervous systems of A. craccivora and T. cinnabarinus by binding to neuronal nicotinic acetylcholine receptors. These findings suggest that compounds 3h and 3i represent promising leads for further development in insecticide and fungicide research. [ABSTRACT FROM AUTHOR]

Iron overload-associated osteoporosis presents a significant challenge to bone health. This study examines the effects of arecoline (ACL), an alkaloid found in areca nut, on bone metabolism under iron overload conditions induced by ferric ammonium citrate (FAC) treatment. The results indicate that ACL mitigates the FAC-induced inhibition of osteogenesis in zebrafish larvae, as demonstrated by increased skeletal mineralization and upregulation of osteogenic genes. ACL attenuates FAC-mediated suppression of osteoblast differentiation and mineralization in MC3T3-E1 cells. RNA sequencing analysis suggests that the protective effects of ACL are related to the regulation of ferroptosis. We demonstrate that ACL inhibits ferroptosis, including oxidative stress, lipid peroxidation, mitochondrial damage, and cell death under FAC exposure. In this study, we have identified heme oxygenase-1 (HO-1) as a critical mediator of ACL inhibiting ferroptosis and promoting osteogenesis, which was validated by HO-1 knockdown and knockout experiments. The study links ACL to HO-1 activation and ferroptosis regulation in the context of bone metabolism. These findings provide new insights into the mechanisms underlying the modulation of osteogenesis by ACL. Targeting the HO-1/ferroptosis axis is a promising therapeutic approach for treating iron overload-induced bone diseases. [ABSTRACT FROM AUTHOR]

Oral submucous fibrosis (OSF) is a chronic disorder with a high malignant transformation rate. Epithelial-mesenchymal transition (EMT) and angiogenesis are key events in OSF. The Notch signaling plays an essential role in the pathogenesis of various fibrotic diseases, including OSF. Our study aimed to explore the effects of Notch on the EMT and angiogenesis processes during the development of OSF. The expression of Notch in OSF tissues versus normal buccal mucosa samples was compared. Arecoline was used to induce myofibroblast transdifferentiation of buccal mucosal fibroblasts (BMFs). Short hairpin RNA technique was used to knockdown Notch in BMFs. Pirfenidone and SRI-011381 were used to inhibit and activate the TGF-β1 signaling pathway in BMFs, respectively. The expression of Notch was markedly upregulated in OSF tissues and fibrotic BMFs. Knockdown of Notch significantly decreased the viability and promoted apoptosis in BMFs subjected to arecoline stimulation. Downregulation of Notch also significantly suppressed the EMT process, as shown by the reduction of N-cadherin and vimentin with concomitant upregulation of E-cadherin. In addition, knockdown of Notch upregulated VEGF and enhanced the angiogenic activity of fBMFs. Moreover, inhibition of TGF-β1 suppressed viability and EMT, promoted apoptosis, and induced angiogenesis of fBMFs, while activation of TGF-β1 significantly diminished the effects of Notch knockdown on fBMFs. Knockdown of Notch suppressed EMT and induced angiogenesis in OSF by regulating TGF-β1, suggesting that the Notch-TGF-β1 pathway may serve as a therapeutic intervention target for OSF. Highlights: Notch is upregulated in oral submucous fibrosis tissues and fibrotic buccal mucosal fibroblasts (fBMFs). Knockdown of Notch suppresses the viability and epithelial-mesenchymal transition, promotes apoptosis, and induces angiogenesis in fBMFs. Activation of the transforming growth factor beta 1 signaling diminished the effects of Notch knockdown on fBMFs. [ABSTRACT FROM AUTHOR]

The aim of this review is to enumerate medicinal plants and their bioactive compounds that may become potential leads in the mitigation of oral submucous fibrosis (OSMF) in the forthcoming future. It is focused on pathophysiology, risk factors, current treatment regimen, potential plant leads, and future therapies for OSMF. Data were extracted from a vast literature survey by using SciFinder, Web of Science, Google Scholar, and PubMed search engines with relevant keywords. Upon literature survey, we found that the phytochemical 'arecoline' present in the areca nut is the main causative agent of OSMF condition. Currently, OSMF is treated by immunomodulatory and anti‐inflammatory agents such as corticosteroids, enzymes (hyaluronidase, chymotrypsin, and collagenase), anti‐inflammatory mediators (isoxsuprine and pentoxifylline), dietary supplements (vitamins, antioxidants, and micronutrients), and anti‐fibrotic cytokines like interferon‐gamma that provides short‐term symptomatic relief to OSMF patients. However, some plant leads have been proven effective in alleviating symptoms and mitigating OSMF, which ultimately improves the quality of OSMF patients' life. We concluded that plant drugs like lycopene, curcumin, Aloe vera, colchicine, and Glycyrrhiza glabra are effective against OSMF in various in vitro and/or clinical studies and are being used by modern and traditional practitioners. [ABSTRACT FROM AUTHOR]

Background: This study aimed to assess silymarin's anticancer and antifibrotic potential through in silico analysis and investigate its impact on in vitro arecoline-induced fibrosis in primary human buccal fibroblasts (HBF). Methods & results: The study utilized iGEMDOCK for molecular docking, evaluating nine bioflavonoids, and identified silymarin and baicalein as the top two compounds with the highest target affinity, followed by subsequent validation through a 100ns Molecular Dynamic Simulation demonstrating silymarin's stable behavior with Transforming Growth Factor Beta. HBF cell lines were developed from tissue samples obtained from patients undergoing third molar extraction. Arecoline, a known etiological factor in oral submucous fibrosis (OSMF), was employed to induce fibrogenesis in these HBFs. The inhibitory concentration (IC50) of arecoline was determined using the MTT assay, revealing dose-dependent cytotoxicity of HBFs to arecoline, with notable cytotoxicity observed at concentrations exceeding 50µM. Subsequently, the cytotoxicity of silymarin was assessed at 24 and 72 h, spanning concentrations from 5µM to 200µM, and an IC50 value of 143µM was determined. Real-time polymerase chain reaction (qPCR) was used to analyze the significant downregulation of key markers including collagen, epithelial-mesenchymal transition (EMT), stem cell, hypoxia, angiogenesis and stress markers in silymarin-treated arecoline-induced primary buccal fibroblast cells. Conclusion: Silymarin effectively inhibited fibroblast proliferation and downregulated genes associated with cancer progression and EMT pathway, both of which are implicated in malignant transformation. To our knowledge, this study represents the first exploration of silymarin's potential as a novel therapeutic agent in an in vitro model of OSMF. [ABSTRACT FROM AUTHOR]

Background: Annual production of areca nut in Karnataka state exceeds 1.08 million tonnes, contributing 80% and 49% to Indian and global production, respectively. Areca nut (pericarp of Areca catechu L.) is found to be a rich source of valuable phenolic compounds. Total phenolic content (TPC) and total flavonoid content (TFC) were estimated in 21 unripe areca nut samples collected from the major areca nut growing regions of Karnataka state. Arecoline, a prominent alkaloid present in areca nut was estimated and phenolic profile of one areca nut sample was generated using UHPLC–MS/MS studies. Results: A significant variability was found in TPC, TFC and arecoline content among the samples, belongs to different agroclimatic zones. Flavonoids were found to be the major phenolic compounds present in these unripe areca nut samples. The median values of TPC, TFC and arecoline were found to be 99.609 ± 0.002 mg gallic acid equivalent, 78.86 ± 0.007 mg catechin equivalent and 2.17 ± 0.13 mg/g of the sample on fresh weight basis. A positive correlation was found to exist between TPC and arecoline content in the green unripe areca nuts of 6–7 months' maturity. Through UHPLC–MS/MS studies, 61 prominent compounds have been identified. Conclusion: The TPC and TFC of areca nuts collected from different districts of Karnataka falling in various agroclimatic zones varied significantly. In general, the arecoline content found in all these samples was less than that reported elsewhere, and the variability among the samples was also found to be minimal. A positive correlation was observed between TPC and arecoline. UHPLC–MS/MS studies showed the presence of about 52 unique phenolic compounds. [ABSTRACT FROM AUTHOR]

Areca nut is a major contributor to the high prevalence of oral cancer in Asia. The precise mechanisms by which areca nut stimulates mucosal cells and contributes to the progression of oral cancer urgently require clarification. The current study aimed to assess the effects of arecoline on the normal human gingival epithelium cell line S-G. Cell viability, levels of reactive oxygen species (ROS), protein expression, cellular morphology, and gene expression were evaluated using the MTT test, flow cytometry, Western blot analysis, optical or confocal microscopy, and RT-qPCR. Keratin (KRT6) analysis involved matched normal and cancer tissues from clinical head and neck specimens. The results demonstrated that 12.5 µg/mL of arecoline induced ROS production, tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) mRNA expression in S-G cells. This activation of the MAPK/ERK pathway increased KRT6 expression while limiting cell migration. In head and neck cancer tissues, KRT6B gene expression exceeded that of normal tissues. This study confirms that arecoline induces ROS accumulation in normal cells, leading to the secretion of proinflammatory factors and KRT6 expression. This impedes oral mucosal healing, thereby promoting the progression of oral cancer. [ABSTRACT FROM AUTHOR]

Background: This study aimed to assess silymarin’s anticancer and antifibrotic potential through in silico analysis and investigate its impact on in vitro arecoline-induced fibrosis in primary human buccal fibroblasts (HBF). Methods & results: The study utilized iGEMDOCK for molecular docking, evaluating nine bioflavonoids, and identified silymarin and baicalein as the top two compounds with the highest target affinity, followed by subsequent validation through a 100ns Molecular Dynamic Simulation demonstrating silymarin’s stable behavior with Transforming Growth Factor Beta. HBF cell lines were developed from tissue samples obtained from patients undergoing third molar extraction. Arecoline, a known etiological factor in oral submucous fibrosis (OSMF), was employed to induce fibrogenesis in these HBFs. The inhibitory concentration (IC50) of arecoline was determined using the MTT assay, revealing dose-dependent cytotoxicity of HBFs to arecoline, with notable cytotoxicity observed at concentrations exceeding 50µM. Subsequently, the cytotoxicity of silymarin was assessed at 24 and 72 h, spanning concentrations from 5µM to 200µM, and an IC50 value of 143µM was determined. Real-time polymerase chain reaction (qPCR) was used to analyze the significant downregulation of key markers including collagen, epithelial-mesenchymal transition (EMT), stem cell, hypoxia, angiogenesis and stress markers in silymarin-treated arecoline-induced primary buccal fibroblast cells. Conclusion: Silymarin effectively inhibited fibroblast proliferation and downregulated genes associated with cancer progression and EMT pathway, both of which are implicated in malignant transformation. To our knowledge, this study represents the first exploration of silymarin’s potential as a novel therapeutic agent in an in vitro model of OSMF. [ABSTRACT FROM AUTHOR]

Background: The use of areca nut also known as supari or chaali is an age-old tradition and very popular in people living in South Asian countries. However, in general, people know very little about its ill effects. Aims: This study aimed to examine knowledge, attitudes, and practices regarding the health risks associated with chewing areca nuts and betel quid among the adult population and to evaluate the knowledge about its possible role as a contributing factor in oral cancer among the adult population. Materials and Methods: The unicentric cross-sectional survey was conducted on 1644 adult subjects belonging to the adult population of Aligarh and nearby places between March 2021 and December 2021. We analyzed the data using the Statistical Package for the Social Sciences (SPSS) software version 22. Results: The overall average age of the participants was 39.32 ± 14.18. The male-to-female ratio was 2:1. Among the study subjects, 54% were betel nut or betel quid chewers. Only 30.8% knew that areca nut may cause oral cancer and with low knowledge related to its systematic effect. Conclusion: Areca nut is a known carcinogenic agent and carries the risk of cancer even if it is used alone. However, information about the systemic ill effect especially its carcinogenic effect is very low among the general population. [ABSTRACT FROM AUTHOR]

Arecoline is the primary active carcinogen found in areca nut and has been implicated in the pathogenesis of oral squamous cell carcinoma (OSCC) and oral submucous fibrosis (OSF). For this study, we conducted a stepwise review process by combining iterative scoping reviews with a post hoc search, with the aim of identifying the specific mechanisms by which arecoline initiates and promotes oral carcinogenesis. Our initial search allowed us to define the current trends and patterns in the pathophysiology of arecoline-induced OSF and OSCC, which include the induction of cell proliferation, facilitation of invasion, adhesion, and migration, increased collagen deposition and fibrosis, imbalance in immune and inflammatory mechanisms, and genotoxicity. Key molecular pathways comprise the activation of NOTCH1, MYC, PRDX2, WNT, CYR61, EGFR/Pl3K, DDR1 signaling, and cytokine upregulation. Despite providing a comprehensive overview of potential pathogenic mechanisms of OSF, the involvement of molecules functioning as areca alkaloid receptors, namely, the muscarinic and nicotinic acetylcholine receptors (AChRs), was not elucidated with this approach. Accordingly, our search strategy was refined to reflect these evidence gaps. The results of the second round of reviews with the post hoc search highlighted that arecoline binds preferentially to muscarinic AChRs, which have been implicated in cancer. Consistently, AChRs activate the signaling pathways that partially overlap with those described in the context of arecoline-induced carcinogenesis. In summary, we used a theory-driven interpretive review methodology to inform, extend, and supplement the conventional systematic literature assessment workflow. On the one hand, the results of this critical interpretive synthesis highlighted the prevailing trends and enabled the consolidation of data pertaining to the molecular mechanisms involved in arecoline-induced carcinogenesis, and, on the other, brought up knowledge gaps related to the role of the local cholinergic axis in oral carcinogenesis, thus suggesting areas for further investigation. [ABSTRACT FROM AUTHOR]

Arecoline is a pyridine alkaloid derived from areca nut in the Arecaceae family. It has extensive medicinal activity, such as analgesic, anti-inflammatory, and anti-allergic. However, the toxicity of Arecoline limits its application. Most current studies on its toxicity mainly focus on immunotoxicity, carcinogenesis, and cancer promotion. However, there are few systematic studies on its hepatotoxicity and mechanisms. Therefore, this research explored the mechanism of hepatotoxicity induced by Arecoline in rats and analyzed endogenous metabolite changes in rat plasma by combining network toxicology with metabolomics. The differential metabolites after Arecoline exposure, such as D-Lysine, N4-Acetylaminobutanal, and L-Arginine, were obtained by metabolomics study, and these differential metabolites were involved in the regulation of lipid metabolism, amino acid metabolism, and vitamin metabolism. Based on the strategy of network toxicology, Arecoline can affect the HIF-1 signaling pathway, MAPK signaling pathway, PI3K-Akt signaling pathway, and other concerning pathways by regulating critical targets, such as ALB, CASP3, EGFR, and MMP9. Integration of metabolomics and network toxicology results were further analyzed, and it was concluded that Arecoline may induce hepatotoxicity by mediating oxidative stress, inflammatory response, energy and lipid metabolism, and cell apoptosis. [ABSTRACT FROM AUTHOR]

Arecoline is a psychoactive alkaloid containing a reduced pyridine nucleus, isolated from Areca catechu L. (Arecaceae) with different biological activities on cardiovascular, digestive, nervous, and endocrine systems. Arecoline is the main toxic component of A. catechu responsible for oral carcinoma. It possesses a variety of pharmacological activities; it exhibits anticancer activity. It was reported that arecoline causes cytotoxicity through apoptosis in human endothelial cells. Moreover, the death of human leukemia K562 cells was induced by arecoline. Biotransformation is a structural modification of compounds such as amino acids, toxins, and drugs by enzymatic chemical reactions within living organisms. According to enzymatic sources, biotransformation is classified into three major types; microbial, plant cell culture, and animal cell culture transformation. It was suggested that microorganisms could be employed as a model of mammalian metabolism. Studying both mammalian and microbial transformation of arecoline is of interest by which we can reduce its toxicity, increase its bioavailability, and produce more active metabolites. [ABSTRACT FROM AUTHOR]

Areca nut and slaked lime, with or without tobacco wrapped in Piper betle leaf, prepared as betel quid, is extensively consumed as a masticatory product in many countries across the world. Betel Quid can promote the malignant transformation of oral lesions as well as trigger benign cellular and molecular changes. In the oral cavity, it causes changes at the compositional level in oral microbiota called dysbiosis. This dysbiosis may play an important role in Oral Cancer in betel quid chewers. The abnormal presence and increase of bacteria Fusobacterium nucleatum, Capnocytophaga gingivalis, Prevotella melaninogenica, Peptostreptococcus sp., Porphyromonas gingivalis, and Streptococcus mitis in saliva and/or other oral sites of the cancer patients has attracted frequent attention for its association with oral cancer development. In the present review, the authors have analysed the literature reports to revisit the oncogenic potential of betel quid and oral microbiome alterations, evaluating the potential of oral microbiota both as a driver and biomarker of oral cancer. The authors have also shared a perspective that the restoration of local microbiota can become a potentially therapeutic or prophylactic strategy for the delay or reversal of lip and oral cavity cancers, especially in high-risk population groups. [ABSTRACT FROM AUTHOR]

Arecoline is an alkaloid extracted from betel nut, which has various pharmacological effects. In the present study, we showed that arecoline aggravated experimental acute ulcerative colitis (UC) induced by dextran sodium sulfate (DSS) in mice. We measured body weight and colon length, evaluated disease activity index, colon pathology sections, and levels of colonic inflammatory factors. Arecoline exacerbated the clinical signs of UC and the colonic inflammatory response in mice. The results of 16S rRNA sequencing of fecal samples showed a significant decrease in the percentage of probiotic bacteria Ligilactobacillus, Limosilactobacillus and Lactobacillus and a significant increase in the percentage of conditionally pathogenic bacteria Odoribacter and Bacteroides after arecoline treatment. Serum untargeted metabolomics showed that arecoline intervention reduced the levels of ergothioneine, pentostatin, diadenosine tetraphosphate and other metabolites and modulated nicotinate and nicotinamide metabolism, metabolic pathways, glyoxylate and dicarboxylate metabolism, and other metabolic pathways of intestinal microorganisms. According to the combined microbial and metabolite analysis, arecoline influences metabolite levels by modulating the intestinal microbiota. In summary, it was found that arecoline treatment exacerbated colonic injury and intestinal inflammatory responses in UC mice, disrupted the host's intestinal flora, and affected changes in florametabolites, thereby exacerbating the development of colonic inflammation. Therefore, the consumption of betel nut can be associated with the risk of aggravating UC. [ABSTRACT FROM AUTHOR]

Oral submucous fibrosis (OSF) is a chronic progressive fibrosis disease that affects in oral mucosal tissues. Interleukin (IL)‐13 has been implicated in the development of fibrosis in multiple organs. Indeed, it contributes to diseases such as pulmonary fibrosis, liver cirrhosis among others. Currently, its expression in OSF and the specific mechanisms are not well understood. The aim of this study was to investigate the role of IL‐13 in OSF and further explore whether IL‐13 regulates—polarization of M2‐macrophages in OSF. Initially, in the tissues of patients with OSF, we observed a high expression of M2‐macrophages and IL‐13 protein. Additionally, we found a correlation between the expression of IL‐13 and the stage of OSF. Arecoline inhibited the proliferation of fibroblasts (FBs) and promoted IL‐13 production in vitro. Furthermore, our observations revealed that M2‐macrophages increased upon co‐culturing M0‐macrophages with supernatants containing the IL‐13 cytokine. In conclusion, our study demonstrated that arecoline stimulates FBs leading to increased secretion of IL‐13, which in turn IL‐13 leads to polarization of M2‐macrophages and promotes the occurrence of OSF. This suggests that IL‐13 may be a potential therapeutic target of OSF. [ABSTRACT FROM AUTHOR]

The areca nut is often consumed as a chewing food in the Asian region. Our previous study revealed that the areca nut is rich in polyphenols with high antioxidant activity. In this study, we further assessed the effects and molecular mechanisms of the areca nut and its major ingredients on a Western diet-induced mice dyslipidemia model. Male C57BL/6N mice were divided into five groups and fed with a normal diet (ND), Western diet (WD), WD with areca nut extracts (ANE), areca nut polyphenols (ANP), and arecoline (ARE) for 12 weeks. The results revealed that ANP significantly reduced WD-induced body weight, liver weight, epididymal fat, and liver total lipid. Serum biomarkers showed that ANP ameliorated WD-enhanced total cholesterol and non-high-density lipoprotein (non-HDL). Moreover, analysis of cellular signaling pathways revealed that sterol regulatory element-binding protein 2 (SREBP2) and enzyme 3-hydroxy-3-methylglutaryld coenzyme A reductase (HMGCR) were significantly downregulated by ANP. The results of gut microbiota analysis revealed that ANP increased the abundance of beneficial bacterium Akkermansias and decreased the abundance of the pathogenic bacterium Ruminococcus while ARE shown the opposite result to ANP. In summary, our data indicated that areca nut polyphenol ameliorated WD-induced dyslipidemia by increasing the abundance of beneficial bacteria in the gut microbiota and reducing the expressions of SREBP2 and HMGCR while areca nut ARE inhibited this improvement potential. [ABSTRACT FROM AUTHOR]

Oral submucous fibrosis (OSF) caused by areca nut chewing is a prevalent fibrotic disease in Asia‐Pacific countries. Arecoline‐induced migration of fibroblasts (FBs) plays a vital role in the development of OSF. However, the specific molecular mechanisms involved remain unclear. Many studies have shown that tyrosine sulphation of chemokines can influence cell migration. Herein, we demonstrated that arecoline stimulates tyrosine sulphation of the chemokine receptor 4 (CXCR4) through the tyrosylprotein sulphotransferase‐1 (TPST‐1) to enhance the migration ability of FBs. Moreover, by RNA‐Seq analysis, we found that the most significantly altered pathway was the EGFR pathway after the arecoline stimulation for FBs. After the knockdown of arecoline‐induced EGFR expression, the tyrosine sulphation of CXCR4 was significantly decreased by the inhibition of TPST‐1 induction. Finally, in human OSF specimens, TPST‐1 expression was directly correlated with the expression of CXCR4. These data indicate that the arecoline‐induced tyrosine sulphation of CXCR4, which is regulated by TPST‐1, might be a potential mechanism that contributes to FB migration in OSF. [ABSTRACT FROM AUTHOR]

Betel quid and areca nut are complex mixture carcinogens, but little is known about whether their derived single-agent arecoline or arecoline N-oxide (ANO) is carcinogenic, and the underlying mechanisms remain unclear. In this systematic review, we analyzed recent studies on the roles of arecoline and ANO in cancer and strategies to block carcinogenesis. In the oral cavity, flavin-containing monooxygenase 3 oxidizes arecoline to ANO, and both alkaloids conjugate with N-acetylcysteine to form mercapturic acid compounds, which are excreted in urine, reducing arecoline and ANO toxicity. However, detoxification may not be complete. Arecoline and ANO upregulated protein expression in oral cancer tissue from areca nut users compared to expression levels in adjacent normal tissue, suggesting a causal relationship between these compounds and oral cancer. Sublingual fibrosis, hyperplasia, and oral leukoplakia were diagnosed in mice subjected to oral mucosal smearing of ANO. ANO is more cytotoxic and genotoxic than arecoline. During carcinogenesis and metastasis, these compounds increase the expression of epithelial–mesenchymal transition (EMT) inducers such as reactive oxygen species, transforming growth factor-β1, Notch receptor-1, and inflammatory cytokines, and they activate EMT-related proteins. Arecoline-induced epigenetic markers such as sirtuin-1 hypermethylation, low protein expression of miR-22, and miR-886-3-p accelerate oral cancer progression. Antioxidants and targeted inhibitors of the EMT inducers used reduce the risk of oral cancer development and progression. Our review findings substantiate the association of arecoline and ANO with oral cancer. Both of these single compounds are likely carcinogenic to humans, and their mechanisms and pathways of carcinogenesis are useful indicators for cancer therapy and prognosis. [ABSTRACT FROM AUTHOR]

Introduction: Oral submucous fibrosis (OSMF) is a potentially malignant disorder which occurs due to dysregulation of collagen metabolism. It is also known as Atrophica idiopathica mucosae oris and is characterized by a burning sensation in the oral cavity, reduced mouth opening, burning sensation, and decreased tongue movement. Clinically there is blanching of oral mucosa due to the deposition of excessive collagen fibers. Aims: This study aims to estimate the prevalence of oral cancer in a cohort of patients suffering from OSMF and to understand the clinical pattern of oral cancer in these patients. Materials and Methods: It was a unicentric cross-sectional study conducted between January 2022 and January 2023. The study was conducted on 630 patients with clinical presentation of OSMF. Informed consent was obtained from the patient before the start of the study. Results: Data obtained were tabulated and Statistical Package for Social Sciences version 22 was used for analysis. Of 630 subjects, 176 subjects (27.83%) had oral cancer with OSMF. The most common site of the oral cancer was found to be buccal mucosa that was followed by lateral border of the tongue and retromolar trigone. Conclusion: OSMF is a potentially malignant disorder and use of areca nut with smokeless tobacco is the main cause. The use of areca nut and smokeless tobacco must be regularized. [ABSTRACT FROM AUTHOR]

Areca nut has been listed as one of the most addictive substances, along with tobacco, alcohol and caffeine. Areca nut contains seven psychoactive alkaloids; however, the effects of these alkaloids on embryonic development and motor behavior are rarely addressed in zebrafish embryo-larvae. Herein, we investigated the effects of exposure to three alkaloids (arecoline and secondary metabolites—arecaidine and arecoline N-oxide) on the developmental parameters, locomotive behavior, oxidative stress and transcriptome of zebrafish embryos. Zebrafish embryos exposed to different concentrations (0, 0.1, 1, 10, 100 and 1000 μM) of arecoline, arecaidine and arecoline N-oxide showed no changes in mortality and hatchability rates, but the malformation rate of zebrafish larvae was significantly increased in a dose-dependent manner and accompanied by changes in body length. Moreover, the swimming activity of zebrafish larvae decreased, which may be due to the increase in reactive oxygen species and the imbalance between oxidation and antioxidation. Meanwhile, transcriptome analysis showed that endoplasmic reticulum stress and the apoptosis p53 signaling pathway were significantly enriched after exposure to arecoline and arecoline N-oxide. However, arecaidine exposure focuses on protein synthesis and transport. These findings provide an important reference for risk assessment and early warning of areca nut alkaloid exposure. [ABSTRACT FROM AUTHOR]

Introduction: Non-alcoholic fatty liver disease (NAFLD) has gradually become the primary cause of fatty liver disease. Betel nuts have been used to treat gastrointestinal diseases. Methods: In the present study, we analyzed the pathology, serology, gut flora, and metabolites in a rat model of NAFLD, with and without betel nut alkaloid treatment, using an integrated approach involving pathology, serological testing, 16S rRNA gene sequencing, and ultra-performance liquid chromatography-mass spectrometry metabolomics. Results: Two rats were used for model validation. Thirty SD rats were included and divided into the normal group (C group), NAFLD model group (M group), low-dose group, medium-dose group (T group), and high-dose group with intraperitoneal injection of arecoline. The expression of blood lipids was significantly downregulated at all three arecoline concentrations (p < 0.05). Alpha-diversity analysis of the intestinal flora showed significant differences among the three groups, with a significant reduction in population diversity in the M group and a recovery of population diversity after arecoline treatment. At the phylum level, the relative abundance of Firmicutes was significantly higher in the T group and Proteobacteria in the M group. The KEGG metabolic pathways included polyketide sugar unit biosynthesis and hypertrophic cardiomyopathy. Thirty-three significantly different metabolites were identified among the groups. Significantly different metabolites between groups T and M included indolepyruvate, 2-deoxystreptamine, sakuranetin, glycyl-leucine, and riboflavin. The KEGG metabolic pathway suggested a potential role for arachidonic acid metabolism, serotonergic synapses, neuroactive ligand-receptor interactions, tyrosine metabolism, and regiomelanin. Vitamin digestion and absorption, as well as regulation of lipolysis in adipocytes, were the main metabolic pathways that distinguished the T vs. M groups. PGE2 is involved in several metabolic pathways. Correlation analysis showed that 29 bacterial species were significantly associated with PGE2 levels in the M and T groups. Vagococcus, Lawsonia, Christensenella, unidentified Erysipelotrichaceae, unidentified Coriobacteriaceae, and five other bacterial groups are unique in the PGE2 metabolic pathway regulated by arecoline. Discussion: Arecoline has lipid-lowering effects and may exert therapeutic effects in NAFLD through intestinal metabolites and intestinal flora, as well as through the Butyricicoccus/Christensenella/Coriobacteriaceae-COX2/PGE2 pathway. Thus, arecoline may represent a potential drug or target for NAFLD treatment. [ABSTRACT FROM AUTHOR]

Background: Betel nut chewing plays a role in the pathogenesis of oral submucous fibrosis (OSF) and oral squamous cell carcinoma (OSCC). As the major active ingredient of the betel nut, the effect of arecoline and its underlying mechanism to OSF and OSCC pathogenesis remain unclear. Methods: Next-generation sequencing-based transcriptome and dRRBS analysis were performed on OSF and OSCC cells under low-dose arecoline exposure. Functional analyses were performed to compare the different roles of arecoline during OSF and OSCC pathogenesis, and key genes were identified. Results: In this study, we identified that low-dose arecoline promoted cell proliferation of both NFs and OSCC cells via the acceleration of cell cycle progression, while high-dose arecoline was cytotoxic to both NFs and OSCC cells. We performed for the first time the transcriptome and methylome landscapes of NFs and OSCC cells under low-dose arecoline exposure. We found distinct transcriptome and methylome profiles mediated by low-dose arecoline in OSF and OSCC cells, as well as specific genes and signaling pathways associated with metabolic disorders induced by low-dose arecoline exposure. Additionally, low-dose arecoline displayed different functions at different stages, participating in the modulation of the extracellular matrix via Wnt signaling in NFs and epigenetic regulation in OSCC cells. After exposure to low-dose arecoline, the node roles of FMOD in NFs and histone gene clusters in OSCC cells were found. Meanwhile, some key methylated genes induced by arecoline were also identified, like PTPRM and FOXD3 in NFs, SALL3 and IRF8 in OSCC cells, indicating early molecular events mediated by arecoline during OSF and OSCC pathogenesis. Conclusions: This study elucidated the contribution of low-dose arecoline to OSF and OSCC pathogenesis and identified key molecular events that could be targeted for further functional studies and their potential as biomarkers. [ABSTRACT FROM AUTHOR]

Areca nut is used worldwide as a hallucinogenic addicting drug along the tropical belt. Arecoline, a toxic compound, is the most important alkaloid in areca nuts. The adverse effects of oral uptake and chewing of areca nut are well known. For example, the possibility of cancer caused by chewing areca nuts is widely discussed. Chewing areca nut has other adverse effects on other organs, including abnormal cell differentiation, oral cancer, and several other diseases. The use of areca nut is also associated with low birthweight. Skeletal musculature is the largest organ in the body and is attached to the bones. During embryo development, the differentiation of bone and muscle cells is critical. In this article, we reviewed the effects of areca nut and arecoline on embryonic cell differentiation, particularly osteoblasts, myoblasts, and fibroblasts. [ABSTRACT FROM AUTHOR]

The major predisposing factors of developing oral cancer include smoking, alcohol drinking, and betel quid chewing. Betel quid chewing could cause the abrasion and damage of oral mucosa by crude fibers, chemical insults by additive slaked lime, and arecoline from areca nut. These would lead to the local consequence of oral submucosal fibrosis, which is regarded clinically as a precancer lesion and a major cause of trismus. In addition, the components and additives in betel quid contain chemical toxins and carcinogens, which would further affect the oral mucosa and gradually develop a malignancy. Following literature review, aside from having a greater total tumor burden and more local diseases in the oral cavity and digestive tract, patients with betel quid-related oral cancer also have more systemic diseases from metabolic syndrome, hypertension, cardiovascular disease, type II diabetes mellitus, and obesity than those without this habit. In conclusion, those patients who have the history of smoking, alcohol drinking, and betel quid chewing would present much more unique clinical characteristics than those who only have a history of smoking and alcohol drinking. More attention should therefore be paid to pretreatment evaluation, treatment strategy, and posttreatment follow-up among betel quid chewers. [ABSTRACT FROM AUTHOR]

Areca nut is a popular and addictive food as well as a traditional herbal medicine in many countries. Areca nut contains alkaloids including arecoline, guvacine, and arecaidine, which are the major bioactive compounds in areca products. Areca alkaloids can be carcinogenic, and thus sensitive and specific analytical methods are urgently desired for the identification and quantification of these compounds. High‐performance liquid chromatography‐based methods are often preferred, but areca alkaloids do not have chromophores, and detection using a traditional UV detector can be difficult. The complexity of areca sample extracts can also lead to the co‐elution of peaks leading to poor quantitative performance. We report here high‐performance liquid chromatography coupled with an ion mobility spectrometer for sensitive determination of areca alkaloids in various products including areca nut, areca nut products, and herbal oral liquid. An X‐Bridge reversed‐phase C18 column was used in the experiment and was combined with high‐performance liquid chromatography coupled to an ion mobility spectrometer system. A custom‐made adjustable post‐column splitter acted as an interface between the high‐performance liquid chromatography and the ion mobility spectrometer; it also acted as the electrospray ionization source. The mobile phase was methanol and 0.5% ammonium hydroxide. The results demonstrate that the splitter can afford a wide range of split ratios that match the ion mobility spectrometer ionization source while keeping the separation efficiency of high‐performance liquid chromatography. Three major alkaloid compounds were then accurately determined using the resulting method without dativization steps. Many coeluted high‐performance liquid chromatography peaks are effectively separated in the ion mobility spectrometer dimension, which in turn improved the quantification accuracy. [ABSTRACT FROM AUTHOR]

Areca nut (AN) is widely consumed all over the world, bringing great harm to human health and economy. Individuals with AN chewing are at high risk of cardiovascular disease and impaired immune system and metabolic system. Despite a growing number of studies having reported on the adverse effects brought by AN chewing, the exact mechanism of it is limited and the need for additional exploration remains. In recent years, the interaction between microorganisms, especially intestinal microorganism and host, has been extensively studied. AN chewing might disrupt the oral and intestinal microbiota communities through direct connect with the microbes it contains, altering PH, oxygen of oral and intestinal microenvironment, and disturbing the immune homeostasis. These mechanisms provide insights into the interplay between areca nut and host microbiota. Emerging studies have proposed that bidirectional interaction between polyphenols and intestinal microbes might play a potential role in the divergence of polyphenol, extracted from AN, among individuals with or without AN-induced cancer development and progression. Although some AN chewers have been aware of the harmful effects brought by AN, they cannot abolish this habit because of the addiction of AN. Increasing studies have tried to revealed that gut microbiota might influence the onset/development of addictive behaviors. Altogether, this review summarizes the possible reasons for the disturbance of host microbiota caused by areca nut chewing and clarifies the complex interaction between human microbiome and major constituents and the addiction and carcinogenicity of AN, tempting to provide novel insights into the development and utilization of it, and to control the adverse consequences caused by AN chewing. [ABSTRACT FROM AUTHOR]

Background: Arecoline is known as the main active carcinogen found in areca nut extract that drives the pathological progression of oral squamous cell carcinoma (OSCC). Studies have revealed that dysregulation of RNA N6-methyladenosine (m6A) methyltransferase components is intimately linked to cancer initiation and progression, including oral cancer. Methods: The arecoline-induced dysregulated methyltransferase-like 3 (METTL3) gene was identified using RNA-seq transcriptome assay. Using in vitro and in vivo models, the biological roles of METTL3 in arecoline-transformed oral cancer were examined. Results: We found that METTL3 was markedly elevated in arecoline-exposed OSCC cell lines and OSCC tissues of areca nut chewers. We identified that hypoxia-inducible factor 1-alpha (HIF-1α) stimulated METTL3 expression at the transcriptional level and further proved that METTL3-MYC-HIF-1α formed a positive autoregulation loop in arecoline-transformed OSCC cells. Subsequently, we manifested that METTL3 depletion profoundly reduced cell proliferation, cell migration, oncogenicity, and cisplatin resistance of arecoline-exposed OSCC cells. Conclusions: Developing novel strategies to target METTL3 may be a potential way to treat OSCC patients, particularly those with areca nut chewing history and receiving cisplatin treatment. [ABSTRACT FROM AUTHOR]

Areca nut (AN) is consumed by millions of people for its therapeutic and psychoactive effects, making it one of the most widely self-administered psychoactive substances in the world. Even so, AN use/abuse is associated with myriad oral and systemic side effects, affecting most organ systems in the body. Alkaloids abundant in the nut (e.g. arecoline, arecaidine, guvacoline, and guvacine), collectively called the areca alkaloids, are presumably responsible for the major pharmacological effects experienced by users, with arecoline being the most abundant alkaloid with notable toxicological properties. However, the mechanisms of arecoline and other areca alkaloid elimination in humans remain poorly documented. Therefore, the purpose of this review is to provide an in-depth review of areca alkaloid pharmacokinetics (PK) in biological systems, and discuss mechanisms of metabolism by presenting information found in the literature. Also, the toxicological relevance of the known and purported metabolic steps will be reviewed. In brief, several areca alkaloids contain a labile methyl ester group and are susceptible to hydrolysis, although the human esterase responsible remains presumptive. Other notable mechanisms include N-oxidation, glutathionylation, nitrosamine conversion, and carbon–carbon double-bond reduction. These metabolic conversions result in toxic and sometimes less-toxic derivatives. Arecoline and arecaidine undergo extensive metabolism while far less is known about guvacine and guvacoline. Metabolism information may help predict drug interactions with human pharmaceuticals with overlapping elimination pathways. Altogether, this review provides a first-of-its-kind comprehensive analysis of AN alkaloid metabolism, adds perspective on new mechanisms of metabolism, and highlights the need for future metabolism work in the field. [ABSTRACT FROM AUTHOR]

The search for anticancer drugs is of continuous interest. Arecoline is an alkaloid with anticancer activity. Herein, the metabolism of arecoline through fungal transformation was investigated for the discovery of potential anticancer drugs with higher activity and selectivity. Compounds 1–5 were isolated, and their structures were fully elucidated using various spectroscopic analyses, including 1D and 2D NMR, ESIMS, and HRESIMS. This is the first report for the isolation of compounds 1 and 2. An MTT assay was performed to determine the cytotoxic activity of arecoline and its metabolites in vitro using non-small-cell lung cancer A549 and leukemia K562 cell lines compared to staurosporine and doxorubicin as positive controls. For the non-small-cell lung A549 cell line, arecoline hydrobromide, staurosporine, and doxorubicin resulted in IC50 values of 11.73 ± 0.71 µM, 10.47 ± 0.64 µM, and 5.05 ± 0.13 µM, respectively, while compounds 1, 3, and 5 exhibited IC50 values of 3.08 ± 0.19 µM, 7.33 ± 0.45 µM, and 3.29 ± 0.20 µM, respectively. For the leukemia K562 cell line, the IC50 values of arecoline hydrobromide, staurosporine, and doxorubicin were 15.3 ± 1.08 µM, 5.07 ± 0.36 µM, and 6.94 ± 0.21 µM, respectively, while the IC50 values of compounds 1, 3 and 5 were 1.56 ± 0.11 µM, 3.33 ± 0.24 µM, and 2.15 ± 0.15 µM, respectively. The selectivity index value of these compounds was higher than 3. These results indicated that compounds 1, 3, and 5 are very strong cytotoxic agents with higher activity than the positive controls and good selectivity toward the tested cancer cell lines. Cell cycle arrest was then studied by flow cytometry to investigate the apoptotic mechanism. Docking simulation revealed that most compounds possessed good binding poses and favorable protein-ligand interactions with muscarinic acetylcholine receptor M3-mAChR protein. In silico study of pharmacokinetics using SwissADME predicted compounds 1–5 to be drug-like with a high probability of good oral bioavailability. [ABSTRACT FROM AUTHOR]

Background: Previous studies on oral submucous fibrosis (OSF) mostly focused on the activation of fibroblasts and collagen metabolism, while little involved in the epithelium. As we have reported the role of differentiated embryo-chondrocyte expressed gene 1 (DEC1) in oral cancer and other precancerous lesions, this research aimed to explore its role in the OSF epithelium.Methods: Expression of DEC1 and other proteins were investigated in tissue array constructed with 33 OSF and 14 normal oral mucosa (NOM) tissues. Human oral keratinocytes treated with arecoline and/or hypoxia were used to simulate OSF epithelium and detected for morphological and protein alterations. Inhibition of DEC1 was used to explore its mediating role. Finally, animal models of OSF constructed by locally arecoline injecting in buccal mucosa were used to verify our findings.Results: DEC1 overexpression could be detected in the epithelium of OSF compared with that in NOM followed by phosphorylated FAK and Akt, and DEC1 showed a significant positive correlation with them. Cytology experiment revealed that OSF-like treatment could upregulate DEC1 expression followed by phosphorylated FAK, Akt, but inhibit E-cadherin, while knockdown of DEC1 could suppress the effects. In addition, OSF mice revealed higher expression of DEC1 in the epithelium of buccal mucosa, along with synchronized alterations of phosphorylated FAK and Akt.Conclusion: In the epithelium of OSF, overexpression of DEC1 induced activation of FAK/Akt signal axis, caused mesenchymal transition in epithelial cells, and may promote malignant transformation of OSF. Targeting DEC1 in OSF could be promising a new target for the diagnosis and treatment of this process. [ABSTRACT FROM AUTHOR]

Areca nut chewing is one of the major risk factors for oral cancer, with large-magnitude risks reported in studies comparing betel quid chewers and never users, and it has been evaluated as a group 1 carcinogen by the International Agency for Research on Cancer. Data from a high-quality meta-analysis examining risk estimates are presented in summary form with additional information from more recent studies (pooled adjusted relative risk, 7.9; 95% CI, 7.1 to 8.7). The risk of oral cancer increases in a dose-response manner with the daily number of quids consumed and the number of years chewing. In the Indian subcontinent and in Taiwan, approximately half of oral cancers reported are attributed to betel quid chewing (population attributable fraction, 53.7% for residents in Taiwan and 49.5% for the Indian population), a disease burden that could be prevented. Oral leukoplakia and oral submucous fibrosis are 2 main oral potentially malignant disorders caused by areca nut chewing that can progress to oral cancer with continued use. Ex-chewers seem to demonstrate lower risks than current chewers, but the impact of areca nut cessation on oral cancer risk has not been scientifically evaluated on the basis of randomized controlled studies. These data strongly reconfirm that betel quid chewing, primarily areca nut use, should be taken into account in assessing the cancer risk of South Asian, East Asian populations and Pacific Islanders for the development of oral cancer. [ABSTRACT FROM AUTHOR]

The high prevalence of oral squamous cell carcinoma (OSCC) in South Asia is associated with habitual areca nut chewing. Arecoline, a primary active carcinogen within areca nut extract, is known to promote OSCC pathological development. Dysregulation of N6‐methyladenosine (m6A) modification has begun to emerge as a significant contributor to cancer development and progression. However, the biological effects and molecular mechanisms of m6A modification in arecoline‐promoted OSCC malignance remain elusive. We reveal that chronic arecoline exposure substantially induces upregulation of fat mass and obesity‐associated protein (FTO), MYC, and programmed cell death‐ligand 1 (PD‐L1) in OSCC cells. Moreover, upregulation of PD‐L1 is observed in OSCC cell lines and tissues and is associated with areca nut chewing in OSCC patients. We also demonstrate that arecoline‐induced FTO promotes the stability and expression levels of PD‐L1 transcripts through mediating m6A modification and MYC activity, respectively. PD‐L1 upregulation confers superior cell proliferation, migration, and resistance to T‐cell killing to OSCC cells. Blockage of PD‐L1 by administration of anti‐PD‐L1 antibody shrinks tumor size and improves mouse survival by elevating T‐cell‐mediated tumor cell killing. Therefore, targeting PD‐L1 might be a potential therapeutic strategy for treating PD‐L1‐positive OSCC patients, especially those with habitual areca nut chewing. [ABSTRACT FROM AUTHOR]

Arecoline, a major alkaloid of the areca nut, has potential toxicity to the nervous system. Our previous study reveals that the neurotoxicity of arecoline involves in inhibited endogenous hydrogen sulfide (H2S) generation. Therefore, the present study investigated whether exogenous H2S protects against arecoline‐induced neurotoxicity and further explore the underlying mechanisms focusing on leptin/leptin receptor signaling pathway. The cell viability was measured by CCK‐8 kit. The apoptosis were detected by Hoechst 33258 and Annexin V/PI (propidium iodide) staining. The protein expressions were determined by Western blot analysis. Our results demonstrated that NaHS, an exogenous H2S donor, significantly increases the cell viability, decreases apoptosis ratio, and reduces caspase‐3 activity as well as Bax/Bcl‐2 ratio in PC12 cells exposed to arecoline, indicating the protection of H2S against arecoline‐induced cytotoxicity and apoptosis. Also, NaHS attenuated arecoline‐induced endoplasmic reticulum (ER) stress, as evidenced by the decreases in the expressions of glucose‐regulated protein 78 (GRP78), C/EBP homologous protein (CHOP), and Cleaved caspase‐12. Meanwhile, NaHS promoted leptin/leptin receptor signaling pathway in arecoline‐exposed PC12 cells, as illustrated by upregulations of leptin and leptin receptor expressions. Furthermore, leptin tA, an antagonist of leptin receptor, obviously abolished the inhibitory effects of NaHS on arecoline‐induced cytotoxicity, apoptosis, and ER stress in arecoline‐exposed PC12 cells. Taken together, these results suggested that H2S prevents arecoline‐induced neurotoxicity via enhancing the leptin/leptin receptor signaling pathway. [ABSTRACT FROM AUTHOR]

Background: Arecoline is a well-known risk factor for oral submucosal fibrosis and cancer. However, the mechanistic correlation between arecoline and hepatocellular cancer remains elusive. Here, we investigated the effect of arecoline on the proliferation and migration of human HepG2 hepatoma cells and its potential oncogenic mechanisms. Methods: Bioinformatic technologies were used to identify the deferentially expressed miRNAs (DE-miRNAs) and hub target genes of arecoline-induced cancers. These DE-miRNAs, hub genes and pathway were proved in arecoline-treated HepG2 cells. Results: A total of 86 DE-miRNAs and 460 target genes were identified. These target genes are associated with DNA-templated regulation of transcription and other biological processes. Significant molecular functions were protein binding, calcium ion binding, and enrichment in the nucleus and cytoplasm. These genes are involved in the PI3K-AKT pathway. CDK1, CCND1, RAF1, CDKN1B and BTRC were defined as the top 5 hub target genes, and patients with high expression of CDK1 showed poor prognosis. Compared with control group, 2.5 µM arecoline treatment increased the proliferation and migration ability of the HepG2 cells. Treatment with 2.5 µM arecoline increased the levels of miR-21-3p, miR-21-5p and miR-1267, upregulated the expression of PI3K-AKT pathway factors, CDK1, CCND1 but decreased RAF1 expression. Conclusion: A low concentration arecoline can induce the proliferation and migration of HepG2 cells, with the potential mechanism of action linked to high levels of exosomal miR-21 and miR-1267, activation of the PI3K-AKT pathway, upregulation of CDK1 and CCND1, and downregulation of RAF1. [ABSTRACT FROM AUTHOR]

Background: Metastatic disease remains the primary cause of death in patients with oral squamous cell carcinoma (OSCC), especially those who use betel nut. The different steps of the metastatic cascade rely on reciprocal interactions between cancer cells and the tumor microenvironment (TME). Cancer-associated fibroblasts (CAFs) are regarded as a significant component in the TME of OSCC. However, the precise mechanisms regulating CAFs in OSCC are poorly understood. Methods: Thirteen genes related to the arecoline were analyzed to explore the significant ones involved in arecoline-related OSCC metastasis. The GSE139869 (n = 10) and The Cancer Genome Atlas (TCGA)-OSCC data (n = 361) were mined for the identification of the differentially expressed genes. The least absolute shrinkage and selection operator (LASSO) regression was performed to identify the independent prognostic signatures. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were conducted to explore the functional enrichment of selected genes, and gene set enrichment analysis of cuproptosis-related genes was completed. Spearman's analysis and Tumor Immune Estimation Resource (TIMER) were used to visualize the correlation between the infiltration of CAFs and the gene expression. The correlation analysis of the cells and different genes, including CAF infiltration and transcripts per million expression, was assessed. The relationship between arecoline and CAFs was confirmed by cell counting kit-8 assay (CCK-8). CancerSEA was searched to identify the single-cell phenotype. Result: Arecoline-associated fibrosis-related OSCC differentially expressed genes (AFOC-DEGs), namely, PLAU, IL1A, SPP1, CCL11, TERT, and COL1A2, were screened out and selected from the Gene Expression Omnibus (GEO) database and TCGA database. AFOC-DEGs were highly expressed in OSCC, which led to poor survival of patients. Functional enrichment analysis, protein-protein interaction network construction, and Spearman's correlation analysis all suggested that AFOC-DEGs were closely associated with cuproptosis. Cellular experiments demonstrated that arecoline stimulation could significantly increase the cell viability of CAFs. Single-sample Gene Set Enrichment Analysis (ssGSEA) results showed that GLS and MTF1 were highly expressed when fibroblasts proliferated at high enrichment levels. In addition, analysis of single-cell sequencing results suggested that OSCC cells with high expression of AFOC-DEGs were associated with OSCC metastasis. Conclusion: We found a close association between arecoline, cuproptosis, and CAFs, which might play an important role in the metastasis of OSCC. [ABSTRACT FROM AUTHOR]

Arecoline, the most abundant alkaloid of the areca nut, induces toxicity to neurons. Hydrogen sulfide (H2S) is an endogenous gas with neuroprotective effects. We recently found that arecoline reduced endogenous H2S content in PC12 cells. In addition, exogenously administration of H2S alleviated the neurotoxicity of arecoline on PC12 cells. Increasing evidence has demonstrated the neuroprotective role of improvement of autophagic flux. Therefore, the aim of the present work is to explore whether improvement of autophagic flux mediates the protection of H2S against arecoline-caused neurotoxicity. Transmission electron microscope (TEM) for observation of ultrastructural morphology. Western blotting was used to detect protein expression of the related markers. Functional analysis contained LDH release assay, Hoechst 33,258 nuclear staining and flow cytometry were used to detect cytotoxicity and apoptosis. In the present work, we found that arecoline disrupted autophagy flux in PC12 cells as evidenced by accumulation of autophagic vacuoles, increase in LC3II/LC3I, and upregulation of p62 expression in PC12 cells. Notably, we found that sodium hydrosulfide (NaHS), the donor of H2S improved arecoline-blocked autophagy flux in PC12 cells. Furthermore, we found that blocking autophagic flux by chloroquine (CQ), the inhibitor of autophagy flux, antagonized the inhibitory role of NaHS in arecoline-induced cytotoxicity apoptosis and endoplasmic reticulum (ER) stress. In conclusion, H2S improves arecoline-caused disruption of autophagic flux to exert its protection against the neurotoxicity of arecoline. [ABSTRACT FROM AUTHOR]

Background: Oral submucosal fibrosis (OSF) is a precancerous condition that closely related to the habit of chewing betel nut. The OSF patients of 3%–19% may develop cancer, and this probability is increasing year by year. Epigenetics modifications have been reported as part of the pathogenesis of OSF. However, in OSF field, the role and mechanism of arecoline‐induced activation of transforming growth factor β (TGF‐β) signaling on N6‐methyladenosine (m6A) modification remain unclear. In this study, we investigated the effect and mechanism of arecoline on m6A modification. Methods: MeRIP‐Seq and RNA‐seq were performed in arecoline‐stimulated cells. Quantitative polymerase chain reaction and western blot were performed to detect the expression of m6A writers and erasers. CCK‐8 and flow cytometry analyses were performed to measure the cell viability and apoptosis. Results: m6A level was increased in OSF tissues compared to normal tissues; arecoline promoted the m6A methyltransferase Mettl3 and Mettl14 through TGF‐β. MeRIP‐seq and RNA‐seq analyses found that MYC was the target gene of Mettl14. In addition, Mettl14 silence reversed the effects of arecoline on cell proliferation and apoptosis in Hacat cells. Conclusion: TGF‐β‐METTL14‐m6A‐MYC axis was crucially implicated in arecoline‐mediated OSF and may be an effective therapeutic strategy for OSF treatment. [ABSTRACT FROM AUTHOR]

Arecoline is the principle psychoactive alkaloid in areca nuts. Areca nuts are chewable seeds of Areca catechu L., which are epidemic plants that grow in tropical and subtropical countries and cause dependency after long-term use. However, the mechanisms underlying such dependency remain largely unclear, and therefore, no effective interventions for its cessation have been developed. The present study aimed to examine the effects of arecoline on neurons of the ventral tegmental area (VTA). After rats were anesthetized and craniotomized, electrophysiological electrodes were lowered into the VTA to obtain extracellular recordings. The mean firing rate of dopaminergic and GABAergic neurons were then calculated and analyzed before and after arecoline treatment. The burst characteristics of the dopaminergic neurons were also analyzed. The results showed that arecoline evoked a significant enhancement of the firing rate of dopaminergic neurons, but not GABAergic neurons. Moreover, arecoline evoked remarkable burst firings in the dopaminergic neurons, including an increase in the burst rate, elongation in the burst duration, and an enhancement in the number of spikes per burst. Collectively, the findings revealed that arecoline significantly excited VTA dopaminergic neurons, which may be a mechanism underlying areca nut dependency and a potential target for areca nut cessation therapy. [ABSTRACT FROM AUTHOR]