Search

Gnathostomiasis, caused by the advanced third-stage larvae of Gnathostoma spinigerum , demands novel treatment avenues. The ethanolic root extract of Stemona collinsiae has been postulated to have anthelminthic properties, suggesting its potential as an alternative remedy. In this study, S. collinsiae roots were collected, identified, and extracted with 95 % ethanol. The crude extracts were standardized using didehydrostemofoline as chemical marker. The efficacy of the S. collinsiae root extract against third-stage larvae of G. spinigerum and its toxicity to Wistar rats were evaluated. Both in vitro and in vivo tests were performed, where the in vitro tests assessed the anthelminthic potential of S. collinsiae extract against G. spinigerum larvae, while in vivo tests examined the extract's efficacy against G. spinigerum larvae in infected Wistar rats and the efficacy was compared with albendazole. Parallelly, Wistar rats underwent acute and sub-chronic toxicity tests to establish the safe dosage of the extract. The in vitro tests showcased significant anthelminthic activity, marked by discernible morphological alterations in the exposed larvae. Acute toxicity proved fatal at 2000 mg/kg body weight, while a dose of 300 mg/kg proved non-toxic. Using the Globally Harmonized Classification System, an LD50 of 500 mg/kg was determined. In vivo trials revealed a pronounced decline in G. spinigerum larvae among rats treated with the S. collinsiae extract. The larvae were also observed to be encysted post-treatment, while those treated with albendazole were not encysted. The S. collinsiae extract, with its noteworthy in vitro efficacy and favorable safety metrics in rodents, can be a potential anthelminthic agent. The diminished inflammatory response compared to albendazole hints at S. collinsiae being a safer gnathostomiasis treatment alternative. The promising results in these preliminary trials warrant a deeper investigation to determine the root extract's optimal dosing, suitable delivery methods, and its broader clinical implications., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

Stemona collinsiae Craib., Stemonaceae, has been traditionally used as medicinal plants for insecticides, treatment of parasitic worms and various diseases in Southeast Asian countries. Its ethanolic root extract has been postulated for anthelminthic activities which has a potential for development for human gnathostomiasis drug. To investigate the pharmacokinetic profile, liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) method for the quantification of didehydrostemofoline in rats' plasma was developed and validated. The chromatographic separation was performed on a C 18 column using 1 mM ammonium acetate in water and methanol (50:50, v/v). Tetrahydropalmatine was used as an internal standard. The multiple reaction monitoring mode was used for quantitative analysis. The validated method showed good sensitivity, linearity, precision, and accuracy. The results of stability showed that didehydrostemofoline was stable in the extracted samples in auto-sampler for 24 h and in the plasma samples under room temperature for 24 h, -20 °C for 1 month, and after three freeze-thaw processes. The developed method was applied to the pharmacokinetic study of didehydrostemofoline after oral administration of S. collinsiae root extract. Didehydrostemofoline was rapidly absorbed from the gastrointestinal tract. The time to peak drug concentration was 1.75 ± 0.62 h with maximum drug concentration of 1152.58 ± 271.18 ng/mL. Didehydrostemofoline was rapidly eliminated from the body with terminal half-life of 1.86 ± 0.50 h. Calculated drug clearance of didehydrostemofoline was 96.82 ± 23.51 L/h and volume of distribution was 260.40 ± 96.81 L. The present study provided useful data for understanding drug disposition in the body with dynamic time-course which could be beneficial for further clinical trials., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could appear to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

Alpha7 nicotinic acetylcholine receptor (α7 nAChR) is an ion-gated calcium channel that plays a significant role in various aspects of cancer pathogenesis, particularly in lung cancer. Preclinical studies have elucidated the molecular mechanism underlying α7 nAChR-associated lung cancer proliferation, chemotherapy resistance, and metastasis. Understanding and targeting this mechanism are crucial for developing therapeutic interventions aimed at disrupting α7 nAChR-mediated cancer progression and improving treatment outcomes. Drug research and discovery have determined natural compounds and synthesized chemical antagonists that specifically target α7 nAChR. However, approved α7 nAChR antagonists for clinical use are lacking, primarily due to challenges related to achieving the desired selectivity, efficacy, and safety profiles required for effective therapeutic intervention. This comprehensive review provided insights into the molecular mechanisms associated with α7 nAChR and its role in cancer progression, particularly in lung cancer. Furthermore, it presents an update on recent evidence about α7 nAChR antagonists and addresses the challenges encountered in drug research and discovery in this field., Competing Interests: The authors declare no competing financial interest., (© 2023 American Chemical Society.)

α 3 β 4 Nicotinic acetylcholine receptor (nAChR) has been recognized as an emerging biomarker for the early detection of drug addiction. Herein, α 3 β 4 nAChR ligands were designed and synthesized to improve the binding affinity and selectivity of two lead compounds, ( S ) - QND8 and ( S ) - T2 , for the development of an α 3 β 4 nAChR tracer. The structural modification was achieved by retaining the key features and expanding the molecular structure with a benzyloxy group to increase the lipophilicity for blood-brain barrier penetration and to extend the ligand-receptor interaction. The preserved key features are a fluorine atom for radiotracer development and a p -hydroxyl motif for ligand-receptor binding affinity. Four ( R )- and ( S )-quinuclidine-triazole ( AK1 - AK4 ) were synthesized and the binding affinity, together with selectivity to α 3 β 4 nAChR subtype, were determined by competitive radioligand binding assay using [ 3 H]epibatidine as a radioligand. Among all modified compounds, AK3 showed the highest binding affinity and selectivity to α 3 β 4 nAChR with a K i value of 3.18 nM, comparable to ( S ) - QND8 and ( S ) - T2 and 3069-fold higher affinity to α 3 β 4 nAChR in comparison to α 7 nAChR. The α 3 β 4 nAChR selectivity of AK3 was considerably higher than those of ( S ) - QND8 (11.8-fold) and ( S ) - T2 (294-fold). AK3 was shown to be a promising α 3 β 4 nAChR tracer for further development as a radiotracer for drug addiction.

Skin hyperpigmentation is commonly treated by topical drug application. Several naturally occurring compounds exhibit attractive biological effects including anti-melanogenic activity. Chemically modified derivatives of those compounds are expected to be more efficient. However, efficacy and safety testing processes are of significant consideration to identify the most effective compound among them. Herein, we demonstrated a tiered approach to investigate the antipigmentation activity of 17 trans-N-coumaroyltyramine derivatives. First, we evaluated the in chemico antityrosinase activity, then the cytotoxicity of the most potent derivatives using a mitochondrial activity-based assay, followed with the in vitro anti-melanogenic activity in two dimensional (2D) monolayer human melanocytes. The selected derivatives were topically applied on a three dimensional (3D) pigmented-reconstructed human epidermis (pRhE) containing melanocytes and keratinocytes to evaluate their depigmenting activity. Two of the 17 derivatives displayed a significant reduction in pigmentation in the 3D pRhE, comparable to kojic acid, a known tyrosinase inhibitor. In addition, a molecular docking experiment indicated an interaction of the three derivatives and tyrosinase, suggesting that these derivatives have potent anti-melanogenic activity through tyrosinase inhibition. Our findings provide an alternative approach for investigating skin-whitening agents, thereby facilitating the research and development of skin-whitening products that need not be tested on animals., (© 2022 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Context: Direct evidence of Triphala-drug interactions has not been provided to date., Objective: This study was aimed to determine the effects of Triphala on cytochrome P450 (CYP) isoforms and P-glycoprotein (P-gp) in vitro, and to investigate pharmacokinetic interactions of Triphala with CYP-probes in rats., Materials and Methods: Effects of Triphala on the activities of CYP isoforms and P-gp were examined using human liver microsomes (HLMs) and Caco-2 cells, respectively. Pharmacokinetic interactions between Triphala and CYP-probes (i.e., phenacetin and midazolam) were further examined in rats., Results: Triphala extract inhibited the activities of CYP isoforms in the order of CYP1A2>3A4>2C9>2D6 with the IC 50 values of 23.6 ± 9.2, 28.1 ± 9.8, 30.41 ± 16.7 and 93.9 ± 27.5 μg/mL, respectively in HLMs. It exhibited a non-competitive inhibition of CYP1A2 and 2C9 with the K i values of 23.6 and 30.4 μg/mL, respectively, while its inhibition on CYP3A4 was competitive manner with the K i values of 64.9 μg/mL. The inhibitory effects of Triphala on CYP1A2 and 3A4 were not time-dependent. Moreover, Triphala did not affect the P-gp activity in Caco-2 cells. Triphala, after its oral co-administration at 500 mg/kg, increased the bioavailabilities of phenacetin and midazolam by about 61.2% and 40.7%, respectively, in rats., Discussion and Conclusions: Increases observed in the bioavailabilities of phenacetin and midazolam after oral co-administration of Triphala in rats provided a direct line of evidence to show Triphala-drug interactions via inhibition of CYP1A and CYP3A activities, respectively. These results, together with the lack of time-dependency of CYP 1A2 and 3A4 inhibition in vitro , suggested that the inhibitory effect of Triphala is primarily reversible., Competing Interests: The authors declare no conflict of interest., (© 2022 The Author(s).)

Cancer metastasis is a major cause of the high mortality rate in lung cancer patients. The cytoskeletal rearrangement and degradation of extracellular matrix are required to facilitate cell migration and invasion and the suppression of these behaviors is an intriguing approach to minimize cancer metastasis. Even though Erianthridin (ETD), a phenolic compound isolated from the Thai orchid Dendrobium formosum exhibits various biological activities, the molecular mechanism of ETD for anti-cancer activity is unclear. In this study, we found that noncytotoxic concentrations of ETD (≤ 50 μM) were able to significantly inhibit cell migration and invasion via disruption of actin stress fibers and lamellipodia formation. The expression of matrix metalloproteinase-2 (MMP-2) and MMP-9 was markedly downregulated in a dose-dependent manner after ETD treatment. Mechanistic studies revealed that protein kinase B (Akt) and its downstream effectors mammalian target of rapamycin (mTOR) and p70 S6 kinase (p70 S6K ) were strongly attenuated. An in silico study further demonstrated that ETD binds to the protein kinase domain of Akt with both hydrogen bonding and van der Waals interactions. In addition, an in vivo tail vein injection metastasis study demonstrated a significant effect of ETD on the suppression of lung cancer cell metastasis. This study provides preclinical information regarding ETD, which exhibits promising antimetastatic activity against non-small-cell lung cancer through Akt/mTOR/p70 S6K -induced actin reorganization and MMPs expression.

The selective binding of six ( S )-quinuclidine-triazoles and their ( R )-enantiomers to nicotinic acetylcholine receptor (nAChR) subtypes α3β4 and α7, respectively, were analyzed by in silico docking to provide the insight into the molecular basis for the observed stereospecific subtype discrimination. Homology modeling followed by molecular docking and molecular dynamics (MD) simulations revealed that unique amino acid residues in the complementary subunits of the nAChR subtypes are involved in subtype-specific selectivity profiles. In the complementary β4-subunit of the α3β4 nAChR binding pocket, non-conserved AspB173 through a salt bridge was found to be the key determinant for the α3β4 selectivity of the quinuclidine-triazole chemotype, explaining the 47-327-fold affinity of the ( S )-enantiomers as compared to their ( R )-enantiomer counterparts. Regarding the α7 nAChR subtype, the amino acids promoting a however significantly lower preference for the ( R )-enantiomers were the conserved TyrA93, TrpA149 and TrpB55 residues. The non-conserved amino acid residue in the complementary subunit of nAChR subtypes appeared to play a significant role for the nAChR subtype-selective binding, particularly at the heteropentameric subtype, whereas the conserved amino acid residues in both principal and complementary subunits are essential for ligand potency and efficacy.

Objective: The current study was conducted to improve the understanding of relationships between regional cortical amyloid load, glucose metabolism, cortical morphology (volume), and severity of clinical symptoms in patients with AD, MCI, and age-matched controls., Methods: To objectivize the radiological evaluation of patients with suspected AD, head-to-head multi-modality imaging studies were conducted using MRI and PET/CT with [ 18 F]FDG and [ 18 F]AV45 for visualization and quantitation of brain morphology, glucose metabolism, and amyloid levels, respectively. A total of 84 subjects was studied, including 33 patients with AD, 31 patients with MCI, and 20 age-matched healthy controls (HC). A new quantitative index was calculated as a ratio of regional SUV of [ 18 F]AV45 (normalized to cerebellar cortex) over the corresponding regional SUV of [ 18 F]FDG, divided by the corresponding regional volume, measured from the co-registered MRI and normalized to the normal age-matched control group (AV45/FDG/NVol index). Relationships between clinical scores (TMSE, ADAS) and AV45/FDG/NVol indices for different structures of the brain in study groups were determined using linear regression analyses., Results: A significant direct linear correlation was observed between the AV45/FDG/NVol index and ADAS-Cog test score and an inverse correlation with TMSE score at baseline and with the degree of changes in ADAS and TMSE scores assessed one year later (disease progression). The observed correlations between AV45/FDG/NVol index and clinical scores were higher than those with MRI-based cortical volumes, FDG SUV, or cerebellum-normalized AV45 SUV alone., Conclusions: Current study demonstrated that AV45/FDG/NVol index mapping of the brain is a novel quantitative molecular imaging biomarker that correlates with clinical neurocognitive status and may facilitate more accurate diagnosis, staging, and prognosis of AD. Additional larger scale clinical studies are required to further evaluate the efficacy of this new quantitative index as a diagnostic and prognostic biomarker of AD as well as for the evaluation of safety and efficacy of novel agents undergoing clinical trials for therapy of AD.

Lung cancer, one of the most commonly found carcinoma type, has the highest mortality rate in cancer patients worldwide. Therapeutic interventions targeting to lung cancer become remaining the world significant challenge. Recently, the α7-nicotinic acetylcholine receptor (α7-nAChR) was reported to play an important role in the mechanism underlying lung cancer progression, being intriguing drug target for lung cancer therapy. Hence, the top four α7-nAChR antagonists (QND7, PPRD10, PPRD11 and PPRD12) among our previously developed ligands were proceeded to the in vitro anti-cancer evaluations in non-small cell lung cancer (NSCLC) cell lines (H460 and A549). In this study, we found that QND7 exhibited the highest cytotoxic effect and induced cell apoptosis in both cell lines at a level comparable to cisplatin, whereas the PPRD compounds showed much lower cytotoxicity. Low doses of QND7 and PPRD11 were able to suppress H460 and A549 cell proliferation, whereas PPRD10 and PPRD12 were considered ineffective. In an in vitro wound healing assay, QND7-treatment showed the greatest suppression of H460 and A549 cell migration. The variations in the anti-cancer activities of PPRD compounds might be, at least in part of, their non-selective antagonisms to serotonin receptor (5-HT3) and α4β2-nAChR. Further investigation revealed that QND7 was able to minimize protein kinase B/mammalian target of rapamycin (Akt/mTOR) activity, in correlating to its anti-cancer effects. These findings warrant QND7 for further preclinical evaluation and demonstrate the potential of α7-nAChR as cancer drug target., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Recent pharmacologic data revealed the implication of α3β4 nicotinic acetylcholine receptors (nAChRs) in nicotine and drug addiction. To image α3β4 nAChRs in vivo, we aimed to establish the synthesis of a [ 18 F]-labelled analog of the highly affine and selective α3β4 ligand (S)-3-(4-(4-fluorophenyl)-1H-1,2,3-triazol-1-yl)quinuclidine ((S)-T1). (S)-[ 18 F]T1 was synthesized from ethynyl-4-[ 18 F]fluorobenzene ([ 18 F]5) and (S)-azidoquinuclidine by click reaction. After a synthesis time of 130min (S)-[ 18 F]T1 was obtained with a radiochemical yield (non-decay corrected) of 4.3±1.3%, a radiochemical purity of >99% and a molar activity of >158 GBq/μmol. The brain uptake and the brain-to-blood ratio of (S)-[ 18 F]T1 in mice at 30min post injection were 2.02 (SUV) and 6.1, respectively. According to an ex-vivo analysis, the tracer remained intact (>99%) in brain. Only one major radiometabolite was detected in plasma and urine samples. In-vitro autoradiography on pig brain slices revealed binding of (S)-[ 18 F]T1 to brain regions associated with the expression of α3β4 nAChRs, which could be reduced by the α3β4 nAChR selective drug AT-1001. These findings make (S)-[ 18 F]T1 a potential tool for the non-invasive imaging of α3β4 nAChRs in the brain by PET., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

The novel quinuclidine anti -1,2,3-triazole derivatives T1 - T6 were designed based on the structure of QND8 . The binding studies revealed that the stereochemistry at the C3 position of the quinuclidine scaffold plays an important role in the nAChR subtype selectivity. Whereas the ( R )-enantiomers are selective to α7 over α4β2 (by factors of 44-225) and to a smaller degree over α3β4 (3-33), their ( S )-counterparts prefer α3β4 over α4β2 (62-237) as well as over α7 (5-294). The ( R )-derivatives were highly selective to α7 over α3β4 subtypes compared to ( RS )- and ( R )- QND8 . The ( S )-enantiomers are 5-10 times more selective to α4β2 than their ( R ) forms. The overall strongest affinity is observed for the ( S )-enantiomer binding to α3β4 ( K i , 2.25-19.5 nM) followed by their ( R )-counterpart binding to α7 ( K i , 22.5-117 nM), with a significantly weaker ( S )-enantiomer binding to α4β2 ( K i , 414-1980 nM) still above the very weak respective ( R )-analogue affinity ( K i , 5059-10436 nM).

Structure modification of a lead compound (NSC13378) was accomplished in the present work by an in silico target-based design aimed at ligands acting on the nicotinic acetylcholine receptor (nAChR) for neurodegenerative diseases. A 187-compound focused library derived from the scaffold of the lead compound was screened against acetylcholine-binding proteins (AChBPs). Six compounds were identified and synthesized for binding and biological evaluations. Five compounds were found to bind with AChBPs. Among these compounds, QN1 and BZ1 showed the highest affinity binding with AChBP, with Kd values of 260 and 10 nm, respectively. Functional assays on isolated cell lines containing ligand-gated ion channels revealed that QN1 and BZ1 are a4b2-nAChR antagonists. QN1 and BZ1 significantly alleviated the memory impairment caused by the muscarinic cholinergic antagonist scopolamine (p < 0.05) in mice. Our findings demonstrate the potential of nAChR antagonists in drug development for cognitive impairments., (© 2015 John Wiley & Sons A/S.)

Three series of substituted anti-1,2,3-triazoles (IND, PPRD, and QND), synthesized by cycloaddition from azide and alkyne building blocks, were designed to enhance selectivity and potency profiles of a lead α7 nicotinic acetylcholine receptor (α7-nAChR) agonist, TTIn-1. Designed compounds were synthesized and screened for affinity by a radioligand binding assay. Their functional characterization as agonists and antagonists was performed by fluorescence resonance energy transfer assay using cell lines expressing transfected cDNAs, α7-nAChRs, α4β2-nAChRs, and 5HT3A receptors, and a fluorescence cell reporter. In the IND series, a tropane ring of TTIn-1, substituted at N1, was replaced by mono- and bicyclic amines to vary length and conformational flexibility of a carbon linker between nitrogen atom and N1 of the triazole. Compounds with a two-carbon atom linker optimized binding with Kd's at the submicromolar level. Further modification at the hydrophobic indole of TTIn-1 was made in PPRD and QND series by fixing the amine center with the highest affinity building blocks in the IND series. Compounds from IND and PPRD series are selective as agonists for the α7-nAChRs over α4β2-nAChRs and 5HT3A receptors. Lead compounds in the three series have EC50's between 28 and 260 nM. Based on the EC50, affinity, and selectivity determined from the binding and cellular responses, two of the leads have been advanced to behavioral studies described in the companion article (DOI: 10.1021/acschemneuro.5b00059).

The α7 nicotinic acetylcholine receptor (nAChR) is a recognized drug target for dementias of aging and certain developmental disorders. Two selective and potent α7-nAChR agonists, winnowed from a list of 43 compounds characterized in a companion article (DOI: 10.1021/acschemneuro.5b00058), 5-((quinuclid-3-yl)-1H-1,2,3-triazol-4-yl)-1H-indole (IND8) and 3-(4-hydroxyphenyl-1,2,3-triazol-1-yl) quinuclidine (QND8), were evaluated for cognitive improvement in both short- and long-term memory. Tacrine, a centrally active acetylcholinesterase inhibitor, and PNU-282987, a congeneric α7 nAChR agonist, were employed as reference standards. Three behavioral tests, modified Y-maze, object recognition test (ORT), and water maze, were performed in scopolamine-induced amnesic mice. Intraperitoneal injection of these two compounds significantly improved the cognitive impairment in a modified Y-maze test (5 μmol/kg for IND8 and 10 μmol/kg for QND8), ORT (10 μmol/kg), and water maze test (25 μmol/kg). For delay induced memory deficit or natural memory loss in mice, IND8 and QND8 at 10 μmol/kg were able to enhance memory comparable to PNU-282987 when evaluated using ORT time delay model. Cognitive enhancement of IND8 and QND8 was mediated through α7-nAChRs as evidenced by its complete abolition after pretreatment with a selective α7-nAChR antagonist, methyllycaconitine. These data demonstrate that IND8 and QND8 and their congeners are potential candidates for treatment of cognitive disorders, and the substituted triazole series formed by cycloaddition of alkynes and azides warrant further preclinical optimization.