Search

BACKGROUND RESULTS CONCLUSION Apple peel is rich in natural molecules, many exhibiting a significant bioactivity. In this study, our objective was to establish a novel callus line derived from the apple peel of the Italian local variety Annurca, known to accumulate high levels of dihydrochalcones and terpenes. In this regard, we tested the impact of one elicitor, yeast extract, on the expression of genes encoding key enzymes involved in phloridzin and ursolic acid biosynthesis, leading to the accumulation of these antioxidant compounds. We also assessed the bioactivity of callus extracts enriched in these phytochemicals.After the elicitation, data showed increased expression of genes directly related to the synthesis of phloridzin and ursolic acid that were found to accumulate within the cultures. This presumably could explain the remarkable activity of extracts from the elicited‐calli in inhibiting the growth of Staphylococcus aureus and Bacillus cereus. Also, the extracts enriched in antioxidant compounds inhibited reactive oxygen species (ROS) production in human cells exposed to ultraviolet‐A (UV‐A) radiation.Our results underscore the vast potential of the Annurca apple peel cell line in producing natural compounds that can be employed as food components to promote human health. © 2024 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Two previously undescribed dihydrochalcones, 4,2′-dihydroxy- [2″, 2″-dimethylpyrano (3″, 4″: 4′, 5′]) dihydrochalcone (1) and 4, 2′, 4′, 2″-tetrahydroxy-5′-(3″-methylbut-3″-enyl) dihydrochalcone (2), along with six known compounds (3 - 8) were isolated from chloroform-methanol (1:1) extract of Baphia Massaiensis twigs. Their chemical structures were determined using NMR analysis, mass spectrometry, electronic circular dichroism (ECD), density functional theory (DFT) calculations, and a thorough comparison with reported data from the literature. All the isolated compounds (1−8) were assessed for their antioxidant activities, α-amylase and α-glucosidase inhibition effects. Dihydrochalcone 1 showed significant antioxidant activity with IC 50 value of 118.8 ± 2.95 µM, and a more potent antioxidant activity was exhibited by compounds 3 and 6 with IC 50 values of 84.3 ± 0.07 µM and 62.1 ± 1.59 µM, respectively, compared to the positive control, gallic acid with IC 50 value of 92.9 µM. Dihydrochalcone 2 showed moderate inhibition against α-amylase and α-glucosidase with IC 50 values of 44.0 ± 4.83 µM and 51.7 ± 9.72 µM compared to the standard acarbose with IC 50 values of 22.9 ± 0.92 µM and 31.5 ± 0.63 µM, respectively. Molecular docking studies of the new dihydrochalcones 1 and 2 , revealed the active binding sites which support the observed α-amylase and α-glucosidase inhibitory effects. [Display omitted] • Two undescribed dihydrochalcones were isolated from Baphia massaiensis. • The structures were confirmed by extensive spectroscopic analyses. • Compounds 1 and 2 showed significant inhibitory activities against α-amylase and α-glucosidase. • Compounds 1 , 3 and 6 also showed potent antioxidant activities. [ABSTRACT FROM AUTHOR]

Summary: Biosynthesis of flavonoid aglycones and glycosides is well established. However, key genes involved in their catabolism are poorly understood, even though the products of hydrolysis and oxidation play important roles in plant resistance to biotic stress.Here, we report on catabolism of dihydrochalcones (DHCs), the most abundant flavonoids in domesticated apple and wild Malus. Two key genes, BGLU13.1 and PPO05, were identified by activity‐directed protein purification. BGLU13.1‐A hydrolyzed phlorizin, (the most abundant DHC in domesticated apple) to produce phloretin which was then oxidized by PPO05. The process differed in some wild Malus, where trilobatin (a positional isomer of phlorizin) was mainly oxidized by PPO05.The effects of DHC catabolism on apple resistance to biotic stresses was investigated using transgenic plants. Either directly or indirectly, phlorizin hydrolysis affected resistance to the phytophagous pest two‐spotted spider mite, while oxidation of trilobatin was involved in resistance to the biotrophic fungus Podosphaera leucotricha. DHC catabolism did not affect apple resistance to necrotrophic pathogens Valsa mali and Erwinia amylovara.These results suggest that different DHC catabolism pathways play different roles in apple resistance to biotic stresses. The role of DHC catabolism on apple resistance appeared closely related to the mode of invasion/damage used by pathogen/pest. [ABSTRACT FROM AUTHOR]

Năm hợp chất gồm hai dihydrochalcone, 2’,6’-dihydroxy-4’-methoxydihydrochalcone (1), dihydroflavokawin B (2), một flavanone, pinocembrin (3) và hai diarylheptanoid, dihydroyashabushiketol (4), 5-methoxy-1,7-diphenyl-3-heptanone (5) đã được phân lập lần đầu tiên từ cao chiết n-hexane của loài Conamomum rubidum. Cấu trúc hóa học của chúng được xác định bằng phương pháp phổ cộng hưởng từ hạt nhân và so sánh với các dữ kiện phổ đã công bố. Hoạt tính kháng viêm trên mô hình ức chế sản sinh NO và gây độc tế bào của các hợp chất đã được đánh giá. Theo đó, hợp chất 2, 4 và 5 ức chế sản sinh NO với các giá trị IC50 trong khoảng từ 58,16 ± 3,02 đến 81,95 ± 2,87 µM. Hợp chất 1 ức chế tế bào ung thư phổi SK-LU-1 với giá trị IC50 = 58,45 ± 2,26 µM.

Aims: To investigate the potential antimalarial plant belonging to the Artocarpus genus, Artocarpus sericicarpus, and isolate the antimalarial active compound from leaves extract. Methods: The isolation of the antimalarial compound was based on bioassay-guided isolation. The compound isolation was conducted by chromatography and identified using spectroscopic techniques, including 1H, 13C, and 2D NMR. The compound was tested for its antimalarial activity against Plasmodium falciparum and evaluated for cytotoxicity using several cell lines, including Huh7, HepG2, BHK-21, and Vero cells. In silico investigation of the compound against falcipain-2 protein was conducted as well. Results: Fractionation and purification of dichloromethane leaves extract led to the isolation of a dihydrochalcone compound identified as 1-(2,4-dihydroxyphenyl)-3-[4-hydroxy-3-(3-methylbut-2-en-1-yl)phenyl]propan-1-one. The dihydrochalcone compound exhibited antimalarial activity with an IC50 value of 34.80 µM. Cytotoxicity test revealed CC50 values of the compound were more than 20 µg/mL, and the selectivity indexes (SI) were 4.50, 5.52, 3.02, and 6.68 on Huh7, HepG2, BHK-21, and Vero cells, respectively. The CC50 and SI indicated the nontoxic criteria of the compound. In silico investigation showed that the compound could bind to the falcipain-2 active sites. Conclusions: The dihydrochalcone compound identified as 1-(2,4-dihydroxyphenyl)-3-[4-hydroxy-3-(3-methylbut-2-en-1-yl)phenyl]propan-1-one was isolated from Artocarpus sericicarpus leaves extract showed antimalarial activity and the ability to bind to the falcipain-2 active sites on in silico investigation.

Two new dihydrochalcone glucosides, phloretin-4′-O-(4′′-O-galloyl)-β-D-glucoside (1) and phloretin-4′-O-(3′′-O-galloyl)-β-D-glucoside (2), were isolated from the fresh aerial part of Balanophora subcupularis P.C.Tam, together with eight known flavonoid glycosides, phloretin-4′-O-(6′′-O-galloyl)-β-D-glucoside (3), trilobatin (4), 3-hydroxyphloretin-4′-O-β-D-glucoside (5), phloretin-4′-O-(4′′,6′′-O-Sa-hexahydroxydiphenoyl)-β-D-glucoside (6), naringenin-7-O-β-D-glucoside (7), eriodictyol-7-O-β-D-glucoside (8), kaempferol-7-O-β-D-glucoside (9), and quercetin-7-O-β-D-glucoside (10). All of the compounds were elucidated by spectroscopic methods. Their antioxidant activities were examined by DPPH and ABTS assay. Compounds 1–3, 5, 6, and 10 showed significant radical scavenging activities compared with ascorbic acid. [ABSTRACT FROM AUTHOR]

Three new compounds, 4,5,6,7-tetramethoxy-3-benzoylbenzofuran (1), 4-hydroxy-3,5,6-trimethoxydihydrochalcone-2-O-β-D-glucopyranoside (2) and 2-hydroxy-3,4,5,6-tetramethoxyphenylethyl benzoate (3) along with five known flavonoids were isolated from the dichloromethane fraction of the stems of Fissistigma acuminatissimum Merr.'s ethanol extracts. The compounds were obtained by chromatographic methods and the structure elucidation was completed primarily on the basis of spectroscopic analyses, all of these compounds were isolated from F. acuminatissimum for the first time. All the fractions and compounds were evaluated for their anti-inflammatory activity against lipopolysaccharide (LPS)-stimulated tumor necrosis factor α (TNF-α) production in RAW264.7 cells in vitro. The dichloromethane fraction showed the most potent inhibition(38.2%) at 60 μg/mL, compound 1 (70.2%) and 3 (65.2%) showed significant inhibition at 10 μM. [ABSTRACT FROM AUTHOR]

Kiwifruit (Actinidia chinensis) roots instead of fruits are widely used as Chinese medicine, but the functional metabolites remain unclear. In this study, we conducted comparative metabolome analysis between root and fruit in kiwifruit. A total of 410 metabolites were identified in the fruit and root tissues, and of them, 135 metabolites were annotated according to the Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathway. Moreover, 54 differentially expressed metabolites (DEMs) were shared in root and fruit, with 17 DEMs involved in the flavonoid pathway. Of the 17 DEMs, three flavonols (kaempferol-3-rhamnoside, L-Epicatechin and trifolin) and one dihydrochalcone (phloretin) showed the highest differences in the content level, suggesting that flavonols and dihydrochalcones may act as functional components in kiwifruit root. Transcriptome analysis revealed that genes related to flavonols and dihydrochalcones were highly expressed in root. Moreover, two AP2 transcription factors (TFs), AcRAP2-4 and AcAP2-4, were highly expressed in root, while one bHLH TF AcbHLH62 showed extremely low expression in root. The expression profiles of these TFs were similar to those of the genes related to flavonols and dihydrochalcones, suggesting they are key candidate genes controlling the flavonoid accumulation in kiwifruit. Our results provided an insight into the functional metabolites and their regulatory mechanism in kiwifruit root. [ABSTRACT FROM AUTHOR]

Cancer treatment is an evolving field with various challenges to clinical practice. One unresolved problem in this field is multidrug resistance (MDR) mediated by ABC efflux transporters, particularly P-glycoprotein (P-gp). In this study, by prescreening compounds, we identified the potential of a dihydrochalcone compound, 2-hydroxy-4,5,6-trimethoxydihydrochalcone, for P-gp inhibition. Therefore, we investigated its ability to inhibit P-gp and reverse P-gp-mediated MDR, as well as the underlying mechanisms. The P-gp-inhibitory effects of 2-hydroxy-4,5,6-trimethoxydihydrochalcone were investigated as follows. A P-gp efflux assay and an ATPase assay were used to understand the modulatory mechanisms in the drug-binding and ATP-binding areas, respectively. Prominent reversal effects observed in MDR cancer cell lines; thus, reversal, cytotoxicity, cell cycle, apoptosis, and reactive oxygen species assays were conducted to investigate the underlying mechanism. The results indicated that 2-hydroxy-4,5,6-trimethoxydihydrochalcone functionally inhibited P-gp in a noncompetitive manner, and this inhibition was unrelated to expression. In addition, 2-hydroxy-4,5,6-trimethoxydihydrochalcone served as an ATPase stimulator but not as a P-gp substrate. Moreover, a low binding energy of − 6.85 kcal/mol and one hydrogen bond were obtained, indicating that 2-hydroxy-4,5,6-trimethoxydihydrochalcone has a high affinity for P-gp. P-gp-mediated MDR was reversed by 31.6 μM 2-hydroxy-4,5,6-trimethoxydihydrochalcone in combination with paclitaxel, with a reversal fold value of 379.42. In conclusion, this study provides evidence of the ability of 2-hydroxy-4,5,6-trimethoxydihydrochalcone to inhibit P-gp and reverse MDR.

A new dihydrochalcone, 2',4'-dimethoxydihydrochalcone (1), together with 7 known compounds, 2',4'-dihydroxydihydrochalcone (2), 2'-hydroxy-4'-methoxydihydrochalcone (3), 2'-hydroxy-4'-methoxychalcone (4), 1-(3,5-dihydroxy-4-methoxyphenyl)-2-(3-hydroxyphenyl) ethane (5), 2,3,4,7-tetramethoxy-9,10-dihydrophenanthrene (6), 5-hydroxy-2,3,4-trimethoxy-9,10-dihydrophenanthrene (7) and 5,7-dihydroxy-6,8-dimethyl flavanone (8) were isolated from the shoots of Empetrum nigrum L. The structures of these compounds were elucidated using 1D and 2D NMR experiments along with HR-ESI-MS. Compound 6 is reported for the genus Empetrum for the first time. [ABSTRACT FROM AUTHOR]

Singlet oxygen-mediated fragmentation of various dihydrochalcones and chalcones was reported. (Dihydro)cinnamic acids formed in the fragmentation showed a B-ring substitution pattern of the precursor (dihydro)chalcone. For the first time, the intrinsic generation of singlet oxygen by aspalathin and ascorbic acid under mild aqueous conditions (37 °C, pH 7.0) and exclusion of light was verified using HPLC-(+)-APCI-MS 2 experiments. If a 4 molar excess of aspalathin or ascorbic acid was used, fragmentation of dihydrochalcones with monohydroxy and o -hydroxymethoxy B-ring substitution was induced up to 2 mol %, respectively. Incubations of the dihydrochalcone phloretin with ascorbic acid not only led to p -dihydrocoumaric acid but also to a novel ascorbyl adduct, which was isolated and identified as 2,4,6-trihydroxy-5-[3-(4-hydroxyphenyl)propanoyl]-2-[(1 R , 2 S )-1,2,3-trihydroxypropyl]-1-benzofuran-3(2 H )-one. The impact of different structural elements on adduct formation was evaluated and verified to be a phloroglucinol structure linked to an acyl moiety. Formation of the ascorbyl adduct was shown to occur in apple puree when both ascorbic acid and phloretin were present at the same time.

Phloretin is a key secondary metabolite produced by apple trees. Known for its strong antioxidant properties, this dihydrochalcone has been extensively studied in animals but less so in plants. Recently, we identified phloretin as a phytotoxic allelochemical that inhibits growth in the model plant Arabidopsis by disrupting auxin metabolism and distribution in the roots. In this study, we found that phloretin significantly hinders the growth of Arabidopsis seedlings' aerial parts after a short-term treatment (10 days) and causes their decay after long-term exposure (28 days). These effects result from ultrastructural damage in the mesophyll cells of the leaves, including chloroplast displacement and swelling, lesions, and alterations in thylakoid and cell wall organization. Interestingly, phloretin-treated plants showed a decrease in malondialdehyde levels and antioxidant enzyme activities, while hydrogen peroxide and proline levels remained unchanged. This suggests that phloretin-induced chlorosis and seedling decay are not due to oxidative stress but rather to severe chloroplast structural damage, leading to inefficient photosynthesis, starch degradation, starvation, and activation of micro- and macroautophagic processes for self-preservation. Ultimately, these processes result in programmed cell death. These new insights into the phytotoxic effects of phloretin on Arabidopsis shoots could pave the way for future research into phloretin as a potential multitarget bioherbicide and enhance our understanding of autoallelopathy in apple trees., Competing Interests: Declaration of competing interest 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., (Copyright © 2024 Elsevier GmbH. All rights reserved.)

Averrhoa carambola L. is reported for its anti-obese and anti-diabetic activities. The present study aimed to investigate its aqueous methanol leaf extract (CLL) in vivo anti-obese activity along with the isolation and identification of bioactive compounds and their in vitro α-glucosidase inhibition assessment. CLL improved all obesity complications and exhibited significant activity in an obese rat model. Fourteen compounds, including four flavone glycosides (1–4) and ten dihydrochalcone glycosides (5–12), were isolated and identified using spectroscopic techniques. New compounds identified in planta included (1) apigenin 6-C-(2-deoxy-β-D-galactopyranoside)-7-O-β-D-quinovopyranoside, (8) phloretin 3′-C-(2-O-(E)-cinnamoyl-3-O-β-D-fucopyranosyl-4-O-acetyl)-β-D-fucopyranosyl-6′-O-β-D fucopyranosyl-(1/2)-α-L arabinofuranoside, (11a) phloretin3′-C-(2-O-(E)-p-coumaroyl-3-O-β-D-fucosyl-4-O-acetyl)-β-D-fucosyl-6′-O-(2-O-β-D-fucosyl)-α-L-arabinofuranoside, (11b) phloretin3′-C-(2-O-(Z)-p-coumaroyl-3-O-β-D-fucosyl-4-O-acetyl)-β-D-fucosyl-6′-O-(2-O-β-D-fucosyl)-α-L-arabinofuranoside. Carambolaside M (5), carambolaside Ia (6), carambolaside J (7), carambolaside I (9), carambolaside P (10a), carambolaside O (10b), and carambolaside Q (12), which are reported for the first time from A. carambola L. leaves, whereas luteolin 6-C-α-L-rhamnopyranosyl-(1-2)-β-D-fucopyranoside (2), apigenin 6-C-β-D-galactopyranoside (3), and apigenin 6-C-α-L-rhamnopyranosyl-(1-2)-β-L-fucopyranoside (4) are isolated for the first time from Family. Oxalidaceae. In vitro α-glucosidase inhibitory activity revealed the potential efficacy of flavone glycosides, viz., 1, 2, 3, and 4 as antidiabetic agents. In contrast, dihydrochalcone glycosides (5–11) showed weak activity, except for compound 12, which showed relatively strong activity. [ABSTRACT FROM AUTHOR]

Plants typically contain a broad spectrum of flavonoids in varying concentrations. As a rule, several flavonoid classes occur in parallel, and, even for a single flavonoid, divergent glycosylation patterns are frequently observed, many of which are not commercially available. This can be challenging in studies in which the distribution between flavonoid classes, or features that are not affected by glycosylation patterns, are adressed. In addition, hydrolysis simplifies the quantification process by reducing peak interferences and improving the peak intensity due to the accumulation of the respective aglycone. Effective removal of glycose moieties can also be relevant for technological applications of flavonoid aglycones. Herein, we present a fast and reliable method for the enzymatic hydrolysis glycosides from plant extracts using the commercial enzyme mix snailase, which provided the highest aglycone yields across all investigated flavonoids (aurones: leptosidin, maritimetin, sulfuretin; chalcones: butein, lanceoletin, okanin, phloretin; dihydroflavonols: dihydrokaempferol; flavanones: eriodictyol, hesperetin; flavones: acacetin, apigenin, diosmetin, luteolin; flavonols: isorhamnetin, kaempferol, myricetin, quercetin; isoflavones: biochanin A, formononetin, genistein) from methanolic extracts of nine plants (Bidens ferulifolia, Coreopsis grandiflora, Fagus sylvatica, Malus × domestica, Mentha × piperita, Petunia × hybrida, Quercus robur, Robinia pseudoacacia , and Trifolium pratense) in comparison to four other enzymes (cellobiase, cellulase, β-glucosidase, and pectinase), as well as to acidic hydrolysis by hydrochloric acid. [ABSTRACT FROM AUTHOR]

One of the main areas of interest of synthetic organic chemistry is the rapid construction of small molecules with proven diverse biological activities for the development of new strategies to cure human health. In particular, the development of novel synthetic strategies is the most important option for reaching the molecular scaffolds of active molecules of natural origin. Balsacone A and asebogenin are compounds that exhibit a wide variety of important biological activities. In this respect, it has become very important to develop new strategies for the construction of biologically active natural and synthetic balsacone analogues. In particular, balsacone derivatives with hydroxy-substituted dihydrochalcone skeletons can be isolated from plant sources or obtained by hemi-syntheses using bio-sourced precursors. An efficient synthetic strategy to synthetically obtain balsacone A is the aim of the present study that considers the limited natural availability of these molecules as well as other factors, such as cost and time. Starting with phloroglucinol, a nine-step synthesis of the precursor of balsacone A was achieved at a 10% overall yield. Furthermore, asebogenin, which has a dihydrochalcone structure and plays a key role in the synthesis of balsacone A, was synthesised with a good yield. [ABSTRACT FROM AUTHOR]

A new dihydrochalcone, phloridzin-5′-(1′′,4′′-butyrolactam) (1), was isolated from the ethyl acetate extract of Malus pumila Mill. The structure was established by spectroscopic analyses including 1D and 2D NMR (1H, 13C, COSY, HMBC, and HSQC) and HR-EI-MS and comparison with the data of known analogues. [ABSTRACT FROM AUTHOR]

Sweet tea (Lithocarpus polystachyus Rehd.) has been consumed as herbal tea to prevent and manage diabetes for a long time. Recent studies indicate that sweet tea is rich in a variety of bioactive compounds, especially a class of nonclassical flavonoids, dihydrochalcones. In order to provide a better understanding of sweet tea and its main dihydrochalcones on human health, this review mainly summarizes related literature in the recent ten years, with the potential molecular mechanisms emphatically discussed. Phlorizin, phloretin, and trilobatin, three natural sweeteners, are the main dihydrochalcones in sweet tea. In addition, sweet tea and its dihydrochalcones exhibit plenty of health benefits, such as antioxidant, anti-inflammatory, antimicrobial, cardioprotective, hepatoprotective, antidiabetic, and anticancer effects, which are associated with the regulation of different molecular targets and signaling pathways. Therefore, sweet tea, as a rare natural source of dihydrochalcones, can be processed and developed into nutraceuticals or functional foods, with the potential application in the prevention and management of certain chronic diseases. [ABSTRACT FROM AUTHOR]

Polyphenols can interact with dietary fibers and these interactions can affect polyphenols bioactivities. The interactions can be studied with the adsorption process, and adsorptions of flavan-3-ols (procyanidin B1, procyanidin B2), dihydrochalcones (phloretin, phloretin-2-glucoside), and anthocyanins (cyanidin-3-glucoside, cyanidin-3-galactoside) onto ß-D-glucan from barley were studied in this work. The intention was to reveal the kinetics of the adsorption process. Adsorption was carried out using model solutions at room temperature. The results showed that in the flavan-3-ol group procyanidin B1 showed higher adsorption capacity than procyanidin B2. Phloretin showed a higher adsorption capacity than phloretin-2-glucoside in the dihydrochalcone group and anthocyanins showed similar adsorption capacities. Parameter k1 for all polyphenols was in the range from 0.30 h-1 to 0.93 h-1. Adsorption capacity qe for all polyphenols ranged from 2.90 mmol g-1 to 9.76 mmol g-1, parameter k2 was in the range 70-225 g mol-1 h-1, and adsorption capacities qe ranged from 3.70 mmol g-1 to 9.90 mmol g-1. [ABSTRACT FROM AUTHOR]

Aspalathin (2′,3,4,4′,6′-pentahydroxy-3′-C-β-D-glucopyranosyldihydrochalcone) is a natural C-linked glucosyl dihydrochalcone present in Aspalathus linearis (Burm.f.) R.Dahlgren (rooibos), a South African endemic plant, popularly consumed globally as a herbal tea. Aspalathin is reported to possess potent anti-oxidant properties that are believed to be responsible for the health benefits of rooibos. Other pharmacological properties ascribed to the molecule include antidiabetic, antimutagenic, anti-inflammatory, antithrombotic, and xanthine oxidase inhibitory activities. The role of aspalathin in limiting the progression of metabolic disorders and preventing diabetes-induced cardiovascular complications has been reported. The aforementioned potential health benefits of aspalathin have rendered it a popular natural ingredient that is incorporated in various nutraceutical and cosmeceutical products for protection against different conditions. Percutaneous permeation studies revealed some degree of absorption through the skin, supporting its use in cosmetic preparations. To perform an in-depth assessment of the scientific literature available on aspalathin, a bibliometric analysis was carried out on publications for the period 1965–2020, using the Scopus database. A total of 140 articles were retrieved, indicating that South African authors are major contributors to aspalathin research. The most common areas of investigation were identified as anti-oxidation, chemistry/chemical profiling, antidiabetic and anti-inflammatory activities. A comprehensive literature search showed that there are currently only two available reviews on aspalathin. Hence, the present review aims to explore the history and fill gaps with regards to collating aspects of the synthesis, quality control, metabolism and various biological activities of the molecule. [ABSTRACT FROM AUTHOR]

Kiwifruit (Actinidia chinensis) roots instead of fruits are widely used as Chinese medicine, but the functional metabolites remain unclear. In this study, we conducted comparative metabolome analysis between root and fruit in kiwifruit. A total of 410 metabolites were identified in the fruit and root tissues, and of them, 135 metabolites were annotated according to the Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathway. Moreover, 54 differentially expressed metabolites (DEMs) were shared in root and fruit, with 17 DEMs involved in the flavonoid pathway. Of the 17 DEMs, three flavonols (kaempferol-3-rhamnoside, L-Epicatechin and trifolin) and one dihydrochalcone (phloretin) showed the highest differences in the content level, suggesting that flavonols and dihydrochalcones may act as functional components in kiwifruit root. Transcriptome analysis revealed that genes related to flavonols and dihydrochalcones were highly expressed in root. Moreover, two AP2 transcription factors (TFs), AcRAP2-4 and AcAP2-4, were highly expressed in root, while one bHLH TF AcbHLH62 showed extremely low expression in root. The expression profiles of these TFs were similar to those of the genes related to flavonols and dihydrochalcones, suggesting they are key candidate genes controlling the flavonoid accumulation in kiwifruit. Our results provided an insight into the functional metabolites and their regulatory mechanism in kiwifruit root.

A phytochemical investigation of an ethanolic extract of Anneslea fragrans twigs collected from Thailand resulted in the discovery of a new dihydrochalcone glucopyranoside named fragranone C (1), together with six previously reported compounds. The structural elucidation of the new compound was achieved by HRFABMS, NMR spectroscopic analysis and acid hydrolysis. [ABSTRACT FROM AUTHOR]

Three new phlorizin derivatives, 6"-O-vanilloylphlorizin (1), 6"-O-(4-hydroxybenzoyl)phlorizin (2), 6"-O-feruloylphlorizin (3), along with four known dihydrochalcones, phlorizin (4), 3-hydroxyphlorizin, trilobatin, and 6"-O-acetylphlorizin were isolated from the leaves of Lithocarpus litseifolius. Their structures were established by analysis of extensive spectroscopic data. The new compounds were shown to be non-cytotoxic when tested against A549, HeLa, HepG2, and MCF-7 cell lines. [ABSTRACT FROM AUTHOR]

A new C-linked chalcone-dihydrochalcone dimer, named dracidione, was isolated from the ethyl acetate extract of dragon's blood resin of Dracaena cinnabari Balf. f. Structure elucidation of the new compound was carried out by means of one- and two-dimensional NMR spectroscopy in addition to high resolution mass spectrometry. The unique structure incorporated a chalcone and a dihydrochalcone, which is reported for the first time from nature. Furthermore, dracidione showed moderate α-glucosidase inhibitory activity with IC50= 40.27 µg/ml. [ABSTRACT FROM AUTHOR]

Averrhoa carambola L. is reported for its anti-obese and anti-diabetic activities. The present study aimed to investigate its aqueous methanol leaf extract (CLL) in vivo anti-obese activity along with the isolation and identification of bioactive compounds and their in vitro α-glucosidase inhibition assessment. CLL improved all obesity complications and exhibited significant activity in an obese rat model. Fourteen compounds, including four flavone glycosides (1–4) and ten dihydrochalcone glycosides (5–12), were isolated and identified using spectroscopic techniques. New compounds identified in planta included (1) apigenin 6-C-(2-deoxy-β-D-galactopyranoside)-7-O-β-D-quinovopyranoside, (8) phloretin 3′-C-(2-O-(E)-cinnamoyl-3-O-β-D-fucopyranosyl-4-O-acetyl)-β-D-fucopyranosyl-6′-O-β-D fucopyranosyl-(1/2)-α-L arabinofuranoside, (11a) phloretin3′-C-(2-O-(E)-p-coumaroyl-3-O-β-D-fucosyl-4-O-acetyl)-β-D-fucosyl-6′-O-(2-O-β-D-fucosyl)-α-L-arabinofuranoside, (11b) phloretin3′-C-(2-O-(Z)-p-coumaroyl-3-O-β-D-fucosyl-4-O-acetyl)-β-D-fucosyl-6′-O-(2-O-β-D-fucosyl)-α-L-arabinofuranoside. Carambolaside M (5), carambolaside Ia (6), carambolaside J (7), carambolaside I (9), carambolaside P (10a), carambolaside O (10b), and carambolaside Q (12), which are reported for the first time from A. carambola L. leaves, whereas luteolin 6-C-α-L-rhamnopyranosyl-(1-2)-β-D-fucopyranoside (2), apigenin 6-C-β-D-galactopyranoside (3), and apigenin 6-C-α-L-rhamnopyranosyl-(1-2)-β-L-fucopyranoside (4) are isolated for the first time from Family. Oxalidaceae. In vitro α-glucosidase inhibitory activity revealed the potential efficacy of flavone glycosides, viz., 1, 2, 3, and 4 as antidiabetic agents. In contrast, dihydrochalcone glycosides (5–11) showed weak activity, except for compound 12, which showed relatively strong activity.

One of the main areas of interest of synthetic organic chemistry is the rapid construction of small molecules with proven diverse biological activities for the development of new strategies to cure human health. In particular, the development of novel synthetic strategies is the most important option for reaching the molecular scaffolds of active molecules of natural origin. Balsacone A and asebogenin are compounds that exhibit a wide variety of important biological activities. In this respect, it has become very important to develop new strategies for the construction of biologically active natural and synthetic balsacone analogues. In particular, balsacone derivatives with hydroxy-substituted dihydrochalcone skeletons can be isolated from plant sources or obtained by hemi-syntheses using bio-sourced precursors. An efficient synthetic strategy to synthetically obtain balsacone A is the aim of the present study that considers the limited natural availability of these molecules as well as other factors, such as cost and time. Starting with phloroglucinol, a nine-step synthesis of the precursor of balsacone A was achieved at a 10% overall yield. Furthermore, asebogenin, which has a dihydrochalcone structure and plays a key role in the synthesis of balsacone A, was synthesised with a good yield.

Three novel dihydrochalcones, flemilineatins C-E ( 1-3 ), and two known flavanones ( 4-5 ) were isolated from Flemingia lineata (L.) W.T. Aiton leaves. Dihydrochalcones 1-3 structures were established using NMR spectrum and high-resolution ESIMS data. Compounds 1-5 were assayed to Plasmodium falciparum lactate dehydrogenase ( Pf LDH) for their antiplasmodial activity. Compounds 2 and 5 exhibited high activity with an IC 50 value of 0.74 and 0.79 µg/mL, respectively.

Periorbital hyperpigmentation (POH) is a common dermatological condition that presents as dark periorbital area beneath the lower eyelids, and it is commonly found in females belonging to the age group of 16 to 45 years. The data presented in this review include studies conducted on patients with a clinical/histological diagnosis of POH or melasma. Many diverse topical depigmenting agents comprising an array of naturally obtained actives such as arabinoxylans, α‐arbutin, asiaticoside, azelaic acid, beta‐carotene, boswellic acid, caffeine, chrysin, curcumin, cyanidin‐3‐glucoside, d‐glucoronic acid, dihydrochalcone, dipalmitoyl‐hydroxyprolene, fucoxanthin, genistein, glabridin, b‐glucogallin, hyaluronic acid, lactic acid, lycopene, niacinamide, pycnogenol, retinol, salidroside, and xymenynic acid demonstrated significant benefits in the management of POH. An exhaustive literature search revealed that other techniques such as blepharoplasty, carboxytherapy, calcium hydroxylapatite fillers, tear trough implant, Q‐switched ruby laser, medicated tattoo, fat transfer, micro‐needling, chemical peels, nitrogen plasma skin regeneration, intense pulsed light, and radiofrequency have been evaluated and reported to be beneficial in the treatment of POH. The use of topical depigmenting agents is the most widely reported method in the clinical management of POH. Of these, α‐arbutin, caffeine, cyanidin‐3‐glucoside, and dihydrochalcone are reported to exhibit significant benefits. Combination products containing a blend of actives are reported to be better than single active containing products. This review aims to provide a comprehensive perspective on the role of several topical actives in the modulation of melanin and tyrosinase biosynthesis pathway involved in the complex pathophysiology of POH. It also presents the advantages of combination products and other alternative therapies used in the management of POH. [ABSTRACT FROM AUTHOR]

Summary: Apples (Malus spp.) accumulate significant quantities of the dihydrochalcone glycoside, phloridzin, whilst pears (Pyrus spp.) do not. To explain this difference, we hypothesized that a metabolic bottleneck in the phenylpropanoid pathway might exist in apple. Expression analysis indicated that transcript levels of early phenylpropanoid pathway genes in apple and pear leaves were similar, except for chalcone isomerase (CHI), which was much lower in apple. Apples also showed very low CHI activity compared with pear. To relieve the bottleneck at CHI, transgenic apple plants overexpressing the Arabidopsis AtCHI gene were produced. Unlike other transgenic apples where phenylpropanoid flux was manipulated, AtCHI overexpression (CHIox) plants were phenotypically indistinguishable from wild‐type, except for an increase in red pigmentation in expanding leaves. CHIox plants accumulated slightly increased levels of flavanols and flavan‐3‐ols in the leaves, but the major change was a 2.8‐ to 19‐fold drop in phloridzin concentrations compared with wild‐type. The impact of these phytochemical changes on insect preference was studied using a two‐choice leaf assay with the polyphagous apple pest, the two‐spotted spider mite (Tetranychus urticae Koch). Transgenic CHIox leaves were more susceptible to herbivory, an effect that could be reversed (complemented) by application of phloridzin to transgenic leaves. Taken together, these findings shed new light on phenylpropanoid biosynthesis in apple and suggest a new physiological role for phloridzin as an antifeedant in leaves. [ABSTRACT FROM AUTHOR]

Type 2 diabetes mellitus (T2DM) is one of the major diseases of our times. Besides being a considerable inconvenience for the patient, the associated healthcare expenses are tremendous. One of the cornerstones of T2DM prevention is a healthy diet, including a variety of fruits and vegetables. Apples are touted to have health benefits, and the apple polyphenol, phloridzin, has gained interest in recent years as it can reduce intestinal sugar uptake by inhibition of the Na/glucose cotransporter 1. By researching the amount of phloridzin in different food sources and linking them to their consumption data, we could estimate the average and high-level phloridzin consumption in Europe. On average, European people consume 0·7–7·5 mg/d phloridzin, the main contributors being apples and apple juice. High-level consumers may get up to 52 mg/d of phloridzin. Older people are more at risk of developing T2DM, yet they consume less phloridzin than adolescents and adults, as determined by our survey. Management of blood glucose levels might be improved by the consumption of phloridzin, as has been shown in recent clinical trials; these trials used phloridzin-enriched apple extract at doses exceeding those from normal food consumption. There are, however, indications that consumption of average to high levels of phloridzin via food might also contribute to reduced sugar load and a reduction in T2DM risk. [ABSTRACT FROM AUTHOR]

Phlorizin is the most abundant glucoside of phloretin from the apple tree and its products. Phlorizin and its aglycone phloretin are currently considered health-beneficial polyphenols from apples useful in treating hyperglycemia and obesity. Recently, we showed that phloretin could be regioselectively hydroxylated to make 3-OH phloretin by Bacillus megaterium CYP102A1 and human P450 enzymes. The 3-OH phloretin has a potent inhibitory effect on differentiating 3T3-L1 preadipocytes into adipocytes and lipid accumulation. The glucoside of 3-OH phloretin would be a promising agent with increased bioavailability and water solubility compared with its aglycone. However, procedures to make 3-OH phlorizin, a glucoside of 3-OH phloretin, using chemical methods, are not currently available. Here, a biocatalytic strategy for the efficient synthesis of a possibly valuable hydroxylated product, 3-OH phlorizin, was developed via CYP102A1-catalyzed regioselective hydroxylation. The production of 3-OH phlorizin by CYP102A1 was confirmed by HPLC and LC–MS spectroscopy in addition to enzymatic removal of its glucose moiety for comparison to 3-OH phloretin. Taken together, in this study, we found a panel of mutants from B. megaterium CYP102A1 could catalyze regioselective hydroxylation of phlorizin to produce 3-OH phlorizin, a catechol product.

Abstract Background Chalcones are the biogenetic precursors of all known flavonoids, which play an essential role in various metabolic processes in photosynthesizing organisms. The use of whole cyanobacteria cells in a two-step, light-catalysed regioselective bio-reduction of chalcone, leading to the formation of the corresponding dihydrochalcone, is reported. The prokaryotic microalgae cyanobacteria are known to produce phenolic compounds, including flavonoids, as natural components of cells. It seems logical that organisms producing such compounds possess a suitable “enzymatic apparatus” to carry out their biotransformation. Therefore, determination of the ability of whole cells of selected cyanobacteria to carry out biocatalytic transformations of chalcone, the biogenetic precursor of all known flavonoids, was the aim of our study. Results Chalcone was found to be converted to dihydrochalcone by all examined cyanobacterial strains; however, the effectiveness of this process depends on the strain with biotransformation yields ranging from 3% to >99%. The most effective biocatalysts are Anabaena laxa, Aphanizomenon klebahnii, Nodularia moravica, Synechocystis aquatilis (>99% yield) and Merismopedia glauca (92% yield). The strains Anabaena sp. and Chroococcus minutus transformed chalcone in more than one way, forming a few products; however, dihydrochalcone was the dominant product. The course of biotransformation shed light on the pathway of chalcone conversion, indicating that the process proceeds through the intermediate cis-chalcone. The scaled-up process, conducted on a preparative scale and by using a mini-pilot photobioreactor, fully confirmed the high effectiveness of this bioconversion. Moreover, in the case of the mini-pilot photobioreactor batch cultures, the optimization of culturing conditions allowed the shortening of the process conducted by A. klebahnii by 50% (from 8 to 4 days), maintaining its >99% yield. Conclusions This is the first report related to the use of whole cells of halophilic and freshwater cyanobacteria strains in a two-step, light-catalysed regioselective bio-reduction of chalcone, leading to the formation of the corresponding dihydrochalcone. The total bioconversion of chalcone in analytical, preparative, and mini-pilot scales of this process creates the possibility of its use in the food industry for the production of natural sweeteners.

A new compound, conamonin A ( 1 ), was isolated from the whole plants of Conamomum rubidum with eight known dihydrochalcones ( 2 - 9 ). Their structures were elucidated by a combination of spectroscopic methods as well as by comparison with previously reported data. The absolute configuration of 1 was assigned by TDDFT-ECD method. Compounds 1 and 8 showed inhibitory activity against LPS-induced NO production in the RAW 264.7 cells, with IC 50 values of 58.29 ± 2.88 and 81.77 ± 5.99 μM, respectively. Compounds 3/4 and 5/6 exhibited inhibitory effects, with IC 50 values of 28.76 ± 1.16 and 29.89 ± 1.79 μg/mL, respectively. Compounds 2 , 7 - 9 exhibited significant cytotoxic activity against human lung carcinoma (the SK-LU-1 cell line) with IC 50 values ranging from 9.87 to 17.99 µM. This study offers valuable insights into the chemical constituents and biological activities of Conamomum rubidum , highlighting its potential as a source for discovering new anti-inflammatory and cytotoxic agents.

Several families of naturally occurring C-alkylated dihydrochalcones display a broad range of biological activities, including antimicrobial and cytotoxic properties, depending on their alkylation sidechain. The catalytic Friedel–Crafts alkylation of the readily available aglycon moiety of neohesperidin dihydrochalcone was performed using cinnamyl, benzyl, and isoprenyl alcohols. This procedure provided a straightforward access to a series of derivatives that were structurally related to natural balsacones, uvaretin, and erioschalcones, respectively. The antibacterial and cytotoxic potential of these novel analogs was evaluated in vitro and highlighted some relations between the structure and the pharmacological properties of alkylated dihydrochalcones.

• Oxidation during drying led to relative enrichment of apple pomace in flavonols. • Hydroxycinnamic acids, dihydrochalcones, and procyanidins decreased during drying. • Procyanidins were extracted selectively by aqueous ethanol (48%). • Most polyphenols extracted after drying were either oxidised or condensed. • Antioxidant capacities (Folin-Ciocalteu) of the extracts were not influenced by drying. Little data are available on the impact of pomace pre-treatment, notably drying, on the nature and yield of polyphenols. Pomace from two apple varieties ('Avrolles' and 'Kermerrien'), pressed with and without oxidation, were air-dried to different degrees. Drying led to the loss of native molecules, notably 5-O-caffeoylquinic acid and flavan-3-ols. Total polyphenol yields, after sequential pressurized liquid extraction (water 10 MPa, 70 °C, then ethanol 48%, 10 MPa, 70 °C), varied between 5 and 15 g/kg dry weight but showed no marked trend with drying. Extracts from dried pomace contained few native polyphenols. Water extracts from 'Kermerrien' contained flavonols, flavanols and phloridzin and those from 'Avrolles' contained phloridzin. Water:ethanol extracts were rich in procyanidins, especially from 'Avrolles', where they represented >80% of analysable polyphenols. Presence of polyphenol molecules with modified structures in the extracts of dried pomaces might lead to different biological properties than those with native molecules. [ABSTRACT FROM AUTHOR]

• New yellow pigments were isolated from sweet tea Lithocarpus polystachyus. • Structures of the pigments were determined by spectroscopic methods. • The pigments were prepared by enzymatic oxidation of a dihydrochalcone glycoside. • Precursors of the pigments were characterized by chemical derivatization. • Detailed oxidation mechanisms of dihydrochalcone glycosides were disclosed. From the dried leaves of Lithocarpus polystachyus , yellow pigments, lithocarputins B (11) and C (12), were isolated with a colorless dihydrochalcone dimer, lithocarputin A (10). The pigments 11 and 12 are dimeric dihydrochalcone glycosides with bicyclo[3.2.1]octane structures. Each pigment is a diastereomeric mixture with enantiomeric aglycones that could not be separated. The production mechanisms of the pigments were proposed based on the in vitro enzymatic preparation from trilobatin (1), the major dihydrochalcone glucoside of L. polystachyus. The majority of the pigments in the dried leaves were the oligomers of the dihydrochalcone glycosides generated by a mechanism similar to dimerization. The pigments are probably artifacts produced in the drying process. This is the first report disclosing a detailed chemical mechanism for pigment formation from dihydrochalcone. [ABSTRACT FROM AUTHOR]

The aim of our study was the evaluation of the biotransformation capacity of hydroxychalcones—2-hydroxy-4′-methylchalcone (1) and 4-hydroxy-4′-methylchalcone (4) using two strains of aerobic bacteria. The microbial reduction of the α,β-unsaturated bond of 2-hydroxy-4′-methylchalcone (1) in Gordonia sp. DSM 44456 and Rhodococcus sp. DSM 364 cultures resulted in isolation the 2-hydroxy-4′-methyldihydrochalcone (2) as a main product with yields of up to 35%. Additionally, both bacterial strains transformed compound 1 to the second, unexpected product of reduction and simultaneous hydroxylation at C-4 position—2,4-dihydroxy-4′-methyldihydrochalcone (3) (isolated yields 12.7–16.4%). During biotransformation of 4-hydroxy-4′-methylchalcone (4) we observed the formation of three products: reduction of C=C bond—4-hydroxy-4′-methyldihydrochalcone (5), reduction of C=C bond and carbonyl group—3-(4-hydroxyphenyl)-1-(4-methylphenyl)propan-1-ol (6) and also unpredictable 3-(4-hydroxyphenyl)-1,5-di-(4-methylphenyl)pentane-1,5-dione (7). As far as our knowledge is concerned, compounds 3, 6 and 7 have never been described in the scientific literature.

Psoriasis is a skin disorder characterized by epidermal hyperplasia, hyperkeratosis, and inflammation. The treatments currently available on the market only improve patients’ quality of life and are associated with undesirable side effects. Thus, research leading to the development of new, effective, and safer therapeutic agents is still relevant. Populus balsamifera L. buds were used traditionally by Native Americans to treat various skin pathologies such as eczema and psoriasis. In this study, the antipsoriatic activities of dihydrochalcone derivatives from Populus balsamifera L. buds, known as balsacones, were investigated. The experiments were performed in vitro using a psoriatic skin substitute model. Also, anti-inflammatory and antioxidant activities were investigated. The tested balsacones showed promising antipsoriatic properties by slowing down cell growth and by regulating the expression of involucrin, loricrin, and Ki67 better than methotrexate in psoriatic substitutes. All five tested compounds could be an effective topical treatment for psoriasis, with promising anti-inflammatory and antioxidant actions that may contribute to clinical improvement in patients with psoriasis.

Two new compounds, 3',5'-dimethyl-4',6'-dimethoxy-2'-hydroxydihydrochalcone (1) and 3',5'-dimethyl-6'- methoxy-2',4'-dihydroxydihydrochalcone (2), were isolated from the CHCl3 extract from Empetrum nigrum L. var. japonicum K. Koch. Their structures were elucidated by spectroscopic methods, including UV, IR, HR-ESI-MS, and extensive 1D and 2D NMR techniques. [ABSTRACT FROM AUTHOR]

Muntingia calabura (Tiliaceae) is commercially used in healthcare for the improvement of hypertension, myocardial infarction, spasm, and inflammatory conditions. Its fruits can be processed into jam and the leaves can be used for making tea. In the work reported herein a new biflavan, (M),(2S),(2''S)-,(P),(2S),(2''S)-7,8,3',4',5',7'',8'',3''',4''',5'''-decamethoxy-5,5'' biflavan (1), a new flavone, 4'-hydroxy-7,8,3',5'-tetramethoxyflavone (2), and a new dihydrochalcone, (R)-2',β-dihydroxy-3',4'-dimethoxydihydrochalcone (3), have been isolated from the stem wood of M. calabura, together with 12 known compounds (4–15). The structures of these new compounds were elucidated by the interpretations of extensive spectroscopic data. Among the isolated compounds, 5-hydroxy-7-methoxyflavone (5), quercetin (6), and (2S)-7-hydroxyflavanone (10) exhibited potent inhibition of fMLP-induced superoxide anion generation by human neutrophils, with IC50 values of 1.77 ± 0.70, 3.82 ± 0.46, and 4.92 ± 1.71 μM, respectively.

Risk factors of type 2 diabetes mellitus (T2D) and cardiovascular disease (CVD) cluster together and are termed the metabolic syndrome. Key factors driving the metabolic syndrome are inflammation, oxidative stress, insulin resistance (IR), and obesity. IR is defined as the impairment of insulin to achieve its physiological effects, resulting in glucose and lipid metabolic dysfunction in tissues such as muscle, fat, kidney, liver, and pancreatic β-cells. The potential of rooibos extract and its major C-glucosyl flavonoids, in particular aspalathin, a C-glucoside dihydrochalcone, as well as the phenolic precursor, Z-2-(β-D-glucopyranosyloxy)-3-phenylpropenoic acid, to prevent the metabolic syndrome, will be highlighted. The mechanisms whereby these phenolic compounds elicit positive effects on inflammation, cellular oxidative stress and transcription factors that regulate the expression of genes involved in glucose and lipid metabolism will be discussed in terms of their potential in ameliorating features of the metabolic syndrome and the development of serious metabolic disease. An overview of the phenolic composition of rooibos and the changes during processing will provide relevant background on this herbal tea, while a discussion of the bioavailability of the major rooibos C-glucosyl flavonoids will give insight into a key aspect of the bioefficacy of rooibos. [ABSTRACT FROM AUTHOR]

Phloridzin (phloretin 2′- O -glucoside) is the most abundant phenolic compound in Malus species, accounting for up to 18% of the dry weight in leaves. Glycosylation of phloretin at the 2′ position is the last and key step in phloridzin biosynthesis. It is catalyzed by a uridine diphosphate (UDP)-glucose:phloretin 2′- O -glucosyltransferase (P2′GT), which directly determines the concentration of phloridzin. However, this process is poorly understood. We conducted a large-scale investigation of phloridzin accumulations in leaves from 64 Malus species and cultivars. To identify the responsible P2′GT, we performed a genome-wide analysis of the expression patterns of UDP-dependent glycosyltransferase genes ( UGT s). Two candidates were screened preliminarily in Malus spp. cv. Adams (North American Begonia). Results from further qRT-PCR analyses of the genotypes showed a divergence in phloridzin production. Our assays of enzyme activity also suggested that MdUGT88F4 and MdUGT88F1 regulate the conversion of phloretin to phloridzin in Malus plants. Finally, when they were silenced in ‘GL-3’ (‘Royal Gala’), the concentrations of phloridzin and phloretin (and trilobatin) were significantly reduced and increased, respectively. [ABSTRACT FROM AUTHOR]

A new dihydrochalcone, 2‘,4‘-dihydroxy-3‘-methoxy-3,4-methylenedioxy-8-hydroxymethylene dihydrochalcone 1 and two new steroidal saponins, (25 S )-ruscogenin-1- O -α- l -rhamnopyranosyl-(1 → 2)-β- d -glucopyranoside 2 , (25 S )-ruscogenin-3- O -α- l -rhamnopyranosyl-(1 → 4)-β- d -glucopyranoside 3 , together with three known steroidal saponins (25 S )-ruscogenin-3- O -β- d -glucopyranoside 4 , (25 S )-ruscogenin-1- O -α- l -rhamnopyranosyl-(1 → 2)-[β- d -xylopyranosyl-(1 → 3)]-α- l -arabinopyranoside 5 and (25 R )-26- O -β- d -glucopyranosyl-furost-5-ene-1β,3β,22α,26-tetrol-1- O -α-L-rhamnopyranosyl-(1 → 2)-[β- d -xylopyranosyl-(1 → 3)]-α- l -arabinopyranoside 6 were isolated from the aerial parts of Sansevieria cylindrica . The structures of the new compounds were established by UV, IR, EI-MS, HR-ESI–MS as well as 1D ( 1 H, 13 C and DEPT-135) and 2D (HSQC, HMBC and TOCSY) NMR spectral analysis. The isolated compounds 1 - 6 were assayed for in vitro cytotoxicities against the three human tumor cell lines HT116, MCF7 and HepG2. Compound 1 showed a moderate cytotoxicity against MCF7. Compounds 2 , 3 and 6 exhibited moderate cytotoxicities against the three used cell lines and compound 5 showed marked cytotoxicities against all used cell lines. [ABSTRACT FROM AUTHOR]

Biotransformations were performed on eight selected yeast strains, all of which were able to selectively hydrogenate the chalcone derivatives 3-(2”-furyl)- (1) and 3-(2”-thienyl)-1-(2’-hydroxyphenyl)-prop-2-en-1-one (3) into 3-(2”-furyl)- (2) and 3-(2”-thienyl)-1-(2’-hydroxyphenyl)-propan-1-one (4) respectively. The highest efficiency of hydrogenation of the double bond in the substrate 1 was observed in the cultures of Saccharomyces cerevisiae KCh 464 and Yarrowia lipolytica KCh 71 strains. The substrate was converted into the product with > 99% conversion just in six hours after biotransformation started. The compound containing the sulfur atom in its structure was most effectively transformed by the Yarrowia lipolytica KCh 71 culture strain (conversion > 99%, obtained after three hours of substrate incubation). Also, we observed that, different strains of tested yeasts are able to carry out the bioreduction of the used substrate with different yields, depending on the presence of induced and constitutive ene reductases in their cells. The biggest advantage of this process is the efficient production of one product, practically without the formation of side products.

Previous studies have shown that accumulation of advanced glycation end products (AGEs) can be the cause of diabetic nephropathy (DN) in diabetic patients. Dihydrochalcone 3′-O-β-d-glucopyranosyl α,4,2′,4′,6′-pentahydroxy–dihydrochalcone (1) is a powerful antiglycation compound previously isolated from Eysenhardtia polystachya. The aim was to investigate whether (1) was able to protect against diabetic nephropathy in streptozotocin (STZ)-induced diabetic mice, which displayed renal dysfunction markers such as body weight, creatinine, uric acid, serum urea, total urinary protein, and urea nitrogen in the blood (BUN). In addition, pathological changes were evaluated including glycated hemoglobin (HbA1c), advanced glycation end products (AGEs) in the kidney, as well as in circulation level and pro-inflammatory markers ICAM-1 levels in diabetic mice. After 5 weeks, these elevated markers of dihydrochalcone treatment (25, 50 and 100 mg/kg) were significantly (p < 0.05) attenuated. In addition, they ameliorate the indices of renal inflammation as indicated by ICAM-1 markers. The kidney and circulatory AGEs levels in diabetic mice were significantly (p < 0.05) attenuated by (1) treatment. Histological analysis of kidney tissues showed an important recovery in its structure compared with the diabetic group. It was found that the compound (1) attenuated the renal damage in diabetic mice by inhibiting AGEs formation.

A highly efficient liquid-phase hydrogenation reaction using a recyclable palladium on carbon (Pd/C) catalyst has been used for the transformation of naringin to its corresponding dihydrochalcone. The effects of various solvents on the hydrogenation process were studied, with water being identified as the optimal solvent. The analysis also revealed that sodium hydroxide (NaOH) can accumulate on the surface of the Pd/C catalyst in alcoholic solvents, leading to its inactivation. The higher solubility of NaOH in water implies that it remains in solution and does not accumulate on the Pd/C catalyst surface, ensuring the catalytic activity and stability.

A group of flavones, isoflavones, flavanones, and chalcones was subjected to small-scale biotransformation studies with the Gram-negative Stenotrophomonas maltophilia KB2 strain in order to evaluate the capability of this strain to transform flavonoid compounds and to investigate the relationship between compound structure and transformation type. The tested strain transformed flavanones and chalcones. The main type of transformation of compounds with a flavanone moiety was central heterocyclic C ring cleavage, leading to chalcone and dihydrochalcone structures, whereas chalcones underwent reduction to dihydrochalcones and cyclisation to a benzo-γ-pyrone moiety. Substrates with a C-2-C-3 double bond (flavones and isoflavones) were not transformed by Stenotrophomonas maltophilia KB2. [ABSTRACT FROM AUTHOR]

Five dihydrochalcone compounds, including phlorizin, trilobatin, 3-hydroxyphlorizin, sieboldin and phloretin 2′-xyloglucoside, were isolated from ornamental Malus ‘Red Splendor’ fruit. The chemical structures of these compounds were elucidated by LC-ESI-MS and NMR. Phloretin and 3-hydroxyphloretin were produced by hydrolysis. The antioxidant capacities of these seven compounds were examined by DPPH and ABTS assays, while their cytotoxicity to five cancer cell lines were evaluated by the MTT assay. The results showed that the DPPH assay mainly reflected the antioxidant capacity of the B ring, whereas the ABTS assay was mostly related to the A ring of the dihydrochalcone molecule. Moreover, 3-hydroxyphloretin was the best antioxidant among the seven compounds. Both glycosylation of the A ring and the ortho phenolic hydroxyl groups of the B ring were important for the cytotoxicity of dihydrochalcone molecules. Sieboldin and 3-hydroxyphlorizin exhibited better cytotoxicity than other dihydrochalcone compounds. Dihydrochalcones from Malus may benefit human health. [ABSTRACT FROM AUTHOR]

Two new dihydrochalcone enantiomers (+)-1 and (-)-1, along with eight known compounds 3-10, were obtained from Pteris ensiformis. The planar structures were determined on the basis of extensive 1D and 2DNMR and HRESIMS. The resolution of (+)-1 and (-)-1 was achieved by chiral HPLC analysis. The absolute configurations of (+)-1 and (-)-1 were established by the bulkiness rule using Rh2(O2CCF3)4-induced circular dichroism (ICD) method. Compounds (+)-1, (-)-1, 8, 9 and 10 exhibited the inhibitory assay of NO production in mouse macrophages stimulated by LPS, with IC50 values of 2.0, 2.5, 8.0, 9.5 and 5.6 μM, respectively. Otherwise, compound 10 showed moderate cytotoxic activity against HCT-116, HepG-2 and BGC-823 cell lines with IC50 values of 3.0, 10.5 and 6.3 μM, respectively [ABSTRACT FROM AUTHOR]

Background: Chalcones are the biogenetic precursors of all known flavonoids, which play an essential role in various metabolic processes in photosynthesizing organisms. The use of whole cyanobacteria cells in a two-step, lightcatalysed regioselective bio-reduction of chalcone, leading to the formation of the corresponding dihydrochalcone, is reported. The prokaryotic microalgae cyanobacteria are known to produce phenolic compounds, including flavonoids, as natural components of cells. It seems logical that organisms producing such compounds possess a suitable "enzymatic apparatus" to carry out their biotransformation. Therefore, determination of the ability of whole cells of selected cyanobacteria to carry out biocatalytic transformations of chalcone, the biogenetic precursor of all known flavonoids, was the aim of our study. Results: Chalcone was found to be converted to dihydrochalcone by all examined cyanobacterial strains; however, the effectiveness of this process depends on the strain with biotransformation yields ranging from 3% to >99%. The most effective biocatalysts are Anabaena laxa, Aphanizomenon klebahnii, Nodularia moravica, Synechocystis aquatilis (>99% yield) and Merismopedia glauca (92% yield). The strains Anabaena sp. and Chroococcus minutus transformed chalcone in more than one way, forming a few products; however, dihydrochalcone was the dominant product. The course of biotransformation shed light on the pathway of chalcone conversion, indicating that the process proceeds through the intermediate cis-chalcone. The scaled-up process, conducted on a preparative scale and by using a minipilot photobioreactor, fully confirmed the high effectiveness of this bioconversion. Moreover, in the case of the minipilot photobioreactor batch cultures, the optimization of culturing conditions allowed the shortening of the process conducted by A. klebahnii by 50% (from 8 to 4 days), maintaining its >99% yield. Conclusions: This is the first report related to the use of whole cells of halophilic and freshwater cyanobacteria strains in a two-step, light-catalysed regioselective bio-reduction of chalcone, leading to the formation of the corresponding dihydrochalcone. The total bioconversion of chalcone in analytical, preparative, and mini-pilot scales of this process creates the possibility of its use in the food industry for the production of natural sweeteners. [ABSTRACT FROM AUTHOR]