Phytochemical Profiling and Biological Activities of Pericarps and Seeds Reveal the Controversy on "Enucleation" or "Nucleus-Retaining" of Cornus officinalis Fruits

The fruits of Cornus officinalis are used not only as a popular health food to tonify the liver and kidney, but also as staple materials to treat dementia and other age-related diseases. The pharmacological function of C. officinalis fruits with or without seeds is controversial for treating some symptoms in a few herbal prescriptions. However, the related metabolite and pharmacological information between its pericarps and seeds are largely deficient. Here, comparative metabolomics analysis between C. officinalis pericarps and seeds were conducted using an ultra-performance liquid chromatography-electrospray ionization-tandem mass spectrometry, and therapeutic effects were also evaluated using several in vitro bioactivity arrays (antioxidant activity, α-glucosidase and cholinesterase inhibitory activities, and cell inhibitory properties). A total of 499 secondary metabolites were identified. Thereinto, 77 metabolites were determined as key differential metabolites between C. officinalis pericarps and seeds, and the flavonoid biosynthesis pathway was identified as the most significantly different pathway. Further, 47 metabolites were determined as potential bioactive constituents. In summary, C. officinalis seeds, which demonstrated higher contents in total phenolics, stronger in vitro antioxidant activities, better α-glucosidase and butyrylcholinesterase inhibitory activities, and stronger anticancer activities, exhibited considerable potential for food and health fields. This work provided insight into the metabolites and bioactivities of C. officinalis pericarps and seeds, contributing to their precise development and utilization.

Identification and molecular mechanism of novel bifunctional peptides from Duroc × (Landrace × Yorkshire) pig dry-cured ham: A peptidomics and in silico analysis

Duroc × (Landrace × Yorkshire) pigs are popular in the Chinese market because of their rapid growth, leanness, and economic value. Despite their widespread use in dry-cured ham processing, there is a lack of research on the bioactive peptides of Duroc × (Landrace × Yorkshire) pig ham (DLYH). This study aimed to investigate the presence of peptides with antioxidant and α-glucosidase inhibitory activities in DLYH using peptidomics and in silico analysis. A total of 453 peptides were identified from DLYH, originating mainly from myosin, actin, and the EF-hand domain-containing protein. Notably, two peptides, YDEAGPSIVH (YH10) and FAGDDAPRAVF (FF11), emerged as novel bioactive peptides with antioxidant and α-glucosidase inhibitory activities. Among these peptides, YH10 exhibited a high DPPH radical scavenging activity (IC50 = 1.93 mM), ABTS radical scavenging activity (IC50 = 0.10 mM), α-glucosidase inhibitory activity (IC50 = 2.13 mM), and good gastrointestinal tolerance. Molecular docking analysis showed that YH10 was bound to the ABTS and DPPH radicals and the active site of α-glucosidase (3A4A) primarily through hydrogen bonding and hydrophobic interactions. Furthermore, molecular dynamics (MD) simulation indicated that the YH10-3A4A complexes maintained stable and compact conformations. In conclusion, our findings indicated that peptide YH10 derived from DLYH possesses bifunctional properties of α-glucosidase inhibition and antioxidant activity, which could be beneficial for maintaining ham quality and promoting human health.

[Two new benzyl-benzoate glucosides from Plumeria rubra]

The components with hypoglycemic activity in Plumeria rubra were isolated and purified by various column chromatography techniques and activity tracing methods. The physical and chemical properties of all the purified monomer compounds were characterized and analyzed, and a total of six compounds were isolated and identified, including 6″-acetyl-6-hydroxy-benzyl-benzoate-2-O-β-D-glucoside(1), 6-acetyl-6-hydroxy-benzyl-benzoate-2-O-β-D-glucoside-(1→6″)-β-D-glucoside(2), 2-hydroxy-6-methoxy-benzyl-benzoate-2-O-β-D-glucoside(3), 6-hydroxy-benzyl-benzoate-2-O-β-D-glucoside(4), 6-hydroxy-benzyl-benzoate-2-O-β-D-glucoside-(1→6″)-β-D-glucoside(5), and 6-hydroxy-benzyl-benzoate-2-O-β-D-glucoside-(1→6″)-β-D-xyloside(6). Compounds 1 and 2 were new compounds, and compounds 3-6 were isolated from Plumeria for the first time. The α-glucosidase inhibitory activity of six identified compounds was tested. The results show that compounds 1-6 show certain inhibitory activity with an IC_(50) value ranging from 8.2 to 33.5 μmol·L~(-1).

Identification and α-glucosidase inhibitory activity evaluation of two new coumarins derived from Mansonia gagei J. R. Drumm

Five coumarins were isolated from the heartwood of Mansonia gagei, which included two newly discovered compounds, namely 11-hydroxypopulene E (1) and mansorin D (2), along with three previously identified compounds. The structures were determined through the utilisation of comprehensive spectroscopic data, ECD calculations, and a thorough comparison with existing literature data. The α-glucosidase inhibitory activities of all isolated compounds were assessed in yeast. Out of the compounds tested, compound 2 exhibited the most significant activity, displaying a percentage inhibition of 34.33% at a concentration of 200 μM.

Engleromophilane, a new broad spectrum bioactive eremophilane-type sesquiterpene from Engleromyces sinensis fungus

A new eremophilane sesquiterpene, named engleromophilane (1) together with known eremoxylarin E (2) and steroids (3-7) were isolated from the fungus Engleromyces sinensis culture. The structures were deduced by the analysis of spectroscopic and MS data, together with the comparison of calculated 13C NMR chemical shifts and Electronic Circular Dichroism (ECD) spectra. Compound 1 showed cytotoxic effects against Hela, PC-3, HT29 and A549 cell lines with IC50 in the ranges of 4.84-9.48 μg/mL. Compounds 1 and 2 exhibited substantial antimicrobial activity against E. coli, S. aureus, and B. subtilis. Moreover, compounds 1-3 showed α-glucosidase inhibitory activity, in which 2 displayed a strong inhibitory effect with an IC50 value of 0.13 ± 0.01 µg/mL. This work has given additional value to the E. sinensis fungus as a remarkable bioactive compound producer, together with the possibility of increasing cultivation to industrial scales.

Phomopamide A, a cyclic pentadepsipeptide with α-glucosidase inhibition activity from the endophytic fungus Diaporthe sp

An undescribed cytotoxic cyclopeptide named phomopamide A (1) was isolated from Diaporthe sp., which is an endophytic fungus from Artemisia argyi. Phomopamide A (1) featured an pentadepsipeptide skeleton and composed of two Phe, one Val, one Leu, and one 2-hydroxyoctanoic acid units. The structure of this new compound was fully characterised on the basis of extensive spectroscopic analysis. Moreover, phomopamide A was evaluated for in vitro cyctotoxic and α-glucosidase inhibitory activity. As a result, phomopaminde A exhibited no cytotoxic activity against four tumour cell lines, while it showed a potent α-glucosidase inhibition effect with IC50 value of 62.35 µM.

Lanostane triterpenoids from the fruiting bodies of Ganoderma amboinense

Lanostane-type triterpenoids are the main characteristic constituents in Ganoderma mushrooms. Phytochemical analysis on the ethanol extract of the fruiting bodies of Ganoderma amboinense led to isolation and identification of twelve previously undescribed lanostane triterpenoids (1-12). Their chemical structures were determined by HR-ESI-MS, IR, and NMR spectroscopic analysis, NMR calculation, as well as X-ray crystallography. All isolates were evaluated for the α-glucosidase inhibitory and anti-inflammatory activities. Compounds 1, 5, 6, and 11 showed significant α-glucosidase inhibitory activity with IC50 values ranging from 33.5 μM to 96.0 μM. Moreover, compound 12 showed anti-inflammatory activity with IC50 value of 21.7 ± 2.1 μM.

Isolation of a Potential Probiotic Levilactobacillus brevis and Evaluation of Its Exopolysaccharide for Antioxidant and α-Glucosidase Inhibitory Activities

The probiotic properties of ten lactic acid bacteria and antioxidant and α-glucosidase inhibitory activities of the exopolysaccharide (EPS) of the selected strain were investigated in this study. Levilactobacillus brevis L010 was one of the most active strains across all the in vitro tests. The cell-free supernatant (50 g/l) of L. brevis L010 showed high levels of both α-glucosidase inhibitory activity (98.73 ± 1.32%) and 2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity (32.29 ± 3.86%). The EPS isolated from cell-free supernatant of L. brevis L010 showed 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) radical-scavenging activity (80.27 ± 2.51%) at 80 g/l, DPPH radical-scavenging activity (38.19 ± 9.61%) at 40 g/l, and ferric reducing antioxidant power (17.35 ± 0.20 mg/l) at 80 g/l. Further, EPS exhibited inhibitory activities against α-glucosidase at different substrate concentrations. Kinetic analysis suggests that the mode of inhibition was competitive, with a kinetic constant of Km = 2.87 ± 0.88 mM and Vmax = 0.39 ± 0.06 μmole/min. It was concluded that the EPS might be one of the plausible candidates for possible antioxidant and α-glucosidase activities of the L. brevis L010 strain.

Tandem mass spectrometry (MS/MS) molecular networking guided profiling of small molecules from Aquilaria sinensis (Lour.) Gilg leaves and their bioactivity evaluation

INTRODUCTION

Agarwood, a fragrant resinous wood mainly formed by Aquilaria spp., is used worldwide as a natural fragrance and traditional medicine. A large amount of Aquilaria sinensis (Lour.) Gilg leaves are underutilised during the process of the agarwood industry, and the development of A. sinensis leaves as tea has recently attracted more and more attention. However, the small molecule profile of A. sinensis leaves and their bioactivities has been rarely reported.

OBJECTIVE

To conduct a rapid untargeted liquid chromatography-mass spectrometry (LC-MS) analysis of A. sinensis leaves with a molecular networking (MN) strategy and evaluate its antioxidant and antidiabetic value.

METHOD

A MN-assisted tandem mass spectrometry (MS/MS) analysis strategy was used to investigate the small molecule profile of A. sinensis leaves. Additionally, the integration of antioxidant and α-glucosidase inhibitory assays with MN analysis was executed to expeditiously characterise the bioactive compounds for potential prospective application.

RESULTS

Five main chemical groups including phenol C-glycosides, organic acids, 2-(2-phenylethyl) chromones, benzophenone O-glycosides and flavonoids were rapidly revealed from the A. sinensis leaves. Eighty-one compounds were provisionally identified by comparing their MS/MS fragments with canonical pathways. The featured xanthone C-glycosides and benzophenone C-glycosides were recognised as the primary components of A. sinensis leaves. Several dimers and a trimer of mangiferin were reported firstly in A. sinensis leaves. Furthermore, 17 and 14 potential bioactive molecules were rapidly annotated from antioxidant and α-glucosidase inhibitory fraction, respectively.

CONCLUSION

Our findings will help expand the utilisation of A. sinensis leaves and thus promote the high-quality development of agarwood industry.

A new amine isolated from Urtica thunbergiana Siebold & Zucc

One new amine 2-dimethyl-Penidilamine (1), together with seventeen known compounds (2-18) were isolated from the 95% ethanol extract of Urtica thunbergiana Siebold & Zucc. Their structures were characterised by extensive spectroscopic analysis including NMR, mass spectra and single X-ray crystallography. Among them, compound 1 is a new compound, and compounds 3, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 17 and 18 were isolated from Urtica thunbergiana Siebold & Zucc for the first time. Among them, compound 1, 10, 15, 17 and 18 exhibited significant α-glucosidase inhibitory activity with an IC50 value of 65.12 μM, 7.42 μM, 26.24 μM, 71.31 μM and 72.55 μM, respectively. Our study provided the scientific report for the medicinal value of Urtica thunbergiana Siebold & Zucc.

[Chemical constituents from Salacia polysperma]

Nine compounds were isolated from the 90% ethanol extract of Salacia polysperma by silica gel, Sephadex LH-20 column chromatography, together with preparative HPLC methods. Based on HR-ESI-MS, MS, 1D and 2D NMR spectral analyses, the structures of the nine compounds were identified as 28-hydroxy wilforlide B(1), wilforlide A(2), 1β,3β-dihydroxyurs-9(11),12-diene(3),(-)-epicatechin(4),(+)-catechin(5),(-)-4'-O-methyl-ent-galloepicatechin(6), 3-hydroxy-1-(4-hydroxy-3-methoxy-phenyl)propan-1-one(7),(-)-(7S,8R)-4-hydroxy-3,3',5'-trimethoxy-8',9'-dinor-8,4'-oxyneoligna-7,9-diol-7'-aldehyde(8), and vanillic acid(9). Compound 1 is a new oleanane-type triterpene lactone. Compounds 1, 3, 4, 7-9 were isolated from the Salacia genus for the first time. All compounds were assayed for their α-glucosidase inhibitory activity. The results suggested that compound 8 exhibited moderate α-glucosidase inhibitory activity, with an IC_(50) value of 37.2 μmol·L~(-1), and the other compounds showed no α-glucosidase inhibitory activity.

Phenolic profile and α-glucosidase inhibitory potential of wampee (Clausena lansium (Lour.) Skeels) peel and pulp: In vitro digestion/in silico evaluations

To investigate the changes in phenolics, flavonoids, and their bio-activities of wampee (Clausena lansium (Lour.) Skeels) during digestion, the peel and pulp were subjected to simulated in vitro digestion, encompassing oral, gastric, small intestine, and large intestine digestion stages. The peel exhibited a total release of 91.93 mg GAE/g DW of phenolics and 61.86 mg RE/g DW of flavonoids, whereas the pulp displayed a release of 27.83 mg GAE/g DW of phenolics and 8.94 mg RE/g DW of flavonoids. Notably, the phenolics and flavonoids were mostly released during the oral digestion stage for peel, while they were mostly released during the small intestine digestion stage for pulp. The results of the targeted flavonoids analysis indicated that rutin and l-epicatechin were the two most widely released compounds in each digestion step. Moreover, myricetin has been identified as the best inhibitor against α-glucosidase, probably because it formed the most H-bonds, 8, with 6 catalytic residues, which was the highest number. Furthermore, the soluble substances released from the peel exhibited significantly higher antioxidant activities and inhibitory activity against α-glucosidase (p < 0.05) compared to those from the pulp. Positive correlations were observed between the total phenolic content or total flavonoid content and the antioxidant activities (r > 0.73 (peel), > 0.61 (pulp)), as well as α-glucosidase inhibitory activity (r <  - 0.48 (peel), < -0.64 (pulp)) of peel and pulp. In conclusion, these findings provide valuable insights into the digestive characteristics and health benefits of both wampee peel and pulp.

In vitro α-glucosidase inhibitory activity of isolated compounds and semisynthetic derivative from aerial parts of Erythrina senegalensis DC

The current study was conducted to isolate the phytoconstituents from Erythrina senegalensis leaves and stem bark and evaluate their inhibitory activity against α-glucosidase, digestive enzyme related to diabetes mellitus. Phytochemical investigation of the leaves resulted in the isolation of three saponins (3-5), two triterpenoids (7 and 8) and two steroids (10a and 10b) as inseparable mixture, while one saponin (6), one triterpenoid (9) and one mixture of two cinnamates (2a and 2b) were isolated from the stem bark. Except for compounds 2 b, 7, 8, 10a and 10 b all the isolated compounds are reported here for the first time from the genus Erythrina. Acetylation of the mixture of two cinnamates (2a and 2b) led to a new diester derivative (1) trivially called erythrinamate. The extracts and pure compounds (3, 4, 6) showed good α-glucosidase inhibitory activity compared to the standard drug acarbose. The findings suggest that saponins of E. senegalensis could be used to develop potential anti-hyperglycemic drugs.

24-Nor-allobetulins possess strong α-glucosidase inhibitory activity

A series of 24-nor-allobetulin derivatives holding 3β-hydroxy-, oxime, methoxyoxime, lactame and 4-bromobenzylidene substituents have been synthesized and their differences in the NMR spectra were studied in detail. It was revealed that 3-oxo-24-nor-allobetulin loses selectivity in the reaction of oximation and forms a mixture of Z/E oximes (and methoxyoximes) in contract to the related derivatives of native scaffold (that forms only E-isomers). The screening of α-glucosidase inhibitory activity revealed that 24-nor-allobetulins are more active than allobetulins. The lead 3-oxo-24-nor-allobetulin with IC50 0.49 µM was more than 60-fold and 500-fold active than acarbose and 3-oxo-allobetulin, respectively. We can conclude that the removal of the C-24 methyl group significantly increased the antidiabetic effect and 24-nor-allobetulins should be identified as the new and promising scaffolds as α-glucosidase inhibitors on the basis of triterpenoids.

Grevillosides R-S: glucosides of 5-alkylresorcinol derivatives from roots of Ardisia crispa (Thunb.) A. DC

Grevillosides R-S (1-2), two new glucosides of 5-alkylresorcinol derivatives, were isolated from the roots of Ardisia crispa (Thunb.) A. DC. The structures of grevillosides R-S (1-2) were determined by 1D and 2D NMR, HR-MS, UV, IR experiments and by comparison of their spectroscopic and physical data with literature values. In this paper, grevillosides R-S (1-2) were tested for their radical-scavenging activity (DPPH and ABTS) and α-glucosidase inhibitory activity in vitro. Grevillosides R-S (1-2) exhibited weak DPPH radical-scavenging activity with IC50 values of 72.3 and 485.2 μM, respectively. Grevillosides R-S (1-2) exhibited no inhibitory activity against α-glucosidase.

[Chemical constituents and their α-glucosidase inhibitory activities of seeds of Moringa oleifera]

The chemical constituents of the seeds of Moringa oleifera were isolated and purified by using Sephadex LH-20, Toyo-pearl HW-40F, silica gel, ODS, and MCI column chromatography. The structures of compounds were identified by high-resolution mass spectrometry, ~1H-NMR, ~(13)C-NMR, HMQC, HMBC, and ~1H-~1H COSY, as well as physicochemical properties of compounds and literature data. Twelve compounds were isolated from 30% ethanol fraction of the seeds of M. oleifera and identified as ethyl-4-O-α-L-rhamnosyl-α-L-rhamnoside(1), ethyl-3-O-α-L-rhamnosyl-α-L-rhamnoside(2),(4-hydroxybenzyl)ethyl carbamate(3),(4-aminophenyl)acetic acid(4), ethyl-α-L-rhamnoside(5), methyl-α-L-rhamnoside(6), moringapyranosyl(7), 2-[4-(α-L-rhamnosyl)phenyl]methyl acetate(8), niaziridin(9), 5-hydroxymethyl furfural(10), 4-hydroxybenzeneacetamide(11), and 4-hydroxybenzoic acid(12). Among them, compounds 1 and 2 are two new compounds, compound 3 is a new natural product, and compounds 4-5 were yielded from Moringa plant for the first time. All compounds were evaluated for α-glucosidase inhibitory activity in vitro. Compound 10 showed excellent inhibitory activity with IC_(50) of 210 μg·mL~(-1).

Identification of Efficacy-Associated Markers to Discriminate Flos Chrysanthemum and Flos Chrysanthemi Indici Based on Fingerprint-Activity Relationship Modeling: A Combined Evaluation over Chemical Consistence and Quality Consistence

Monitoring the quality consistency of traditional Chinese medicines, or herbal medicines (HMs), is the basis of assuring the efficacy and safety of HMs during clinical applications. The purpose of this work was to characterize the difference in hydrophilic antioxidants and related bioactivities between Flos Chrysanthemum (JH) and its wild relatives (Chrysanthemum indicum L.; YJH) based on the establishment of fingerprint-efficacy relationship modeling. The concentrations of the total phenolics and flavonoids of JH samples were shown to be generally higher than those of YJH, but the concentration distribution ranges of YJH were significantly greater compared to JH samples, possibly related to environmental stress factors leading to the concentration fluctuations of phytochemicals during the growth and flowering of Chrysanthemum cultivars. Correspondingly, the total antioxidant capabilities of JH were greatly higher than those of YJH samples, as revealed by chemical assays, including DPPH and ABTS radical scavenging activities and FRAP assays. In addition, cellular-based antioxidant activities confirmed the results of chemical assays, suggesting that the differences in antioxidant activities among the different types of Chrysanthemums were obvious. The extracts from YJH and JH samples showed significant α-glucosidase inhibitory activity and lipase-inhibitory activity, implying the modulatory effects on lipid and glucose metabolisms, which were also confirmed by an untargeted cell-based metabolomics approach. The selected common peaks by similarity analysis contributed to the discrimination of YJH and JH samples, and the modeling of the fingerprint-bioactivity relationship identified neochlorogenic acid, isochlorogenic acid A, and linarin as efficacy-associated chemical markers. These results have demonstrated that integrating HPLC fingerprints and the analysis of similarity indexes coupled with antioxidant activities and enzyme-inhibitory activities provides a rapid and effective approach to monitoring the quality consistency of YJH/JH samples.

Chemical Constituents, Antioxidant, and α-Glucosidase Inhibitory Activities of Different Fermented Gynostemma Pentaphyllum Leaves and Untargeted Metabolomic Measurement of the Metabolite Variation

To assess the effects of microbial fermentation on Gynostemma pentaphyllum leaves (GPL), four probiotics were used to ferment GPL (FGPL) for 7 days. At different stages of fermentation, changes in the active components and biological activities of FGPL were determined. The findings suggest that short-term fermentation with probiotics can enhance both the content and bioactivity of active components in GPL. However, prolonged fermentation may lead to a decline in these aspects. Among them, the best effect was observed with SWFU D16 fermentation for 2 days. This significantly improved the total phenolic and total flavonoid content, antioxidant capacity, and inhibitory ability against α-glucosidase activity with an increase of 28%, 114.82%, 7.42%, and 31.8%, respectively. The high-performance liquid chromatography (HPLC) analysis results also supported this trend. Untargeted metabolomics analysis revealed metabolite changes between GPL and FGPL and the key metabolites associated with these functional activities. These key metabolites are mainly organic acids, flavonoids, carbohydrates, terpenoids, and other substances. KEGG analysis demonstrated that microbial metabolism in diverse environments and carbon metabolism were the most significantly enriched pathways. Among them, 3-(3-hydroxyphenyl) propanoic acid, d-glucose, gallic acid, gluconic acid, l-lactic acid, and l-malic acid were mostly involved in the microbial metabolism of diverse environmental pathways. In contrast, D-glucose, gluconic acid, and l-malic acid were mainly related to the carbon metabolism pathway. This study revealed the positive effect of probiotic fermentation on GPL and its potential metabolism mechanism, which could provide supporting data for further research.

Structurally Diverse Phenolic Amides from the Fruits of Lycium barbarum with Potent α-Glucosidase, Dipeptidyl Peptidase-4 Inhibitory, and PPAR-γ Agonistic Activities

A total of nine new phenolic amides (1-9), including four pairs of enantiomeric mixtures (3-5 and 8), along with ten known analogues (10-19) were identified from the fruits of Lycium barbarum using bioassay-guided chromatographic fractionation. Their structures were elucidated by comprehensive spectroscopic and spectrometric analyses, chiral HPLC analyses, and quantum NMR, and electronic circular dichroism calculations. Compounds 5-7 are the first example of feruloyl tyramine dimers fused through a cyclobutane ring. The activity results indicated that compounds 1, 11, and 13-17 exhibited remarkable inhibition against α-glucosidase with IC₅₀ of 1.11-33.53 μM, 5-150 times stronger than acarbose (IC₅₀ = 169.78 μM). Meanwhile, compounds 4a, 4b, 5a, 5b, 13, and 14 exerted moderate agonistic activities for peroxisome proliferator-activated receptor (PPAR-γ), with EC₅₀ values of 10.09-44.26 μM. Especially,compound 14 also presented inhibitory activity on dipeptidyl peptidase-4 (DPPIV), with an IC₅₀ value of 47.13 μM. Furthermore, the banding manner of compounds 14 and 17 with the active site of α-glucosidase, DPPIV, and PPAR-γ was explored by employing molecular docking analysis.

Two new diterpenoids from the rhizomes of Zingiber officinale

Two undescribed labdane diterpenoids (5S,8S,9R,10S,11E)-8,17-epoxy-13,14-dinorlabd-11-en-13-one (1) and (5S,9R,10S,12E)-17-hydroxy-labd-7,12-dien-15(16)-olide (2), together with seven known sesquiterpenoids (3-9) and two known monoterpenoids (10-11) were isolated from the dried rhizome of Zingiber officinale. Their structures were elucidated by detailed spectroscopic data (IR, UV, HR-ESI-MS, 1D and 2D NMR), X-ray crystallographic and ECD analysis. Moreover, all the 11 compounds were tested for α-glucosidase inhibitory effects and 9 was found to exhibit stronger inhibitory effects at IC50 = 4.8 μM against a positive control acarbose with IC50 = 414.6 μM.

New Hydrolyzable Tannin with Potent Antioxidant and α-Glucosidase Inhibitory Activity from Black Tea Produced from Camellia taliensis

Camellia taliensis (W. W. Smith) Melchior, belonging to the genus Camellia sect. Thea., is mainly distributed from northern Myanmar to western and southwestern Yunnan province of China, and its leaves have been used to make various teas by the locals of its growing regions. The chemical constituents of C. taliensis are significantly related to those of cultivated tea plants, C. sinensis and C. sinensis var. assamica. The HPLC-ESI-MS analysis of black tea prepared from the leaves of C. taliensis showed a rich existence of polyphenols. Further comprehensive chemical study led to the separation and recognition of 32 compounds (1-32), including one new hydrolyzable tannin, 1-O-galloyl-4,6-tetrahydroxydibenzofurandicarboxyl-β-D-glucopyranose (1), and one new natural product (24). The known compounds referred to seven hydrolyzable tannins (2-8), 10 flavonols and glycosides (9-18), and 14 simple phenolics (19-32). Their structures were elucidated by comprehensive spectroscopic analyses. Among them, 20 compounds (2, 3, 6, 7, 8, 15, 17, 18, 20-22, 24-32) were isolated from black tea for the first time. Most isolates displayed obvious antioxidant activities on DPPH and ABTS⁺ assays, and the hydrolyzable tannins 1, 3-5, 7, and 8 exhibited stronger inhibitory activities on α-glycosidase than quercetin and acarbose (IC₅₀ = 5.75 and 223.30 μM, respectively), with IC₅₀ values ranging from 0.67 to 2.01 μM.

One undescribed glycoside benzofuran derivative and a new p-hydroxybenzoate glycoside from the leaves of Illicium dunnianum Tutcher

One undescribed benzofuran derivative (illiciumphenolicacid A, 1) and one new phenolic glycoside (illiciumphenolicacid B, 2), together with six known compounds (3-8) were isolated from the leaves of Illicium dunnianum Tutcher. Their structures were elucidated by detailed spectroscopic data (UV, IR, HR-ESI-MS, 1D and 2D NMR). In addition, we determined the α-glucosidase inhibitory activity of the isolates in vitro using spectrophotometric methods. Compared with the positive control acarbose (IC₅₀ 306.2 ± 4.1 μM), compounds 1-8 were shown to be moderate potential α-glucosidase inhibitory activity with IC₅₀ values in the range 380-655 μM.

And their α-glucosidase inhibitory activity

Four new diastereoisomeric neolignan glycosides (1-4) along with nine known lignan glycosides (5-13) were isolated from the root bark of Lycium chinense Mill. Their structures with absolute configurations were elucidated on the basis of NMR spectroscopy, ECD, Mo₂(OAc)₄-induced ECD spectra, enzymatic hydrolysis and acid hydrolysis. The isolated compounds were evaluated for their α-glucosidase inhibitory activity. Compounds 8 and 13 exhibited moderate inhibitory activities against α-glucosidase with IC₅₀ values of 26.82 ± 2.71 and 43.14 ± 2.81 μg/mL.

Stilbenoids and Flavonoids from Cajanus cajan (L.) Millsp. and Their α-Glucosidase Inhibitory Activities

Two new stilbenoids, cajanstilbenoid C (1) and cajanstilbenoid D (2), together with eight other known stilbenoids (3-10) and seventeen known flavonoids (11-27), were isolated from the petroleum ether and ethyl acetate portions of the 95% ethanol extract of leaves of Cajanus cajan (L.) Millsp. The planar structures of the new compounds were elucidated by NMR and high-resolution mass spectrometry, and their absolute configurations were determined by comparison of their experimental and calculated electronic circular dichroism (ECD) values. All the compounds were assayed for their inhibitory activities against yeast α-glucosidase. The results demonstrated that compounds 3, 8-9, 11, 13, 19-21, and 24-26 had strong inhibitory activities against α-glucosidase, with compound 11 (IC₅₀ = 0.87 ± 0.05 μM) exhibiting the strongest activity. The structure-activity relationships were preliminarily summarized. Moreover, enzyme kinetics showed that compound 8 was a noncompetitive inhibitor, compounds 11, 24-26 were anticompetitive, and compounds 9 and 13 were mixed-competitive.

Effects on Goat Meat Extracts on α-Glucosidase Inhibitory Activity, Expression of Bcl-2-Associated X (BAX), p53, and p21 in Cell Line and Expression of Atrogin-1, Muscle Atrophy F-Box (MAFbx), Muscle RING-Finger Protein-1 (MuRF-1), and Myosin Heavy Chain-7 (MYH-7) in C2C12 Myoblsts

This study examined the α-glucosidase inhibitory, and apoptosis- and anti-muscular-related factors of goat meat extracts from forelegs, hind legs, loin, and ribs. The goat meat extracts were evaluated for their α-glucosidase inhibitory activity. The gene and protein expression levels of Bcl-2-associated X (bax), p53, and p21 were examined by reverse transcription polymerase chain reaction (RT-PCR) and immunoblotting in AGS and HT-29 cells. The expression levels of Atrogin-1 and MHC1b were examined by RT-PCR in C2C12 myoblasts, and the expression levels of Atrogin-1, muscle atrophy F-box (MAFbx), muscle RING-finger protein-1 (MuRF-1), and myosin heavy chain-7 were investigated by immunoblotting. α-Glucosidase inhibitory activity was higher in ethanol extract than in hydrous and hot water extracts. BAX and p53 expression levels were higher (p<0.05) in AGS cells treated with goat meat extract than those of cells treated with no goat meat extract. In HT-29 cells, the protein expression levels of BAX, p53, and p21 were higher (p<0.05) in the cells treated with goat meat extract than those of cells not treated with goat meat extract. In dexamethasone-treated C2C12 cells, goat meat extract treatment lower (p<0.05) the expression of Atrogin-1 and lower (p<0.05) the expression of MAFbx and MuRF-1. The results of the present study indicate that goat meat extracts have α-glucosidase inhibitory activity in vitro. In addition, apoptosis was induced in AGS cells and HT-29 cells treated with goat meat extract, and anti-muscular atrophy activity was also observed in C2C12 cells treated with goat meat extract.

In Vitro α-Amylase, α-Glucosidase, Pancreatic Lipase, Xanthine Oxidase Inhibiting Activity of Agaricus bisporus Extracts

In this study, the α-amylase inhibitory activity, α-glucosidase inhibitory activity, pancreatic lipase inhibitory activity, and Xanthine Oxidase inhibitory activity of the fruiting body extracts of 5 varieties of Agaricus bisporus (AB) were confirmed. First, the α-amylase inhibitory activity of AB12, AB13, AB18, AB34, and AB40 methanol extracts was lower than that of acarbose, a positive control, in all concentration ranges. The α-glucosidase inhibitory activity of the AB40, AB13, and AB12 methanol extracts at the extract concentration of 1.0 mg/mL was 80.5%, 81.3%, and 78.5%, respectively, similar to that of acarbose, a positive control. The pancreatic lipase inhibitory activity of the methanol extract of Agaricus bisporus fruiting body was significantly lower than that of the positive control orlistat in the concentration range of 50 ∼ 1.000 (mg/mL). The Xanthine Oxidase inhibitory activity was 0.5 ∼ 8.0 mg/mL of each extract, which was significantly lower than that of the positive control allopurinol in the same concentration range. However, the Xanthine Oxidase inhibitory activity of AB13 and AB40 at 8.0 mg/mL was about 70%, which was higher than that of other mushrooms. In conclusion, five kinds of Agaricus bisporus fruiting bodies seem to have inhibitory effects on enzymes such as α-amylase, α-glucosidase, pancreatic lipase, and Xanthine Oxidase that degrade starch and protein. In particular, it has an inhibitory effect and a reduction effect on xanthine oxidase that causes gout, so it is expected that it can be developed and used as a food or health supplement with health functional properties through future research.

Two new isoflavones from the roots of Sophora tonkinensis

Two new isoflavones (1 and 2), as well as eight known ones were isolated from the roots of Sophora tonkinensis Gagnep. Compound 1 represents an unprecedented polymerization pattern constructed by isoflavone and cytisine. Their structures were elucidated by comprehensive spectroscopic data analysis, combined with ECD calculations. Compound 1 displayed significant anti-tobacco mosaic virus (TMV) activity compared with the positive control ningnanmycin. Moreover, compound 6 exhibited potent α-glucosidase inhibitory activity with IC₅₀ value of 47.4 mg/L.

Metabolomics analysis of differential chemical constituents and α-glucosidase inhibiting activity of Phyllanthus urinaria L. root, stem, leaf and fruit

The differential chemical constituents of the different Phyllanthus urinaria L. (PUL) parts were investigated by UPLC/Q-TOF MS-based metabolomics. A total of 69 compounds were tentatively identified in the whole plant extract and 35 of them were common to root, stem, leaf and fruit parts. And four compounds were selected as biomarkers for leaves, fruits, stems and roots, respectively. The four PUL parts all had good α-glucosidase inhibitory activities and the activities of fruit, root and stem extracts were about fivefold higher than the leaf part. The hierarchical cluster analysis and heat map were used to explore the relationship between the α-glucosidase inhibitory activities and chemical constituent differences of four PUL parts.

Alkaloids and Styryl lactones from Goniothalamus ridleyi King and Their α-Glucosidase Inhibitory Activity

Gonioridleylactam (1), a new compound, is a unique dimeric aristolactam isolated from the EtOAc extract of the twigs of Goniothalamus ridleyi King. The structure of gonioridleylactam (1) consists of two different aristolactams linked together with two methylenedioxy bridges at C-3/C-3' and C-4/C-4', generating a ten-membered ring of [1,3,6,8]tetraoxecine. A new natural product, gonioridleyindole (3-hydroxymethyl-1-methyl-1H-benz[f]indole-4,9-dione, 2), together with eight known compounds (3-10) were also isolated from this plant. Their structures were extensively characterized by spectroscopic methods and comparisons were made with the literature. Compounds 1-4, 7, and 9 were evaluated for their α-glucosidase inhibitory activity. Of these, 3,5-demethoxypiperolide (7) displayed the highest α-glucosidase inhibitory activity, with an IC₅₀ value of 1.25 µM.

Scabiosa atropurpurea: A rich source of iridoids with α-glucosidase inhibitory activity evaluated by in vitro and in silico studies

Scabiosa atropurpurea L. subsp. maritima (L.) Arc. (Caprifoliaceae) is a plant widely distributed in the Mediterranean region and represented by 32 taxa in the flora of Turkey. In the present study, an in-depth phytochemical investigation of S. atropurpurea methanol extract of the whole plant was carried out using a combination of LC-ESI-FT-MS and NMR analysis. This approach allowed the isolation and structural elucidation of 28 compounds: 17 iridoids, 7 flavonoids, and 4 phenolic acids. Among these compounds, three previously unreported iridoids named secologanin-methyl-hemiacetal, atropurpurin A, and atropurpurin B were identified. The methanol extract of S. atropurpurea was assayed for its antioxidant and antihyperglycemic activity, showing a potent α-glucosidase inhibitory activity (IC₅₀ = 100 μg/mL), higher than that exerted by acarbose (IC₅₀ = 196 μg/mL), used as the positive control. Thus, the most abundant iridoids were selected to be tested for their antihyperglycemic activity, and molecular docking experiments were carried out to assess the possibility for selected compounds to form complexes with α-glucosidase enzyme active site.

Polyisoprenylated benzophenones and xanthones from the pericarp of Garcinia planchonii Pierre

Two new polyisoprenylated benzophenones, planchoniones A (1) and B (2), together with two known benzophenones (3, 4) and six known xanthones (5-10), were isolated from an ethyl acetate extract of the pericarp of Garcinia planchonii Pierre. Their structures were established using spectroscopic methods, mainly 1D and 2D NMR. The four benzophenones were evaluated for their cytotoxicity against MCF-7 human breast cancer cells, and showed almost no activity. Meanwhile, compounds 5-10 were investigated for their inhibitory effects towards α-glucosidase, and γ-mangostin (5) exhibited the most remarkable effect with IC₅₀ value of 15.3 ± 0.9 µM (compared with acarbose, IC₅₀ = 224.9 ± 3.6 µM).

Individual or mixing extrusion of Tartary buckwheat and adzuki bean: Effect on quality properties and starch digestibility of instant powder

Introduction

Tartary buckwheat and adzuki bean, which are classified as coarse grain, has attracted increasing attention as potential functional ingredient or food source because of their high levels of bioactive components and various health benefits.

Methods

This work investigated the effect of two different extrusion modes including individual extrusion and mixing extrusion on the phytochemical compositions, physicochemical properties and in vitro starch digestibility of instant powder which consists mainly of Tartary buckwheat and adzuki bean flour.

Results

Compared to mixing extrusion, instant powder obtained with individual extrusion retained higher levels of protein, resistant starch, polyphenols, flavonoids and lower gelatinization degree and estimated glycemic index. The α-glucosidase inhibitory activity (35.45%) of the instant powder obtained with individual extrusion was stronger than that obtained with mixing extrusion (26.58%). Lower levels of digestibility (39.65%) and slower digestion rate coefficient (0.25 min^-1) were observed in the instant powder obtained with individual extrusion than in mixing extrusion (50.40%, 0.40 min^-1) by logarithm-of-slope analysis. Moreover, two extrusion modes had no significant impact on the sensory quality of instant powder. Correlation analysis showed that the flavonoids were significantly correlated with physicochemical properties and starch digestibility of the instant powder.

Discussion

These findings suggest that the instant powder obtained with individual extrusion could be used as an ideal functional food resource with anti-diabetic potential.

Cassane diterpenoids with α-glucosidase inhibitory activity from the fruits of Pterolobium macropterum

Two new cassane diterpenoids, 14β-hydroxycassa-11(12),13(15)-dien-12,16-olide (1) and 6'-acetoxypterolobirin B (3), together with a known analogue, identified as 12α,14β-dihydroxycassa-13(15)-en-12,16-olide (2), were isolated from the fruits of Pterolobium macropterum. Compound 1 is a cassane diterpenoid with a Δ¹¹⁽¹²⁾ double bond conjugated with an α,β-butenolide-type, whereas compound 3 is a dimeric caged cassane diterpenoid with unique 6/6/6/6/6/5/6/6/6 nonacyclic ring system. The structures of 1 and 3 were characterized by extensive spectroscopic analysis combined with computational ECD analyses. The α-glucosidase inhibitory activity of isolated compounds was evaluated, and compounds 1 and 3 showed significant α-glucosidase inhibitory activity with IC₅₀ values of 66 and 44 μM.

Chemical constituents from aerial parts of Scoparia dulcis

Objective

To study the chemical constituents from the aerial parts of Scoparia dulcis.

Methods

Various chromatographic techniques were used to separate the constituents and their structures were elucidated using spectroscopic methods and by comparing their data to those reported in the literatures. The α-glucosidase inhibitory activity assay was used to identify potential α-glucosidase inhibitors.

Results

Nine compounds were isolated from the aerial parts of S. dulcis. Their structures were identified as Scoparic zolone (1), (2S)-2,7-dihydroxy-2H-1,4-benzoxazin-3(4H)-one (2), (2R)-7-hydroxy-2H-1,4-benzoxazin-3(4H)-one-2-O-β-d-glucopyranoside (3), (2R)-7-methoxy-2H-1,4-benzoxazin-3(4H)-one-2-O-β-d-glucopyranoside (4), (2S)-7-hydroxy-2H-1,4-benzoxazin-3(4H)-one-2-O-β-d-glucopyranoside (5), 6-methoxy-benzoxazolin-2(3H)-one (6), 4-acetonyl-3,5-dimethoxy-p-quinol (7), zizyvoside I (8), and 3,4-dihydroxy benzeneacetic acid (9). Compound 2 showed the potent α-glucosidase inhibitory activity with an IC₅₀ value of (132.8 ± 11.5) μmol/L, which is 28-fold higher than the positive control acarbose.

Conclusion

Compound 1 is a new natural product. Compounds 2 and 9 have not been reported in Scoparia before. Compounds 3, 5, 7, 8 are isolated from Scrophulariaceae for the first time.

against Diabetic

Cydonia Oblonga Mill. is widely distributed in Turkey, Uzbekistan and China and commonly used by the food industry to produce jam, jelly and candies. The aim of this study was to investigate the in vitro antidiabetic activity and anti-diabetic mechanism of Cydonia Oblonga Mill. fruit (COMF). The chemical compositions were further characterized in COMF by UPLC-Q-Orbitrap/MS and 65 components including 22 flavonoids, 16 organic acids, 11 polyphenols, 5 amino acids, 3 pentacyclic triterpenoids and 8 other compounds were identified. The antioxidant activity by DPPH scavenging method and α-glucosidase inhibitory activity were tested. Furthermore, we detected the effects of COMF extract on the proliferation activity of HUVECs, cell viability of HUVECs under H₂O₂-induced oxidative stress, and NO production. Then, molecular docking activity and α-glucosidase inhibitory activity of seven key flavonoid components selected by bioinformatics analysis and literature in the COMF were studied. Among them, quercetin showed potent inhibitory activity, kaempferol, isorhamnetin, luteolin and apigenin demonstrated moderate inhibitory activity, while rutin and epicatechin exhibited poor inhibitory activity. Subsequently, the effects of quercetin, kaempferol, isorhamnetin, leteolin and apigenin on the gene expression levels of AKT1, IL-6 and VEGFA were verified by real-time fluorescence quantification (RT-qPCR). Molecular biology result showed that different active ingredients can significantly recover the levels of AKT1, IL-6 and VEGFA in HUVECs injured by high glucose.

ZYX-Z-16

Marine fungi can metabolize structurally diverse active components, and have become an important source of drug lead molecules. In the present study, the chemical investigation on the EtOAc extract of the fermentation broth of the marine-derived fungus Trametes sp. ZYX-Z-16 led to the isolation of eight meroterpenoids (1-8), including two undescribed ones, together with ten ergostane steroid analogues (9-18). The structures of two new spiromeroterpenoids, asnovolin H (1) and asnovolin I (2), were determined based on 1D, 2D NMR, and HRESIMS spectroscopic data along with ECD spectra calculations. All compounds were tested for antibacterial and α-glucosidase inhibitory activity. Among them, compound 12 showed definite antibacterial activities against Staphylococcus aureus ATCC 6538 (MIC 32 μg/mL) and Bacillus subtilis ATCC 6633 (MIC 16 μg/mL). In addition, compounds 9 and 10 showed superior inhibitory activity, with IC₅₀ values of 104.1 and 111.3 μM, respectively, to the positive control acarbose (304.6 μM).

Chemical Diversity and α-Glucosidase Inhibitory Activity in Needles Essential Oils of Four Pinus Species from Northwestern Himalaya, India

This work describes the study of the chemical profiling and α-glucosidase inhibitory activity of essential oils (EOs) from four Pinus species (P. wallichiana, P. patula, P. roxburghii and P. gerardiana). The identification and quantification of EOs metabolites were performed by GC/MS, GC-FID and ¹³ C-NMR. The needles of P. wallichiana and P. gerardiana presented the highest oil yields (0.35 % and 0.36 %, respectively). Twenty-four constituents were characterized in among samples exhibiting 93.8-97.7 % of the total EOs. The components and yields of the targeted samples were varied according to the species. Major components of the oils were α-pinene (20.5-34.1 %), β-pinene (1.4-53.0 %), δ-3-carene (0.2-47.0 %), limonene (1.7-13.4 %), β-phellandrene (0.2-23.4 %), β-myrcene (1.8-7.2 %) and α-terpinolene (0.6-7.9 %). The extracted EOs showed strong α-glucosidase inhibitory activity, which was close to the positive control, acarbose. This study showed that the EOs of Pinus species may be used as natural antidiabetic.

Influence of Degree of Polymerization of Low-Molecular-Weight Chitosan Oligosaccharides on the α-Glucosidase Inhibition

Chitosan oligosaccharide (COS) is a bioactive compound derived from marine by-products. COS consumption has been demonstrated to lower the risk of diabetes. However, there are limited data on the inhibitory effect of low-molecular-weight COSs with different degrees of polymerization (DP) on α-glucosidase. This study investigates the α-glucosidase inhibitory activity of two low-molecular-weight COSs, i.e., S-TU-COS with DP2−4 and L-TU-COS with DP2−5, both of which have different molecular weight distributions. The inhibition constants of the inhibitors binding to free enzymes (Ki) and an enzyme−substrate complex (Kii) were investigated to elucidate the inhibitory mechanism of COSs with different chain lengths. The kinetic inhibition model of S-TU-COS showed non-completive inhibition results which are close to the uncompetitive inhibition results with Ki and Kii values of 3.34 mM and 2.94 mM, respectively. In contrast, L-TU-COS showed uncompetitive inhibition with a Kii value of 5.84 mM. With this behavior, the IC50 values of S-TU-COS and L-TU-COS decreased from 12.54 to 11.84 mM and 20.42 to 17.75 mM, respectively, with an increasing substrate concentration from 0.075 to 0.3 mM. This suggests that S-TU-COS is a more potent inhibitor, and the different DP of COS may cause significantly different inhibition (p < 0.05) on the α-glucosidase activity. This research may provide new insights into the production of a COS with a suitable profile for antidiabetic activity.

Phytochemical properties and health benefits of pregelatinized Tartary buckwheat flour under different extrusion conditions

This work investigated the phytochemical properties and health benefits of Tartary buckwheat flour obtained with different extrusion conditions including high, medium, and low temperature. Extrusion significantly decreased the fat content and changed the original color of Tartary buckwheat flour. The contents of protein, total flavonoids, and D-chiro-inositol were affected by the extrusion temperature and moisture. Extrusion significantly decreased the total flavonoids and flavonoid glycosides contents, while it significantly increased aglycones. Compared to native Tartary buckwheat flour and pregelatinization Tartary buckwheat flour obtained with traditional extrusion processing technology, the pregelatinization Tartary buckwheat flour obtained with improved extrusion processing technology contained higher aglycones and lower flavonoid glycosides, which had stronger antioxidant capacity, α-glucosidase inhibitory activity and relatively mild α-amylase inhibitory activity. Correlation analysis proved that the aglycone content was positively correlated with antioxidant and α-glucosidase inhibitory activities. These findings indicate that the pregelatinization Tartary buckwheat flour obtained with improved extrusion processing technology could be used as an ideal functional food resource with antioxidant and anti-diabetic potential.

Inhibitory potential of phenolic compounds of Thai colored rice (Oryza sativa L.) against α-glucosidase and α-amylase through in vitro and in silico studies

BACKGROUND

This study investigated the inhibitory efficiency of phenolic compounds content methyl vanillate, syringic acid and vanillic acid against α-glucosidase and α-amylase. The phenolic compound contents of 10 Thai colored rice cultivars were also determined, and the relationship between the inhibitory efficiency of colored rice extract with methyl vanillate, syringic acid and vanillic acid was evaluated.

RESULTS

The results revealed that the inhibition efficiency of methyl vanillate, syringic acid and vanillic acid was higher against α-glucosidase than against α-amylase. Inhibitory activity of vanillic acid against α-glucosidase and α-amylase was highest, with IC₅₀ of 0.100 ± 0.01 and 0.130 ± 0.02 mmol L^-1 , respectively. Docking study showed strong binding by three hydrogen bonds and four hydrogen bonds between vanillic acid with the amino acid in the binding site of α-glucosidase and α-amylase, respectively. Inhibition modes of these phenolic compounds were defined as a mixed type inhibition against α-glucosidase. Highest phenolic compound contents of methyl vanillate, syringic acid and vanillic acid were obtained from methanol extracts of all rice cultivars. The methanol extracts of all colored rice cultivars such as Khao Leum Pua also showed the highest inhibition potential against α-glucosidase and α-amylase. The results indicated that these phenolic compound contents were closely related to the inhibition potential of colored rice extracts against α-glucosidase and α-amylase.

CONCLUSION

Our results suggest that rice, especially colored rice cultivars, has the source of phenolic compounds. Moreover, the phenolic compounds had the greatest source of natural inhibitor against α-glucosidase and α-amylase. © 2022 Society of Chemical Industry.

Lignans and flavonoids from Cajanus cajan (L.) Millsp. and their α-glucosidase inhibitory activities

A pair of new lignan conformers (1-2), one new flavonoid glycoside (3), as well as nineteen known compounds were purified from the twigs and leaves of Cajanus cajan (L.) Millsp..The planar structures of the unknown compounds were determined via NMR and high-resolution mass spectrometry, while their absolute configurations were elucidated via comparison between their experimental and calculated electronic circular dichroism (ECD) values. All the isolated compounds were assayed for their α-glucosidase inhibitory activities. The results demonstrated that compounds 8-12, 15-16, 18-19, 21-22 had strong inhibition activities, with compound 10 (IC50 = 0.4 ± 0.21 μM) most active. The structure-activity relationships were preliminarily summarized. Enzyme kinetics showed that compounds 8, 9, 15-16, 18-19, 21-22 were non-competitive inhibitors and compounds 10-12 were anti-competitive ones.

The effect of aqueous extracts of some plants on in vitro antioxidant and antidiabetic activity of probiotic yogurt

In this study, aqueous extracts of some medicinal and aromatic plants (garlic, Turkish Oregano, rosemary, basil, and peppermint) were used in probiotic yogurt production to increase functionality of probiotic yogurt. The in vitro antidiabetic, antioxidant activity, total phenolic compound content and phenolic compounds of yogurts were evaluated during the 28 day of storage period. Yogurt sample with Turkish Oregano had the highest α-amylase and α-glucosidase inhibitory activity. A strong correlation was found between total phenolic compound content and antioxidant activity (r = 0.84) and between total phenolic compounds content and α-amylase inhibitory activity (r = 0.82). In conclusion, it can be said that the total phenolic compound content and in vitro antioxidant and antidiabetic activities of probiotic yogurt could be increased by adding aqueous extracts of some plants.

Antidiabetic lanostane triterpenoids from the fruiting bodies of Ganoderma weberianum

Eight previously undescribed lanostane triterpenoids, ganodeweberiols A ∼ H (1-8), together with eighteen known compounds (9-26), were isolated from the fruiting bodies of Ganoderma weberianum. The structures and absolute configurations of the new compounds were determined by extensive spectroscopic analysis, as well as NMR chemical shifts and electronic circular dichroism (ECD) calculations. Compounds 2, 7, 12, and 14 showed significant α-glucosidase inhibitory activity with IC₅₀ values ranging from 35.3 μM ∼ 223.4 μM compared to the positive control acarbose (IC₅₀, 304.6 μM). Kinetic study indicated that the most potent compound 12 was a mixed type inhibitor for α-glucosidase. Molecular docking simulation revealed the interactions of 12 with α-glucosidase. Additionally, Compounds 3 and 6 inhibited glucagon-induced hepatic glucose production in HepG2 cells with EC₅₀ values of 42.0 and 85.9 μM, respectively. Further study revealed that compounds 3 and 6 inhibited hepatic glucose production by suppression glucagon-induced cAMP accumulation. Moreover, compounds 3 and 26 were active against HeLa cell line with IC₅₀ values of 17.0 and 6.8 μM, respectively.

[Chemical constituents with α-glucosidase inhibitory activities from seeds of Morinda citrifolia (Noni)]

The present study investigated the chemical constituents and inhibitory activities against α-glucosidase from the seeds of Morinda citrifolia(Noni) by the chromatographic technique and semi-preparative HPLC.Fifteen compounds were isolated from the ethyl acetate extract of the seeds, and their structures were identified on the basis of physiochemical characteristics and spectroscopic data as(9S,2E,4Z,7Z)-9-hydroxydeca-2,4,7-trienoic acid(1), azelaic acid(2), scopoletin(3), ursolic acid(4), quercetin(5), cyclo-(L-Leu-L-Ile)(6), cyclo-(L-Phe-L-Ile)(7), cyclo-(L-Phe-L-Val)(8), cyclo-(L-Leu-L-Val)(9), cyclo-(L-Phe-L-Leu)(10), caffeic acid(11), 3,4-dihydroxycinnamaldehyde(12), p-hydroxybenzoic acid(13), p-hydroxy-cinnamic acid(14), and p-hydroxyphenethyl alcohol(15).Among them, compound 1 was a new fatty acid and compounds 7-10 and 12 were isolated from Morinda plant in the Rubiaceae family for the first time.Compounds 1, 2 and 4-15 were isolated from the seeds of M.citrifolia(Noni) for the first time.All isolated compounds were evaluated for the inhibitory activities against α-glucosidase and compounds 3-5 showed potential inhibitory activity with IC_(50) values of 160, 133, and 120 μmol·L~(-1), respectively.

Terpenoids with α-glucosidase inhibitory activity from Rhododendron minutiflorum Hu

Five undescribed triterpenoids, two unusual omphalane-type sesquiterpenoids together with twenty-five known compounds were isolated from the leaves and stems of Rhododendron minutiflorum Hu. The absolute configurations of 1-3 and 6 were established by single-crystal X-ray diffraction analysis and electronic circular dichroism (ECD). Compounds 6-7 feature the rare omphalane-type sesquiterpene skeleton and are verified by single-crystal X-ray diffraction analysis for the first time. In the biological activity assay, most of the triterpenoids have different degrees of inhibitory effects on α-glucosidase, with IC₅₀ values ranging from 6.97 to 229.3 μM (the positive control drug acarbose has an IC₅₀ value of 3.07 × 10^-3 μM). Structure and activity relationship (SAR) study reveals that the oxidation degrees of C-3, C-8, or C-11 to C-13 of the ursane-type triterpenoid influence the inhibitory activity dramatically.

Phenolic profiles, antioxidant activity and inhibition of digestive enzymes of water caltrop pericarps

BACKGROUND

Water caltrop (Trapa natans L.) is widely cultivated as a popular vegetable or fruit in Asian countries. In China, water caltrop pericarp is also used as a functional food to treat metabolic syndrome. However, the profiling of bioactive substances and their pharmacological activities in different water caltrop varieties remains to be investigated. In the present study, three varieties of water caltrop pericarps collected from 13 origins in China were analyzed for their phenolic substances. To investigate the pharmacological activities, samples were tested for their free radical scavenging capacity and inhibitory potency against α-glucosidase and pancreatic lipase.

RESULTS

In total, 46 phenolic compounds were identified in the ethanol extract of water caltrop pericarp using a liquid chromatography-quadrupole time of flight-tandem mass spectrometry method, most of which were hydrolyzable tannins. Two cultivated varieties samples exhibited a relatively higher phenolic content and stronger antioxidant and inhibitory activities against α-glucosidase and pancreatic lipase compared to those from the wild variety. Correlation analysis between phenolic contents and biological activities suggested that phenolic compounds exhibited potential free radical scavenging capacity, α-glucosidase and pancreatic lipase inhibitory activities.

CONCLUSION

It is concluded that the phenolic compounds of water caltrop pericarp are promising sources of natural antioxidants, α-glucosidase and pancreatic lipase inhibitors. © 2021 Society of Chemical Industry.

Two lanostane triterpenoids with α-glucosidase inhibitory activity from the fruiting bodies of Ganoderma weberianum

A new oxygenated lanostane-type triterpenoid, 20S,24S-epoxy-lanosta-7,9(11)-dien-3β,15α,25R,26-tetraol (1), together with three known compounds (2-4) were isolated from the fruiting bodies of Ganoderma weberianum. Extensive NMR spectrometry and HRESIMS analysis, as well as NMR and ECD calculations elucidated the structure of the new compound. 27-nor-3β-hydroxylanosta-7,9(11),23E-trien-25-one (2) showed superior α-glucosidase inhibitory activity with IC₅₀ value of 122.1 μM to that of positive control acarbose (304.6 μM).

α-Glucosidase inhibitory and α-amylase inhibitory activities of compounds isolated from Uvaria rufa Blume

A new C-benzylated flavone, uvariaruflavone (1), along with 13 known compounds (2-14) were isolated from the twig and leaf extracts of Uvaria rufa Blume. Their structures were established by extensive spectroscopic methods. Flavones (5-8) and cyclohexene (10) were isolated from U. rufa for the first time. Most of the isolated compounds were evaluated for their α-glucosidase and α-amylase inhibitory activities. Of these, uvariaruflavone (1) showed the highest α-glucosidase inhibitory activity with an IC₅₀ value of 44.3 µM, while ferrudiol (12) displayed the highest α-amylase inhibitory activity with an IC₅₀ value of 73.5 µM.

α-Glucosidase Inhibitory Activity of Fermented Okara Broth Started with the Strain Bacillus amyloliquefaciens SY07

In this work, a new strain of Bacillus amyloliquefaciens SY07 isolated from a traditional fermented soybean food was reported to possess remarkable α-glucosidase inhibitor-producing ability. Different culture media were applied for the proliferation of B. amyloliquefaciens SY07, and it was found that fermented okara broth presented the highest α-glucosidase inhibitory activity, while Luria-Bertani medium showed a negative effect. The extract from fermented okara broth acted in a dose-dependent manner to inhibit α-glucosidase activity, with an IC50 value of 0.454 mg/mL, and main inhibitors in the fermentation extract presented a reversible, uncompetitive pattern according to Lineweaver-Burk plots. Moreover, 1-deoxynojirimycin, a recognized α-glucosidase inhibitor, was found in the extract. Results indicated that B. amyloliquefaciens SY07 could utilize okara, a by-product from the soy processing industry, to generate α-glucosidase inhibitors effectively, and be regarded as a novel excellent microbial candidate for safe, economical production of potential functional foods or ingredients with hypoglycemic effect.

Paresordin A, a new diphenyl cyclic peroxide from the lichen Parmotrema praesorediosum

From the lichen Parmotrema praesorediosum, one new diphenyl peroxide, named praesordin A (1), together with four depsidones, including virensic acid (2), protocetraric acid (3), 8'-O-methylprotocetraric acid (4), and furfuric acid (5) were purified. Their structures were chacracterized using extensive HR-ESI-MS and NMR spectroscopic methods. The isolated compounds (2-5) possessed stronger α-glucosidase inhibitory activity (IC₅₀ = 43.7-110.1 μM) than the standard drug acarbose (IC₅₀ = 214.5 μM).