Flavonoids as potential agents in the management of type 2 diabetes through the modulation of α-amylase and α-glucosidase activity: a review

Efficient Screening of α-Glucosidase Inhibitory Peptides From Seahorse Through the Innovative Joint Technique: De Novo Sequencing and Parallel SPOT Synthesis

In this research, de novo sequencing was innovatively combined with parallel SPOT synthesis for the efficient screening of biological peptides from TCM or seafood: seahorse with synergistic antioxidant and α-glucosidase inhibitory activities, which is promising for postprandial hyperglycemia management. Gastrointestinal digestion mimic and de novo sequencing were sequentially carried out to predict new peptides from seahorse. After bioinformatic analysis using Peptide Ranker, 82 peptides were eventually synthesized by efficient parallel SPOT technique, and Ser-Val-Try-Leu-Gly-Gly-Ser-Leu-Leu (SVWLGGSLL) was screened out as the most efficient peptide with synergistic antioxidant (DPPH radical scavenging activity of 77%) and α-glucosidase inhibitory activity (IC50 = 0.36 mM). Molecular docking was further carried out to illustrate the favorable ligand-receptor interactions formed such as hydrogen bonding and van der Waals force with low binding free energy of -7.8 kcal/mol. Moreover, pharmacokinetic analysis indicated that SVWLGGSLL was unrelated to toxicity with the advantage of gastrointestinal stability.

Phytochemical Profiling and Biological Evaluation of Dianthus sylvestris subsp. aristidis: A Chromatographic and Mass Spectrometry Approach to Uncovering Bioactive Metabolites for Dermatological and Metabolic Disorder Management

Background/Objectives: This study provides the first comprehensive phytochemical composition and biological evaluation of Dianthus sylvestris subsp. aristidis (Batt.) Greuter & Burdet, a plant endemic to Algeria with unexplored pharmacological potential. The objective is to identify novel bioactive metabolites in the plant's extracts and assess their potential applications for skincare and metabolic disorder management, addressing gaps in the current understanding of its medicinal value. Methods: Liquid chromatography coupled with electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) profiling was used to analyze the hydromethanolic (HMeOH) leaf extract and identify bioactive compounds. The biological activities of HMeOH, ethyl acetate (EtOAc), and butanolic (n-BuOH) extracts were tested for cytotoxicity using the brine shrimp lethality test, photoprotective potential by calculating the sun protection factor (SPF), and enzymatic inhibitory activities against alpha-amylase, urease, and tyrosinase. Results: The LC-ESI-MS/MS profiling of the MeOH extract identified 22 bioactive compounds, including phenolic acids and flavonoids, some of which have not been previously reported in this species. Cytotoxicity tests showed that all extracts were non-toxic (half-lethal concentration (LC50) > 100 micrograms per milliliter). The SPF values indicated significant photoprotective potential, with EtOAc (SPF = 45.19 ± 0.73) and n-BuOH (SPF = 43.81 ± 0.59) extracts showing high sun protection activity. The n-BuOH extract exhibited strong alpha-amylase inhibitory activity (half-maximal inhibitory concentration (IC50) = 307.08 micrograms per milliliter), surpassing the standard acarbose (IC50 = 3650.93 micrograms per milliliter), suggesting potential applications in diabetes management. Conclusions: Dianthus sylvestris subsp. aristidis demonstrates significant pharmacological potential as a source of bioactive secondary metabolites for skincare and metabolic disorder management. These findings provide new insights into the plant's therapeutic potential and set a foundation for future pharmacological and clinical investigations.

A Comprehensive Review of Metabolic Dysfunction-Associated Steatotic Liver Disease: Its Mechanistic Development Focusing on Methylglyoxal and Counterbalancing Treatment Strategies

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a multifactorial disorder characterized by excessive lipid accumulation in the liver which dysregulates the organ's function. The key contributor to MASLD development is insulin resistance (IR) which affects many organs (including adipose tissue, skeletal muscles, and the liver), whereas the molecular background is associated with oxidative, nitrosative, and carbonyl stress. Among molecules responsible for carbonyl stress effects, methylglyoxal (MGO) seems to play a major pathological function. MGO-a by-product of glycolysis, fructolysis, and lipolysis (from glycerol and fatty acids-derived ketone bodies)-is implicated in hyperglycemia, hyperlipidemia, obesity, type 2 diabetes, hypertension, and cardiovascular diseases. Its causative effect in the stimulation of prooxidative and proinflammatory pathways has been well documented. Since metabolic dysregulation leading to these pathologies promotes MASLD, the role of MGO in MASLD is addressed in this review. Potential MGO participation in the mechanism of MASLD development is discussed in regard to its role in different signaling routes leading to pathological events accelerating the disorder. Moreover, treatment strategies including approved and potential therapies in MASLD are overviewed and discussed in this review. Among them, medications aimed at attenuating MGO-induced pathological processes are addressed.

Assessment of Artemisia Campestris L. Leaf Extract Effects on Polycystic Ovarian Syndrome in Rats, Antioxidant and α-Amylase Inhibition Activities

Polycystic Ovarian Syndrome (PCOS) is characterized by metabolic and reproductive dysfunction, often associated with elevated oxidative stress markers in the bloodstream. This study examines the potential antioxidant properties and α-amylase inhibitory activity of Artemisia campestris leaves extract (Artemisia campestris L) and its effects on rats with induced PCOS. Estradiol valerate was administered to ten mature Wistar rats to induce PCOS, while a control group consisted of five mature Wistar rats. Following a 16-day induction period, the rats were categorized into three groups: a control group, a PCOS group, and an experimental group receiving 200 mg/kg body weight of A. campestris L. extract orally for 15 days. Serum levels of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) were measured using the ELISA technique. The group treated with A. campestris L. extract exhibited significantly reduced LH levels compared to the PCOS group. Histomorphometric analysis indicated notable changes in follicle counts and the thickness of the theca layer. These findings suggest a significant alleviation of PCOS symptoms, potentially linked to the effects of A. campestris L. on oxidative stress pathways. Furthermore, aqueous extracts of A. campestris L. displayed potent in vitro inhibition of α-amylase, with an IC50 value of 2.418 μg/mL.

A comparative study on the bioactivities and chemical compositions of Dancong summer tea and Anhua dark tea: Excavation of glycolipid-lowering functional factors

Drinking tea is beneficial to reduce the incidence of obesity. Unlike Fuzhuan brick tea (DT, a typical dark tea) widely reported to have good glycolipid-lowering activity (GLA), there is little information on GLA of Dancong summer tea (OT, a typical oolong tea). A comparative study on GLA and chemical compositions of OT and DT was systematically conducted. The results showed that OT had advantages in high content of polyphenols, leading to its better GLA including glycolipid digestion enzyme inhibitory activity and cholesterol micellar solubility inhibition activity than DT's. A total of 21 compounds mainly including catechins, flavonoids, phenolic acids and phenylpropanoids were screened as the key differentially active micromolecules (KDAM) by UPLC-QTOF-MS/MS-based untargeted metabolomic analysis combined with multivariate analysis, which resulted in the difference of GLA between OT and DT. Moreover, the high affinity capacity and interaction mode between KDAM with α-glucosidase/α-amylase/pancreatic lipase/cholesterol esterase were validated by molecular docking. Although the accumulation of polyphenols makes OT has a poor flavor as a beverage, our research demonstrated that OT with high content of polyphenols could be used in functional foods to facilitate the prevention of obesity.

Screening for Safe and Efficient Monascus Strains with Functions of Lowering Blood Lipids, Blood Glucose, and Blood Pressure

Monascus is a fungus widely used in food fermentation. This study employed microbial technology, combined with microscopic morphological observations and ITS sequence analysis, to isolate, purify, and identify 10 strains of red yeast mold from various Monascus products. After the HPLC detection of metabolic products, the M8 strain containing the toxic substance citrinin was excluded. Using the EWM-TOPSIS model, the remaining nine safe Monascus strains were evaluated for their inhibitory activities against pancreatic lipase, α-glucosidase, α-amylase, and the angiotensin-converting enzyme. The M2 strain with the highest comprehensive scores for lowering blood sugar, blood lipids, and blood pressure was selected. Its fermentation product at a concentration of 3 mg/mL had inhibition rates of 96.938%, 81.903%, and 72.215%, respectively. The contents of the blood lipid-lowering active substance Monacolin K and the blood sugar and blood pressure-lowering active substance GABA were 18.078 mg/g and 5.137 mg/g, respectively. This strain can be utilized for the biosynthesis of important active substances such as Monacolin K and GABA, as well as for the fermentation production of safe and effective functional foods to address health issues like high blood lipids, high blood sugar, and high blood pressure in people. This study also provides insights into the use of natural fungi to produce healthy foods for combating chronic diseases in humans.

Clinical features of pneumatosis intestinalis induced by alpha- glucosidase inhibitor in patients with type 2 diabetes mellitus: a single center retrospective study

Purpose

Pneumatosis intestinalis (PI) is a rare but significant side effect associated with the use of alpha-glucosidase inhibitor (αGI) in the treatment of diabetes. This study aims to analyze the clinical features of PI induced by αGIs in patients with type 2 diabetes mellitus.

Methods

We conducted a retrospective analysis of patients diagnosed with PI between January 2018 and December 2023. Data collected included demographic characteristics, clinical symptoms and signs, laboratory findings, imaging results, endoscopic manifestations, treatments, and outcomes. Clinical characteristics were compared between patients who used acarbose and those who did not.

Results

A total of 48 patients with PI were included in the study, of whom 22 had used acarbose and 26 had not. The acarbose taken group was significantly older than the acarbose untaken group. Additionally, the prevalence of coronary heart disease and hypertension was markedly higher in patients taking acarbose. Importantly, total bilirubin levels were lower in those with PI who were on acarbose therapy.

Conclusion

Our findings highlight the need for increased vigilance regarding the potential development of PI in older diabetic patients with cardiovascular conditions following αGI administration. Timely intervention is crucial to prevent adverse outcomes. This study offers valuable insights for the future management of αGI in diabetes treatment.

Flavonoids and their metal complexes as potential agents for diabetes mellitus with future perspectives

Type 2 diabetes mellitus (T2DM) is a global health burden, with hyperglycemia as the main hallmark. This review commences with a concise overview of the intricate mechanisms underlying glucose uptake and utilization in organisms. Notably, we emphasize that T2DM management strategies pivot on delaying carbohydrate digestion, augmenting insulin secretion, and enhancing insulin sensitivity in target tissues. Unfortunately, the drugs currently available in the market for the treatment of T2DM have unpleasant side effects, spurring an urgent quest for safer and more efficacious alternatives. Flavonoids, emerging as a promising class of bioactive compounds derived from plants, offer a multi-faceted approach to diabetes treatment. Specifically, they potently inhibit enzymes such as α-amylase, α-glucosidase, dipeptidyl peptidase-4 (DPP-4), glycogen phosphorylase (GP) and protein-tyrosine phosphatase-1B (PTP1B). Through an in-depth analysis, this review not only summarizes these inhibitory actions but also establishes the structure-activity relationship (SAR), providing a blueprint for rational drug design. However, the clinical translation of flavonoids has been hampered by their suboptimal water solubility and bioavailability, attributable to the characteristic carbonyl and hydroxyl groups. Ingeniously, this chemical quirk has been harnessed to engineer metal chelates, which exhibit enhanced pharmacokinetic profiles. Herein, we offer an exhaustive overview of the latest advancements in flavonoid metal complexes research, spotlighting their potential as next-generation diabetes therapeutics. Available data are poised to galvanize the development of novel flavonoid derivatives, be it as potent drugs or functional foods, for combating T2DM.

Natural products targeting AMPK signaling pathway therapy, diabetes mellitus and its complications

Diabetes mellitus (DM) ranks among the most prevalent chronic metabolic diseases, characterized primarily by a persistent elevation in blood glucose levels. This condition typically stems from either insufficient insulin secretion or a functional defect in the insulin itself. Clinically, diabetes is primarily classified into type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM), with T2DM comprising nearly 90% of all diagnosed cases. Notably, the global incidence of T2DM has surged dramatically over recent decades. The adenylate-activated protein kinase (AMPK) signaling pathway is crucial in regulating cellular energy metabolism, marking it as a significant therapeutic target for diabetes and related complications. Natural products, characterized by their diverse origins, multifaceted bioactivities, and relative safety, hold considerable promise in modulating the AMPK pathway. This review article explores the advances in research on natural products that target the AMPK signaling pathway, aiming to inform the development of innovative antidiabetic therapies.

BuZhong YiQi Formula Alleviates Postprandial Hyperglycemia in T2DM Rats by Inhibiting α-Amylase and α-Glucosidase In Vitro and In Vivo

Background/Objectives: BuZhong YiQi Formula (BZYQF) can alleviate type 2 diabetes mellitus (T2DM). However, its efficacy in managing postprandial hyperglycemia in T2DM needs to be further confirmed, and its underlying mechanism and pharmacodynamic material basis have not been sufficiently investigated. Methods: A T2DM rat model was induced to measure postprandial glycemic responses following glucose and starch ingestion. In vitro assays of enzymatic inhibition and the kinetic mode were performed to evaluate the inhibitory effect of BZYQF on α-amylase and α-glucosidase activities. The main constituent contents of BZYQF in a simulated digestion assay were measured to screen the active constituents in BZYQF against α-amylase and α-glucosidase activities via Pearson correlation and multiple linear regression analyses. Finally, the total flavonoids were purified from BZYQF to perform in vitro activity validation, and the flavonoid constituent activity was verified through molecular docking. Results: In vivo assays showed that BZYQF significantly reduced the blood glucose values of CON rats but not T2DM rats after glucose ingestion, while BZYQF significantly reduced the blood glucose levels by 15 min after starch ingestion in CON and T2DM rats, with more significant decreases in blood glucose levels in T2DM rats. In vitro enzymatic assays showed that BZYQF could inhibit the activities of α-amylase and α-glucosidase in competitive and non-competitive modes and in an uncompetitive mode, respectively. Furthermore, BZYQF showed a stronger inhibitory effect on α-glucosidase activity than on α-amylase activity. Simulated digestion showed that simulated gastric fluid and intestinal fluid changed the main constituent contents of BZYQF and their inhibition rates against α-amylase and α-glucosidase activities, and similar results were rarely found in simulated salivary fluid. Pearson correlation and multiple linear regression analyses revealed that the total flavonoids were the active constituents in BZYQF inhibiting α-amylase and α-glycosidase activities. This result was verified by examining the total flavonoids purified from BZYQF. A total of 1909 compounds were identified in BZYQF using UPLC-MS/MS, among which flavones were the most abundant and consisted of 467 flavonoids. Molecular docking showed that flavonoids in BZYQF were bound to the active site of α-amylase, while they were bound to the inactive site of α-glucosidase. This result supported the results of the enzyme kinetic assay. Conclusions: BZYQF significantly alleviated postprandial hyperglycemia in T2DM rats by inhibiting α-amylase and α-glycosidase activities, in which flavonoids in BZYQF were the active constituents.

Biofortification of flavonoids in nuts along the agro-food chain for improved nutritional and health benefits, a comprehensive review and future prespectives

Flavonoids are found ubiquitous in dietary sources with potential antioxidant properties, and have received widespread attention for their health benefits. Nuts, rich in flavonoids, are popular among consumers for their crunchy flavor and nutritious content. The review summarizes studies pertaining to the diverse types and distribution of flavonoids in nuts, their potential health benefits, as well as management strategies for flavonoids accumulation and enhancement across the whole agro-food chain, including the selection of nut varieties, the suitable growing conditions, the optimal harvesting period of nuts, and appropriate post-harvest measures, such as chemical conditioning, ideal storage conditions, and post-harvest processing methods. Furthermore, associated metabolic pathways, and applied metabolic engineering to improve flavonoids´ levels in nuts are described. This review examines the application of flavonoids biofortification in nuts across the agro-food chain, exploring its potential for sustainable development in the nut flavonoids industry, and emphasizing its importance for people's diet and health.

Exploring synergistic inhibitory mechanisms of flavonoid mixtures on α-glucosidase by experimental analysis and molecular dynamics simulation

The study was the first to evaluate the synergistic interaction of luteolin + quercetin, luteolin + 3-O-methylquercetin, and quercetin + 3-O-methylquercetin mixtures on α-glucosidase and the binding mechanisms were explored using both experimental and theoretical approaches. The results showed that three flavonoid mixtures exhibited a mixed type of inhibition and demonstrated the most potent synergistic effects on α-glucosidase inhibition at 6:4 ratio, with interaction index (γ) of 0.85, 0.78 and 0.73, respectively. The three mixtures had a great influence on α-glucosidase secondary structures. Molecular simulation further demonstrated that three flavonoid mixtures formed hydrophobic interactions and hydrogen bonds with amino acid residues at different sites of α-glucosidase. Collectively, luteolin + quercetin, luteolin + 3-O-methylquercetin and quercetin + 3-O-methylquercetin were found to inhibit α-glucosidase in a synergistic manner and can be potentially used for the development of hypoglycemic food products.

Investigating the antidiabetic properties of Apium graveolens extract and its inhibition of enzymes associated with hyperglycemia

BACKGROUND

Apium graveolens Linn., also known as celery, is a member of the Apiaceae family and has shown promising pharmacological properties, including diabetes. Indeed, the current investigation aimed to investigate the potential inhibitory effects of A. graveolens seed aqueous extract on the digestive enzymes involved in carbohydrate metabolism and its efficiency in reducing blood sugar levels in diabetic mice induced by streptozotocin.

METHODS

I administered oral doses of an aqueous extract from A. graveolens seeds to both normal and diabetic animals to evaluate acute toxicity and its potential antidiabetic effects. I observed the glycemia and body weight of the animals for four weeks. In vitro tests were also done to see how the seed extract affected the activities of α-amylase and α-glucosidase. Following administration of the extract, diabetic mice showed a notable reduction in blood glucose concentration. This reduction was similar to the standard metformin treatment after two and four weeks. Moreover, A. graveolens demonstrated significant inhibitory effects on α-amylase and α-glucosidase activity, with IC50 values of 840.15 ± 0.02 and 114.81 ± 0.05, respectively. At 500 mg/kg/day, histological analysis indicated degenerative alterations in pancreatic islet cells. These results indicate that the aqueous extract derived from the seeds of A. graveolens possesses promising antihyperglycemic properties in diabetic mice, along with notable inhibition of α-amylase and α-glucosidase activity. Further investigation is needed to characterize the active compounds present in A. graveolens seeds.

Polymethoxylated flavone variations and in vitro biological activities of locally cultivated Citrus varieties in China

Citrus peels are rich in polymethoxylated flavones (PMFs), which have beneficial health and pharmacological properties. In this study, the profiles, variations, and biological activities of PMFs in the peel extracts of 27 Citrus varieties (eight species) native to China were investigated. UPLC-QTOF-MS/MS analysis revealed that mandarin accumulated more diversity and higher detectable PMF contents. Wangcangzhoupigan (ZPG) possessed the highest antioxidant capacity. Gailiangcheng (GLC) and Bingtangcheng (BTC), sweet oranges showed excellent inhibitory effects against pancreatic lipase and α-glucosidase, respectively. Most citrus extracts effectively inhibited the production of ROS and pro-inflammatory cytokines, while increasing the accumulation of anti-inflammatory cytokines. In addition, Limeng (LM), Cupig-oushigan (GSG), and Yanxiwanlu (YXWL) showed anti-proliferative effects against DU145 and PC3 cancer cells. This study provides a comprehensive PMF profile and biological activities of various citrus species and will benefit future functional citrus breeding practices aimed at designing plants rich in total or specific PMFs for health benefits.

Flavonoids for gastrointestinal tract local and associated systemic effects: A review of clinical trials and future perspectives

BACKGROUND

Flavonoids are naturally occurring dietary phytochemicals with significant antioxidant effects aside from several health benefits. People often consume them in combination with other food components. Compiling data establishes a link between bioactive flavonoids and prevention of several diseases in animal models, including cardiovascular diseases, diabetes, gut dysbiosis, and metabolic dysfunction-associated steatotic liver disease (MASLD). However, numerous clinical studies have demonstrated the ineffectiveness of flavonoids contradicting rodent models, thereby challenging the validity of using flavonoids as dietary supplements.

AIM OF REVIEW

This review provides a clinical perspective to emphasize the effective roles of dietary flavonoids as well as to summarize their specific mechanisms in animals briefly.

KEY SCIENTIFIC CONCEPTS OF REVIEW

First, this review offers an in-depth elucidation of the metabolic processes of flavonoids within human, encompassing the small, large intestine, and the liver. Furthermore, the review provides a comprehensive overview of the various functions of flavonoids in the gastrointestinal tract, including hindering the breakdown and assimilation of macronutrients, such as polysaccharides and lipids, regulating gut hormone secretion as well as inhibition of mineral iron absorption. In the large intestine, an unabsorbed major portion of flavonoids interact with the gut flora leading to their biotransformation. Once absorbed and circulated in the bloodstream, bioactive flavonoids or their metabolites exert numerous beneficial systemic effects. Lastly, we examine the protective effects of flavonoids in several metabolic disorders, including endothelial dysfunction, MASLD, cardiovascular disease, obesity, hyperlipidemia, and insulin resistance. In conclusion, this review outlines the safety and future prospects of flavonoids in the field of health, especially in the prevention of metabolic syndrome (MetS).

Recent advancements in drug delivery system of flavonoids with a special emphasis on the flavanone naringenin: exploring their application in wound healing and associated processes

Numerous flavonoids have been identified in citrus fruits which show potential to cure several complex diseases. These natural polyphenolic bioactive compounds are the secondary metabolites of various plants, among which naringenin has been explored in several pre-clinical research for its beneficial role in promoting health by modulating various biochemical processes. Its antioxidant, anti-inflammatory, and anti-microbial effects have been projected toward healing of wounds. Further, its application has also been shown to regrow vascular networks, which are known to facilitate the healing of chronic wounds. Thus, the potential of naringenin to modulate various molecular pathways aids in the healing process of wounds. Considering the recent literature, an update has been attempted to present the correlation between the healing mechanisms of wounds by the application of naringenin. Furthermore, the application of naringenin is challenging because of its properties of poor solubility and limited permeability, which can be overcome by the nanotechnology platform. Thus, several nanocarriers that have been employed for the improvement of naringenin delivery are highlighted. Thereby, it can be concluded that a suitable nanocarrier of naringenin could be an effective tool in treating wounds to improve the quality of life of such patients.

Synthesis, characterization, and enzyme inhibition evaluation of sitagliptin derivatives and their metal complexes

AIMS

This study focuses on the synthesis and characterization of novel sitagliptin derivatives, aiming to develop potent, orally active anti-diabetic agents with minimal side effects for the management of type 2 diabetes mellitus. Copper (II) (SCu1-SCu9) and zinc (II) (SZn1-SZn9) metal complexes of sitagliptin-based derivatives were synthesized via a template reaction.

MATERIAL & METHOD

The synthesized complexes were comprehensively characterized using elemental analysis, FTIR, UV-Vis, 1 h NMR, and 13C NMR spectroscopy. The biological efficacy of these compounds was assessed through α-amylase and α-glucosidase enzyme inhibition assays, with molecular simulation studies providing additional confirmation of their inhibitory activity.

RESULTS

Among the tested derivatives, SD7, SD4, SD3, SD5, and SD9 demonstrated enzyme inhibition profiles comparable to the standard inhibitors. However, the metal complexes exhibited absorption challenges, which may influence their bioavailability.

CONCLUSION

These findings highlight the significant anti-diabetic potential of the synthesized compounds against targeted enzymes, establishing a foundation for their development as lead molecules in future therapeutic research.

Identification of Selected Flavonoids Extracted from Cap and Stem of Wild and Cultivated Ganoderma Species (Agaricomycetes) and Bioactivities

The objective of this study was to assess the bioactivities of flavonoids extracted from two distinct sections of the fruiting bodies of Ganoderma species. The flavonoids were extracted from the cap and stem of four Ganoderma species using a methanolic extraction method. The extraction rate, total flavonoid content, antioxidant activities, in vitro hypoglycemic effects, and antimicrobial activity of flavonoids derived from the wild and cultivated Ganoderma extracts were determined and analyzed. The findings indicated that the extract derived from cultivated black Ganoderma stem exhibited the most favorable outcomes among the four sample extracts. The lowest EC50 value of the DPPH radical scavenging assay was 36.9 μg/mL, and the extract demonstrated the highest inhibitory activity of α-glucosidase (35.88 μg/mL). However, the cap extract of the cultivated black Ganoderma demonstrated the highest inhibitory activity of α-amylase, with the IC50 value of 34.69 μg/mL. The cap extracts of the cultivated red Ganoderma exhibited the most pronounced antimicrobial activity. These findings indicate notable differences in the bioactivities of flavonoids extracted from the caps and stems of the four Ganoderma species. Consequently, the Ganoderma flavonoids have the potential to serve as potent bioactive ingredients with disease-prevention properties.

Bolanthus turcicus: a promising antidiabetic with in-vitro antioxidant, enzyme inhibitory and antiadipogenic activities

It is crucial to investigate new anti-diabetic agents and therapeutic approaches targeting molecules in potential signaling pathways for the treatment of Type 2 diabetes mellitus (T2DM). The objective of the study was to investigate the total phenolic content, antioxidant capacity, α-glucosidase, and α-amylase inhibitory activities of Bolanthus turcicus (B. turcicus), as well as their cytotoxic, anti-adipogenic, anti-diabetic, apoptotic, and anti-migration potential on adipocytes. B. turcicus samples were extracted with methanol (MeOH), ethyl acetate (EA) and aqueous (Aq) solvents. The MeOH extract had the highest phenolic content (81.14 mg GAE/g), followed by EA (74.93 mg GAE/g) and Aq (51.09 mg GAE/g). All extracts exhibited dose-dependent increases in α-glycosidase and α-amylase inhibitory activity. B. turcicus extracts showed cytotoxic effect on adipocytes with IC50 values of MeOH (141.0 µg/mL) < Aq (155.3 µg/mL) < EA (199.5 µg/mL). Furthermore, B. turcicus extracts reduced lipid droplet formation and adipocyte diameter size. All extracts altered cell morphology to resemble fibroblasts. B. turcicus extracts exhibited anti-migratory effect delaying wound healing for up to 96 h. The B. turcicus extracts showed a pro-apoptotic effects on adipocytes by increasing Caspase-3 enzyme activity and the population of DAPI-positive cell with apoptotic nuclear-morphology. B. turcicus extracts upregulated the expression of the Glut-4 gene at the mRNA, protein and intracellular level in adipocytes. In conclusion, our findings indicate that B. turcicus not only exhibits strong antioxidant properties and enzyme inhibitory activities but also exerts significant anti-adipogenic and pro-apoptotic effects in adipocytes, thereby providing a comprehensive mechanism through which it may contribute to the management of T2DM. These effects highlight the potential of B. turcicus as a therapeutic agent for improving glucose homeostasis and insulin sensitivity.

Composition, Anti-Diabetic, and Antioxidant Potential of Raphanus sativus Leaves

Limiting and/or slowing down the starch digestion process and consequently the release of glucose can be an important strategy for the prevention of type 2 diabetes (T2D). The aim of the current in vitro study was to assess the anti-diabetic and antioxidant potential of red radish leaves of the Carmen, Jutrzenka, Saxa, and Warta cultivars. In the context of anti-diabetic activity, the effect of leaves on potato starch digestion and free glucose binding, as well as inhibitory effects of leaf extracts against α-amylase and α-glucosidase and non-enzymatic glycation (AGEs) were determined. The basic chemical composition, quantitative composition of phenolic compounds, and antioxidant activity of leaves were also estimated. This study showed that all radish leaves inhibited the breakdown of potato starch and showed their ability to bind glucose. This activity was correlated with the content of hydroxycinnamic acids, protein and dietary fiber while flavones was probably responsible for glucose binding. Leaf extracts inhibited α-glucosidase activity and formation of AGEs but were practically inactive towards α-amylase. Inhibition of α-glucosidase activity was related to the content of proanthocyanidins and inhibition of AGEs formation to flavonols. These results point to radish leaves, especially the Warta and Jutrzenka cultivars, as a potential natural remedy for treating T2D.

Mechanistic in vitro study of the effect of Cucurbita moschata (Cucurbitaceae) on carbohydrate digestive enzymes

Diabetes is marked by postprandial hyperglycemia (PHG), an abnormal rise in blood glucose after meals. A key therapeutic goal to reduce PHG is the inhibition of α-amylase (αAM) and α-glucosidase (αGL), enzymes that break down carbohydrates into sugars. Cucurbita moschata has been shown to inhibit both enzymes. However, its inhibition mechanism has not been explored. This study investigated the in vitro inhibition mechanisms of αAM and αGL and conducted a metabolomic analysis of C. moschata (edible part) water-extract (CME), aiming to preliminarily identify its bioactive compounds (BCs). The inhibitory mechanisms were determined using Lineweaver-Burk plots. The BCs were identified and quantified using HPLC-QTOF-MS, employing both targeted and untargeted metabolomic approaches. CME had a significant higher effect (p < 0.05) on αAM activity than against αGL with IC50 of 28.99 and 698.42 mg/mL, respectively. The extract showed mixed and uncompetitive type inhibitions on αAM and αGL, respectively. The lowest inhibition constant (Ki) was 47.68 mg/mL on αAM activity at 20 mg/mL. Untargeted metabolic profiling by UPLC-MS-ESI-QTOF putatively identified 30 compounds in CME, such as amino acids, vitamins, phytohormones, fatty acids, cucurbitacins and phenolic acids, and flavonoids. Functional analysis of CME identified significant pathways, including pantothenate and CoA biosynthesis and phenylpropanoids, among others. The targeted analysis by UPLC-MS-ESI-QqQ allowed us to identify 12 compounds, with l-phenylalanine, p-hydroxybenzoic, and p-coumaric acid as majors. This study demonstrated the inhibitory potential of CME on αAM and αGL activities, which may be attributed to its metabolites. Thus, this plant represents a valuable source of BC against PHG. Practical Application: The research highlights that Cucurbita moschata has significant potential in managing postprandial hyperglycemia in diabetic patients by inhibiting enzymes like α-amylase and α-glucosidase. In addition, the identification of its compounds emphasizes its importance as a source of bioactive compounds. Therefore, C. moschata could be effectively utilized in the development of nutraceuticals or as an ingredient in functional foods specifically designed for postprandial hyperglycemia management. Thus, integrating C. moschata as part of the daily diet could offer patients with diabetes a natural alternative to control their blood glucose levels after eating.

Exploring plant-based alpha-glucosidase inhibitors: promising contenders for combatting type-2 diabetes

OBJECTIVE

This systematic review aimed to provide comprehensive details on the α-G inhibitory potential of various bioactive compounds derived from natural sources.

METHODS

A comprehensive literature search was conducted using various databases and search engines, including Science Direct, Google Scholar, SciFinder, Web of Science, and PubMed until May, 2023.

RESULTS AND CONCLUSIONS

The enzyme alpha-glucosidase (α-G) is found in the brush border epithelium of the small intestine and consists of duplicated glycoside hydrolase (GH31) domain. It involves the conversion of disaccharides and oligosaccharides into monosaccharides by acting on alpha (1 → 4) and (1 → 6) linked glucose residue. Once absorbed, glucose enters the bloodstream and elevates postprandial glucose, which is associated with the development of type 2 Diabetes (T2D). Epidemic obesity, cardiovascular disease, and nephropathy are linked to T2D. Traditional medicinal plants with α-G inhibitory potential are commonly used to treat T2D due to the adverse effects of currently used α-G inhibitors miglitol, acarbose, and voglibose. Various bioactive compounds derived from natural sources, including lupenone, Wilforlide A, Baicalein, Betulinic acid, Ursolic acid, Oleanolic acid, Katononic acid, Carnosol, Hypericin, Astilbin, lupeol, betulonic acid, Fagomine, Lactucaxanthin, Erythritol, GP90-1B, Procyanidins, Galangin, and vomifoliol retain α-G inhibitory potential for regulating hyperglycaemia.

Advances in microbial exopolysaccharides as α-amylase inhibitors: Effects, structure-activity relationships, and anti-diabetic effects in vivo

The rapid digestion of starch, as the main source of energy in the human diet, causes an acute increase in blood sugar levels that will affect blood glucose homeostasis. The inhibition of α-amylase activity is an effective way of reducing starch digestibility, thereby controlling postprandial glycemia. As a class of carbohydrate polymers, microbial exopolysaccharides (EPSs) have garnered widespread attention for their inhibitory effects on α-amylase, but there is a lack of comprehensive review in this area. This paper aimed to review the inhibitory activity of microbial EPSs on α-amylase and their interaction mechanisms, and the effect of microbial EPSs on lowering blood glucose levels and regulating glycolipid metabolism in vivo were also discussed. Numerous studies have reported that EPSs with α-amylase inhibition activity are primarily produced by lactic acid bacteria. Microbial EPSs with an appropriate range of molecular weight, high proportion of glucose or mannose or arabinose residues, and high uronic acid content might be acceptable to inhibit α-amylase activity. Additionally, microbial EPSs exhibited potential anti-diabetic effects in mice, reducing blood glucose levels, and regulating glycolipid metabolism and gut microbiota. The information covered in this review may enhance the development and application of EPSs in functional food and pharmaceutical research.

Multiple roles of food-derived bioactive peptides in the management of T2DM and commercial solutions: A review

Type 2 diabetes mellitus (T2DM), a disease that threatens public health worldwide and can cause a series of irreversible complications, has been a major concern. Although the treatment based on hypoglycemic drugs is effective, its side effects should not be ignored, which has led to an urgent need for developing new hypoglycemic drugs. Bioactive peptides with antidiabetic effects obtained from food proteins have become a research hotspot as they are safer and with higher specificity than traditional hypoglycemic drugs. Here, we reviewed antidiabetic peptides that have the ability to inhibit key enzymes (α-glucosidase, α-amylase, and DPP-IV) in T2DM, the hypoglycemic mechanisms and structure-activity relationships were summarized, some antidiabetic peptides that improve insulin resistance and reverse gut microbiota and their metabolites were overviewed, the bitterness of antidiabetic peptides was predicted in silico, proposed solutions to the current challenges encountered in the development of antidiabetic peptide drugs, and provided an outlook on the future focus of commercial production. It provides a reference for the application of food-derived antidiabetic peptides.

Suppression of the postprandial hyperglycemia in patients with type 2 diabetes by a raw medicinal herb powder is weakened when consumed in ordinary hard gelatin capsules: A randomized crossover clinical trial

INTRODUCTION

Contradictory claims about the efficacy of several medicinal plants to promote glycemic control in patients with type 2 diabetes mellitus (T2DM) have been explained by divergences in the administration form and by extrapolation of data obtained from healthy individuals. It is not known whether the antidiabetic effects of traditional herbal medicines are influenced by gelatin capsules. This randomized crossover trial aimed to evaluate the acute effect of a single dose of raw cinnamon consumed orally either dissolved in water as a beverage or as ordinary hard gelatin capsules on postprandial hyperglycemia (>140 mg/dL; >7.8 mmol/L) in T2DM patients elicited by a nutritionally-balanced meal providing 50 g of complex carbohydrates.

METHODS

Fasting T2DM patients (n = 19) randomly ingested a standardized meal in five experimental sessions, one alone (Control) and the other after prior intake of 3 or 6 g of crude cinnamon in the form of hard gelatin capsules or powder dissolved in water. Blood glucose was measured at fasting and at 0.25, 0.5, 0.75, 1, 1.5 and 2 hours postprandially. After each breakfast, its palatability scores for visual appeal, smell and pleasantness of taste were assessed, as well as the taste intensity sweetness, saltiness, bitterness, sourness and creaminess.

RESULTS

The intake of raw cinnamon dissolved in water, independently of the dose, decreased the meal-induced large glucose spike (peak-rise of +87 mg/dL and Δ1-hour glycemia of +79 mg/dL) and the hyperglycemic blood glucose peak. When cinnamon was taken as capsules, these anti-hyperglycemic effects were lost or significantly diminished. Raw cinnamon intake did not change time-to-peak or the 2-h post-meal glycaemia, but flattened the glycemic curve (lower iAUC) without changing the shape that is typical of T2DM patients.

CONCLUSIONS

This cinnamon's antihyperglycemic action confirms its acarbose-like property to inhibit the activities of the carbohydrate-digesting enzymes α-amylases/α-glucosidases, which is in accordance with its exceptionally high content of raw insoluble fiber. The efficacy of using raw cinnamon as a diabetes treatment strategy seems to require its intake at a specific time before/concomitantly the main hyperglycemic daily meals. Trial registration: Registro Brasileiro de Ensaios Clínicos (ReBEC), number RBR-98tx28b.

Phenolic Compositions of Different Fractions from Coffee Silver Skin and Their Antioxidant Activities and Inhibition towards Carbohydrate-Digesting Enzymes

Seeking food-derived antioxidants and inhibitors of α-glucosidase and α-amylase has been recognized as an effective way for managing diabetes. Coffee silver skin (CSS) is rich in phenolic compounds, which may be potential agents as antioxidants and for α-glucosidase and α-amylase inhibition. But whether phenolics in different forms show similar bioactivity remains unknown. In this study, phenolic compounds in CSS were extracted as free phenolics (FPs), esterified phenolics (EPs), and bound phenolics (BPs). The phenolic profiles and antioxidant activities of them were investigated. Their inhibitory effects on α-glucosidase and α-amylase were analyzed, and the inhibitory mechanisms were elucidated by molecular docking and molecular dynamic simulation. Results showed that FPs exhibited the best antioxidant ability and inhibitory effects on α-glucosidase and α-amylase. A total of 17 compounds were identified in FPs with 3-caffeoylquinic acid, 4-feruloylquinic acid, and dicaffeoylquinic acids as the dominant ones. Typical phenolics in FPs could bind to α-glucosidase and α-amylase through hydrogen bonds and form hydrophobic interaction with several key amino acid residues. In addition, 3,4-dicaffeoylquinic acid and 3-caffeoylquinic acid might be the principal components that account for the inhibitory effect of FPs on α-glucosidase. The results of this study may provide some scientific support for CSS utilization as a health-beneficial component in functional food development for type 2 diabetes mellitus management.

Antioxidants from Rubus idaeus leaves: LC-MS/MS chemical profiling, in vitro antiglycation, α-glucosidase and α-amylase inhibitory activities

The present study evaluated a range of biological activities of Rubus idaeus leaves, often considered as by-products, in relation to hyperglycemia. The antiglycation potential of this plant has not been previously reported. In this research, the methanolic leaf extract of R. idaeus was assessed for its antioxidant, enzyme inhibitory and antiglycation activities. The bioactive compounds present in the extract were screened using LC-MS/MS. Enzyme inhibitory activities were tested on α-glucosidase and α-amylase, and the antiglycation effect was investigated using BSA-fructose model. The methanolic extract showed a high polyphenolic contents (176.26 ± 2.26 mg GAE/g) and important IC50 values for DPPH (34.79 ± 2.40 µg/mL) and ABTS radical scavenging activities (49.75 ± 2.47 µg/mL). In addition, the plant leaf extract significantly inhibited hyperglycemia-related enzymes in a dose-dependent manner and demonstrated a reduction in fluorescent AGEs, fructosamine, and dicarbonyl compounds. Therefore, R. idaeus cv Maravilla could be an effective source of therapeutics for improving the healthcare outcomes of diabetic patients.

Liposomal quercetin: A promising strategy to combat hepatic insulin resistance and inflammation in type 2 diabetes mellitus

In type 2 diabetes mellitus, hepatic insulin resistance is intricately associated with oxidative stress and inflammation. Nonetheless, the lack of therapeutic interventions directly targeting hepatic dysfunction represents a notable gap in current treatment options. Flavonoids have been explored due to their potential antidiabetic effects. However, these compounds are associated with low bioavailability and high metabolization. In the present study, four flavonoids, kaempferol, quercetin, kaempferol-7-O-glucoside and quercetin-7-O-glucoside, were studied in a cellular model of hepatic insulin resistance using HepG2 cells. Quercetin was selected as the most promising flavonoid and incorporated into liposomes to enhance its therapeutic effect. Quercetin liposomes had a mean size of 0.12 µm, with an incorporation efficiency of 93 %. Quercetin liposomes exhibited increased efficacy in modulating insulin resistance. This was achieved through the modulation of Akt expression and the attenuation of inflammation, particularly via the NF-κB pathway, as well as the regulation of PGE2 and COX-2 expression. Furthermore, quercetin liposomes displayed a significant advantage over free quercetin in attenuating the production of reactive pro-oxidant species. These findings open new avenues for developing innovative therapeutic strategies to manage diabetes, emphasizing the potential of quercetin liposomes as a promising approach for targeting both hepatic insulin resistance and associated inflammation.

Thiazolidine-2,4-dione hybrids as dual alpha-amylase and alpha-glucosidase inhibitors: design, synthesis, in vitro and in vivo anti-diabetic evaluation

Twelve 3,5-disubstituted-thiazolidine-2,4-dione (TZD) hybrids were synthesized using solution phase chemistry. Continuing our previous work, nine O-modified ethyl vanillin (8a-i) derivatives were synthesized and reacted with the TZD core via Knoevenagel condensation under primary reaction conditions to obtain final derivatives 9a-i. Additionally, three isatin-TZD hybrids (11a-c) were synthesized. The intermediates and final derivatives were characterized using 1H and 13C NMR spectroscopy, and the observed chemical shifts agreed with the proposed structures. The in vitro alpha-amylase and alpha-glucosidase inhibitory evaluation of newly synthesized derivatives revealed compounds 9F and 9G as the best dual inhibitors, with IC50 values of 9.8 ± 0.047 μM for alpha-glucosidase (9F) and 5.15 ± 0.0017 μM for alpha-glucosidase (9G), 17.10 ± 0.015 μM for alpha-amylase (9F), and 9.2 ± 0.092 μM for alpha-amylase (9G). The docking analysis of synthesized compounds indicated that compounds have a higher binding affinity for alpha-glucosidase as compared to alpha-amylase, as seen from docking scores ranging from -1.202 to -5.467 (for alpha-amylase) and -4.373 to -7.300 (for alpha-glucosidase). Further, the molecules possess a high LD50 value, typically ranging from 1000 to 1600 mg kg-1 of body weight, and exhibit non-toxic properties. The in vitro cytotoxicity assay results on PANC-1 and INS-1 cells demonstrated that the compounds were devoid of significant toxicity against the tested cells. Compounds 9F and 9G showed high oral absorption, i.e., oral absorption >96%, and their molecular dynamics simulation yielded results closely aligned with the observed docking outcomes. Finally, compounds 9F and 9G were evaluated for in vivo antidiabetic assessment by the induction of diabetes in Wistar rats using streptozotocin. Molecule 9G has been identified as the most effective anti-diabetic molecule due to its ability to modulate several biochemical markers in blood plasma and tissue homogenates. The results were further confirmed by histology investigations conducted on isolated pancreas, liver, and kidney.

Evaluation of phytochemical profile, and antioxidant, antidiabetic activities of indigenous Thai fruits

Background

This research aims to explore the phenolics identification, phenolics quantification, antioxidant and potential biofunctional properties of lesser-known Thai fruits and their potency to treat type 2 diabetes mellitus (T2DM). Including, Antidesma puncticulatum, Dillenia indica, Diospyros decandra, Elaeagnus latifolia, Flacourtia indica, Garcinia dulcis, Lepisanthes fruticose, Mimusops elengi, Muntingia calabura, Phyllanthus reticulatus, Streblus asper, Syzygium cumini, Syzygium malaccense, Willughbeia edulis and Schleichera oleosa were analyzed by their phenolic and flavonoid content. These fruits have received limited scientific attention, prompting an investigation into their health benefits, particularly their relevance to diabetes management.

Methods

The study utilized methanolic crude extracts to measure phenolic and flavonoid levels. Additionally, UHPLC-DAD was utilized to identify and quantify phenolics. The methanolic extracts were assessed for antioxidant and antidiabetic abilities, including α-glucosidase and α-amylase inhibition.

Results and Conclusion

The study highlighted S. cumini as a rich source of phenolic (980.42 ± 0.89 mg GAE/g and flavonoid (3.55 ± 0.02 mg QE/g) compounds with strong antioxidant activity (IC50 by DPPH; 3.00 ± 0.01 µg/ml, IC50 by ABTS; 40 ± 0.01 µg/ml, FRAP; 898.63 ± 0.02 mg TE/ml). Additionally, S. cumini exhibited promising antidiabetic effects (S. cumini IC50; 0.13 ± 0.01 mg/ml for α-glucosidase inhibition, 3.91 ± 0.05 mg/ml for α-amylase inhibition), compared to Acarbose (IC50; 0.86 ± 0.01 mg/ml for α-glucosidase inhibition, 0.39 ± 0.05 mg/ml for α-amylase inhibition). Remarkably, compounds like catechins, gallic acid, kaempferol, and ellagic acid were identified in various quantities.This study suggests that these fruits, packed with phenolics, hold the potential to be included in an anti-diabetic diet and even pharmaceutical applications due to their health-promoting properties.

Review on the Anti-Hyperglycemic Potential of Psidium guajava and Seriphium plumosum L

The treatment and management of diabetes mellitus (DM) with conventional therapies, such as insulin injections and oral hypoglycemic agents, present significant challenges due to their side effects and burdensome administration. Therapies often manage symptoms rather than addressing insulin regulation, akin to medications like thiazolidinediones and glinides, which resemble many medicinal plants. Medicinal plants offer potential alternative treatments due to bioactive compounds targeting diabetes causes. We aimed to explore the antidiabetic potential of two medicinal plants, Psidium guajava and Seriphium plumosum L., by investigating their phytochemical constituents, medicinal uses, pharmacological actions, and mechanisms. This review followed specific guidelines and searched databases including PubMed, Scopus, ScienceDirect, and Web of Science for studies on medicinal plants and DM. Eligible studies underwent quality assessment and were categorized based on their design and interventions for data synthesis. This review identified the phytochemical constituents in Psidium guajava and Seriphium plumosum L., including tannins, flavonoids, phenols, and steroids, exerting antidiabetic effects through various mechanisms like antioxidant activity, anti-inflammatory effects, stimulation of insulin secretion, glucose regulation, and inhibition of carbohydrate-digesting enzymes. Psidium guajava and Seriphium plumosum L. exhibit promising antidiabetic potential, offering alternative approaches to diabetes management. Polyherbalism, combining multiple plant extracts, may enhance therapeutic efficacy in diabetes treatment. Comprehensive research is needed to explore the combined therapeutic effects of these plants and develop more effective antidiabetic treatments. This review highlights the importance of harnessing natural resources to combat the global burden of DM. Further research is warranted to fully explore the combined therapeutic effects of these plants and develop novel treatments.

Discovery of novel flavonoid derivatives as potential dual inhibitors against α-glucosidase and α-amylase: virtual screening, synthesis, and biological evaluation

Diabetes mellitus is one of the top ten causes of death worldwide, accounting for 6.7 million deaths in 2021, and is one of the most rapidly growing global health emergencies of this century. Although several classes of therapeutic drugs have been invented and applied in clinical practice, diabetes continues to pose a serious and growing threat to public health and places a tremendous burden on those affected and their families. The strategy of reducing carbohydrate digestibility by inhibiting the activities of α-glucosidase and α-amylase is regarded as a promising preventative treatment for type 2 diabetes. In this study, we investigated the dual inhibitory effect against two polysaccharide hydrolytic enzymes of flavonoid derivatives from an in-house chemical database. By combining molecular docking and structure-activity relationship analysis, twelve compounds with docking energies less than or equal to - 8.0 kcal mol-1 and containing required structural features for dual inhibition of the two enzymes were identified and subjected to chemical synthesis and in vitro evaluation. The obtained results showed that five compounds exhibited dual inhibitory effects on the target enzymes with better IC50 values than the approved positive control acarbose. Molecular dynamics simulations were performed to elucidate the binding of these flavonoids to the enzymes. The predicted pharmacokinetic and toxicological properties suggest that these compounds are viable for further development as type 2 diabetes drugs.

Interactions between corn starch and lingonberry polyphenols and their effects on starch digestion and glucose transport

This study investigated the interaction mechanism between corn starch (CS) and lingonberry polyphenols (LBP) during starch gelatinization, focusing on their effects on starch structure and physicochemical properties. Moreover, it explored the effect of this interaction on starch digestion and glucose transport. The results indicated that LBP interacted non-covalently with CS during starch gelatinization, disrupted the short-range ordered structure of starch, decreased gelatinization enthalpy of starch, and formed a dense network structure. Furthermore, the incorporation of LBP remarkably reduced the digestibility of CS. In particular, the addition of 10 % LBP decreased the terminal digestibility (C∞) from 77.87 % to 60.43 % and increased the amount of resistant starch (RS) by 21.63 %. LBP was found to inhibit α-amylase and α-glucosidase in a mixed manner. Additionally, LBP inhibited glucose transport in Caco-2 cells following starch digestion. When 10 % LBP was added, there was a 34.17 % decrease in glucose transport compared with starch digestion without LBP. This study helps establish the foundation for the development of LBP-containing starch or starch-based healthy foods and provides new insights into the mechanism by which LBP lowers blood glucose.

Synchronous reducing anti-nutritional factors and enhancing biological activity of soybean by the fermentation of edible fungus Auricularia auricula

Auricularia auricula fermentation was performed to reduce anti-nutritional factors, improve nutritional components, and enhance biological activity of soybean. Results showed that the contents of raffinose, stachyose, and trypsin inhibitor were significantly decreased from initial 1.65 g L-1, 1.60 g L-1, and 284.67 μg g-1 to 0.14 g L-1, 0.35 g L-1, and 4.52 μg g-1 after 144 h of fermentation, respectively. Simultaneously, the contents of polysaccharide, total phenolics, and total flavonoids were increased, and melanin was secreted. The isoflavone glycosides were converted to their aglycones, and the contents of glyctin and genistin were decreased from initial 1107.99 μg g-1 and 2852.26 μg g-1 to non-detection after 72 h of fermentation, respectively. After 96 h of fermentation, the IC50 values of samples against DPPH and ABTS radicals scavenging were decreased from 17.61 mg mL-1 and 3.43 mg mL-1 to 4.63 mg mL-1 and 0.89 mg mL-1, and those of samples inhibiting α-glucosidase and angiotensin I-converting enzyme were decreased from 53.89 mg mL-1 and 11.27 mg mL-1 to 18.24 mg mL-1 and 6.78 mg mL-1, respectively, indicating the significant increase in these bioactivities. These results suggested A. auricula fermentation can enhance the nutritional quality and biological activity of soybean, and the fermented soybean products have the potential to be processed into health foods/food additives.

Probiotic-fermented tomato with hepatic lipid metabolism modulation effects: analysis of physicochemical properties, bioactivities, and potential bioactive compounds

Lactiplantibacillus plantarum NCUH001046 (LP)-fermented tomatoes exhibited the potential to alleviate obesity in our previous study. This subsequent study further delves deeper into the effects of LP fermentation on the physicochemical properties, bioactivities, and hepatic lipid metabolism modulation of tomatoes, as well as the analysis of potential bioactive compounds exerting obesity-alleviating effects. Results showed that after LP fermentation, viable bacterial counts peaked at 9.11 log CFU mL-1 and sugar decreased, while organic acids, umami amino acids, total phenols, and total flavonoids increased. LP fermentation also improved the inhibition capacities of three digestive enzyme activities and Enterobacter cloacae growth, as well as antioxidant activities. Western blot results indicated that fermented tomatoes, especially live probiotic-fermented tomatoes (LFT), showed improved effects compared to unfermented tomatoes in reducing hepatic lipid accumulation by activating the AMPK signal pathway. UHPLC-Q-TOF/MS-based untargeted metabolomics analysis showed that chlorogenic acid, capsiate, tiliroside, irisflorentin, and homoeriodictyol levels increased after fermentation. Subsequent cell culture assays demonstrated that irisflorentin and homoeriodictyol reduced lipid accumulation via enhancing AMPK expression in oleic acid-induced hyperlipidemic HepG2 cells. Furthermore, Spearman's correlation analysis indicated that the five phenols were positively associated with hepatic AMPK pathway activation. Consequently, it could be inferred that the five phenols may be potential bioactive compounds in LFT to alleviate obesity and lipid metabolism disorders. In summary, these findings underscored the transformative potential of LP fermentation in enhancing the bioactive profile of tomatoes and augmenting its capacity to alleviate obesity and lipid metabolism disorders. This study furnished theoretical underpinnings for the functional investigation of probiotic-fermented plant-based foods.

Inhibition of α-glucosidase activity and intestinal glucose transport to assess the in vivo anti-hyperglycemic potential of dodecyl-acylated phlorizin and polydatin derivatives

A diet containing natural active compounds that can inhibit the hydrolytic activity of α-glucosidase on carbohydrates and intestinal glucose absorption is an effective means of controlling postprandial hyperglycemia. Phlorizin and polydatin as phenolic glycosides have a high affinity for the catalytic site of α-glucosidase, but exhibited unsatisfactory competitive inhibitory capacity, with an IC50 of 0.97 and >2 mM, respectively. However, dodecyl-acylated derivatives of phlorizin and polydatin exerted α-glucosidase inhibitory capacity, with an IC50 of 55.10 and 70.95 μM, respectively, which were greatly enhanced and much stronger than that of acarbose with an IC50 of 2.46 mM. The SPR assay suggested the high affinity of dodecyl phlorizin and dodecyl polydatin to α-glucosidase with equilibrium dissociation constant (KD) values of 12.0 and 7.9 μM, respectively. Both dodecyl phlorizin and dodecyl polydatin reduced the catalytic ability of α-glucosidase by reversible noncompetitive and uncompetitive mixed inhibition, which bind noncovalently to the allosteric site 2 through hydrogen bonds and hydrophobic interactions, thereby inducing the secondary structure unfolding and intrinsic fluorescence quenching of α-glucosidase. Confocal microscopy detection visually showed significant inhibitory effects on FITC-labeled glucose uptake in intestinal Caco-2 cells by phlorizin, polydatin, dodecyl phlorizin and dodecyl polydatin. In addition, based on the differentiated Caco-2 cell monolayer model, dodecyl phlorizin and dodecyl polydatin suppressed intestinal glucose transport more effectively than phlorizin and polydatin, suggesting that they were promising in vivo hypoglycemic active compounds.

Study on the potential hypoglycemic flavonoids in Abrus precatorius leaves: purification process, quality profile and activity mechanisms by transcriptomics and network pharmacology

The aim of the study was to investigate the relationship between flavonoids in Abrus precatorius leaves (APL) and their hypoglycaemic effects, which have not been studied before. An efficient purification process, transcriptomics and network pharmacology analysis were applied for the first time. High-performance liquid chromatography (HPLC) was used to determine the content of total flavonoids. The results showed that D101 resin was most suitable for purification of flavonoids of APL, which could increase its purity from 25.2% to 85.2% and achieve a recovery rate of 86.9%. The analysis of transcriptomics and network pharmacology revealed that flavonoids of APL could play a hypoglycaemic role by regulating 31 targets through AGE-RAGE and other signal pathways. Flavonoids of APL could exert hydroglycaemic effects by inhibiting AGEs, α-glucosidase and DPPH. This study provides a solid basis for hypoglycaemic product development and in-depth research of flavonoids in APL.

Two new monoterpene esters from Illigera paviflora Dunn roots

Two new monoterpene esters, illigerates H and I (1 and 2), and six known compounds actinodaphine (3), bulbocupnine (4), stephanine (5), hypserpanine B (6), betulinic acid (7) and gallic acid (8) were obtained from the root of Illigera paviflora Dunn. Their structures were elucidated by spectroscopic analysis. Anti-inflammatory and α-glucosidase inhibitory activity of some isolated compounds were assessed. Two monoterpenes 1 and 2 exhibited weak in vitro anti-inflammatory activity (IC50 64.5 ± 5.3 and 79.2 ± 7.5 μM) while compounds 3-6 showed inhibition of α-glucosidase with IC50 values ranged from 87.17 to 118.74 μM.

Antiobesity and antidiabetes effects of Cyperus rotundus rhizomes presenting protein tyrosine phosphatase, dipeptidyl peptidase 4, metabolic enzymes, stress oxidant and inflammation inhibitory potential

Diabetes is a significant global health concern that increases the vulnerability to various chronic illnesses. In view of this issue, the current research aimed to examine the effects of administering an extract derived from the tubers of Cyperus rotundus L (CrE) on obesity, type 1 diabetes, and liver-kidney toxicity. Through the utilization of HPLC-DAD analysis, it was discovered that the extract contained several components, including quercetin (47.8%), luteolin glucoside (17%), luteolin (7.56%), apigenin-7-glucoside (6.29%), naringinin (4.52%), and seven others. In vitro experiments they have demonstrated that CrE effectively inhibited key digestive enzymes associated with obesity and type 2 diabetes, such as DPP-4, PTP1B, lipase, and α-amylase, as evidenced by their respective IC50 values are about 23, 51,83, and 67 μg/ml respectively. Furthermore, when diabetic rats were administered CrE, the activity of pancreatic enzymes linked to inflammation, namely 5-lipoxygenase (5-LO), hyaluronidase (HAase), and myeloperoxidase (MPO), was significantly suppressed by 48, 41, 75, and 47%, respectively. Moreover, CrE exhibited protective effects on pancreatic β-cells by inhibiting the formation of thiobarbituric acid reactive substances (TBARS) by 65% and the induction of superoxide Dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) activities by 62, 108, and 112% respectively as compared to diabetic untreated rat. Additionally, CrE significantly inhibited the activities of intestinal, pancreatic, and serum lipase and α-amylase activities. In diabetic rats, CrE administration suppressed glycogen phosphorylase (GP) stimulated glycogen synthase (GS) activities by 45 and 30%; and this increased liver glycogen content by 45%. Furthermore, CrE modulated key hepatic enzymes involved in carbohydrate metabolism, including hexokinase (HK), glucose-6-phosphate dehydrogenase (G6PD), glucose-6-phosphatase (G6P), and fructose-1,6-bisphosphatase (FBP). Notably, the average food and water intake (AFI and AWI) of diabetic rats treated with CrE was reduced by 15 and 16% respectively as compared to those without any treatment. Therefore, this study demonstrated the effectiveness of Cyperus rotundus tubers in preventing and treating obesity and diabetes.

Coconut (Cocos nucifera (L.)) Water Improves Glucose Uptake with Concomitant Modulation of Antioxidant and Purinergic Activities in Isolated Rat Psoas Muscles

The present study investigated the effect of coconut water on glucose uptake and utilization, and metabolic activities linked to hyperglycemia in isolated rat psoas muscles. Coconut water was subjected to in vitro antioxidant and antidiabetic assays, which cover 2,2'-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity, ferric reducing antioxidant power (FRAP), and inhibition of α-glucosidase and α-amylase activities. Psoas muscles were isolated from male Sprague Dawley rats and incubated with coconut water in the presence of glucose. Control consisted of muscles incubated with glucose only, while normal control consisted of muscles not incubated in coconut water and/or glucose. The standard antidiabetic drug was metformin. Incubation with coconut water led to a significant increase in muscle glucose uptake, with concomitant exacerbation of glutathione level, and SOD and catalase activities, while suppressing malondialdehyde level, and ATPase and E-NTDase activities. Coconut water showed significant scavenging activity against DPPH, and significantly inhibited α-glucosidase and α-amylase activities. LC-MS analysis of coconut water revealed the presence of ellagic acid, butin, quercetin, protocatechuic acid, baicalin, and silibinin. Molecular docking analysis revealed potent molecular interactions between the LC-MS-identified compounds, and AKT-2 serine and PI-3 kinase. These results indicate the potential of coconut water to enhance glucose uptake, while concomitantly improving antioxidative and purinergic activities. They also indicate the potential of coconut water to suppress postprandial hyperglycemia. These activities may be attributed to the synergistic effects of the LC-MS-identified compounds.

Antioxidant Metabolism Pathways in Vitamins, Polyphenols, and Selenium: Parallels and Divergences

Free radicals (FRs) are unstable molecules that cause reactive stress (RS), an imbalance between reactive oxygen and nitrogen species in the body and its ability to neutralize them. These species are generated by both internal and external factors and can damage cellular lipids, proteins, and DNA. Antioxidants prevent or slow down the oxidation process by interrupting the transfer of electrons between substances and reactive agents. This is particularly important at the cellular level because oxidation reactions lead to the formation of FR and contribute to various diseases. As we age, RS accumulates and leads to organ dysfunction and age-related disorders. Polyphenols; vitamins A, C, and E; and selenoproteins possess antioxidant properties and may have a role in preventing and treating certain human diseases associated with RS. In this review, we explore the current evidence on the potential benefits of dietary supplementation and investigate the intricate connection between SIRT1, a crucial regulator of aging and longevity; the transcription factor NRF2; and polyphenols, vitamins, and selenium. Finally, we discuss the positive effects of antioxidant molecules, such as reducing RS, and their potential in slowing down several diseases.

Enhancement of anti-diabetic activity of pomelo peel by the fermentation of Aspergillus oryzae CGMCC23295: In vitro and in silico docking studies

In this work, pomelo peel was fermented by Aspergillus oryzae CGMCC23295 to enhance its anti-diabetic properties. Results showed the total phenolic and flavonoids contents, ferric reducing antioxidant power (FRAP), scavenging capacities against 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl radicals, as well as inhibitory abilities against α-amylase and α-glucosidase of pomelo peel were increased and fermentation for 8 days was the best. Additionally, the fermented sample could also enhance the glucose consumption and glycogen of HepG2 cell. Based on UPLC-MS/MS analysis, binding energy calculation, concentration determination and IC50 measurement, purpurin, apigenin, genistein, and paxilline could be concluded to be the main compounds to enhance the inhibition activities of fermented sample against α-amylase and α-glucosidase. Furthermore, computational studies were performed to reveal the the binding site and molecular interactions between paxilline and α-amylase, as well as purpurin and α-glucosidase. These findings provide a base for the utilization and valorization of pomelo peels as functional food additives by fermentation.

A review on ethnopharmacology, phytochemistry, pharmacology and potential uses of Portulaca oleracea L

ETHNOPHARMACOLOGICAL RELEVANCE

Portulaca oleracea L. (PO), popularly known as purslane, has been documented in ethnopharmacology in various countries and regions. Traditional application records indicated that PO might be used extensively to treat the common cold, dysentery, urinary tract infections, coughing, eye infections, skin problems, gynecological diseases, and pediatric illnesses.

AIM OF THE REVIEW

This paper includes a systematic review of the traditional usage, phytochemicals, pharmacological activity, and potential uses of PO to provide an overview of the research for further exploitation of PO resources.

MATERIALS AND METHODS

This article uses "Portulaca oleracea L." and "purslane" as the keywords and collects relevant information on PO from different databases, including PubMed, Web of Science, Springer, Science Direct, ACS, Wiley, CNKI, Baidu Scholar, Google Scholar, and ancient meteria medica.

RESULTS

PO is a member of the Portulacaceae family and is grown worldwide. Traditional Chinese medicine believes that purslane has the effect of improving eyesight, eliminating evil qi, quenching thirst, purgation, diuresis, hemostasis, regulating qi, promoting hair growth, detoxifying, and avoiding epidemic qi. Recent phytochemical investigations have shown that PO is a rich source of flavonoids, homoisoflavonoids, alkaloids, organic acids, esters, lignans, terpenoids, catecholamines, sterols, and cerebrosides. The purslane extracts or compounds have exhibited numerous biological activities such as anti-inflammatory, immunomodulatory, antimicrobial, antiviral, antioxidant, anticancer, renoprotective, hepatoprotective, gastroprotective, metabolic, muscle relaxant, anti-asthmatic and anti-osteoporosis properties. The significant omega-3 fatty acids, vital amino acids, minerals, and vitamins found in purslane also provide nutritional benefits. Purslane as a food/feed additive in the food industry and animal husbandry has caused concern. Its global wide distribution and tolerance to abiotic stress characteristics make it in the future sustainable development of agriculture a certain position.

CONCLUSIONS

Based on traditional usage, phytochemicals, and pharmacological activity, PO is a potential medicinal and edible plant with diverse pharmacological effects. Due to purslane's various advantages, it may have vast application potential in the food and pharmaceutical industries and animal husbandry.

Mechanistic study on the inhibition of α-amylase and α-glucosidase using the extract of ultrasound-treated coffee leaves

BACKGROUND

Our previous studies have shown that ultrasound-treated γ-aminobutyric acid (GABA)-rich coffee leaves have higher angiotensin-I-converting enzyme inhibitory activity than their untreated counterpart. However, whether they have antidiabetic activity remains unknown. In this study, we aimed to investigate the inhibitory activities of coffee leaf extracts (CLEs) prepared with ultrasound (CLE-U) or without ultrasound (CLE-NU) pretreatment on α-amylase and α-glucosidase. Subsequently, we evaluated the binding interaction between CLE-U and both enzymes using multi-spectroscopic and in silico analyses.

RESULTS

Ultrasound pretreatment increased the inhibitory activities of CLE-U against α-amylase and α-glucosidase by 21.78% and 25.13%, respectively. CLE-U reversibly inhibits both enzymes, with competitive inhibition observed for α-amylase and non-competitive inhibition for α-glucosidase. The static quenching of CLE-U against both enzymes was primarily driven by hydrogen bond and van der Waals interactions. The α-helices of α-amylase and α-glucosidase were increased by 1.8% and 21.3%, respectively. Molecular docking results showed that the key differential compounds, including mangiferin, 5-caffeoylquinic acid, rutin, trigonelline, GABA, caffeine, glutamate, and others, present in coffee leaves interacted with specific amino acid residues located at the active site of α-amylase (ASP197, GLU233, and ASP300). The binding of α-glucosidase and these bioactive components involved amino acid residues, such as PHE1289, PRO1329, and GLU1397, located outside the active site.

CONCLUSION

Ultrasound-treated coffee leaves are potential anti-diabetic substances, capable of preventing diabetes by inhibiting the activities of α-amylase and α-glucosidase, thus delaying starch digestion. Our study provides valuable information to elucidate the possible antidiabetic capacity of coffee leaves through the inhibition of α-amylase and α-glucosidase activities. © 2023 Society of Chemical Industry.

Flavonoids as dual-target inhibitors against α-glucosidase and α-amylase: a systematic review of in vitro studies

Diabetes mellitus remains a major global health issue, and great attention is directed at natural therapeutics. This systematic review aimed to assess the potential of flavonoids as antidiabetic agents by investigating their inhibitory effects on α-glucosidase and α-amylase, two key enzymes involved in starch digestion. Six scientific databases (PubMed, Virtual Health Library, EMBASE, SCOPUS, Web of Science, and WHO Global Index Medicus) were searched until August 21, 2022, for in vitro studies reporting IC50 values of purified flavonoids on α-amylase and α-glucosidase, along with corresponding data for acarbose as a positive control. A total of 339 eligible articles were analyzed, resulting in the retrieval of 1643 flavonoid structures. These structures were rigorously standardized and curated, yielding 974 unique compounds, among which 177 flavonoids exhibited inhibition of both α-glucosidase and α-amylase are presented. Quality assessment utilizing a modified CONSORT checklist and structure-activity relationship (SAR) analysis were performed, revealing crucial features for the simultaneous inhibition of flavonoids against both enzymes. Moreover, the review also addressed several limitations in the current research landscape and proposed potential solutions. The curated datasets are available online at https://github.com/MedChemUMP/FDIGA .

Antiviral Flavonoids: A Natural Scaffold with Prospects as Phytomedicines against SARS-CoV2

Flavonoids are vital candidates to fight against a wide range of pathogenic microbial infections. Due to their therapeutic potential, many flavonoids from the herbs of traditional medicine systems are now being evaluated as lead compounds to develop potential antimicrobial hits. The emergence of SARS-CoV-2 caused one of the deadliest pandemics that has ever been known to mankind. To date, more than 600 million confirmed cases of SARS-CoV2 infection have been reported worldwide. Situations are worse due to the unavailability of therapeutics to combat the viral disease. Thus, there is an urgent need to develop drugs against SARS-CoV2 and its emerging variants. Here, we have carried out a detailed mechanistic analysis of the antiviral efficacy of flavonoids in terms of their potential targets and structural feature required for exerting their antiviral activity. A catalog of various promising flavonoid compounds has been shown to elicit inhibitory effects against SARS-CoV and MERS-CoV proteases. However, they act in the high-micromolar regime. Thus a proper leadoptimization against the various proteases of SARS-CoV2 can lead to high-affinity SARS-CoV2 protease inhibitors. To enable lead optimization, a quantitative structure-activity relationship (QSAR) analysis has been developed for the flavonoids that have shown antiviral activity against viral proteases of SARS-CoV and MERS-CoV. High sequence similarities between coronavirus proteases enable the applicability of the developed QSAR to SARS-CoV2 proteases inhibitor screening. The detailed mechanistic analysis of the antiviral flavonoids and the developed QSAR models is a step forward toward the development of flavonoid-based therapeutics or supplements to fight against COVID-19.

Comparative bioactivity evaluation and metabolic profiling of different parts of Duhaldea nervosa based on GC-MS and LC-MS

Duhaldea nervosa (Wallich ex Candolle) Anderberg has been widely used as medicine and food additive in China for a long history. Its roots, known as Xiaoheiyao, are the mainly used medicinal part, while the other tissues of D. nervosa are ignored as non-medicinal parts despite their high biomass, resulting in a huge waste of resources. To mine and expand the medicinal values of different parts of D. nervosa, metabolic analysis by GC/LC-MS and bioactivity evaluation were performed. Based on the antioxidant activity and correlation analysis, a metabolite-related network was constructed. A total of 45 volatile and 174 non-volatile compounds were identified. Among them, caffeoylquinic acids and derivatives were more abundant in roots and flowers, while coumaroyltartaric acids and derivatives were mainly present in stems and leaves. By multivariate analysis, 13 volatile and 37 non-volatile differential metabolites were found, respectively. In the bioactivity evaluation of different parts, the order of antioxidant capacity was flowers > roots > leaves or stems. The flowers showed the highest FRAP value (354.47 μM TE/g DW) and the lowest IC50 values in the DPPH (0.06 mg/mL) and ABTS (0.19 mg/mL) assay, while higher inhibitory activity against α-glucosidase was exhibited by flowers and leaves. This study first established the similarities and differences of phytochemicals and bioactivities in D. nervosa, providing a scientific basis for developing non-medicinal parts and guiding the clinical application of this medicinal and edible herb.

Chemical profile of phenolic extracts from rapeseed meal and inhibitory effects on α-glucosidase: UPLC-MS/MS analysis, multispectral approaches, molecular simulation and ADMET analysis

Rapeseed meal (RSM) is the by-product of rapeseed processing that enriches phenolic compounds. However, the comprehensive characterization of its phenolic substances in terms of composition and potential activities remains incomplete, leading to limited utilization in the food industry. In this study, the phenolic profile from RSM (referred to as RMP) was identified, and their inhibitory effects on α-glucosidase were investigated. UPLC-MS/MS analysis showed that a total of 466 phenolic compounds were detected in RMP. The primary components were sinapic acid (SA), caffeic acid (CA), salicylic acid (SAA), and astragalin (AS). Multispectral approaches demonstrated significant inhibitory capacity of RMP against α-glucosidase with a half inhibition value (IC50) of 0.32 mg/mL, with a stronger inhibition compared to CA/SAA/AS (IC50: 4.0, 5.9, and 0.9 mg/mL) in addition to the previously reported SA, suggesting a synergistic effect. Both RMP and CA/SAA/AS altered the secondary structure of α-glucosidase to quench its intrinsic fluorescence. Molecular simulation results revealed that hydrogen bonds and van der Waals forces primarily contributed to the interaction between CA/SAA/AS and α-glucosidase, as well as verified the stability of the binding process over the entire simulation duration. The ADMET analysis showed that CYP2D6 was not inhibited by CA/SAA/AS, which had no AMES toxicity, hepatotoxicity, and skin sensitization. This finding suggests the potential of RMP against α-glucosidase for the treatment of diabetes.