Antidiabetic Flavonoids from Fruits of Morus alba Promoting Insulin-Stimulated Glucose Uptake via Akt and AMP-Activated Protein Kinase Activation in 3T3-L1 Adipocytes

Effects of Quercetin Metabolites on Glucose-Dependent Lipid Accumulation in 3T3-L1 Adipocytes

The aim of the study was to assess the effects of quercetin metabolites (QMs) on lipid accumulation in adipocytes under high-glucose and physiological-glucose concentrations and to elucidate the mechanisms involved. 3T3-L1 mature adipocytes were exposed to a physiological glucose concentration, as a model of caloric restriction (CR), or high glucose (control), with and without QMs (quercetin-3-glucuronide [Q3G] and isorhamnetin [ISOR]). Cells were treated with Q3G (0.3 and 0.6 µmol/L) and ISOR (0.2 and 0.4 µmol/L) for 48 h. Lipid accumulation (Oil Red O staining) and Δ glucose level (HPLC) were assessed. Under high glucose, Q3G and ISOR reduced lipid accumulation (-10.8% and -10.4%; p < 0.01) and Δ glucose level (-13.6% and -14.2%; p < 0.05). Under CR, QMs increased Δ glucose level (+21.6% for Q3G and +21% for ISOR; p < 0.05). ISOR increased pAMPK levels under high glucose (+1.4-fold; p < 0.05). Under CR, Q3G and ISOR increased pAMPK (+1.4- and +1.5-fold; p < 0.05), while ISOR upregulated SIRT1 and PGC-1α (+2.3- and +1.5-fold; p < 0.05). Findings support, for the first time, the potential contribution of QMs, especially ISOR, in the regulation of lipid metabolism in vitro, possibly via AMPK activation. Further studies, including in vivo, are encouraged to strengthen evidence of the mechanisms observed.

Exploring the Therapeutic Role of Flavonoids Through AMPK Activation in Metabolic Syndrome: A Narrative Review

Metabolic syndrome (MetS) is a cluster of interrelated metabolic abnormalities that significantly elevate the risk of cardiovascular disease, obesity, and diabetes. Flavonoids, a diverse class of bioactive polyphenolic compounds found in plant-derived foods and beverages, have garnered increasing attention as potential therapeutic agents for improving metabolic health. This review provides a comprehensive analysis of the therapeutic effects of flavonoids in the context of the MetS, with a particular focus on their modulation of the AMP-activated protein kinase (AMPK) pathway. AMPK serves as a central regulator of cellular energy balance, glucose metabolism, and lipid homeostasis, making it a critical target for metabolic intervention. Through a systematic review of the literature up to April 2024, preclinical studies across various flavonoid subclasses, including flavonols, and flavan-3-ols, were analysed to elucidate their mechanistic roles in metabolic regulation. Many studies suggests that flavonoids enhance glycolipid metabolism by facilitating glucose transporter 4 (GLUT4) translocation and activating the AMPK pathway, thereby improving glycemic control in diabetes models. In obesity-related studies, flavonoids demonstrated significant inhibitory effects on lipid synthesis, reduced adipogenesis, and attenuated proinflammatory cytokine secretion via AMPK activation. These findings show the broad therapeutic potential of flavonoids in addressing the MetS and its associated disorders. While these preclinical insights highlight flavonoids as promising natural agents for metabolic health improvement, it is important to note that their excessive concentrations may disrupt these pathways, potentially leading to metabolic imbalance and cytotoxicity. Further studies and clinical trials are essential to determine optimal dosing regimens, formulations, and the long-term safety and efficacy of flavonoids. This review highlights the importance of flavonoids for natural interventions targeting MetS and its comorbidities, offering a foundation for future translational research.

The bioavailability, absorption, metabolism, and regulation of glucolipid metabolism disorders by quercetin and its important glycosides: A review

Quercetin and its glycosides (QG), vitally natural flavonoid, have been popular for health benefits. However, the absorption and metabolism affect their bioavailability, and the metabolic transformation alters their biological activities. This review systematically summarizes the bioavailability and pathways for the absorption and metabolism of quercetin/QG in vivo and in vitro, the biological activities and mechanism of quercetin/QG and their metabolites in treating glucolipid metabolism are discussed. After oral administration, quercetin/QG are mainly absorbed by the intestine, undergo phase II metabolism in the small intestine and liver to form conjugates and are metabolized into small phenolic acids by intestinal microbiota. Quercetin/QG and their metabolites exert beneficial effects on regulating glucolipid metabolism disorders, including improving insulin resistance, inhibiting lipogenesis, enhancing thermogenesis, modulating intestinal microbiota, relieving oxidative stress, and attenuating inflammation. This review enhances understanding of the mechanism of quercetin/QG regulate glucolipid metabolism and provides scientific support for the development of functional foods.

Exploration of potential antidiabetic and antioxidant components from the branches of Mitragyna diversifolia and possible mechanism

In this study, sixteen compounds were isolated from the branches of Mitragyna diversifolia, including twelve triterpenes (1-12), a phenolic compound (13), and three flavonoids (14-16). Among them, compounds 1-7, and 10-16 were reported for the first time from this plant. Compounds 7, 14, and 15 exhibited significant inhibitory activities against α-glucosidase, with IC50 values of 18.48 ± 2.74, 12.14 ± 1.58 and 35.77 ± 4.52 µM, respectively. Furthermore, the inhibitory kinetics of α-glucosidase revealed that all fractions, active compounds 7, 14, and 15 belong to the mix inhibition type. In molecular docking, the analysis showed that compounds 13, 14, 15, and 16 possessed superior binding capacities with α-glucosidase (-8.3, -9.6, -9.9, and -9.2 kcal/mol, respectively). The results of the glucose uptake experiment indicated that only compound 14 showed a significant promotion effect on the glucose uptake rate of 3T3-L1 adipocytes (P < 0.05). Meanwhile, compounds 13, 14, 15, and 16 possessed potent antioxidant abilities with DPPH, ABTS, and FRAP. In DNA and protein oxidative damage assays, compound 15 had a stronger effect than the positive control Vc. The network-based pharmacological analysis platform was used to predict the diabetes-related target proteins of active compounds 7, 13, 14, 15, and 16, and two candidate targets (ALB and PPARG) related to their therapeutic effects on diabetes were identified.

Anti-Hyperglycemic Effects of Thai Herbal Medicines

This study aims to investigate selected medicinal plants' anti-oxidative and antihyperglycemic activities to develop an effective remedy for lowering blood glucose levels and/or reducing diabetes complications. Thai medicinal plants, reported to have blood sugar-lowering effects, were selected for the study: Coccinia grandis, Gymnema inodorum, Gynostemma pentaphyllum, Hibiscus sabdariffa, Momordica charantia, Morus alba, and Zingiber officinale. Each species was extracted by Soxhlet's extraction using ethanol as solvent. The ethanolic crude extract of each species was then evaluated for its phytochemicals, anti-oxidant, and antihyperglycemic activities. The results showed that the extract of Z. officinale gave the highest values of total phenolic and total flavonoid content (167.95 mg gallic acid equivalents (GAE)/g and 81.70 mg CE/g, respectively). Anti-oxidant activity was determined using DPPH and ABTS radical scavenging activity. Among the ethanolic extracts, Z. officinale exhibited the highest anti-oxidant activity with IC50 values of 19.16 and 8.53 µg/mL, respectively. The antihyperglycemic activity was assessed using α-glucosidase inhibitory and glucose consumption activities. M. alba and G. pentaphyllum demonstrated the highest α-glucosidase inhibitory activity among the ethanolic extracts, with IC50 values of 134.40 and 329.97 µg/mL, respectively. Z. officinale and H. sabdariffa showed the highest percentage of glucose consumption activity in induced insulin-resistant HepG2 cells at a concentration of 50 µg/mL with 145.16 and 107.03%, respectively. The results from α-glucosidase inhibitory and glucose consumption activities were developed as an effective antihyperglycemic remedy. Among the remedies tested, the R1 remedy exhibited the highest potential for reducing blood glucose levels, with an IC50 value of 122.10 µg/mL. Therefore, the R1 remedy should be further studied for its effects on animals.

Flavonoids, gut microbiota, and host lipid metabolism

Flavonoids are widely distributed in nature and have a variety of beneficial biological effects, including antioxidant, anti-inflammatory, and anti-obesity effects. All of these are related to gut microbiota, and flavonoids also serve as a bridge between the host and gut microbiota. Flavonoids are commonly used to modify the composition of the gut microbiota by promoting or inhibiting specific microbial species within the gut, as well as modifying their metabolites. In turn, the gut microbiota extensively metabolizes flavonoids. Hence, this reciprocal relationship between flavonoids and the gut microbiota may play a crucial role in maintaining the balance and functionality of the metabolism system. In this review, we mainly highlighted the biological effects of antioxidant, anti-inflammatory and antiobesity, and discussed the interaction between flavonoids, gut microbiota and lipid metabolism, and elaborated the potential mechanisms on host lipid metabolism.

Comprehensive overview of different medicinal parts from Morus alba L.: chemical compositions and pharmacological activities

Morus alba L., a common traditional Chinese medicine (TCM) with a centuries-old medicinal history, owned various medicinal parts like Mori folium, Mori ramulus, Mori cortex and Mori fructus. Different medical parts exhibit distinct modern pharmacological effects. Mori folium exhibited analgesic, anti-inflammatory, hypoglycemic action and lipid-regulation effects. Mori ramulus owned anti-bacterial, anti-asthmatic and diuretic activities. Mori cortex showed counteraction action of pain, inflammatory, bacterial, and platelet aggregation. Mori fructus could decompose fat, lower blood lipids and prevent vascular sclerosis. The main chemical components in Morus alba L. covered flavonoids, phenolic compounds, alkaloids, and amino acids. This article comprehensively analyzed the recent literature related to chemical components and pharmacological actions of M. alba L., summarizing 198 of ingredients and described the modern activities of different extracts and the bioactive constituents in the four parts from M. alba L. These results fully demonstrated the medicinal value of M. alba L., provided valuable references for further comprehensive development, and layed the foundation for the utilization of M. alba L.

Evaluation of Adenanthera pavonina-derived compounds against diabetes mellitus: insight into the phytochemical analysis and in silico assays

Adenanthera pavonina is a medicinal plant with numerous potential secondary metabolites showing a significant level of antidiabetic activity. The objective of the current study was to identify potential phytochemicals from the methanolic leaf extract of Adenanthera pavonina as therapeutic agents against diabetes mellitus using GC-MS and in silico methods. The GC-MS analysis of the leaf extract revealed a total of 17 phytochemicals. Molecular docking was performed using these phytochemicals, targeting the mutated insulin receptor tyrosine kinase (5hhw), which inhibits glucose uptake by cells. Diazoprogesterone (-9.2 kcal/mol), 2,4,4,7a-Tetramethyl-1-(3-oxobutyl)octahydro-1H-indene-2-carboxylic acid (-6.9 kcal/mol), and 2-Naphthalenemethanol, decahydro-.alpha.,.alpha.,4a-trimethyl-8-methylene-, [2R-(2.alpha.,4a.alpha.,8a.beta.)] (-6.6 kcal/mol) exhibited better binding with the target protein. The ADMET analysis was performed for the top three compounds with the best docking scores, which showed positive results with no observed toxicity in the AMES test. Furthermore, the molecular dynamics study confirmed the favorable binding of Diazoprogesterone, 2,4,4,7a-Tetramethyl-1-(3-oxobutyl)octahydro-1H-indene-2-carboxylic acid and 2-Naphthalenemethanol, decahydro-.alpha.,.alpha.,4a-trimethyl-8-methylene-, [2R-(2.alpha.,4a.alpha.,8a.beta.)] with the receptor throughout the 100 ns simulation period.

Metabolic disorders in prediabetes: From mechanisms to therapeutic management

Diabetes, one of the world's top ten diseases, is known for its high mortality and complication rates and low cure rate. Prediabetes precedes the onset of diabetes, during which effective treatment can reduce diabetes risk. Prediabetes risk factors include high-calorie and high-fat diets, sedentary lifestyles, and stress. Consequences may include considerable damage to vital organs, including the retina, liver, and kidneys. Interventions for treating prediabetes include a healthy lifestyle diet and pharmacological treatments. However, while these options are effective in the short term, they may fail due to the difficulty of long-term implementation. Medications may also be used to treat prediabetes. This review examines prediabetic treatments, particularly metformin, glucagon-like peptide-1 receptor agonists, sodium glucose cotransporter 2 inhibitors, vitamin D, and herbal medicines. Given the remarkable impact of prediabetes on the progression of diabetes mellitus, it is crucial to intervene promptly and effectively to regulate prediabetes. However, the current body of research on prediabetes is limited, and there is considerable confusion surrounding clinically relevant medications. This paper aims to provide a comprehensive summary of the pathogenesis of pre-diabetes mellitus and its associated therapeutic drugs. The ultimate goal is to facilitate the clinical utilization of medications and achieve efficient and timely control of diabetes mellitus.

Phytochemical studies of white mulberry fruits (Morus alba L.)

Medicinal preparations made from plant materials have been widely used for many years due to their high pharmacological efficacy and safety of use. Therefore, a study of white mulberry fruits (Morus alba L.) for the content of substances is very important for the pharmaceutical industry such as flavonoids, alkaloids, polysaccharides, minerals, vitamins, and amino acids. White mulberry has a wide distribution area around the world, including in Kazakhstan, especially in the southern regions of the country (Almaty, Zhambyl, and Turkestan regions). The composition of the fruits of this plant is significantly influenced by the area where the trees grow, and therefore, the establishment of a specific composition of biologically active substances is very important. In the course of this study, such methods as gas chromatography were used-mass spectrometry of an extract obtained using carbon dioxide under subcritical conditions, atomic absorption, gravimetric, and spectrophotometric methods. As a result, for the first time in Kazakhstan, the composition of white mulberry fruits (Morus alba L.), namely, biologically active substances, has been identified, such as alkaloids, flavonoids, vitamins, macro- and microelements, and amino acids and fatty acids; in addition, the percentage composition of the above compounds has been determined. The results of the study show a comparative analysis of the component composition of white mulberry fruits (Morus alba L.) in various areas of tree growth, including outside of Kazakhstan. The obtained data testify to the great possibilities of using this raw material in medicine, pharmacology, and the food industry.

Hypoglycemic effect and intestinal transport of phenolics-rich extract from digested mulberry leaves in Caco-2/insulin-resistant HepG2 co-culture model

Phenolics of mulberry (Morus alba L.) leaves (MLs) have potential anti-diabetic effects, but they may be chemically modified during gastrointestinal digestion so affect their biological activity. In this study, an in vitro digestion model coupled with Caco-2 monolayer and Caco-2/insulin-resistant HepG2 coculture model were used to study the transport and hypoglycemic effects of phenolics in raw MLs (U-MLs) and solid-fermented MLs (F-MLs). The results of LC-MS/MS analysis showed that the Papp (apparent permeability coefficient, 10-6cm/s) of phenolics in digested MLs ranged from 0.002 ± 0.00 (quercetin 3-O-glucoside) to 60.19 ± 0.67 (ferulic acid), indicating higher phenolic acids absorbability and poor flavonoids absorbability. The Papp values of phenolic extracts of F-MLs in Caco-2 monolayer were significantly higher (p > 0.05) than that of U-MLs. Digested phenolic extracts inhibited the activities of sucrase (60.13 ± 2.03 %) and maltase (82.35 ± 0.78 %) and decreased 9.28 ± 0.84 % of glucose uptake in Caco-2 monolayer. Furthermore, a decrease in the mRNA expression of glucose transporters SGLT1 (0.64 ± 0.18), GLUT2 (0.14 ± 0.02) and the sucrase-isomaltase (0.59 ± 0.00) was observed. In Caco-2/insulin-resistant HepG2 co-culture model, phenolic extracts regulated glucose metabolism by up-regulating the mRNA expressions of IRS1 (9.32-fold), Akt (17.07-fold) and GYS2 (1.5-fold), and down-regulating the GSK-3β (0.22-fold), PEPCK (0.49-fold) and FOXO1 (0.10-fold) mRNA levels. Both U-MLs and F-MLs could improve glucose metabolism, and the partial least squares (PLS) analysis showed that luteoforol and p-coumaric acid were the primary phenolics that strongly correlated with the hypoglycemic ability of MLs. Results suggested that phenolics of MLs can be used as dietary supplements to regulate glucose metabolism.

The Possibility of Using Fruit-Bearing Plants of Temperate Climate in the Treatment and Prevention of Diabetes

Diabetes mellitus is one of the most dangerous metabolic diseases. The incidence of this disease continues to increase and is often associated with severe complications. Plants and natural plant products with a healing effect have been successfully used in the treatment of many disease entities since the beginning of the history of herbalism and medicine. At present, great emphasis is placed on the biodiversity of crops and the replacement of the monoculture production system of popular temperate climate plants, such as apple, pear, plum, and vine, with alternative fruit species. Very promising fruit plants are Cornelian cherry (Cornus mas); mulberry (Morus alba); bird cherry (Prunus padus); sour cherry (Prunus cerasus); plants of the genus Amelanchier, Sorbus, and Crategus; medlar (Mespilus germanica); quince (Cydonia oblonga); plants of the genus Vaccinium; and wild roses. When promoting the cultivation of alternative fruit-bearing plants, it is worth emphasizing their beneficial effects on health. This systematic review indicates that the antidiabetic effect of various parts of fruit plants is attributed to the presence of polyphenols, especially anthocyanins, which have different mechanisms of antidiabetic action and can be used in the treatment of diabetes and various complications associated with this disease.

Characterizing 3T3-L1 MBX Adipocyte Cell Differentiation Maintained with Fatty Acids as an In Vitro Model to Study the Effects of Obesity

The increasing prevalence of obesity has prompted intensive research into understanding its role in pathogenesis and designing appropriate treatments. To determine the signals generated from the interaction of fat cells with a target organ, a reliable white adipocyte model in vitro is needed. Differentiated fibroblasts are the most extensively studied using in vitro cell models of white adipocytes. However, it can be argued that differentiated fibroblasts minimally recapitulate the consequences of obesity. Here, we describe 3T3-L1 MBX cells as a culture model for studying obese adipocytes and their effects. Differentiation of 3T3-L1 MBX cells was at first optimized and then maintained in the presence of fatty acids cocktail combination to induce the obese condition. Lipid accumulation and adipokine secretion profiles were analyzed. Results showed that fatty acid-maintained, differentiated 3T3-L1 MBX cells had significantly greater accumulation of lipids and significant changes in the adipokine secretions in comparison to differentiated 3T3-L1 MBX cells maintained in medium without fatty acids. To elucidate the molecular changes associated with adipogenesis and lipid accumulation profile of 3T3-L1 MBX cells, we have also explored the expression of some of the regulatory proteins related to the development and maintenance of adipocytes from the preadipocyte lineage.

Paliurus spina-christi Mill fruit extracts improve glucose uptake and activate the insulin signaling pathways in HepG2 insulin-resistant cells

BACKGROUND

Paliurus spina-christi Mill. (PSC) fruit is frequently used in the treatment of diabetes mellitus in Mediterranean regions. Here, we investigated the effects of various PSC fruit extracts (PSC-FEs) on glucose consumption and some key mediators of insulin signaling pathways in high glucose and high insulin-induced insulin-resistant HepG2 cells.

METHODS

The effects of methanolic, chloroform and total extracts on cell proliferation were assessed by the MTT assay. The potential of non-toxic extracts on glucose utilization in insulin-resistant HepG2 cells was checked using a glucose oxidase assay. AKT and AMP-activated protein kinase (AMPK) pathway activation and mRNA expression levels of insulin receptor (INSR), glucose transporter 1 (GLUT1), and glucose transporters 4 (GLUT4) were determined by western blotting and real-time PCR, respectively.

RESULTS

We found that high concentrations of methanolic and both low and high concentrations of total extracts were able to enhance glucose uptake in an insulin-resistant cell line model. Moreover, AKT and AMPK phosphorylation were significantly increased by the high strength of methanolic extract, while total extract raised AMPK activation at low and high concentrations. Also, GLUT 1, GLUT 4, and INSR were elevated by both methanolic and total extracts.

CONCLUSIONS

Ultimately, our results shed new light on methanolic and total PSC-FEs as sources of potential anti-diabetic medications, restoring glucose consumption and uptake in insulin-resistant HepG2 cells. These could be at least in part due to re-activating AKT and AMPK signaling pathways and also increased expression of INSR, GLUT1, and GLUT4. Overall, active constituents present in methanolic and total extracts of PCS are appropriate anti-diabetic agents and explain the use of these PSC fruits in traditional medicine for the treatment of diabetes.

Chemical and Biological Review of Endophytic Fungi Associated with Morus sp. (Moraceae) and In Silico Study of Their Antidiabetic Potential

The chronic nature of diabetes mellitus motivates the quest for novel agents to improve its management. The scarcity and prior uncontrolled utilization of medicinal plants have encouraged researchers to seek new sources of promising compounds. Recently, endophytes have presented as eco-friendly leading sources for bioactive metabolites. This article reviewed the endophytic fungi associated with Morus species and their isolated compounds, in addition to the biological activities tested on their extracts and chemical constituents. The relevant literature was collected from the years 2008-2022 from PubMed and Web of Science databases. Notably, no antidiabetic activity was reported for any of the Morus-associated endophytic fungal extracts or their twenty-one previously isolated compounds. This encouraged us to perform an in silico study on the previously isolated compounds to explore their possible antidiabetic potential. Furthermore, pharmacokinetic and dynamic stability studies were performed on these compounds. Upon molecular docking, Colletotrichalactone A (14) showed a promising antidiabetic activity due to the inhibition of the α-amylase local target and the human sodium-glucose cotransporter 2 (hSGT2) systemic target with safe pharmacokinetic features. These results provide an in silico interpretation of the possible anti-diabetic potential of Morus endophytic metabolites, yet further study is required.

Triterpenoids from Kochiae Fructus: Glucose Uptake in 3T3-L1 Adipocytes and α-Glucosidase Inhibition, In Silico Molecular Docking

In this study, three new triterpenes (1-3) and fourteen known triterpenoids (4-17) were isolated from the ethanol extract of Kochiae Fructus, and their structures were elucidated by analyzing UV, IR, HR-ESI-MS, 1D, and 2D NMR spectroscopic data. Among them, compounds 6, 8, and 11-17 were isolated for the first time from this plant. The screening results of the glucose uptake experiment indicated that compound 13 had a potent effect on glucose uptake in 3T3-L1 adipocytes at 20 μM. Meanwhile, compounds 3, 9 and 13 exhibited significant inhibitory activities against α-glucosidase, with IC50 values of 23.50 ± 3.37, 4.29 ± 0.52, and 16.99 ± 2.70 µM, respectively, and their α-glucosidase inhibitory activities were reported for the first time. According to the enzyme kinetics using Lineweaver-Burk and Dixon plots, we found that compounds 3, 9 and 13 were α-glucosidase mixed-type inhibitors with Ki values of 56.86 ± 1.23, 48.88 ± 0.07 and 13.63 ± 0.42 μM, respectively. In silico molecular docking analysis showed that compounds 3 and 13 possessed superior binding capacities with α-glucosidase (3A4A AutoDock score: -4.99 and -4.63 kcal/mol). Whereas compound 9 showed +2.74 kcal/mol, which indicated compound 9 exerted the effect of inhibiting α-glucosidase activity by preferentially binding to the enzyme-substrate complex. As a result, compounds 3, 9 and 13 could have therapeutic potentials for type 2 diabetes mellitus, due to their potent hypoglycemic activities.

The Spectrum of Pharmacological Actions of Syringetin and Its Natural Derivatives-A Summary Review

Mono- and poly-O-methylated flavonols and their glycoside derivatives belong to the group of natural plant polyphenols with a wide spectrum of pharmacological activities. These compounds are known for their antioxidant, antimutagenic, hepatoprotective, antidiabetic, and antilipogenic properties. Additionally, they inhibit carcinogenesis and cancer development. Having in mind the multidirectional biological activity of methylated flavonols, we would like to support further study on their health-promoting activities; in this review we summarized the most recent reports on syringetin and some of its structural analogues: laricitrin, ayanin, and isorhamnetin. Natural sources and biological potential of these substances were described based on the latest research papers.

Meyeroguilline E, a New Isoindolinone Alkaloid from the Poisonous Mushroom Chlorophyllum molybdites, and Identification of Compounds with Multidrug Resistance (MDR) Reversal Activities

Three isoindolinone alkaloids (1-3), including one new isoindolinone-type alkaloid, meyeroguilline E (1), and six other known compounds (4-9) were isolated from the poisonous mushroom Chlorophyllum molybdites (Agaricaceae). The structure of the new compound was determined using extensive spectroscopic analyses via one-dimensional (1D) and two-dimensional (2D) NMR data interpretation and high-resolution electrospray ionization mass spectrometry (HR-ESI-MS). To the best of our knowledge, compound 1 is the first example of a natural isoindolinone with a butanoic acid moiety, and this study is the first to detect the other known compounds (2-9) in C. molybdites. The isolated compounds (1-9) were examined for their multidrug resistance (MDR) reversal activity against MES-SA, MES-SA/DX5, HCT15, and HCT15/CL02 human cancer cells. Based on the results, 20 μM of compounds 3 and 6 slightly potentiated paclitaxel (TAX)-induced cytotoxicity in MES-SA/DX5, HCT15, and HCT15/CL02 cells; however, the compounds had no effect on the cytotoxicity against MES-SA and nonMDR cells.

Labdane-type Diterpenes from Pinus eldarica Needles and Their Anti-Helicobacter pylori Activity

Pinus eldarica is a medicinal tree used in traditional herbal medicine for the treatment of bronchial asthma and various skin diseases. As part of our ongoing search for bioactive phytochemicals with novel structures in natural products, we performed a phytochemical analysis of the methanol (MeOH) extract from P. eldarica needles collected in Iran. Phytochemical investigation of the MeOH extract, aided by liquid chromatography-mass spectrometry-based analysis, resulted in the isolation and identification of three labdane-type diterpenes (1-3), including a new and relatively unique norlabdane-type diterpene with a peroxide moiety, eldaricoxide A (1). The chemical structures of the isolated labdane-type diterpenes were elucidated by analyzing the spectroscopic data from 1D and 2D NMR and high-resolution electrospray ionization-mass spectrometry. The absolute configuration of eldaricoxide A (1) was established by employing a computational method, including electronic circular dichroism calculation and specific optical rotation. An anti-Helicobacter pylori test was conducted, where compound 3 exhibited the most potent antibacterial activity against H. pylori strain 51, inducing 72.7% inhibition (MIC₅₀ value of 92 μM), whereas eldaricoxide A (1) exhibited moderate antibacterial activity against H. pylori strain 51, inducing 54.5% inhibition (MIC₅₀ value of 95 μM). These findings demonstrated that the identified bioactive labdane-type diterpenes 1 and 3 can be applied in the development of novel antibiotics against H. pylori for the treatment of gastric and duodenal ulcers.

LC-MS Metabolite Profiling and the Hypoglycemic Activity of Morus alba L. Extracts

Morus alba L. is used in traditional Chinese medicine for its anti-diabetic activity; however, the part of the hypoglycemic activity and related active metabolites are still not fully clarified. In this study, the metabolites in the M. alba roots, leaves, twigs, and fruits extracts (70% ethanol extracts) were systematically identified, and their hypoglycemic activity was evaluated by the high-fat diet/streptozotocin-induced 2 diabetes mellitus (T2D) mouse model. A total of 60 high-level compounds, including 16 polyphenols, 43 flavonoids, and one quinic acid, were identified by high-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (HPLC-Q-TOF-MS) combined with the fragmentation pathways of standards and the self-established database. Among them, 23 metabolites were reported for the first time from this plant. In contrast to the extracts of M. alba leaves and fruits, the extracts of roots and twigs displayed significant hypoglycemic activity The glycemia was significantly reduced from 32.08 ± 1.27 to 20.88 ± 1.82 mmol/L and from 33.32 ± 1.98 to 24.74 ± 1.02 mmol/L, respectively, after 4 weeks of treatment with roots and twigs extracts. Compound 46 (morusin), which is a high-level component identified from the extracts of M. alba roots, also displayed significant activity in decreasing the blood glucose level of T2D mice reduced from 31.45 ± 1.23 to 23.45 ± 2.13 mmol/L. In addition, the extracts of roots and twigs displayed significant activity in reducing postprandial glycemia. This work marks the first comparison of the metabolites and hypoglycemic activity of M. alba roots, leaves, twigs, and fruits extracts, and provides a foundation for further development of M. alba extracts as anti-diabetic drugs.

A Critical Review on Role of Available Synthetic Drugs and Phytochemicals in Insulin Resistance Treatment by Targeting PTP1B

Insulin resistance (IR) is a condition of impaired response of cells towards insulin. It is marked by excessive blood glucose, dysregulated insulin signalling, altered pathways, damaged pancreatic β-cells, metabolic disorders, etc. Chronic hyperglycemic conditions leads to type 2 diabetes mellitus (T2DM) which causes excess generation of highly reactive free radicals, causing oxidative stress, further leading to development and progression of complications like vascular dysfunction, damaged cellular proteins, and DNA. One of the causes for IR is dysregulation of protein tyrosine phosphatase 1B (PTP1B). Advancements in drug therapeutics have helped people manage IR by regulating PTP1B, however have been reported to cause side effects. Therefore, there is a growing interest on usage of phytochemical constituents having IR therapeutic properties and aiding to minimize these complications. Medicinal plants have not been utilized to their full potential as a therapeutic drug due to lack of knowledge of their active and effective chemical constituents, mode of action, regulation of IR parameters, and dosage of administration. This review highlights phytochemical constituents present in medicinal plants or spices, their potential effectiveness on proteins (PTP1B) regulating IR, and reported possible mechanism of action studied on in vitro models. The study gives current knowledge and future recommendations on the above aspects and is expected to be beneficial in developing herbal drug using these phytochemical constituents, either alone or in combination, for medication of IR and diabetes.

Antidiabetic potential of Catechu via assays for α-glucosidase, α-amylase, and glucose uptake in adipocytes

ETHNOPHARMACOLOGICAL RELEVANCE

Catechu is the dry water extract of barked branches or stems from Senegalia catechu(L. F.)P. J. H. Hurter & Mabb, which is used as a hypoglycemic regulator in recent researches. Potential anti-hyperglycemic components and the putative mechanisms were evaluated in this investigation.

AIM OF THE STUDY

Evaluated the hypoglycemic activity of Catechu via α-glucosidase, α-amylase inhibition assays, and glucose uptake in 3T3-L1 adipocytes.

MATERIALS AND METHODS

The effects of Catechu on α-glucosidase, α-amylase inhibition assays and glucose uptake experiment were tested after the ethanol extract of Catechu (EE) was sequentially partitioned with petroleum ether (PEE), ethyl acetate (EAE), and n-butanol fractions (NBE). Next, HPLC-MS and traditional Chinese medicine (TCM) database were used to detect and analyze the primary active ingredients presented in hypoglycemic fraction. In addition, in silico molecular docking study was used to evaluate the candidates' inhibitory activity against α-glucosidase and α-amylase.

RESULTS

The results of α-glucosidase and α-amylase inhibition assays indicated that all fractions, with the exception of PEE, presented significant inhibitory effects on α-glucosidase and α-amylase. The inhibitory effect of NBE on α-glucosidase was similar to the positive control (NBE IC₅₀ = 0.3353 ± 0.1215 μg/mL; Acarbose IC₅₀ = 0.1123 ± 0.0023 μg/mL). Furthermore, the inhibitory kinetics of α-glucosidase revealed that all fractions except for PEE belong to uncompetitive type. In silico molecular docking analysis showed that the main compositions of NBE ((-)-epicatechin, cyanidin, and delphinidin) possessed superior binding capacities with α-glucosidase (3WY1 AutoDock score: 4.82 kcal/mol; -5.59 kcal/mol; -5.63 kcal/mol) and α-amylase (4GQR AutoDock score: 4.80 kcal/mol; -5.89 kcal/mol; -4.26 kcal/mol), respectively. The results of glucose uptake experiment indicated that EE, PEE, EAE, and NBE without significant promotion effect on glucose uptake rate of 3T3-L1 adipocytes (P > 0.05).

CONCLUSION

This study revealed that the hypoglycemic effect of Catechu might be related to the inhibitory effects of phenols on digestive enzymes (α-glucosidase and α-amylase), and the possible active phenols were (-)-epicatechin, cyanidin, delphinidin and their derivatives, which provided scientific evidences for Catechu's traditional use to treat T2DM.

Hypoglycemic and Antioxidant Properties of Extracts and Fractions from Polygoni Avicularis Herba

Our research focused on the hypoglycemic capability and the possible mechanisms of extract and fractions from Polygoni Avicularis Herba (PAH) based on α-glucosidase, α-amylase inhibition assays, glucose uptake experiment, HPLC-MS analysis, and molecular docking experiment. In addition, DPPH, ABTS, and FRAP assays were used for determining the antioxidant capability. The results of total flavonoids and phenolics contents showed that ethyl acetate fraction (EAF) possessed the highest flavonoids and phenolics with values of 159.7 ± 2.5 mg rutin equivalents/g and 107.6 ± 2.0 mg galic acid equivalents/g, respectively. The results of in vitro hypoglycemic activity showed that all samples had effective α-glucosidase inhibition capacities, and EAF possessed the best inhibitory effect with IC50 value of 1.58 ± 0.24 μg/mL. In addition, n-butanol fraction (NBF) significantly promoted the glucose uptake rate of 3T3-L1 adipocytes. HPLC-MS analysis and molecular docking results proved the interactions between candidates and α-glucosidase. The results of antioxidation capacities showed that EAF possessed the best antioxidation abilities with DPPH, ABTS, and FRAP. In summary, the hypoglycemic activity of PAH might be related to the inhibition of α-glucosidase (EAF > PEF > NBF) and the promotion of glucose uptake in 3T3-L1 adipocytes (NBF). Simultaneously, the antioxidation capacity of PAH might be related to the abundant contents of flavonoids and other phenolics (EAF > PEF > NBF).

Rosinidin Flavonoid Ameliorates Hyperglycemia, Lipid Pathways and Proinflammatory Cytokines in Streptozotocin-Induced Diabetic Rats

Diabetes is one of the world’s most important public health issues, impacting both public health and socioeconomic advancement; moreover, current pharmacotherapy is still insufficient. The natural flavonoid rosinidin has a long history of use in pharmaceuticals and nutritional supplements, but its role in diabetes has been unknown. The current study was intended to confirm the anti-diabetic activity of rosinidin in our laboratory setting, along with its mechanism. Streptozotocin (60 mg/kg, ip) treatment used to induce type II diabetes in rats and the test medication rosinidin was then administered orally (at doses of 10 mg/kg and 20 mg/kg) for biochemical and histopathological analysis. Treatment with rosinidin reduced negative consequences of diabetes. Rosinidin exerted a protective effect on a number of characteristics, including anti-diabetic responses (lower blood glucose, higher serum insulin and improved pancreatic function) and molecular mechanisms (favorable effects on lipid profiles, total protein, albumin, liver glycogen, proinflammatory cytokine, antioxidant and oxidative stress markers, AST, ALT and urea). Furthermore, the improved pancreatic architecture observed in tissues substantiated the favourable actions of rosinidin in STZ-induced diabetic rats.

Medicinal properties of Morus alba for the control of type 2 diabetes mellitus: a systematic review

Background: The objective of this review was to evaluate the medicinal potential of Morus alba leaves on the control of type 2 diabetes mellitus (DM2). The research question was: what is the therapeutic potential of Morus alba leaves for the control of DM2? Methods: This systematic review was based on the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. The included studies were extracted from Scopus, Pubmed, ScienceDirect, Scielo, and Google Scholar; January 2015 to July 2021. Key search terms were MeSH and DeCS: Morus alba, mulberry, hypoglycemic agent. The inclusion criteria were: studies in rats administered Morus alba leaf extracts; studies that included the dimensions of lipidemia and glycemia; studies that included indicators such as fasting glucose, postprandial glucose, glycosylated hemoglobin, triglycerides, low-density lipoproteins, total cholesterol, and insulin resistance. Exclusion criteria: studies in which Morus alba leaves were administered with other plants; studies with other parts of the Morus alba plant; proteomic studies, cancer, duplicate studies, in vitro studies, and evaluation of included studies. All included investigations were evaluated for biases. Results: Of 253 studies found, 29 were included. The extracts of Morus alba leaves at the phytochemical level improve glucose uptake. Chlorogenic acid, isoquercitrin, and quercitrin, present in the leaves of Morus alba, have hypoglycemic properties and an ameliorating effect on diabetic nephropathy. This leaf has pharmacological effects such as glucose absorption, insulin secretion production, antioxidant and anti-inflammatory agent, antihyperglycemic and antihyperlipidemic activities, and obesity management. Conclusions:Morus alba leaves have pharmacological effects on DM2 that include glucose absorption, production of insulin secretion, antioxidant agent, antihyperglycemic and antihyperlipidemic activities, and obesity control. Beyond these results, there is a lack of studies on the potential and synergistic effects of Morus alba leaves' components, limiting the possibility of a more effective therapy using the plant's leaves.

Artemisia scoparia and Metabolic Health: Untapped Potential of an Ancient Remedy for Modern Use

Botanicals have a long history of medicinal use for a multitude of ailments, and many modern pharmaceuticals were originally isolated from plants or derived from phytochemicals. Among these, artemisinin, first isolated from Artemisia annua, is the foundation for standard anti-malarial therapies. Plants of the genus Artemisia are among the most common herbal remedies across Asia and Central Europe. The species Artemisia scoparia (SCOPA) is widely used in traditional folk medicine for various liver diseases and inflammatory conditions, as well as for infections, fever, pain, cancer, and diabetes. Modern in vivo and in vitro studies have now investigated SCOPA's effects on these pathologies and its ability to mitigate hepatotoxicity, oxidative stress, obesity, diabetes, and other disease states. This review focuses on the effects of SCOPA that are particularly relevant to metabolic health. Indeed, in recent years, an ethanolic extract of SCOPA has been shown to enhance differentiation of cultured adipocytes and to share some properties of thiazolidinediones (TZDs), a class of insulin-sensitizing agonists of the adipogenic transcription factor PPARγ. In a mouse model of diet-induced obesity, SCOPA diet supplementation lowered fasting insulin and glucose levels, while inducing metabolically favorable changes in adipose tissue and liver. These observations are consistent with many lines of evidence from various tissues and cell types known to contribute to metabolic homeostasis, including immune cells, hepatocytes, and pancreatic beta-cells. Compounds belonging to several classes of phytochemicals have been implicated in these effects, and we provide an overview of these bioactives. The ongoing global epidemics of obesity and metabolic disease clearly require novel therapeutic approaches. While the mechanisms involved in SCOPA's effects on metabolic, anti-inflammatory, and oxidative stress pathways are not fully characterized, current data support further investigation of this plant and its bioactives as potential therapeutic agents in obesity-related metabolic dysfunction and many other conditions.