Didymin, a dietary citrus flavonoid exhibits anti-diabetic complications and promotes glucose uptake through the activation of PI3K/Akt signaling pathway in insulin-resistant HepG2 cells

Cinnamaldehyde protects SH-SY5Y cells against advanced glycation end-products induced ectopic cell cycle re-entry

Accumulation of advanced glycation end-products (AGEs) in the brain contributes significantly to cognitive impairment in patients with diabetes by disrupting the post-mitotic state of neuronal cells, thereby triggering ectopic cell cycle re-entry (CCR) and subsequent neuronal apoptosis. Cinnamaldehyde (CINA), a potential mitigator of cognitive impairment due to its blood glucose-lowering properties, warrants exploration for its role in counteracting diabetes-related neurological damage. In this study, we examined the neuroprotective effect of CINA on AGE-damaged SH-SY5Y human neuroblastoma cells differentiated in vitro. We investigated the impact of CINA on AGE-induced neuronal CCR and apoptosis, finding that it substantially suppressed aberrant DNA replication, precluded cells from entering the mitotic preparatory phase, and diminished apoptosis. Additionally, CINA inhibited the expression of eIF4E without altering S6K1 phosphorylation. These findings indicate that CINA safeguards neuronal cells from AGE-related damage by preventing abnormal CCR, preserving the post-mitotic state of neuronal cells, and reducing AGE-induced apoptosis, potentially through the inhibition of eIF4E-controlled cell proliferation. Our results highlight the prospective utility of CINA in managing diabetic neuropathy.

Bioprotective Role of Phytocompounds Against the Pathogenesis of Non-alcoholic Fatty Liver Disease to Non-alcoholic Steatohepatitis: Unravelling Underlying Molecular Mechanisms

Non-alcoholic fatty liver disease (NAFLD), with a global prevalence of 25%, continues to escalate, creating noteworthy concerns towards the global health burden. NAFLD causes triglycerides and free fatty acids to build up in the liver. The excessive fat build-up causes inflammation and damages the healthy hepatocytes, leading to non-alcoholic steatohepatitis (NASH). Dietary habits, obesity, insulin resistance, type 2 diabetes, and dyslipidemia influence NAFLD progression. The disease burden is complicated due to the paucity of therapeutic interventions. Obeticholic acid is the only approved therapeutic agent for NAFLD. With more scientific enterprise being directed towards the understanding of the underlying mechanisms of NAFLD, novel targets like lipid synthase, farnesoid X receptor signalling, peroxisome proliferator-activated receptors associated with inflammatory signalling, and hepatocellular injury have played a crucial role in the progression of NAFLD to NASH. Phytocompounds have shown promising results in modulating hepatic lipid metabolism and de novo lipogenesis, suggesting their possible role in managing NAFLD. This review discusses the ameliorative role of different classes of phytochemicals with molecular mechanisms in different cell lines and established animal models. These compounds may lead to the development of novel therapeutic strategies for NAFLD progression to NASH. This review also deliberates on phytomolecules undergoing clinical trials for effective management of NAFLD.

Photoperiod-Dependent Effects on Blood Biochemical Markers of Phenolic-Enriched Fruit Extracts

Fruits are rich in bioactive compounds, such as (poly)phenols, and their intake is associated with health benefits, although recent animal studies have suggested that the photoperiod of consumption influences their properties. Fruit loss and waste are critical issues that can be reduced by obtaining functional fruit extracts. Therefore, the aim of this study was to obtain phenolic-enriched extracts from eight seasonal fruits that can modulate blood biochemical parameters and to investigate whether their effects depend on the photoperiod of consumption. Eight ethanol-based extracts were obtained and characterized, and their effects were studied in F344 rats exposed to short (6 h light, L6) and long (18 h light) photoperiods. Cherry and apricot extracts decreased blood triacylglyceride levels only when consumed under the L6 photoperiod. Pomegranate, grape, and orange extracts reduced cholesterol and fasting glucose levels during the L6 photoperiod; however, plum extract reduced fasting glucose levels only during the L18 photoperiod. The results showed the importance of photoperiod consumption in the effectiveness of phenolic-enriched fruit extracts and promising evidence regarding the use of some of the developed fruit extracts as potential functional ingredients for the management of several blood biomarkers.

Protective effect of didymin against 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin-induced reproductive toxicity in male rats

PURPOSE

2, 3, 7, 8-Tetrachlorodibenzo-p-dioxin (TCDD) is one of the most potent environmental toxicants, which causes oxidative stress and adversely affects the male reproductive system. The current study aimed to evaluate the ameliorative role of didymin (DDM) against TCDD-induced testicular toxicity.

METHODS

Forty-eight male Sprague-Dawley rats were divided into four equal groups (n=12). (i) Control group, (ii) TCDD-induced group was provided with 10 μg/kg/day of TCDD, (iii) TCDD + DDM group received 10 μg/kg/day of TCDD and 2 mg/kg/day of DDM, and (iv) DDM-treated group was administered with 2 mg/kg/day of DDM. After 56 days of treatment, biochemical, steroidogenic, hormonal, spermatogenic, apoptotic, and histopathological parameters were estimated.

RESULTS

TCDD affected the biochemical profile by reducing the activities of antioxidant enzymes, while increasing the levels of malondialdehyde (MDA) and reactive oxygen species (ROS). Furthermore, it decreased the expressions of steroidogenic enzymes, 3β-hydroxysteroid dehydrogenase (HSD), 17β-HSD, steroidogenic acute regulatory protein (StAR), cholesterol side-chain cleavage enzyme (CYP11A1), and 17α-hydroxylase/17, 20-lyase (CYP17A1), as well as reduced the levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), and plasma testosterone. Besides, epididymal sperm count, viability, and motility were decreased, while sperm morphological anomalies were increased. Moreover, TCDD altered the apoptotic profile by up-regulating the expressions of Bax and caspase-3, while downregulated the Bcl-2 expression. Additionally, histopathological damages were prompted due to TCDD administration. However, DDM restored all the TCDD-induced damages owing to its antioxidant, anti-apoptotic, and androgenic potential.

CONCLUSION

Our data suggested that DDM might play its role as a therapeutic agent against TCDD-prompted testicular toxicity.

The Molecular Mechanism Underlying the Therapeutic Effect of Dihydromyricetin on Type 2 Diabetes Mellitus Based on Network Pharmacology, Molecular Docking, and Transcriptomics

Type 2 diabetes mellitus (T2DM) is a chronic and complex disease, and traditional drugs have many side effects. The active compound dihydromyricetin (DHM), derived from natural plants, has been shown in our previous study to possess the potential for reducing blood glucose levels; however, its precise molecular mechanism remains unclear. In the present study, network pharmacology and transcriptomics were performed to screen the molecular targets and signaling pathways of DHM disturbed associated with T2DM, and the results were partially verified by molecular docking, RT-PCR, and Western blotting at in vivo levels. Firstly, the effect of DHM on blood glucose, lipid profile, and liver oxidative stress in db/db mice was explored and the results showed that DHM could reduce blood glucose and improve oxidative stress in the liver. Secondly, GO analysis based on network pharmacology and transcriptomics results showed that DHM mainly played a significant role in anti-inflammatory, antioxidant, and fatty acid metabolism in biological processes, on lipoprotein and respiratory chain on cell components, and on redox-related enzyme activity, iron ion binding, and glutathione transferase on molecular functional processes. KEGG system analysis results showed that the PI3K-Akt signaling pathway, IL17 signaling pathway, HIF signaling pathway, MAPK signaling pathway, AGE-RAGE signaling pathway in diabetic complications, and TNF signaling pathway were typical signaling pathways disturbed by DHM in T2DM. Thirdly, molecular docking results showed that VEGFA, SRC, HIF1A, ESR1, KDR, MMP9, PPARG, and MAPK14 are key target genes, five genes of which were verified by RT-PCR in a dose-dependent manner. Finally, Western blotting results revealed that DHM effectively upregulated the expression of AKT protein and downregulated the expression of MEK protein in the liver of db/db mice. Therefore, our study found that DHM played a therapeutic effect partially by activation of the PI3K/AKT/MAPK signaling pathway. This study establishes the foundation for DHM as a novel therapeutic agent for T2DM. Additionally, it presents a fresh approach to utilizing natural plant extracts for chemoprevention and treatment of T2DM.

Didymin protects pancreatic beta cells by enhancing mitochondrial function in high-fat diet-induced impaired glucose tolerance

PURPOSE

Prolonged exposure to plasma free fatty acids (FFAs) leads to impaired glucose tolerance (IGT) which can progress to type 2 diabetes (T2D) in the absence of timely and effective interventions. High-fat diet (HFD) leads to chronic inflammation and oxidative stress, impairing pancreatic beta cell (PBC) function. While Didymin, a flavonoid glycoside derived from citrus fruits, has beneficial effects on inflammation dysfunction, its specific role in HFD-induced IGT remains yet to be elucidated. Hence, this study aims to investigate the protective effects of Didymin on PBCs.

METHODS

HFD-induced IGT mice and INS-1 cells were used to explore the effect and mechanism of Didymin in alleviating IGT. Serum glucose and insulin levels were measured during the glucose tolerance and insulin tolerance tests to evaluate PBC function and insulin resistance. Next, RNA-seq analysis was performed to identify the pathways potentially influenced by Didymin in PBCs. Furthermore, we validated the effects of Didymin both in vitro and in vivo. Mitochondrial electron transport inhibitor (Rotenone) was used to further confirm that Didymin exerts its ameliorative effect by enhancing mitochondria function.

RESULTS

Didymin reduces postprandial glycemia and enhances 30-minute postprandial insulin levels in IGT mice. Moreover, Didymin was found to enhance mitochondria biogenesis and function, regulate insulin secretion, and alleviate inflammation and apoptosis. However, these effects were abrogated with the treatment of Rotenone, indicating that Didymin exerts its ameliorative effect by enhancing mitochondria function.

CONCLUSIONS

Didymin exhibits therapeutic potential in the treatment of HFD-induced IGT. This beneficial effect is attributed to the amelioration of PBC dysfunction through improved mitochondrial function.

Functional foods of sub-Saharan Africa and their implications in the management of type 2 diabetes: A review

Throughout the world, the prevalence of metabolic diseases in general and type 2 diabetes (T2DM) in particular is constantly growing, and sub-Saharan Africa (SSA) is not spared. The use of functional foods is a more practical option among the different approaches used in the management of T2DM owing to the fact that they are relatively less costly, safer, and more accessible. In addition to their low glycemic index just like foods currently used to manage diabetes, functional foods contain bioactive compounds such as polyphenols, dietary fibers, saponins, and peptides. They are so named because they have additional health advantages beyond their basic nutritional worth. Bioactive compounds can be found in a variety of SSA plant-based foods, such as spices, fruits, vegetables, legumes, starchy foods, prepared foods, mixed foods, and prepared dishes. The goal of this review is to highlight some of the investigations into the effectiveness of local food and their antidiabetic mechanisms that have been studied in various SSA regions. Using the literature review as a basis, the authors state that SSA foods are rich in various bioactive compounds capable of regulating blood sugar through enhanced glucose tolerance, antioxidant effects, insulin sensitivity, and inhibition or activation of some key enzymes of the glucose metabolism that are linked to the prevention and management of T2DM. Many of the cited findings are preliminary, obtained from cell and preclinical studies, and therefore other studies need to be done to demonstrate the full potential of these foods to serve as bases for dietary guidelines.

Didymin alleviates metabolic dysfunction-associated fatty liver disease (MAFLD) via the stimulation of Sirt1-mediated lipophagy and mitochondrial biogenesis

BACKGROUND

Metabolic dysfunction-associated fatty liver disease (MAFLD) is one of the most prevalent metabolic syndromes worldwide. However, no approved pharmacological treatments are available for MAFLD. Chenpi, one kind of dried peel of citrus fruits, has traditionally been utilized as a medicinal herb for liver diseases. Didymin is a newly identified oral bioactive dietary flavonoid glycoside derived from Chenpi. In this study, we investigated the therapeutic potential of Didymin as an anti-MAFLD drug and elucidated its underlying mechanisms.

METHODS

High-fat diet (HFD)-induced MAFLD mice and alpha mouse liver 12 (AML12) cells were utilized to evaluate the effects and mechanisms of Didymin in the treatment of MAFLD. Liver weight, serum biochemical parameters, and liver morphology were examined to demonstrate the therapeutic efficacy of Didymin in MAFLD treatment. RNA-seq analysis was performed to identify potential pathways that could be affected by Didymin. The impact of Didymin on Sirt1 was corroborated through western blot, molecular docking analysis, microscale thermophoresis (MST), and deacetylase activity assay. Then, a Sirt1 inhibitor (EX-527) was utilized to confirm that Didymin alleviates MAFLD via Sirt1. Western blot and additional assays were used to investigate the underlying mechanisms.

RESULTS

Our results suggested that Didymin may possess therapeutic potential against MAFLD in vitro and in vivo. By promoting Sirt1 expression as well as directly binding to and activating Sirt1, Didymin triggers downstream pathways that enhance mitochondrial biogenesis and function while reducing apoptosis and enhancing lipophagy.

CONCLUSIONS

These suggest that Didymin could be a promising medication for MAFLD treatment. Furthermore, its therapeutic effects are mediated by Sirt1.

Homocysteine May Decrease Glucose Uptake and Alter the Akt/GSK3β/GLUT1 Signaling Pathway in Hippocampal Slices: Neuroprotective Effects of Rivastigmine and Ibuprofen

Homocysteine (Hcy) is a risk factor for neurodegenerative diseases, such as Alzheimer's Disease, and is related to cellular and tissue damage. In the present study, we verified the effect of Hcy on neurochemical parameters (redox homeostasis, neuronal excitability, glucose, and lactate levels) and the Serine/Threonine kinase B (Akt), Glucose synthase kinase-3β (GSK3β) and Glucose transporter 1 (GLUT1) signaling pathway in hippocampal slices, as well as the neuroprotective effects of ibuprofen and rivastigmine alone or in combination in such effects. Male Wistar rats (90 days old) were euthanized and the brains were dissected. The hippocampus slices were pre-treated for 30 min [saline medium or Hcy (30 µM)], then the other treatments were added to the medium for another 30 min [ibuprofen, rivastigmine, or ibuprofen + rivastigmine]. The dichlorofluorescein formed, nitrite and Na+, K+-ATPase activity was increased by Hcy at 30 µM. Ibuprofen reduced dichlorofluorescein formation and attenuated the effect of Hcy. The reduced glutathione content was reduced by Hcy. Treatments with ibuprofen and Hcy + ibuprofen increased reduced glutathione. Hcy at 30 µM caused a decrease in hippocampal glucose uptake and GLUT1 expression, and an increase in Glial Fibrillary Acidic Protein-protein expression. Phosphorylated GSK3β and Akt levels were reduced by Hcy (30 µM) and co-treatment with Hcy + rivastigmine + ibuprofen reversed these effects. Hcy toxicity on glucose metabolism can promote neurological damage. The combination of treatment with rivastigmine + ibuprofen attenuated such effects, probably by regulating the Akt/GSK3β/GLUT1 signaling pathway. Reversal of Hcy cellular damage by these compounds may be a potential neuroprotective strategy for brain damage.

Research Progress on the Pharmacodynamic Mechanisms of Sini Powder against Depression from the Perspective of the Central Nervous System

Depression is a highly prevalent emotional disorder characterized by persistent low mood, diminished interest, and loss of pleasure. The pathological causes of depression are associated with neuronal atrophy, synaptic loss, and neurotransmitter activity decline in the central nervous system (CNS) resulting from injuries, such as inflammatory responses. In Traditional Chinese Medicine (TCM) theory, patients with depression often exhibit the liver qi stagnation syndrome type. Sini Powder (SNP) is a classic prescription for treating such depression-related syndrome types in China. This study systematically summarized clinical applications and experimental studies of SNP for treatments of depression. We scrutinized the active components of SNP with blood-brain barrier (BBB) permeability and speculated about the corresponding pharmacodynamic pathways relevant to depression treatment through intervening in the CNS. Therefore, this article can enhance our understanding of SNP's pharmacological mechanisms and formula construction for depression treatment. Moreover, a re-demonstration of this classic TCM prescription in the modern-science language is of great significance for future drug development and research.

Bioactive Chemical Constituents and Pharmacological Activities of Ponciri Fructus

Ponciri Fructus is a crude drug obtained from the dried immature fruits of Poncirus trifoliata (L). Raf. (Syn. Citrus trifoliata L.). This study aims to compile and analyze the ethnomedicinal uses, bioactive constituents, and pharmacological activities of Ponciri Fructus. Various online bibliographic databases namely, SciFinder, PubMed, Google Scholar, and Web of Science were used for collecting information on traditional uses, biological activities, and bioactive constituents. Concerning ethnomedicinal uses, Ponciri Fructus is extensively used in traditional Korean, Chinese, and Kampo medicines to mitigate allergic reactions, inflammation, edema, digestive complications, respiratory problems, spleen-related problems, liver complications, neuronal pain, hyperlipidemia, rheumatoid arthritis, cardiovascular problems, hernia, sinusitis, and insomnia. Several studies have shown that Ponciri Fructus is a major source of diverse classes of bioactive compounds namely flavonoids, terpenoids, coumarins, phytosterols, and alkaloids. Several in vivo and in vitro pharmacological activity evaluations such as antidiabetic, anti-obesity, anti-inflammatory, antiallergic, antimelanogenic, gastroprotective, anticancer, and neuroprotective effects have been conducted from Ponciri Fructus. However, scientific investigations focusing on bioassay-guided isolation and identification of specific bioactive constituents are limited. Therefore, an in-depth scientific investigation of Ponciri Fructus focusing on bioassay-guided isolation, mechanism based pharmacological studies, pharmacokinetic studies, and evaluation of possible toxicities is necessary in the future.

Didymin, a natural flavonoid, relieves the progression of myocardial infarction via inhibiting the NLR family pyrin domain containing 3 inflammasome

CONTEXT

Globally, the morbidity and mortality of cardiovascular diseases remain high. Didymin, a flavonoid glycoside, has long been used as a dietary antioxidant.

OBJECTIVE

To determine the role of didymin in myocardial infarction (MI), and its possible myocardial protective mechanism.

MATERIALS AND METHODS

C57/BL6 mice (aged 6-8 weeks, n = 40) were divided into five groups: sham group, ischaemia-reperfusion (I/R) group, I/R + didymin (1 mg/kg) group, I/R + didymin (2 mg/kg) group and I/R + didymin (4 mg/kg) group. Didymin was administered intragastrically daily before I/R for 5 consecutive days. H9C2 cells were divided into five groups: control group, H/R group, H/R + didymin (3 μM) group, H/R + didymin (10 μM) group and H/R + didymin (30 μM) group. H9C2 cells were treated with didymin for 24 h before hypoxia/reoxygenation (H/R).

RESULTS

In vivo, didymin reduced the pathological damage and fibrosis of myocardial tissues, decreased the levels of lactate dehydrogenase, creatine kinase, connective tissue growth factor, collagen I and collagen III. Moreover, didymin reduced myocardial apoptosis, inhibited NLRP3, ASC and caspase-1 expression, and alleviated the inflammatory response. In vitro, didymin reduced MI, apoptosis, inflammation and the levels of NLRP3, ASC and caspase-1 in H9C2.

DISCUSSION AND CONCLUSIONS

Didymin prevented the deterioration of MI by inhibiting NLRP3 inflammasome in vivo and in vitro, and may be a potential natural drug for the treatment of MI. Our study provides the scientific basis for further research of didymin.

Strategies in synthetic design and structure-activity relationship studies of novel heterocyclic scaffolds as aldose reductase-2 inhibitors

Heterocyclic scaffolds of natural as well as synthetic origin provide almost all categories of drugs exhibiting a wide range of pharmacological activities, such as antibiotics, antidiabetic and anticancer agents, and so on. Under normal homeostasis, aldose reductase 2 (ALR2) regulates vital metabolic functions; however, in pathological conditions like diabetes, ALR2 is unable to function and leads to secondary diabetic complications. ALR2 inhibitors are a novel target for the treatment of retinopathy (cataract) influenced by diabetes. Epalrestat (stat), an ALR2 inhibitor, is the only drug candidate that was approved in the last four decades; the other drugs from the stat class were retracted after clinical trial studies due to untoward iatrogenic effects. The present study summarizes the recent development (2014 and onwards) of this pharmacologically active ALR2 heterocyclic scaffold and illustrates the rationale behind the design, structure-activity relationships, and biological studies performed on these molecules. The aim of the current review is to pave a straight path for medicinal chemists and chemical biologists, and, in general, to the drug discovery scientists to facilitate the synthesis and development of novel ALR2 inhibitors that may serve as lead molecules for the treatment of diseases related to the ALR2 enzyme.

6-Formyl Umbelliferone, a Furanocoumarin from Angelica decursiva L., Inhibits Key Diabetes-Related Enzymes and Advanced Glycation End-Product Formation

Over the years, great attention has been paid to coumarin derivatives, a set of versatile molecules that exhibit a wide variety of biological activities and have few toxic side effects. In this study, we investigated the antidiabetic potential of 6-formyl umbelliferone (6-FU), a novel furanocoumarin isolated from Angelica decursiva. Numerous pharmacological activities of 6-FU have been previously reported; however, the mechanism of its antidiabetic activity is unknown. Therefore, we examined the action of 6-FU on a few candidate-signaling molecules that may underlie its antidiabetic activity, including its inhibition of protein tyrosine phosphatase 1B (PTP1B), α-glucosidase, human recombinant aldose reductase (HRAR), and advanced glycation end-product (AGE) formation (IC₅₀ = 1.13 ± 0.12, 58.36 ± 1.02, 5.11 ± 0.21, and 2.15 ± 0.13 μM, respectively). A kinetic study showed that 6-FU exhibited mixed-type inhibition against α-glucosidase and HRAR and competitive inhibition of PTP1B. Docking simulations of 6-FU demonstrated negative binding energies and close proximity to residues in the binding pockets of those enzymes. We also investigated the molecular mechanisms underlying 6-FU's antidiabetic effects. 6-FU significantly increased glucose uptake and decreased PTP1B expression in insulin-resistant C2C12 skeletal muscle cells. Moreover, 6-FU (0.8-100 μM) remarkably inhibited the formation of fluorescent AGEs in glucose-fructose-induced human serum albumin glycation over the course of 4 weeks. The findings clearly indicate that 6-FU will be useful in the development of multiple target-oriented therapeutic modalities for the treatment of diabetes and diabetes-related complications.

Didymin Suppresses Microglia Pyroptosis and Neuroinflammation Through the Asc/Caspase-1/GSDMD Pathway Following Experimental Intracerebral Hemorrhage

Neuroinflammation has been proven to exert an important effect on brain injury after intracerebral hemorrhage (ICH). Previous studies reported that Didymin possessed anti-inflammatory properties after acute hepatic injury, hyperglycemia-induced endothelial dysfunction, and death. However, the role of Didymin in microglial pyroptosis and neuroinflammation after ICH is unclear. The current study aimed to investigate the effect of Didymin on neuroinflammation mediated by microglial pyroptosis in mouse models of ICH and shed some light on the underlying mechanisms. In this study, we observed that Didymin treatment remarkably improved neurobehavioral performance and decreased BBB disruption and brain water content. Microglial activation and neutrophil infiltration in the peri-hematoma tissue after ICH were strikingly mitigated by Didymin as well. At the molecular level, administration of Didymin significantly unregulated the expression of Rkip and downregulated the expression of pyroptotic molecules and inflammatory cytokines such as Nlrp3 inflammasome, GSDMD, caspase-1, and mature IL-1β, TNF-α, and MPO after ICH. Besides, Didymin treatment decreased the number of Caspase-1-positive microglia and GSDMD-positive microglia after ICH. Inversely, Locostatin, an Rkip-specific inhibitor, significantly abolished the anti-pyroptosis and anti-neuroinflammation effects of Didymin. Moreover, Rkip binding with Asc could interrupt the activation and assembly of the inflammasome. Mechanistically, inhibition of Caspase-1 by VX-765 attenuated brain injury and suppressed microglial pyroptosis and neuroinflammation by downregulation of GSDMD, mature IL-1β, TNF-α, and MPO based on Locostatin-treated ICH. Taken together, Didymin alleviated microglial pyroptosis and neuroinflammation, at least in part through the Asc/Caspase-1/GSDMD pathway via upregulating Rkip expression after ICH. Therefore, Didymin may be a potential agent to attenuate neuroinflammation via its anti-pyroptosis effect after ICH.

Thyroid-Stimulating Hormone Inhibits Insulin Receptor Substrate-1 Expression and Tyrosyl Phosphorylation in 3T3-L1 Adipocytes by Increasing NF-κB DNA-Binding Activity

Background. Abundant evidence indicates that thyroid-stimulating hormone (TSH) levels are associated with insulin resistance in adipocytes. However, the potential mechanism of the association remains uncertain. The objective of this study was to determine the potential role of TSH in the suppression of insulin receptor substrate-1 (IRS-1) expression and IRS-1 tyrosyl phosphorylation, which might contribute to insulin resistance. Methods. Mouse 3T3-L1 preadipocytes were differentiated into adipocytes. After treatment with 0.01, 0.1, and 1.0 mIU/ml bovine TSH, the TNF-α concentration in the medium was determined by enzyme-linked immunosorbent assay (ELISA). Nuclear factor-kappa B (NF-κB) DNA-binding activity was quantified by electrophoretic mobility shift assay (EMSA). IRS-1 levels in adipocytes were quantified by Western blotting, and tyrosine phosphorylation was measured by immunoprecipitation. Results. TSH induced TNF-α secretion in a dose-dependent manner. There was a significant positive correlation between NF-κB DNA-binding activity and TNF-α secretion. This effect and correlation were weakened by BAY 11-7082 (a nuclear NF-κB inhibitor) and H89 (an inhibitor of cyclic adenosine monophosphate- (cAMP-) dependent protein kinase A (PKA)). Treatment of cultured adipocytes with TSH inhibited insulin-stimulated IRS-1 tyrosyl phosphorylation but promoted TSH-dependent secretion of TNF-α and activation of NF-κB DNA-binding activity. The effects of TSH were significantly inhibited by BAY 11-7082 and H89 and were completely blocked by the TNF-α antagonist WP9QY. Conclusion. TSH inhibited IRS-1 protein expression and tyrosyl phosphorylation in 3T3-L1 adipocytes by stimulating TNF-α production via promotion of NF-κB DNA-binding activity. TSH might play a pivotal role in the development of insulin resistance.

Preparation and Characterization of Auricularia cornea Ehrenb Polysaccharide-Zn Complex and Its Hypoglycemic Activity through Regulating Insulin Resistance in HepG2 Cells

With Auricularia cornea Ehrenb polysaccharide (ACEP) as raw material, the purpose of the study was to prepare Auricularia cornea Ehrenb polysaccharide-zinc (ACEP-Zn) complex. Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), nuclear magnetic resonance (NMR), and other means are used to analyze the physical-chemical properties and structure of ACEP and ACEP-Zn, to investigate the inhibition of α-glycosidase and α-amylase enzymes, and to explore its effects on the glucose metabolism of insulin-resistant HepG2 cells. Nuclear magnetic resonance (NMR) results show that a group of COO-, -CH3, and -OH in the sugar chain binds to Zn2+. Compared with the original polysaccharides, the surface morphology of ACEP-Zn changed obviously, and the molecular weight (Mn) of ACEP-Zn decreased, but the molecular agglomeration of ACEP-Zn increased. Moreover, the inhibitory effect of ACEP-Zn on α-glucosidase and α-amylase was stronger than that of the original polysaccharide. The results indicated that the structure of Auricularia cornea Ehrenb polysaccharide was changed obviously after the zinc complex, and its hypoglycemic activity was enhanced in vitro. In the cell experiment, the glucose consumption of IR-HepG2 cells was significantly increased at a concentration of 50–200 μg/mL ( $P<0.05$ ). The activity of SOD and NOS significantly increased ( $P<0.01$ ), and the activity of intracellular PK increased ( $P<0.05$ ). Therefore, it was speculated that the hypoglycemic effect of Auricularia cornea Ehrenb polysaccharide combined with zinc was related to the alleviation of liver cell damage caused by oxidative stress and the improvement of glucose metabolism of IR-HepG2 cells. The study provides a theoretical basis for the application of the polysaccharide-zinc complex in the hypoglycemic functional food field.

Preparation, Characterization, and Pharmacological Investigation of Withaferin-A Loaded Nanosponges for Cancer Therapy; In Vitro, In Vivo and Molecular Docking Studies

The rapidly growing global burden of cancer poses a major challenge to public health and demands a robust approach to access promising anticancer therapeutics. In parallel, nanotechnology approaches with various pharmacological properties offer efficacious clinical outcomes. The use of new artificial variants of nanosponges (NS) as a transporter of chemotherapeutic drugs to target cells has emerged as a very promising tool. Therefore, in this research, ethylcellulose (EC) NS were prepared using the ultrasonication assisted-emulsion solvent evaporation technique. Withaferin-A (WFA), an active ingredient in Withania somnifera, has been implanted into the nanospongic framework with enhanced anticancer properties. Inside the polymeric structure, WFA was efficiently entrapped (85 ± 11%). The drug (WFA) was found to be stable within polymeric nanosponges, as demonstrated by Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC) studies. The WFA-NS had a diameter of 117 ± 4 nm and zeta potential of −39.02 ± 5.71 mV with a polydispersity index (PDI) of 0.419 ± 0.073. In addition, scanning electron microscopy (SEM) revealed the porous surface texture of WFA-NS. In vitro anticancer activity (SRB assay) results showed that WFA–NS exhibited almost twice the anticancer efficacy against MCF-7 cells (IC₅₀ = 1.57 ± 0.091 µM), as quantified by flow cytometry and comet tests. Moreover, fluorescence microscopy with DAPI staining and analysis of DNA fragmentation revealed apoptosis as a mechanism of cancer cell death. The anticancer activity of WFA-NS was further determined in vivo and results were compared to cisplatin. The anticancer activity of WFA-NS was further investigated in vivo, and the data were consistent to those obtained with cisplatin. At Day 10, WFA-NS (10 mg/kg) significantly reduced tumour volume to 72 ± 6%, which was comparable to cisplatin (10 mg/kg), which reduced tumour volume to 78 ± 8%. Finally, the outcomes of molecular modeling (in silico) also suggested that WFA established a stable connection with nanosponges, generating persistent hydrophobic contacts (polar and nonpolar) and helping with the attractive delayed-release features of the formulation. Collectively, all the findings support the use of WFA in nanosponges as a prototype for cancer treatment, and opened up new avenues for increasing the efficacy of natural product-derived medications.

Citrus polyphenols and risk of type 2 diabetes: Evidence from mechanistic studies

Citrus fruits are a rich source of (poly)phenols, a group of dietary bioactive compounds that protect against developing type 2 diabetes. Our review critically evaluates how experimental in vitro and animal models have elucidated some of the underlying mechanisms on how citrus (poly)phenols affect the markers of type 2 diabetes. According to animal studies, the beneficial effects derived from consuming citrus compounds appear to be related to long-term effects, rather than acute. There are some notable effects from citrus (poly)phenol metabolites on post-absorptive processes, such as modulation of hepatic glucose metabolism and insulin sensitivity in target tissues, but with a more modest effect on digestion and sugar absorption within the gut. Experimental studies on cells and other systems in vitro have indicated some of the possible mechanisms involved, but ∼70% of the studies utilized unrealistically high concentrations and forms of the compounds, compromising physiological relevance. Future studies should discuss the relevance of concentration used in in vitro experiments, relative to the proposed site of action, and also examine the role of catabolites produced by the gut microbiota. Finally, it is important to examine the relationship between the gut microbiota and bioavailability on the action of citrus (poly)phenols.

Phytochemicals as PI3K/ Akt/ mTOR Inhibitors and Their Role in Breast Cancer Treatment

BACKGROUND

Breast cancer is the predominant form of cancer in women; various cellular pathways are involved in the initiation and progression of breast cancer. Among the various types of breast cancer that differ in their growth factor receptor status, PI3K/Akt signaling is a common pathway where all these converge. Thus, the PI3K signaling is of great interest as a target for breast cancer prevention; however, it is less explored.

OBJECTIVE

The present review is aimed to provide a concise outline of the role of PI3K/Akt/mTOR pathway in breast carcinogenesis and its progression events, including metastasis, drug resistance and stemness. The review emphasizes the role of natural and synthetic inhibitors of PI3K/Akt/m- TOR pathway in breast cancer prevention.

METHODS

The data were obtained from PubMed/Medline databases, Scopus and Google patent literature.

RESULTS

PI3K/Akt/mTOR signaling plays an important role in human breast carcinogenesis; it acts on the initiation and progression events associated with it. Numerous molecules have been isolated and identified as promising drug candidates by targeting the signaling pathway. Results from clinical studies confirm their application in the treatment of human breast cancer alone and in combination with classical chemotherapeutics as well as monoclonal antibodies.

CONCLUSION

PI3K/mTOR signaling blockers have evolved as promising anticancer agents by interfering breast cancer development and progression at various stages. Natural products and bioactive components are emerging as novel inhibitors of PI3K signaling and more research in this area may yield numerous drug candidates.

Natural α-Glucosidase and Protein Tyrosine Phosphatase 1B Inhibitors: A Source of Scaffold Molecules for Synthesis of New Multitarget Antidiabetic Drugs

Diabetes mellitus (DM) represents a group of metabolic disorders that leads to acute and long-term serious complications and is considered a worldwide sanitary emergence. Type 2 diabetes (T2D) represents about 90% of all cases of diabetes, and even if several drugs are actually available for its treatment, in the long term, they show limited effectiveness. Most traditional drugs are designed to act on a specific biological target, but the complexity of the current pathologies has demonstrated that molecules hitting more than one target may be safer and more effective. The purpose of this review is to shed light on the natural compounds known as α-glucosidase and Protein Tyrosine Phosphatase 1B (PTP1B) dual-inhibitors that could be used as lead compounds to generate new multitarget antidiabetic drugs for treatment of T2D.

Plants Secondary Metabolites as Blood Glucose-Lowering Molecules

Recently, significant advances in modern medicine and therapeutic agents have been achieved. However, the search for effective antidiabetic drugs is continuous and challenging. Over the past decades, there has been an increasing body of literature related to the effects of secondary metabolites from botanical sources on diabetes. Plants-derived metabolites including alkaloids, phenols, anthocyanins, flavonoids, stilbenoids, saponins, tannins, polysaccharides, coumarins, and terpenes can target cellular and molecular mechanisms involved in carbohydrate metabolism. In addition, they can grant protection to pancreatic beta cells from damage, repairing abnormal insulin signaling, minimizing oxidative stress and inflammation, activating AMP-activated protein kinase (AMPK), and inhibiting carbohydrate digestion and absorption. Studies have highlighted many bioactive naturally occurring plants' secondary metabolites as candidates against diabetes. This review summarizes the current knowledge compiled from the latest studies published during the past decade on the mechanism-based action of plants-derived secondary metabolites that can target various metabolic pathways in humans against diabetes. It is worth mentioning that the compiled data in this review will provide a guide for researchers in the field, to develop candidates into environment-friendly effective, yet safe antidiabetics.

Significant effects of Ganoderma lucidum polysaccharide on lipid metabolism in diabetes may be associated with the activation of the FAM3C-HSF1-CAM signaling pathway

Diabetes is a threat to patient health worldwide. Type 2 diabetes (T2DM), one of the two main types of diabetes, is a long-term metabolic disease caused by heredity and environmental factors. It has been reported that Ganoderma lucidum polysaccharide (GLP) significantly decreased the concentration of blood glucose, promoted insulin secretion, improved glucose tolerance and regulated the concentration of blood lipids. In the present study, a T2DM model was established in db/db mice, following which T2DM mice were treated with GLP (100 and 400 mg/kg) for 8 weeks, with MET used as the positive control. The glycosylated hemoglobin (HbAlc) and fasting blood glucose (FBG) levels, and diabetes-associated clinical chemistry indexes were detected in the blood and serum of each mouse. Hematoxylin and eosin, and oil red O staining were performed on the livers of each mouse to evaluate the level of liver fat. The expression levels of family with sequence similarity 3 (FAM3C), heat shock factor 1 (HSF1), calmodulin (CaM), AKT and phosphorylated (p)-AKT were detected in the hepatocytes of T2DM mice using reverse transcription-quantitative PCR and western blotting. The results demonstrated that the unbalanced levels of HbAlc, FBG and diabetes-related index in T2DM mice were significantly improved by treatment with GLP. Lipid droplets in the hepatocytes of mice shrank in the GLP groups compared with the model control group. The expression levels of FAM3C, HSF1, CaM and p-AKT/AKT in the hepatocytes of T2DM mice were significantly increased following treatment with GLP. In conclusion, GLP exerted significant effects on lipid metabolism in diabetes, which may be associated with the activation of the FAM3C-HSF1-CaM signaling pathway.

Didymin switches M1-like toward M2-like macrophage to ameliorate ulcerative colitis via fatty acid oxidation

Inflammatory response by different polarized macrophages has a critical role in a variety of immunological pathophysiology, such as ulcerative colitis (UC). Herein, targeting the paradigm of macrophage phenotypes by small molecular modulators may influence the disease status. In the present study, we firstly demonstrated that didymin, one of the most abundant flavonoid constituents present in the citrus fruits such as oranges and lemons, remarkably attenuated the clinical symptoms of acute and chronic colitis in mice. Mechanistic studies showed that didymin converted pro-inflammatory M1-like to anti-inflammatory M2-like macrophage phenotype, but did not alter the polarization of M2-like macrophages. Metabolic tracing studies revealed that didymin strengthened fatty acid oxidation rather than glycolysis by inducing Hadhb expression. More importantly, in vivo studies verified that promotion of Hadhb expression resulted in the conversion of M1- toward M2-like macrophages and eventually alleviated colitis. Our data highlights the potential of macrophage paradigm in UC inflammation and put forth the stage for considering didymin as a metabolism regulator in reprogramming macrophage polarization, which may serve as a promising therapeutic approach for treatment of inflammation-associated disorders.

Natural Triterpenoids Isolated from Akebia trifoliata Stem Explants Exert a Hypoglycemic Effect via α-Glucosidase Inhibition and Glucose Uptake Stimulation in Insulin-Resistant HepG2 Cells

The inhibition of α-glucosidase activity is a prospective approach to attenuate postprandial hyperglycemia in the treatment of type 2 diabetes mellitus (T2DM). Herein, the inhibition of α-glucosidase by three compounds T₁ -T₃ of Akebia trifoliata stem, namely hederagenin (T₁ ), 3-epiakebonoic acid (T₂ ), and arjunolic acid (T₃ ) were investigated using enzyme kinetics and molecular docking analysis. The three triterpenoids exhibited excellent inhibitory activities against α-glucosidase. T₁ -T₃ showed the strongest inhibition with IC₅₀ values of 42.1±5.4, 19.6±3.2, and 11.2±2.3 μM, respectively, compared to the acarbose positive control (IC₅₀ =106.3±8.2). Enzyme inhibition kinetics showed that triterpenoids T₁ -T₃ demonstrated competitive, mixed, and noncompetitive-type inhibition against α-glucosidase, respectively. The inhibition constant (K_i ) values were 21.21, 7.70, and 3.18 μM, respectively. Docking analysis determined that the interaction of ligands T₁ -T₃ and α-glucosidase was mainly forced by hydrogen bonds and hydrophobic interactions, which could result in improved binding to the active site of the target enzyme. The insulin resistant (IR)-HepG2 cell model used in this study (HepG2 cells exposed to 10^-7  M insulin for 24 h) and glucose uptake assays showed that compounds T₁ -T₃ had no cytotoxicity with concentrations ranging from 6.25 to 25 μM and displayed significant stimulation of glucose uptake in IR-HepG2 cells. Thus, triterpenoids T₁ -T₃ showed dual therapeutic effects of α-glucosidase inhibition and glucose uptake stimulation and could be used as potential medicinal resources to investigate new antidiabetic agents for the prevention or treatment of diabetes.

Fasudil alleviated insulin resistance through promotion of proliferation, attenuation of cell apoptosis and inflammation and regulation of RhoA/Rho kinase/insulin/nuclear factor-κB signalling pathway in HTR-8/SVneo cells

OBJECTIVES

The aim of this study was to evaluate the effects of fasudil on insulin resistance (IR) in HTR-8/SVneo cells.

METHODS

HTR-8/SVneo cells were treated with insulin or/and fasudil. Cell proliferation, apoptosis, inflammation and related signalling pathways were assessed.

KEY FINDINGS

Insulin treatment significantly enhanced the protein expressions of RhoA and Rho kinase (ROCK1 and ROCK2), but decreased glucose consumption. Administration of fasudil effectively promoted glucose uptake. Moreover, fasudil enhanced cell viability and the level of proliferating cell nuclear antigen (PCNA). Insulin-mediated cell apoptosis was inhibited by fasudil via the down-regulation of bax and cleaved-caspase-3, and the up-regulation of bcl-2. At the same time, fasudil led to the reduction of IL-1β, TNF-α, IL-6 and IL-8 mRNA levels in insulin-treated cells. In addition, RhoA, ROCK2 and phosphorylated myosin phosphatase target subunit-1 (p-MYPT-1) expressions were down-regulated by fasudil. Importantly, fasudil activated insulin receptor substrate-1 (IRS-1) through increasing p-IRS-1 (Tyr612) and p-Akt expressions. The nuclear NF-κB p65 and p-IκB-α levels were reduced via the administration of fasudil in insulin-treated cells.

CONCLUSIONS

Fasudil mitigated IR by the promotion of cell proliferation, inhibition of apoptosis and inflammation and regulation of RhoA/ROCK/insulin/NF-κB signalling pathway through in vitro studies.

Citrus flavonoids and their antioxidant evaluation

The antioxidant ability is the link and bridge connecting a variety of biological activities. Citrus flavonoids play an essential role in regulating oxidative stress and are an important source of daily intake of antioxidant supplements. Many studies have shown that citrus flavonoids promote health through antioxidation. In this review, the biosynthesis, composition and distribution of citrus flavonoids were concluded. The detection methods of antioxidant capacity of citrus flavonoids were divided into four categories: chemical, cellular, animal and clinical antioxidant capacity evaluation systems. The modeling methods, applicable scenarios, and their relative merits were compared based on these four systems. The antioxidant functions of citrus flavonoids under different evaluation systems were also discussed, especially the regulation of the Nrf2-antioxidases pathway. Some shortcomings in the current research were pointed out, and some suggestions for progress were put forward.

Identification of Flavoanoids From Finger Citron and Evaluation on Their Antioxidative and Antiaging Activities

Finger citron (Citrus medica L. var. sarcodactylis Swingle) is a traditional Chinese herb and considered as a healthy food. Flavonoids are the major bioactive substances in Finger citron. In this study, the major flavonoids of finger citron (FFC) were purified with AB-8 macroporous resins, and then three of them were identified as diosmetin-6-8-di-C-glucoside, hesperidin and diosmetin-6-C-glucoside, and other two were preliminarily inferred as limocitrol 3-alpha-l-arabinopyranosyl-(1->3)-galactoside and scutellarein 4′-methyl ether 7-glucoside by high-performance liquid chromatography and ultraperformance liquid chromatography to quadrupole time-of-flight mass spectrometry. Further, their antioxidation and antiaging activities were determined in vitro and in vivo. In vitro, chemical assays revealed that the purified FFC had strong antioxidative activity as demonstrated by its strong DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS [2,2-azinobis (3-ethyl-benzothiazoline-6-sulphonic acid) diammonium salt] radical scavenging activities and ORAC (oxygen radical absorbance capacity). In vivo, the purified FFC significantly increased the mean and maximum lifespan of Caenorhabditis elegans by 31.26 and 26.59%, respectively, and showed no side effects on their physiological functions. Under normal and oxidative stress conditions, purified FFC reduced the accumulation of reactive oxygen species (ROS) and malondialdehyde, while increased superoxide dismutase (SOD) and catalase (CAT) enzyme activities in C. elegans. Together, we successfully identified three major substances in purified FFC of finger citron and determined the excellent antiaging activity of FFC, which is attributed to its strong antioxidative activity and effect on homeostasis of ROS.

Citrus Flavonoids as Promising Phytochemicals Targeting Diabetes and Related Complications: A Systematic Review of In Vitro and In Vivo Studies

The consumption of plant-based food is important for health promotion, especially concerning the prevention and management of chronic diseases. Flavonoids are the main bioactive compounds in citrus fruits, with multiple beneficial effects, especially antidiabetic effects. We systematically review the potential antidiabetic action and molecular mechanisms of citrus flavonoids based on in vitro and in vivo studies. A search of the PubMed, EMBASE, Scopus, and Web of Science Core Collection databases for articles published since 2010 was carried out using the keywords citrus, flavonoid, and diabetes. All articles identified were analyzed, and data were extracted using a standardized form. The search identified 38 articles, which reported that 19 citrus flavonoids, including 8-prenylnaringenin, cosmosiin, didymin, diosmin, hesperetin, hesperidin, isosiennsetin, naringenin, naringin, neohesperidin, nobiletin, poncirin, quercetin, rhoifolin, rutin, sineesytin, sudachitin, tangeretin, and xanthohumol, have antidiabetic potential. These flavonoids regulated biomarkers of glycemic control, lipid profiles, renal function, hepatic enzymes, and antioxidant enzymes, and modulated signaling pathways related to glucose uptake and insulin sensitivity that are involved in the pathogenesis of diabetes and its related complications. Citrus flavonoids, therefore, are promising antidiabetic candidates, while their antidiabetic effects remain to be verified in forthcoming human studies.

Novel Protein Tyrosine Phosphatase 1B Inhibitor-Geranylated Flavonoid from Mulberry Leaves Ameliorates Insulin Resistance

Mulberry leaf is a common vegetable with a variety of beneficial effects, such as hypoglycemic activity. However, the underlying mechanism of its hypoglycemic effect have not been fully revealed. In this study, two flavonoid derivatives were isolated from mulberry leaves, a new geranylated flavonoid compound (1) and its structural analogue (2). The structures of compounds 1 and 2 were elucidated using spectroscopic analysis. To study the potential hypoglycemic properties of these compounds, their regulatory effects on protein tyrosine phosphatase 1B (PTP1B) were investigated. In comparison to oleanolic acid, compounds 1 and 2 showed significant inhibitory activities (IC₅₀ = 4.53 ± 0.31 and 10.53 ± 1.76 μM) against PTP1B, the positive control (IC₅₀ = 7.94 ± 0.76 μM). Molecular docking predicted the binding sites of compound 1 to PTP1B. In insulin-resistance HepG2 cell, compound 1 promoted glucose consumption in a dose-dependent manner. Furthermore, western blot and polymerase chain reaction analyses indicated that compound 1 might regulate glucose consumption through the PTP1B/IRS/PI3K/AKT pathway. In conclusion, geranylated flavonoids in mulberry leaves inhibite PTP1B and increase the glucose consumption in insulin-resistant cells. These findings provide an important basis for the use of mulberry leaf flavonoids as a dietary supplement to regulate glucose metabolism.

Poncirin, an orally active flavonoid exerts antidiabetic complications and improves glucose uptake activating PI3K/Akt signaling pathway in insulin resistant C2C12 cells with anti-glycation capacities

Poncirin, a natural flavanone glycoside present abundantly in many citrus fruits, contains an extensive range of biological activities. However, the antidiabetic mechanism of poncirin is unexplored yet. In this study, we examined the anti-diabetic prospective of poncirin by evaluating its ability to inhibit protein tyrosine phosphatase 1B (PTP1B), α-glucosidase, human recombinant AR (HRAR), rat lens aldose reductase (RLAR), and advanced glycation end-product (AGE) formation (IC₅₀ = 7.76 ± 0.21, 21.31 ± 1.26, 3.56 ± 0.33, 11.91 ± 0.21, and 3.23 ± 0.09 µM, respectively). Kinetics data and docking studies showed the lowest binding energy and highestaffinityforthemixed and competitivetypeof inhibitorsof poncirin. Moreover, the molecular mechanisms underlying the antidiabetic outcomes of poncirin in insulin resistant C2C12 skeletal muscle cells were explored, which significantly increased glucose uptake and decreased the expression of PTP1B in C2C12 cells. Consequently, poncirin increased GLUT-4 expression level by activating the IRS-1/PI3K/Akt/GSK-3 signaling pathway. Moreover, poncirin (0.5-50 µM) remarkably inhibited the formation of fluorescent AGE, nonfluorescent CML, fructosamine, and β-cross amyloid structures in glucose-fructose-induced BSA glycation during 4 weeks of study. Poncirin also notably prevented protein oxidation demonstrated with decreasing the protein carbonyl and the consumption of protein thiol in the dose-dependent manner. The results clearly expressed the promising activity of poncirin for the therapy of diabetes and its related complications.

Assessment of the Phenolic Profiles, Hypoglycemic Activity, and Molecular Mechanism of Different Highland Barley (Hordeum vulgare L.) Varieties

The phenolic profiles, hypoglycemic activity, and molecular mechanism of the effect on type 2 diabetes mellitus (T2DM) of four highland barley varieties were investigated in the present study. The fundamental phenolics in highland barley were ferulic acid, naringin, and catechin, which mainly existed in bound form. These varieties showed favorable hypoglycemic activity via inhibition of α-glucosidase and α-amylase activities, enhancement of glucose consumption, glycogen accumulation and glycogen synthase 2 (GYS2) activity, and down-regulation of glucose-6-phosphatase (G6Pase) and phosphoenolpyruvate carboxykinase (PEPCK) activities. Specifically, ZQ320 variety exhibited the strongest hypoglycemic activity compared to the other varieties. Highland barley phenolics could inhibit gluconeogenesis and motivate glycogen synthesis via down-regulating the gene expression of G6Pase, PEPCK, and glycogen synthase kinase 3β (GSK3β), while activating the expression of insulin receptor substrate-1 (IRS-1), phosphatidylinositol 3 kinase (PI3K), serine/threonine kinase (Akt), GYS2, and glucose transporter type 4 (GLUT4). Therefore, phenolics from highland barley could be served as suitable candidates for therapeutic agent in T2DM to improve human health.

Adipose tissue as a possible therapeutic target for polyphenols: A case for Cyclopia extracts as anti-obesity nutraceuticals

Obesity is a significant contributor to increased morbidity and premature mortality due to increasing the risk of many chronic metabolic diseases such as type 2 diabetes, cardiovascular disease and certain types of cancer. Lifestyle modifications such as energy restriction and increased physical activity are highly effective first-line treatment strategies used in the management of obesity. However, adherence to these behavioral changes is poor, with an increased reliance on synthetic drugs, which unfortunately are plagued by adverse effects. The identification of new and safer anti-obesity agents is thus of significant interest. In recent years, plants and their phenolic constituents have attracted increased attention due to their health-promoting properties. Amongst these, Cyclopia, an endemic South African plant commonly consumed as a herbal tea (honeybush), has been shown to possess modulating properties against oxidative stress, hyperglycemia, and obesity. Likewise, several studies have reported that some of the major phenolic compounds present in Cyclopia spp. exhibit anti-obesity effects, particularly by targeting adipose tissue. These phenolic compounds belong to the xanthone, flavonoid and benzophenone classes. The aim of this review is to assess the potential of Cyclopia extracts as an anti-obesity nutraceutical as underpinned by in vitro and in vivo studies and the underlying cellular mechanisms and biological pathways regulated by their phenolic compounds.