(-)-Epicatechin-3-O-β-D-allopyranoside from Davallia formosana prevents diabetes and dyslipidemia in streptozotocin-induced diabetic mice

Red rice bran aqueous extract ameliorate diabetic status by inhibiting intestinal glucose transport in high fat diet/STZ-induced diabetic rats

Red rice (Oryza sativa L.) consumption has grown recently, partly due to its potential health benefits in several disease prevention. The impact of red rice bran aqueous extract (RRBE) on intestinal glucose uptake and diabetes mellitus (DM) progression has not been thoroughly investigated. This study aimed to evaluate the effect of RRBE on ex vivo intestinal glucose absorption and its potential as an antihyperglycemic compound using a high-fat diet and streptozotocin (STZ)-induced diabetic rats. High-fat diet/STZ-induced diabetic rats were supplemented with either 1000 mg/kg body weight (BW) of RRBE, 70 mg/kg BW of metformin (Met), or a combination of RRBE and Met for 3 months. Plasma parameters, intestinal glucose transport, morphology, liver and soleus muscle glycogen accumulation were assessed. Treatment with RRBE, metformin, or combination markedly reversed hyperglycemia, hypertriglyceridemia, insulin resistance, and pancreatic morphology changes associated with T2DM. Correspondingly, all supplements effectively downregulated glucose transporters, resulting in a reduction of intestinal glucose transport-additionally, liver and soleus muscle glycogen accumulation was reduced in RRBE + Met treated group. Taken together, RRBE potentially suppressed intestinal glucose transporters' function and expression, reducing diabetic status.

The Ethyl Acetate Extract of Phyllanthus emblica L. Alleviates Diabetic Nephropathy in a Murine Model of Diabetes

Oil-Gan is the fruit of the genus Phyllanthus emblica L. The fruits have excellent effects on health care and development values. There are many methods for the management of diabetic nephropathy (DN). However, there is a lack of effective drugs for treating DN throughout the disease course. The primary aim of this study was to examine the protective effects (including analyses of urine and blood, and inflammatory cytokine levels) and mechanisms of the ethyl acetate extract of P. emblica (EPE) on db/db mice, an animal model of diabetic nephropathy; the secondary aim was to examine the expression levels of p- protein kinase Cα (PKCα)/t-PKCα in the kidney and its downregulation of vascular endothelial growth factor (VEGF) and fibrosis gene transforming growth factor-β1 (TGF-β1) by Western blot analyses. Eight db/m mice were used as the control group. Forty db/db mice were randomly divided into five groups. Treatments included a vehicle, EPE1, EPE2, EPE3 (at doses of 100, 200, or 400 mg/kg EPE), or the comparative drug aminoguanidine for 8 weeks. After 8 weeks of treatment, the administration of EPE to db/db mice effectively controlled hyperglycemia and hyperinsulinemia by markedly lowering blood glucose, insulin, and glycosylated HbA1c levels. The administration of EPE to db/db mice decreased the levels of BUN and creatinine both in blood and urine and reduced urinary albumin excretion and the albumin creatine ratio (UACR) in urine. Moreover, EPE treatment decreased the blood levels of inflammatory cytokines, including kidney injury molecule-1 (KIM-1), C-reactive protein (CRP), and NLR family pyrin domain containing 3 (NLRP3). Our findings showed that EPE not only had antihyperglycemic effects but also improved renal function in db/db mice. A histological examination of the kidney by immunohistochemistry indicated that EPE can improve kidney function by ameliorating glomerular morphological damage following glomerular injury; alleviating proteinuria by upregulating the expression of nephrin, a biomarker of early glomerular damage; and inhibiting glomerular expansion and tubular fibrosis. Moreover, the administration of EPE to db/db mice increased the expression levels of p- PKCα/t-PKCα but decreased the expression levels of VEGF and renal fibrosis biomarkers (TGF-β1, collagen IV, p-Smad2, p-Smad3, and Smad4), as shown by Western blot analyses. These results implied that EPE as a supplement has a protective effect against renal dysfunction through the amelioration of insulin resistance as well as the suppression of nephritis and fibrosis in a DN model.

Antidiabetic and antihyperlipidemic activities of Phyllanthus emblica L. extract in vitro and the regulation of Akt phosphorylation, gluconeogenesis, and peroxisome proliferator-activated receptor α in streptozotocin-induced diabetic mice

Background

The fruits of Phyllanthus emblica L. are high in nutrients and have excellent health care function and developmental value. There are many management strategies available for diabetes and hyperlipidemia. Nevertheless, there is a lack of an effective and nontoxic drug.

Objective

The present study was designed to first screen four extracts of P. emblica L. on insulin signaling target gene expression levels, including glucose transporter 4 (GLUT4) and p-Akt/t-Akt. The ethyl acetate extract of P. emblica L. (EPE) exhibited the most efficient activity among the four extracts and was thus chosen to explore the antidiabetic and antihyperlipidemic activities in streptozotocin (STZ)-induced type 1 diabetic mice.

Design

All mice (in addition to one control (CON) group) were administered STZ injections (intraperitoneal) for 5 consecutive days, and then STZ-induced mice were administered EPE (at 100, 200, or 400 mg/kg body weight), fenofibrate (Feno) (at 250 mg/kg body weight), glibenclamide (Glib) (at 10 mg/kg body weight), or vehicle by oral gavage once daily for 4 weeks. Finally, histological examination, blood biochemical parameters, and target gene mRNA expression levels were measured, and liver tissue was analyzed for the levels of malondialdehyde (MDA), a maker of lipid peroxidation.

Results

EPE treatment resulted in decreased levels of blood glucose, HbA1C, triglycerides (TGs), and total cholesterol and increased levels of insulin compared with the vehicle-treated STZ group. EPE treatment decreased blood levels of HbA1C and MDA but increased glutathione levels in liver tissue, implying that EPE exerts antioxidant activity and could prevent oxidative stress and diabetes. The EPE-treated STZ mice displayed an improvement in the sizes and numbers of insulin-expressing β cells. EPE treatment increased the membrane expression levels of skeletal muscular GLUT4, and also reduced hepatic mRNA levels of glucose-6-phosphatase (G6Pase) and phosphoenolpyruvate carboxykinase thereby inhibiting hepatic gluconeogenesis. This resulted in a net glucose lowering effect in EPE-treated STZ mice. Furthermore, EPE increased the expression levels of p-AMPK/t-AMPK in both the skeletal muscle and liver tissue compared with vehicle-treated STZ mice. EPE-treated STZ mice showed enhanced expression levels of fatty acid oxidation enzymes, including peroxisome proliferator-activated receptor α (PPARα), but reduced expression levels of lipogenic genes including fatty acid synthase, as well as decreased mRNA levels of sterol regulatory element binding protein 1c (SREBP1c), apolipoprotein-CIII (apo-CIII), and diacylglycerol acyltransferase-2 (DGAT2). This resulted in a reduction in plasma TG levels. EPE-treated STZ mice also showed reduced expression levels of PPAR γ. This resulted in decreased adipogenesis, fatty acid synthesis, and lipid accumulation within liver tissue, and consequently, lower TG levels in liver tissue and blood. Furthermore, EPE treatment not only displayed an increase in the Akt activation in liver tissue, but also in C2C12 myotube in the absence of insulin. These results implied that EPE acts as an activator of AMPK and /or as a regulator of the insulin (Akt) pathway.

Conclusions

Taken together, EPE treatment exhibited amelioration of the diabetic and hyperlipidemic state in STZ-induced diabetic mice.

The Potential Hepatoprotective Effect of Vaccinium arctostaphylos L. Fruit Extract in Diabetic Rat

OBJECTIVE

Vaccinium arctostaphylos has traditionally been employed in Iranian folk medicine to treat diabetes. However, the precise molecular mechanisms underlying its antidiabetic properties remain incompletely understood. The current experiment intended to explore the modulatory effects of V. arctostaphylos fruit ethanolic extract (VAE) on biochemical and molecular events in the livers of diabetic rats.

MATERIALS AND METHODS

In this experimental study, male Wistar rats were randomly assigned to four groups: normal control, normal rats with VAE treatment, diabetic control, and diabetic rats with VAE treatment. Following 42 days of treatment, the impact of VAE on diabetes-induced rats was assessed by measuring various serum biochemical parameters, including insulin, free fatty acids (FFA), tumor necrosis factor-α (TNF-α), reactive oxygen species (ROS), and adiponectin levels. The activities of hepatic carbohydrate metabolic enzymes and glycogen content were determined. Additionally, expression levels of selected genes implicated in carbohydrate/lipid metabolism and miR-27b expression were evaluated. H and E-stained liver sections were prepared for light microscopy examination.

RESULTS

Treatment with VAE elevated levels of insulin and adiponectin that reduced levels of FFA, ROS, and TNF-α in the serum of diabetic rats. VAE-treated rats exhibited increased activities of hepatic glucokinase (GK), glucose-6-phosphate dehydrogenase (G6PD), and glycogen concentrations, in conjunction with decreased activities of glucose-6-phosphatase (G6Pase) and fructose-1,6-bisphosphatase (FBPase). Furthermore, VAE significantly upregulated the transcription levels of hepatic insulin receptor substrate 1 (Irs1) and glucose transporter 2 (Glut2), while considerably downregulated the expression of peroxisome proliferator-activated receptor gamma (Pparg) and sterol regulatory element-binding protein 1c (Srebp1c). VAE remarkably enhanced the expression of miR27-b in the hepatic tissues of diabetic rats. Abnormal histological signs were dramatically normalized in diabetic rats receiving VAE compared to those in the diabetic control group.

CONCLUSION

Our findings underscore the hypoglycemic and hypolipidemic activities of V. arctostaphylos and assist in better comprehension of its antidiabetic properties.

Antidiabetic and Immunoregulatory Activities of Extract of Phyllanthus emblica L. in NOD with Spontaneous and Cyclophosphamide-Accelerated Diabetic Mice

Oil-Gan, also known as emblica, is the fruit of the genus Phyllanthus emblica L. The fruits are high in nutrients and display excellent health care functions and development values. The primary aim of this study was to investigate the activities of ethyl acetate extract from Phyllanthus emblica L. (EPE) on type 1 diabetes mellitus (T1D) and immunoregulatory activities in non-obese diabetes (NOD) mice with spontaneous and cyclophosphamide (Cyp)-accelerated diabetes. EPE was vehicle-administered to spontaneous NOD (S-NOD) mice or Cyp-accelerated NOD (Cyp-NOD) mice once daily at a dose of 400 mg/kg body weight for 15 or 4 weeks, respectively. At the end, blood samples were collected for biological analyses, organ tissues were dissected for analyses of histology and immunofluorescence (IF) staining (including expressions of Bcl and Bax), the expression levels of targeted genes by Western blotting and forkhead box P3 (Foxp3), and helper T lymphocyte 1 (Th1)/Th2/Th17/Treg regulatory T cell (Treg) cell distribution by flow cytometry. Our results showed that EPE-treated NOD mice or Cyp-accelerated NOD mice display a decrease in levels of blood glucose and HbA1c, but an increase in blood insulin levels. EPE treatment decreased blood levels of IFN-γ and tumor necrosis α (TNF-α) by Th1 cells, and reduced interleukin (IL)-1β and IL-6 by Th17 cells, but increased IL-4, IL-10, and transforming growth factor-β1 (TGF-β1) by Th2 cells in both of the two mice models by enzyme-linked immunosorbent assay (ELISA) analysis. Flow cytometric data showed that EPE-treated Cyp-NOD mice had decreased the CD4⁺ subsets T cell distribution of CD4⁺IL-17 and CD4⁺ interferon gamma (IFN-γ), but increased the CD4⁺ subsets T cell distribution of CD4⁺IL-4 and CD4⁺Foxp3. Furthermore, EPE-treated Cyp-NOD mice had decreased the percentage per 10,000 cells of CD4⁺IL-17 and CD4⁺IFNγ, and increased CD4⁺IL-4 and CD4⁺Foxp3 compared with the Cyp-NOD Con group (p < 0.001, p < 0.05, p < 0.05, and p < 0.05, respectively). For target gene expression levels in the pancreas, EPE-treated mice had reduced expression levels of inflammatory cytokines, including IFN-γ and TNF-α by Th1 cells, but increased expression levels of IL-4, IL-10, and TGF-1β by Th2 cells in both two mice models. Histological examination of the pancreas revealed that EPE-treated mice had not only increased pancreatic insulin-expressing β cells (brown), and but also enhanced the percentage of Bcl-2 (green)/Bax (red) by IF staining analyses of islets compared with the S-NOD Con and the Cyp-NOD Con mice, implying that EPE displayed the protective effects of pancreas β cells. EPE-treated mice showed an increase in the average immunoreactive system (IRS) score on insulin within the pancreas, and an enhancement in the numbers of the pancreatic islets. EPE displayed an improvement in the pancreas IRS scores and a decrease in proinflammatory cytokines. Moreover, EPE exerted blood-glucose-lowering effects by regulating IL-17 expressions. Collectively, these results implied that EPE inhibits the development of autoimmune diabetes by regulating cytokine expression. Our results demonstrated that EPE has a therapeutic potential in the preventive effects of T1D and immunoregulation as a supplementary.

Danlou Tablet May Alleviate Vascular Injury Caused by Chronic Intermittent Hypoxia through Regulating FIH-1, HIF-1, and Angptl4

Background

Danlou tablet (DLT), the traditional Chinese medicine has been commonly used for dyslipidemia, atherosclerosis, and coronary heart disease. Whether it was effective against vascular injury caused by CIH has remained unknown. The aim of the current study was to observe the effects of DLT on chronic intermittent hypoxia (CIH)-induced vascular injury via regulation of blood lipids and to explore potential mechanisms.

Methods

Sixteen 12-week-old male ApoE-/- mice were randomly divided into four groups. The sham group was exposed to normal room air, whereas the other three groups were exposed to CIH. Mice in the CIH + normal saline (NS) group were gavaged with NS. Mice in the CIH + Angptl4-ab group were intraperitoneally injected with Angptl4-antibody. Mice in the CIH + DLT group were gavaged with DLT. After four weeks of intervention, serum lipid concentrations, and serum lipoprotein lipase (LPL) activity were detected. The changes in atherosclerosis in vascular tissue were detected by hematoxylin and eosin (H&E) staining. Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot analysis were applied to detect the expression levels of hypoxia-induciblefactor-1 (HIF-1), factor-inhibiting HIF-1 (FIH-1), angiopoietin-like 4 (Angptl4), and LPL in different tissues.

Results

CIH exposure increases serum lipid levels, decreases serum LPL activity, and exacerbates atherosclerosis. Both Angptl4-ab and DLT treatment reversed the changes in lipid concentration, LPL activity, and atherosclerosis caused by CIH. In the epididymal fat pad, CIH exposure decreased the expression of FIH-1 and increased the expression of HIF-1, whereas DLT treatment increased the expression of FIH-1 and LPL and inhibited the expression of HIF-1 and Angptl4. In heart tissue, the expression levels of LPL and Angptl4 were not affected by modeling or treatment.

Conclusions

DLT improved vascular damage by improving the increase in blood lipids induced by CIH, potentially by upregulating FIH-1 and downregulating HIF-1 and Angptl4 in adipose tissue. Therefore, DLT may be a promising agent for the prevention and treatment of CIH-induced vascular injury.

Beneficial Effects of Flavonoids on Skeletal Muscle Health: A Systematic Review and Meta-Analysis

Skeletal muscle (SkM) is a highly dynamic tissue that responds to physiological adaptations or pathological conditions, and SkM mitochondria play a major role in bioenergetics, regulation of intracellular calcium homeostasis, pro-oxidant/antioxidant balance, and apoptosis. Flavonoids are polyphenolic compounds with the ability to modulate molecular pathways implicated in the development of mitochondrial myopathy. Therefore, it is pertinent to explore its potential application in conditions such as aging, disuse, denervation, diabetes, obesity, and cancer. To evaluate preclinical and clinical effects of flavonoids on SkM structure and function. We performed a systematic review of published studies, with no date restrictions applied, using PubMed and Scopus. The following search terms were used: "flavonoids" OR "flavanols" OR "flavones" OR "anthocyanidins" OR "flavanones" OR "flavan-3-ols" OR "catechins" OR "epicatechin" OR "(-)-epicatechin" AND "skeletal muscle." The studies included in this review were preclinical studies, clinical trials, controlled clinical trials, and randomized-controlled trials that investigated the influence of flavonoids on SkM health. Three authors, independently, assessed trials for the review. Any disagreement was resolved by consensus. The use of flavonoids could be a potential tool for the prevention of muscle loss. Their effects on metabolism and on mitochondria function suggest their use as muscle regulators.

Pharmacological Properties of Polyphenols: Bioavailability, Mechanisms of Action, and Biological Effects in In Vitro Studies, Animal Models, and Humans

Drugs are bioactive compounds originally discovered from chemical structures present in both the plant and animal kingdoms. These have the ability to interact with molecules found in our body, blocking them, activating them, or increasing or decreasing their levels. Their actions have allowed us to cure diseases and improve our state of health, which has led us to increase the longevity of our species. Among the molecules with pharmacological activity produced by plants are the polyphenols. These, due to their molecular structure, as drugs, also have the ability to interact with molecules in our body, presenting various pharmacological properties. In addition, these compounds are found in multiple foods in our diet. In this review, we focused on discussing the bioavailability of these compounds when we ingested them through diet and the specific mechanisms of action of polyphenols, focusing on studies carried out in vitro, in animals and in humans over the last five years. Knowing which foods have these pharmacological activities could allow us to prevent and aid as concomitant treatment against various pathologies.

Oral administration of NPC43 counters hyperglycemia and activates insulin receptor in streptozotocin-induced type 1 diabetic mice

INTRODUCTION

Adenosine, 5'-Se-methyl-5'-seleno-,2',3'-diacetate (NPC43) is a recently identified small, non-peptidyl molecule which restores normal insulin signaling in a mouse model of type 2 diabetes (Lan et al). The present study investigated the ability of NPC43 as an oral and injectable insulin-replacing agent to activate insulin receptor (INSR) and counter hyperglycemia in streptozotocin (STZ)-induced type 1 diabetic (T1D) mice.

RESEARCH DESIGN AND METHODS

In this study, STZ was intraperitoneally injected into wild-type mice to induce hyperglycemia and hypoinsulinemia, the main features of T1D. These STZ-induced T1D mice were given NPC43 orally or intraperitoneally and blood glucose levels were measured using a glucometer. Protein levels of phosphorylated and total Insrβ, protein kinase B (Akt) and AS160 (critical for glucose uptake) in the skeletal muscle and liver of STZ-induced T1D mice following oral NPC43 treatment were determined by western blot analysis. In addition, hepatic expression of activated Insr in STZ-induced T1D mice after intraperitoneal NPC43 treatment was measured by ELISA. Student's t-test was used for statistical analysis.

RESULTS

Oral administration of NPC43 at a dose of 5.4 or 10.8 mg/kg body weight (mpk) effectively lowered blood glucose levels in STZ-induced T1D mice at ≥1 hour post-treatment and the glucose-lowering activity of oral NPC43 persisted for 5 hours. Blood glucose levels were also reduced in STZ-induced T1D mice following intraperitoneal NPC43 (5.4 mpk) treatment. Protein levels of phosphorylated Insrβ, Akt and AS160 were significantly increased in the skeletal muscle and liver of STZ-induced T1D mice after oral NPC43 (5.4 mpk) treatment. In addition, activation of hepatic Insr was observed in STZ-induced T1D mice following intraperitoneal NPC43 (5.4 mpk) treatment.

CONCLUSIONS

We conclude that NPC43 is a de facto fast-acting oral and injectable insulin mimetic which activates Insr and mitigates hyperglycemia in a mouse model of T1D.

Natural products that target macrophages in treating non-alcoholic steatohepatitis

Nonalcoholic steatohepatitis (NASH) is the progressive subtype of non-alcoholic fatty liver disease and potentiates risks for both hepatic and metabolic diseases. Although the pathophysiology of NASH is not completely understood, recent studies have revealed that macrophage activation is a major contributing factor for the disease progression. Macrophages integrate the immune response and metabolic process and have become promising targets for NASH therapy. Natural products are potential candidates for NASH treatment and have multifactorial underlying mechanisms. Macrophage involvement in the development of steatosis and inflammation in NASH has been widely investigated. In this review, we assess the evidence for natural products or their active ingredients in the modulation of macrophage activation, recruitment, and polarization, as well as the metabolic status of macrophages. Our work may highlight the possible natural products that target macrophages as potential treatment options for NASH.

Emerging Therapeutic Activity of Davallia formosana on Prostate Cancer Cells through Coordinated Blockade of Lipogenesis and Androgen Receptor Expression

Background: Prostate cancer (PCa) is the most prevalent malignancy diagnosed in men in Western countries. There is currently no effective therapy for advanced PCa aggressiveness, including castration-resistant progression. The aim of this study is to evaluate the potential efficacy and determine the molecular basis of Davallia formosana (DF) in PCa. Methods: LNCaP (androgen-sensitive) and C4-2 (androgen-insensitive/castration-resistant) PCa cells were utilized in this study. An MTT-based method, a wound healing assay, and the transwell method were performed to evaluate cell proliferation, migration, and invasion. Intracellular fatty acid levels and lipid droplet accumulation were analyzed to determine lipogenesis. Moreover, apoptotic assays and in vivo experiments were conducted. Results: DF ethanol extract (DFE) suppressed proliferation, migration, and invasion in PCa cells. DFE attenuated lipogenesis through inhibition of the expression of sterol regulatory element-binding protein-1 (SREBP-1) and fatty acid synthase (FASN). Moreover, DFE decreased androgen receptor (AR) and prostate-specific antigen (PSA) expression in PCa cells. We further showed the potent therapeutic activity of DFE by repressing the growth and leading to apoptosis of subcutaneous C4-2 tumors in a xenograft mouse model. Conclusions: These data provide a new molecular basis of DFE in PCa cells, and co-targeting SREBP-1/FASN/lipogenesis and the AR axis by DFE could be employed as a novel and promising strategy for the treatment of PCa.

Comparative assessment of nutritional composition, polyphenol profile, antidiabetic and antioxidative properties of selected edible wild plant species of Bangladesh

Wild edible plants are recently recognized as an important source of acquiring macro and micro nutrients beneficial for human health. Hence, the present study was undertaken to assess the antidiabetic and antioxidant potentials, polyphenolic profile, - as well as the ascorbic acid, proximate and mineral compositions of five selected Bangladeshi wild plants. The studied samples were rich in ash, fiber, protein, vitamin C and low in fat. The undertaken plant samples were found to have good amounts of total phenolic, total flavonoid, and antioxidant capacities, documented by DPPH, FRAP, and TEAC assays. They also exhibited varying spectrum of polyphenols estimated by HPLC. Significant inhibition of α-amylase activity by plant extracts was also observed. Evaluation by principal component analysis revealed clear separation among the wild plant varieties. The study findings would enrich the food composition table of Bangladesh and allow the population to consume more wild plants and increase their production.

Insulin-independent stimulation of skeletal muscle glucose uptake by low-dose abscisic acid via AMPK activation

Abscisic acid (ABA) is a plant hormone active also in mammals where it regulates, at nanomolar concentrations, blood glucose homeostasis. Here we investigated the mechanism through which low-dose ABA controls glycemia and glucose fate. ABA stimulated uptake of the fluorescent glucose analog 2-NBDG by L6, and of [¹⁸F]-deoxy-glucose (FDG) by mouse skeletal muscle, in the absence of insulin, and both effects were abrogated by the specific AMPK inhibitor dorsomorphin. In L6, incubation with ABA increased phosphorylation of AMPK and upregulated PGC-1α expression. LANCL2 silencing reduced all these ABA-induced effects. In vivo, low-dose oral ABA stimulated glucose uptake and storage in the skeletal muscle of rats undergoing an oral glucose load, as detected by micro-PET. Chronic treatment with ABA significantly improved the AUC of glycemia and muscle glycogen content in CD1 mice exposed to a high-glucose diet. Finally, both acute and chronic ABA treatment of hypoinsulinemic TRPM2^-/- mice ameliorated the glycemia profile and increased muscle glycogen storage. Altogether, these results suggest that low-dose oral ABA might be beneficial for pre-diabetic and diabetic subjects by increasing insulin-independent skeletal muscle glucose disposal through an AMPK-mediated mechanism.

Antidiabetic and Antihyperlipidemic Effects of Sulphurenic Acid, a Triterpenoid Compound from Antrodia camphorata, in Streptozotocin-Induced Diabetic Mice

The present study was designed to evaluate the protective effect of sulphurenic acid (SA), a pure compound from Antrodia camphorata, on diabetes and hyperlipidemia in an animal model study and to clarify the underlying molecular mechanism. Diabetes was induced by daily 55 mg/kg intraperitoneal injections of streptozotocin (STZ) solution over five days. Diabetic mice were randomly divided into six groups and orally gavaged with SA (at three dosages) or glibenclamide (Glib), fenofibrate (Feno) or vehicle for 3 weeks. Our findings showed that STZ-induced diabetic mice had significantly increased fasting blood glucose, glycated hemoglobin (HbA1C), plasma triglyceride (TG), and total cholesterol (TC) levels (p < 0.001, p < 0.001, p < 0.001, and p < 0.05, respectively) but decreased blood insulin, adiponectin, and leptin levels compared to those of the control group (p < 0.001, p < 0.001, and p < 0.001, respectively). Administration of SA to STZ-induced diabetic mice may lower blood glucose but it increased the insulin levels with restoration of the size of the islets of Langerhans cells, implying that SA protected against STZ-induced diabetic states within the pancreas. At the molecular level, SA treatment exerts an increase in skeletal muscle expression levels of membrane glucose transporter 4 (GLUT4) and phospho-Akt to increase the membrane glucose uptake, but the mRNA levels of PEPCK and G6Pase are decreased to inhibit hepatic glucose production, thus leading to its hypoglycemic effect. Moreover, SA may cause hypolipidemic effects not only by enhancing hepatic expression levels of peroxisome proliferator-activated receptor α (PPARα) with increased fatty acid oxidation but also by reducing lipogenic fatty acid synthase (FAS) as well as reducing mRNA levels of sterol regulatory element binding protein (SREBP)1C and SREBP2 to lower blood TG and TC levels. Our findings demonstrated that SA displayed a protective effect against type 1 diabetes and a hyperlipidemic state in STZ-induced diabetic mice.

Cardiovascular Effects of Flavonoids

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Cardiovascular Disease (CVD) is the major cause of death worldwide, especially in Western society. Flavonoids are a large group of polyphenolic compounds widely distributed in plants, present in a considerable amount in fruit and vegetable. Several epidemiological studies found an inverse association between flavonoids intake and mortality by CVD. The antioxidant effect of flavonoids was considered the main mechanism of action of flavonoids and other polyphenols. In recent years, the role of modulation of signaling pathways by direct interaction of flavonoids with multiple protein targets, namely kinases, has been increasingly recognized and involved in their cardiovascular protective effect. There are strong evidence, in in vitro and animal experimental models, that some flavonoids induce vasodilator effects, improve endothelial dysfunction and insulin resistance, exert platelet antiaggregant and atheroprotective effects, and reduce blood pressure. Despite interacting with multiple targets, flavonoids are surprisingly safe. This article reviews the recent evidence about cardiovascular effects that support a beneficial role of flavonoids on CVD and the potential molecular targets involved.

Aqueous Extract of Davallia mariesii Attenuates 6-Hydroxydopamine-Induced Oxidative Damage and Apoptosis in B35 Cells Through Inhibition of Caspase Cascade and Activation of PI3K/AKT/GSK-3β Pathway

The medicinal ferns of Polydiaceae and Davalliaceae species are called "Gusuibu" by Chinese physicians and used as antiaging dietary medicines. Our previous report revealed that Drynaria fortunei (Polydiaceae) protected against 6-hydroxydopamine (6-OHDA)-induced oxidative damage via the PI3K/AKT pathway in B35 neuroblastoma cells. The present study compares the antioxidant phytoconstituent contents and radical scavenging capacities of five Davalliaceae species. The further aim was to clarify the protective mechanism of Davallia mariesii (DM) against 6-OHDA-induced oxidative damage and apoptosis in B35 cells. The results show that Araiostegia perdurans (AP) and DM extracts have better radical scavenging capacities against 1,1-diphenyl-2-picryhydrazyl (DPPH) and reactive oxygen species (ROS) than other Davalliaceae species. However, only DM extract inhibited 6-OHDA autoxidation under cell-free systems and increased cell viability, compared to B35 cells solely exposed to 6-OHDA. DM extract decreased apoptosis and restored mitochondrial expression in 6-OHDA-treated B35 cells. Additional data indicated that DM extract decreased intracellular ROS and nitric oxide levels generated by 6-OHDA exposure. DM extract also restored glutathione (GSH) levels and the activities of glutathione peroxidase and reductase, and then decreased the elevated malondialdehyde (MDA) levels. Finally, DM extract regulated the protein expression of the caspase cascade and PI3K/AKT/GSK-3β pathways. These results suggest that the protective mechanism of DM extract against 6-OHDA-induced oxidative damage and apoptosis might be related to its radical scavenging capacity, maintaining the mitochondrial function to inhibit the Bcl-2/caspase cascade pathway and activating intracellular antioxidant defenses (GSH recycling, HO-1 and NQO-1) by modulating the activation of the PI3K/AKT/GSK-3β pathway.

Antidiabetic and hypolipidemic activities of eburicoic acid, a triterpenoid compound from Antrodia camphorata, by regulation of Akt phosphorylation, gluconeogenesis, and PPARα in streptozotocin-induced diabetic mice

The study is designed to examine the potential effects and underlying mechanisms of eburicoic acid (TRR), a compound from Antrodia camphorata, in streptozotocin (STZ)-induced diabetic mice. Diabetic mice were randomly divided into six groups and given TRR orally by gavage (at three dosage rates) or fenofibrate (Feno) (250 mg kg⁻¹ body weight) or metformin (Metf) (300 mg kg⁻¹ body weight) or vehicle for 2 weeks. STZ-induced diabetic mice were found to have increased blood glucose, HbA1_C, plasma triglyceride (TG) and total cholesterol (TC) levels, but reduced blood insulin, adiponectin, and leptin levels as compared with the CON group. TRR was found to lower blood glucose and HbA1_C, but increase insulin levels. Plasma TG and TC levels were significantly lowered in TRR, Feno, or Metf-treated STZ-induced diabetic mice as compared with the vehicle-treated STZ group, indicating that TRR, Feno, and Metf ameliorated hyperlipidemia. The islet cells of STZ-induced diabetic mice exhibited a marked reduction from their classic round-shape as compared to the CON mice. The TRR-treated STZ mice revealed restoration of the size of Langerhans islet cells with β-cell repair as compared with the vehicle-treated STZ mice, implying that TRR ameliorated STZ-induced diabetic states within the pancreas. STZ-induction was found to decrease the expressions of membrane glucose transporter 4 (GLUT4), and phosphorylation of Akt in skeletal muscles, and administration of TRR reversed all the decreases. Moreover, administration of TRR increased blood insulin levels and enhanced hepatic expression levels of phospho-Akt and phospho-FoxO1 but decreased the mRNA levels of glucose-6-phosphatase (G6 Pase) and phosphoenolpyruvate carboxykinase (PEPCK) to suppress hepatic glucose production, thus leading to TRR's antidiabetic activity. Additionally, TRR caused an increase in the expression levels of fatty acid oxidation gene peroxisome proliferator-activated receptor α (PPARα), but a decrease in lipogenic fatty acid synthase (FAS) and PPARγ expressions in the liver. TRR treatment suppressed hepatic mRNA levels of sterol regulatory element binding protein (SREBP) 1c and SREBP2, leading to decreased plasma triglyceride and total cholesterol levels. These findings indicate that TRR may effectively enhance therapeutic potential in the treatment of type 1 diabetes mellitus and/or hyperlipidemia.

The study is designed to examine the potential effects and underlying mechanisms of eburicoic acid (TRR), a compound from Antrodia camphorata, in streptozotocin (STZ)-induced diabetic mice.