Effect of a novel proteoglycan PTP1B inhibitor from Ganoderma lucidum on the amelioration of hyperglycaemia and dyslipidaemia in db/db mice

Prospects of Ganoderma polysaccharides: Structural features, structure-function relationships, and quality evaluation

Polysaccharides, the primary bioactive compounds found in Ganoderma, are responsible for a multitude of biological activities. The bioactivity of Ganoderma polysaccharides (GPs) closely correlates to their physicochemical properties. Consequently, the accurate characterization and quantification of GPs are essential for the quality control of these compounds. Regrettably, the complex structural features of GPs have limited research on the relationships between their structures and bioactivities. In addition, a lack of appropriate quality assessment methods has impeded the regulation and application of GPs and related products. Therefore, it is essential to conduct extensive studies to develop reliable for quality control methods based on their pharmacological activities. This review aims to comprehensively and systematically outline the structural features, structure-activity relationships and quality control methods of GPs, thereby supporting their potential value in pharmaceuticals and functional foods. The insights presented in this review will significantly contribute to the research and potential applications of GPs.

Protective effect of Ganoderma lucidum spore extract in trimethylamine-N-oxide-induced cardiac dysfunction in rats

Previous research has shown that the extracts from the Ganoderma lucidum spore (GS) have potentially cardioprotective effects, but there is still abundant room for development in determining its mechanism. In this study, the rat model of cardiac dysfunction was established by intraperitoneal injection of trimethylamine-N-oxide (TMAO), and the extracts of GS (oil, lipophilic components, and polysaccharides) were given intragastrically at a dose of 50 mg/kg/day to screen the pharmacological active components of GS. After 50 days of treatments, we found that the extraction from GS reduced the levels of total cholesterol, triglyceride, and low-density lipoprotein; increased the levels of high-density lipoprotein; and reduced the levels of serum TMAO when compared to the model group (P < 0.05); especially the GS polysaccharides (DT) and GS lipophilic components (XF) exhibited decreases in serum TMAO compared to TMAO-induced control. The results of 16S rRNA sequencing showed that GS could change the gut microbiota, increasing the abundance of Firmicutes and Proteobacteria in the DT-treated group and XF-treated group, while reducing the abundance of Actinobacteria and Tenericutes. Quantitative proteomics analysis showed that GS extracts (DT and XF) could regulate the expression of some related proteins, such as Ucp1 (XF-TMAO/M-TMAO ratio is 2.76), Mpz (8.52), Fasn (2.39), Nefl (1.85), Mtnd5 (0.83), Mtnd2 (0.36), S100a8 (0.69), S100a9 (0.70), and Bdh1 (0.72). The results showed that XF can maintain the metabolic balance and function of the heart by regulating the expression of some proteins related to cardiovascular disease, and DT can reduce the risk of cardiovascular diseases by targeting gut microbiota.

Tubeimoside I Inhibits Cell Proliferation and Induces a Partly Disrupted and Cytoprotective Autophagy Through Rapidly Hyperactivation of MEK1/2-ERK1/2 Cascade via Promoting PTP1B in Melanoma

Tubeimoside I (TBMS1), also referred to as tubeimoside A, is a natural compound extracted from the plant Tu Bei Mu (Bolbostemma paniculatum), which is a traditional Chinese herb used to treat multiple diseases for more than 1,000 years. Studies in recent years reported its anti-tumor activity in several cancers. However, whether it is effective in melanoma remains unknown. In the current study, we discovered that TBMS1 treatment inhibited melanoma cell proliferation in vitro and tumorigenecity in vivo. Besides, we also observed that TBMS1 treatment induced a partly disrupted autophagy, which still remained a protective role, disruption of which by chloroquine (CQ) or 3-methyladenine (3-MA) enhanced TBMS1-induced cell proliferation inhibition. CQ combined with TBMS1 even induced cellular apoptosis. BRAF(V600E) mutation and its continuously activated downstream MEK1/2-ERK1/2 cascade are found in 50% of melanomas and are important for malanomagenesis. However, hyperactivating MEK1/2-ERK1/2 cascade can also inhibit tumor growth. Intriguingly, we observed that TBMS1 rapidly hyperactivated MEK1/2-ERK1/2, inhibition of which by its inhibitor SL-327 rescued the anti-cancerous effects of TBMS1. Besides, the targets of TBMS1 were predicted by the ZINC Database based on its structure. It is revealed that protein-tyrosine phosphatase 1B (PTP1B) might be one of the targets of TBMS1. Inhibition of PTP1B by its selective inhibitor TCS401 or shRNA rescued the anti-cancerous effects of TBMS1 in melanoma cells. These results indicated that TBMS1 might activate PTP1B, which further hyperactivates MEK1/2-ERK1/2 cascade, thereby inhibiting cell proliferation in melanoma. Our results provided the potentiality of TBMS1 as a drug candidate for melanoma therapy and confirmed that rapidly hyperactivating an oncogenic signaling pathway may also be a promising strategy for cancer treatment.

Herbal Medicine for Slowing Aging and Aging-associated Conditions: Efficacy, Mechanisms and Safety

Aging and aging-associated diseases are issues with unsatisfactory answers in the medical field. Aging causes important physical changes which, even in the absence of the usual risk factors, render the cardiovascular system prone to some diseases. Although aging cannot be prevented, slowing down the rate of aging is entirely possible to achieve. In some traditional medicine, medicinal herbs such as Ginseng, Radix Astragali, Ganoderma lucidum, Ginkgo biloba, and Gynostemma pentaphyllum are recognized by the "nourishing of life" and their role as anti-aging phytotherapeutics is increasingly gaining attention. By mainly employing PubMed here we identify and critically analysed 30 years of published studies focusing on the above herbs' active components against aging and aging-associated conditions. Although many plant-based compounds appear to exert an anti-aging effect, the most effective resulted in being flavonoids, terpenoids, saponins, and polysaccharides, which include astragaloside, ginkgolide, ginsenoside, and gypenoside specifically covered in this review. Their effects as antiaging factors, improvers of cognitive impairments, and reducers of cardiovascular risks are described, as well as the molecular mechanisms underlying the above-mentioned effects along with their potential safety. Telomere and telomerase, PPAR-α, GLUTs, FOXO1, caspase-3, bcl-2, along with SIRT1/AMPK, PI3K/Akt, NF-κB, and insulin/insulin-like growth factor-1 pathways appear to be their preferential targets. Moreover, their ability to work as antioxidants and to improve the resistance to DNA damage is also discussed. Although our literature review indicates that these traditional herbal medicines are safe, tolerable, and free of toxic effects, additional well-designed, large-scale randomized control trials need to be performed to evaluate short- and long-term effects and efficacy of these medicinal herbs.

Effect of the Aqueous Extract of Ganoderma lucidum on the Haematology, Oestradiol, Cholesterol and Protein Levels of Wistar Rats Fed with Monosodium Glutamate

Monosodium glutamate (MSG) at high concentration has been reported to alter the physiological and biochemical states of animals and humans. Ganoderma lucidum (G. lucidum) is a polypore mushroom reported to possess many medicinal attributes such as anticholesterolemia and the control of hormonal disorders. The present study investigated the effect of water extract of G. lucidum in the changes of haematology, oestradiol, cholesterol and protein levels of Wistar rats induced by MSG. Haematological analysis was determined from plasma, while oestrogen, serum total protein and cholesterol levels were determined from the serum of the rats. Results showed that MSG significantly raised the level of oestrogen (62.5 ± 0.28 pg/mL) in the rats which was significantly reduced in the rats fed with MSG for 30 days before treating them with the extracts of G. lucidum (30.85 ± 12.94 pg/mL–44.15 ± 0.92 pg/mL) and in rats fed concurrently with MSG and G. lucidum. The cholesterol level was significantly reduced in the rats treated with MSG and G. lucidum (200 mg/kg) concurrently compared to rats fed with MSG alone. The white blood cell (WBC) and red blood cell (RBC) levels were within normal in rats fed with both MSG and G. lucidum as in the control group while the rats fed with MSG only had low WBC, neutrophil (NEU) and RBC. This could imply that G. lucidum ameliorates the effect of MSG on serum oestrogen, serum cholesterol, WBCs, NEU, platelets and lymphocytes.

A proteoglycan extract from Ganoderma Lucidum protects pancreatic beta-cells against STZ-induced apoptosis

The pancreatic β-cell death or dysfunction induced by oxidative stress plays an important effect on the development and progression of diabetes mellitus. Based on our previous findings, a natural proteoglycan extracted from Ganoderma Lucidum, named FYGL, could treat T2DM in vivo. In this study, we investigated the effects of FYGL on STZ-induced apoptosis of INS-1 cells and its underlying mechanisms. The results showed that FYGL significantly improved the cell viability and alleviated the apoptosis in STZ-treated INS-1 cells. Moreover, FYGL markedly decreased the intracellular ROS accumulation and NO release, and deactivated NF-κB, JNK, and p38 MAPK signaling pathways in STZ-induced INS-1 cells. Furthermore, FYGL improved the insulin secretion through inhibiting the activation of JNK and improving the expression of Pdx-1 in INS-1 cells damaged by STZ. These results indicated that FYGL could protect pancreatic β-cells against apoptosis and dysfunction, and be used as a promising pharmacological medicine for diabetes management. Abbreviations: T2DM: type 2 diabetes mellitus; FYGL: Fudan-Yueyang G. lucidum; ROS: reactive oxygen species; NO: reactive oxygen species; NF-κB: nuclear factor kappa beta; JNK: c-jun N-terminal kinase; MAPK: mitogen-activated protein kinase; Pdx-1: Pancreatic duodenal homeobox 1.

Hypoglycemic activity of extracts of Chamaecyparis obtusa var. formosana leaf in rats with hyperglycemia induced by high-fat diets and streptozotocin

Chamaecyparis obtusa var. formosana is a species indigenous to Taiwan and has been used as a medicinal plant. It has been claimed that the hot water extracts of C. obtusa var. formosana leaves (CoLE) with flavonoids and proanthocyanidins have anti-oxidant and anti-hyperglycemic activities in vitro. This study further examines the anti-hyperglycemic activity of CoLE and its possible mechanisms in hyperglycemic rats. Hyperglycemia of rats was induced by streptozotocin (STZ) and high-fat diets (HFD). Hyperglycemic rats treated orally with 30 and 150 mg/kg CoLE were classified into LCO and HCO groups, respectively. After three-month treatment, both LCO and HCO groups showed improved glucose metabolism in oral glucose tolerance and postprandial blood glucose tests. Decrease in HOMA-IR, leptin and adiponectin levels of the HCO group revealed amelioration of insulin and leptin resistance. Obesity and accumulation of visceral fats induced by STZ and HFD could be alleviated in both HCO and LCO groups. These anti-diabetic effects might be contributed by inhibition of intestinal digested enzymes and protein tyrosine phosphatases (PTPases). Although other studies are necessary, these findings suggest that CoLE could be potentially used as a health complement for treating diabetes without significant toxicity.

Ganoderma Lucidum Polysaccharides Ameliorates Hepatic Steatosis and Oxidative Stress in db/db Mice via Targeting Nuclear Factor E2 (Erythroid-Derived 2)-Related Factor-2/Heme Oxygenase-1 (HO-1) Pathway

Background

Type 2 diabetes mellitus (T2DM) and its comorbidities, including obesity, hypertension, and hyperlipidemia, are commonly associated with non-alcoholic fatty liver disease (NAFLD). Ganoderma lucidum polysaccharide (GDLP) is one of the central bioactive components in Ganoderma lucidum with anti-inflammatory, antioxidant, and hepatoprotective properties. However, the effect and mechanisms of GDLP in hepatic steatosis remain largely unknown. In the present study, we aimed to investigate the function of GDLP in hepatic steatosis and the underlying mechanism.

Material/Methods

In this study, male db/db mice were received with a high-fat diet (HFD) to investigate the effect of GDLP in T2DM-induced hepatic steatosis. The biological characteristics of the hepatic steatosis were evaluated through the detection of clinical indicators, including biochemical parameters, histopathology, and related cytokine levels. Additionally, the protein expression levels of Nrf2 (nuclear factor E2 (erythroid-derived 2)-related factor-2) signaling pathway were investigated by using western blotting and immunohistochemical staining.

Results

The levels of food/water intake, body weight, fasting blood glucose, plasma lipids, urinary biomarkers, hepatic lipid accumulation, and tumor necrosis factor (TNF)-α were observably decreased in GDLP-treated db/db mice. Additionally, administration of GDLP increased the expression of various antioxidases, including superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px), whereas it reduced the level of malonaldehyde (MDA). Furthermore, GDLP was significantly promoted protein expression level of Nrf2 and its downstream target gene HO-1 (heme oxygenase-1) while decreased TNF-α expression.

Conclusions

These results indicate that GDLP against T2DM-induced hepatic steatosis, oxidative stress, and inflammation by improving the Nrf2/HO-1 signaling pathway in db/db mice, suggesting the GDLP may serve as an effective strategy for in fatty liver treatment.

Ganoderma lucidum culture supplement ameliorates dyslipidemia and reduces visceral fat accumulation in type 2 diabetic rats

Diabetic rats were daily fed with a high-cholesterol diet containing 1% or 3% freeze-dried whole submerged G. lucidum culture or its mycelia for 5 weeks. Body weight, adipose tissue weight and plasma triglyceride levels were reduced, while high-density lipoprotein-cholesterol levels were elevated in rats fed with G. lucidum powder supplement diets. Notably, G. lucidum supplements downregulated the activities of hepatic acetyl-CoA carboxylase, fatty acid synthase and lipoprotein lipase, but upregulated the activity of hormone-sensitive lipase in the perirenal adipose tissues. Moreover, G. lucidum supplements increased the faecal triglyceride excretion. Therefore, daily supplementation of submerged G. lucidum culture, especially mycelia, can ameliorate dyslipidemia and reduce visceral fat accumulation in diabetic rats fed with a high-fat diet, which is closely related to the modulation of lipid synthesis, metabolism, and excretion.

Evaluation of the hypoglycaemic and antioxidant effects of submerged Ganoderma lucidum cultures in type 2 diabetic rats

We aim to investigate the hypoglycaemic and antioxidant effects of submerged Ganoderma lucidum cultures and elucidate the potential mechanisms behind these effects using a type 2 diabetic rat model. Diabetic rats were daily fed with a high-fat diet supplemented with 1% or 3% freeze-dried whole submerged cultures of G. lucidum or mycelia for 5 weeks. We observed significantly decreased fasting plasma glucose levels, homoeostasis model assessment equation-insulin resistance, and plasma glucose in oral glucose tolerance test. Furthermore, we observed increased levels of glycogen, hepatic hexokinase, glucose-6-phosphate dehydrogenase, and intestinal disaccharidase activities. G. lucidum supplement downregulated the plasma levels of aspartate aminotransferase, alanine aminotransferase, creatinine, and urea nitrogen as well as liver and kidney levels of thiobarbituric acid reactive substances. Based on the hypoglycaemic and antioxidant effects of G. lucidum submerged cultures, we recommend the potential application of these products as functional foods or additives for controlling type 2 diabetes. Abbreviations ALT: Alanine aminotransferase; AST: Aspartate aminotransferase; BUN: Blood urea nitrogen; BW: Body weight; CREA: Creatinine; FPG: Fasting plasma glucose; G6Pase: Glucose-6-phosphatase; G6PD: Glucose-6-phosphate dehydrogenase; HOMA-IR: Homoeostasis model assessment of insulin resistance; OGTT: Oral glucose tolerance test; PTP: Protein tyrosine phosphatase; STZ: Streptozotocin; TBARS: Thiobarbituric acid reactive substances.

Adenine nucleotide-mediated regulation of hepatic PTP1B activity in mouse models of type 2 diabetes

AIMS/HYPOTHESIS

Plasma 5'-AMP (pAMP) is elevated in mouse models of type 2 diabetes. However, the metabolic regulatory role of adenine nucleotides in type 2 diabetes remains unclear.

METHODS

Adenine nucleotides and their metabolites in plasma and liver were examined by HPLC. ¹H NMR-based metabolomics analysis was performed to explore the changes of metabolites in mouse models of type 2 diabetes. Na⁺/K⁺ ATPase and Na⁺/H⁺ exchanger activity were measured in response to adenine nucleotide metabolites. Human recombinant protein tyrosine phosphatase 1B (PTP1B) was used for enzyme kinetic assays. Protein binding assays were performed with microscale thermophoresis. The intracellular pH of hepatocyte AML12 cell lines was measured using the BCECF-AM method. We also analysed pAMP levels in participants with type 2 diabetes.

RESULTS

Elevation of pAMP was a universal phenomenon in all mouse models of type 2 diabetes including db/db vs lean mice (13.9 ± 2.3 μmol/l vs 3.7 ± 0.9 μmol/l; p < 0.01), ob/ob vs lean mice (9.1 ± 2.0 μmol/l vs 3.9 ± 1.2 μmol/l; p < 0.01) and high-fat diet/streptozotocin-induced vs wild-type mice (6.6 ± 1.5 μmol/l vs 4.1 ± 0.9 μmol/l; p < 0.05); this elevation was required for the occurrence of hyperglycaemia in obese mice. ¹H NMR-based metabolomics study following HPLC analysis revealed that the metabolite profile in wild-type mice treated with 5'-AMP was similar to that in db/db diabetic mice, especially the accumulation of a large quantity of ATP and its metabolites. The glucose-lowering drug metformin reduced the severity of hyperglycaemia both in 5'-AMP-induced wild-type mice and db/db mice. Metformin decreased the accumulation of liver ATP but not its metabolites in these hyperglycaemic mice. ATP and metformin reciprocally change cellular pH homeostasis in liver, causing opposite shifts in liver activity of PTP1B, a key negative regulator of insulin signalling. Furthermore, pAMP levels were also elevated in individuals with type 2 diabetes (45.2 ± 22.7 nmol/l vs 3.1 ± 1.9 nmol/l; p < 0.01).

CONCLUSIONS/INTERPRETATION

These results reveal an emerging role for adenine nucleotide in the regulation of hyperglycaemia and provide a potential therapeutic target in obesity and type 2 diabetes.

Dai-Zong-Fang, A Traditional Chinese Herbal Formula, Ameliorates Insulin Resistance in db/db Mice

Intricate health problems, such as insulin resistance (IR) and its associated diseases, call for multi-targeted therapies with few side effects. Based on traditional Chinese medicine (TCM), Dai-Zong-Fang (DZF) is an herbal formula mainly composed of Rhizoma Coptidis (Huanglian) and Fructus Aurantii Immaturus (Zhishi), of which berberine and naringin are the main constituents. Though DZF has been clinically used for treatment of IR and metabolic syndrome for decades, its mechanism in vivo remains unknown. In the present study, we observed that both DZF and metformin, the first-line drug for type 2 diabetes, ameliorated insulin resistance with significant improvement of oral glucose tolerance test (OGTT) and homeostasis model assessment of IR (HOMA-IR) level in diabetic C57BL/Ksj-Lepr db^−/− (db/db) mice. Low-density lipoprotein cholesterol (LDL-C) and fatty acids (FAs) also decreased in the blood. Higher dose of DZF (1 g·kg⁻¹), but not metformin (0.25 g·kg⁻¹), alleviated hepatic steatosis with reduced liver weight and hepatic lipid accumulation and provided protection from hepatic injury with lower alanine aminotransferase and aspartate aminotransferase and increased hepatic superoxide dismutase activity in db/db mice. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) showed a decrease in FA synthase gene (Fasn) and an increase in FA oxidation gene Ppara expression. Western blot demonstrated that both DZF and metformin activated 5′ AMP-activated protein kinase (AMPK) but inhibited Notch intracellular domain (NICD) and Hairy/enhancer-of-split 1 (Hes1) of Notch signaling pathway in the liver. DZF also dramatically improved the ultrastructure of skeletal muscles, AMPK phosphorylation, and GLUT4 translocation. DZF also promoted FA transport and oxidation with Cd36 and Cpt1b up-regulation in the skeletal muscle. In conclusion, DZF improves insulin sensitivity by reducing hepatic lipids through AMPK activation and Notch signal pathway inhibition and enhancing energy metabolism in the skeletal muscle via AMPK. This study provides insights into the treatment of complex conditions, such as IR, where TCM herbal formulas exert multipronged effects through correlating pathways.

Hypoglycemic mechanisms of Ganoderma lucidum polysaccharides F31 in db/db mice via RNA-seq and iTRAQ

This study provides insight into the system-level hypoglycemic mechanisms of Ganoderma lucidum polysaccharides F31 by the integrative analysis of transcriptomics and proteomics data.

Protective effects of a G. lucidum proteoglycan on INS-1 cells against IAPP-induced apoptosis via attenuating endoplasmic reticulum stress and modulating CHOP/JNK pathways

Fudan-Yueyang-G. lucidum (FYGL) is a water-soluble macromolecular proteoglycan extracted from Ganoderma lucidum which has been used for health promotion for a long time in China. The aim of this study was to investigate the protective effects of FYGL on INS-1 rat insulinoma beta cells against IAPP-induced cell apoptosis, as well as the underlying mechanisms. The results showed that apoptotic cells were significantly increased when incubated with islet amyloid polypeptide (IAPP). However, cytotoxicity of IAPP was significantly attenuated by co-incubation of the cells with FYGL. The results of RT-PCR showed that mRNA expression of caspase-3, caspase-12 and C/EBP homologous protein (CHOP) in IAPP-treated cells were inhibited by FYGL. Moreover, FYGL significantly prevented the IAPP-induced abnormal expression of inositol-requiring protein-1α (IRE1α), protein kinase RNA (PKR)-like ER kinase (PERK), activating transcription factor 6 (ATF6), as well as suppressed the activation of CHOP and c-Jun N-terminal kinase (JNK). Taken together, our results suggest that FYGL protects INS-1 pancreatic beta cells against IAPP-induced apoptosis through attenuating endoplasmic reticulum stress (ERS) and modulating CHOP/JNK pathways.

Antidiabetic activity of Ganoderma lucidum polysaccharides F31 down-regulated hepatic glucose regulatory enzymes in diabetic mice

ETHNOPHARMACOLOGICAL RELEVANCE

Ganoderma lucidum (Lin Zhi) has been used to treat diabetes in Chinese folk for centuries. Our laboratory previously demonstrated that Ganoderma lucidum polysaccharides (GLPs) had hypoglycemic effects in diabetic mice. Our aim was to identify the main bioactives in GLPs and corresponding mechanism of action.

MATERIALS AND METHODS

Four polysaccharide-enriched fraction were isolated from GLPs and the antidiabetic activities were evaluated by type 2 diabetic mice. Fasting serum glucose (FSG), fasting serum insulin (FSI) and epididymal fat/BW ratio were measured at the end of the experiment. In liver, the mRNA levels of hepatic glucose regulatory enzymes were determined by quantitative polymerase chain reaction (qPCR) and the protein levels of phospho-AMP-activated protein kinase (p-AMPK)/AMPK were determined by western blotting test. In epididymal fat tissue, the mRNA and protein levels GLUT4, resistin, fatty acid synthase (FAS) and acetyl-CoA carboxylase (ACC1) were determined by qPCR and immuno-histochemistry. The structure of polysaccharide F31 was obtained from GPC, FTIR NMR and GC-MS spectroscopy, RESULTS: F31 significantly decreased FSG (P<0.05), FSI and epididymal fat/BW ratio (P<0.01). In liver, F31 decreased the mRNA levels of hepatic glucose regulatory enzymes, and up-regulated the ratio of phospho-AMP-activated protein kinase (p-AMPK)/AMPK. In epididymal fat tissue, F31 increased the mRNA levels of GLUT4 but decreased fatty acid synthase (FAS), acetyl-CoA carboxylase (ACC1) and resistin. Immuno-histochemistry results revealed F31 increased the protein levels of GLUT4 and decreased resistin.

CONCLUSION

Data suggested that the main bioactives in GLPs was F31, which was determined to be a β-heteropolysaccharide with the weight-average molecular weight of 15.9kDa. The possible action mechanism of F31 may be associated with down-regulation of the hepatic glucose regulated enzyme mRNA levels via AMPK activation, improvement of insulin resistance and decrease of epididymal fat/BW ratio. These results strongly suggest that F31 has antidiabetic potential.

Hypocholesterolemic Properties and Prebiotic Effects of Mexican Ganoderma lucidum in C57BL/6 Mice

Edible and medicinal mushrooms contain bioactive compounds with promising effects on several cardiovascular risk biomarkers. However, strains of Ganoderma lucidum of Mexican origin have not yet been studied. Standardized extracts of G. lucidum (Gl) were given to C57BL/6 mice fed a high-cholesterol diet compared with the drug simvastatin. The effects of the extracts on serum biochemical parameters, liver lipid content, cholesterol metabolism, and the composition of gut microbiota were assessed. Acetylsalicylic acid (10 mM) added to the cultivation substrate modulated properties of Gl extracts obtained from mature basidiomata. Compared to the high-cholesterol diet group, the consumption of Gl extracts significantly reduced total serum cholesterol (by 19.2% to 27.1%), LDL-C (by 4.5% to 35.1%), triglyceride concentration (by 16.3% to 46.6%), hepatic cholesterol (by 28.7% to 52%) and hepatic triglycerides (by 43.8% to 56.6%). These effects were associated with a significant reduction in the expression of lipogenic genes (Hmgcr, Srebp1c, Fasn, and Acaca) and genes involved in reverse cholesterol transport (Abcg5 and Abcg8), as well as an increase in Ldlr gene expression in the liver. No significant changes were observed in the gene expression of Srebp2, Abca1 or Cyp7a1. In several cases, Gl-1 or Gl-2 extracts showed better effects on lipid metabolism than the drug simvastatin. A proposed mechanism of action for the reduction in cholesterol levels is mediated by α-glucans and β-glucans from Gl, which promoted decreased absorption of cholesterol in the gut, as well as greater excretion of fecal bile acids and cholesterol. The prebiotic effects of Gl-1 and Gl-2 extracts modulated the composition of gut microbiota and produced an increase in the Lactobacillaceae family and Lactobacillus genus level compared to the control group, high-cholesterol diet group and group supplemented with simvastatin. Mexican genetic resources of Gl represent a new source of bioactive compounds showing hypocholesterolemic properties and prebiotic effects.

A natural hyperbranched proteoglycan inhibits IAPP amyloid fibrillation and attenuates β-cell apoptosis

A natural amphiphilic hyperbranched proteoglycan efficiently inhibits IAPP fibrillation and attenuates β-cell apoptosis for type 2 diabetes treatment.

Antidiabetic property of Aerva lanata (L.) Juss. ex Schult. is mediated by inhibition of alpha glucosidase, protein glycation and stimulation of adipogenesis

BACKGROUND

Diabetes is the leading cause of morbidity and mortality, with a number currently diagnosed as high as 371 million. Plant-based therapy could be an ideal choice because of fewer side-effects and wider acceptability. Hence, the antihyperglycemic potential of Aerva lanata, a herb prescribed for diabetes in Ayurveda was evaluated to elucidate its possible mechanism of action.

METHODS

High performance liquid chromatography analysis was used for the characterization of 70% ethanolic (aqueous leaf extract [ALE]) and ethyl acetate (AEA) extracts. Further, they were evaluated for their antioxidant, inhibition of alpha glucosidase, protein glycation dipeptidyl peptidase IV (DPP IV), protein tyrosine phosphatase 1B (PTP1B) and stimulation of glucose uptake and glitazone like property (adipogenic potential) using in vitro models. The promising alpha glucosidase inhibitory potential of ALE was further evaluated in normal and streptozotocin (STZ) diabetic rats.

RESULTS

ALE inhibited yeast (IC50 - 81.76 μg/mL) and rat intestinal alpha glucosidase (IC50 - 108.7 μg/mL), protein glycation, DPP IV enzyme (IC50 - 118.62 μg/mL) and PTP1B (IC50 - 94.66 μg/mL). ALE stimulated maximal adipogenesis at 50 μg/mL and enhanced insulin mediated glucose uptake (threefold of basal) at 100 μg/mL in L6 myotubes. ALE (500 mg/kg b.w.) showed a significant antihyperglycemic activity in sucrose loaded STZ normal (15.57%) and diabetic (18.44%) rats. HPLC analysis of ALE revealed the presence of bioactives like alpha amyrin, betulin and beta sitosterol.

CONCLUSIONS

Alpha glucosidase inhibition, antiglycation, and adipogenic potential significantly contribute to the antidiabetic property of Aerva lanata. In addition, insulin sensitization and antioxidant potential also enhance its therapeutic potential.

Accessing biological actions of Ganoderma secondary metabolites by in silico profiling

The species complex around the medicinal fungus Ganoderma lucidum Karst. (Ganodermataceae) is widely known in traditional medicines, as well as in modern applications such as functional food or nutraceuticals. A considerable number of publications reflects its abundance and variety in biological actions either provoked by primary metabolites, such as polysaccharides, or secondary metabolites, such as lanostane-type triterpenes. However, due to this remarkable amount of information, a rationalization of the individual Ganoderma constituents to biological actions on a molecular level is quite challenging. To overcome this issue, a database was generated containing meta-information, i.e., chemical structures and biological actions of hitherto identified Ganoderma constituents (279). This was followed by a computational approach subjecting this 3D multi-conformational molecular dataset to in silico parallel screening against an in-house collection of validated structure- and ligand-based 3D pharmacophore models. The predictive power of the evaluated in silico tools and hints from traditional application fields served as criteria for the model selection. Thus, the focus was laid on representative druggable targets in the field of viral infections (5) and diseases related to the metabolic syndrome (22). The results obtained from this in silico approach were compared to bioactivity data available from the literature. 89 and 197 Ganoderma compounds were predicted as ligands of at least one of the selected pharmacological targets in the antiviral and the metabolic syndrome screening, respectively. Among them only a minority of individual compounds (around 10%) has ever been investigated on these targets or for the associated biological activity. Accordingly, this study discloses putative ligand target interactions for a plethora of Ganoderma constituents in the empirically manifested field of viral diseases and metabolic syndrome which serve as a basis for future applications to access yet undiscovered biological actions of Ganoderma secondary metabolites on a molecular level.

Magnolia officinalis Extract Contains Potent Inhibitors against PTP1B and Attenuates Hyperglycemia in db/db Mice

Protein tyrosine phosphatase 1B (PTP1B) is an established therapeutic target for type 2 diabetes mellitus (T2DM) and obesity. The aim of this study was to investigate the inhibitory activity of Magnolia officinalis extract (ME) on PTP1B and its anti-T2DM effects. Inhibition assays and inhibition kinetics of ME were performed in vitro. 3T3-L1 adipocytes and C2C12 myotubes were stimulated with ME to explore its bioavailability in cell level. The in vivo studies were performed on db/db mice to probe its anti-T2DM effects. In the present study, ME inhibited PTP1B in a reversible competitive manner and displayed good selectivity against PTPs in vitro. Furthermore, ME enhanced tyrosine phosphorylation levels of cellular proteins, especially the insulin-induced tyrosine phosphorylations of insulin receptor β-subunit (IRβ) and ERK1/2 in a dose-dependent manner in stimulated 3T3-L1 adipocytes and C2C12 myotubes. Meanwhile, ME enhanced insulin-stimulated GLUT4 translocation. More importantly, there was a significant decrease in fasting plasma glucose level of db/db diabetic mice treated orally with 0.5 g/kg ME for 4 weeks. These findings indicated that improvement of insulin sensitivity and hypoglycemic effects of ME may be attributed to the inhibition of PTP1B. Thereby, we pioneered the inhibitory potential of ME targeted on PTP1B as anti-T2DM drug discovery.

Hypoglycemic effects of Grifola frondosa (Maitake) polysaccharides F2 and F3 through improvement of insulin resistance in diabetic rats

This study demonstrated the hypoglycemic effects of Grifola frondosa polysaccharides F2 and F3 through insulin sensitivity improvement in diabetic rats.

Weight loss herbal intervention therapy (W-LHIT) a non-appetite suppressing natural product controls weight and lowers cholesterol and glucose levels in a murine model

Background

The prevalence of obesity is increasing in industrialized countries. Obesity increases the risk of coronary artery disease, stroke, cancer, hypertension, and type-2 diabetes. Unfortunately, conventional obesity drug treatment is often associated with adverse effects. The objective of this study was to evaluate a novel natural formula, Weight loss herbal intervention therapy (W-LHIT), developed from traditional Chinese medicine, for weight control in a high-fat-diet (HFD) induced obesity murine model.

Methods

Two sets of experiments were performed. In experiment 1, 14-week-old C57BL/6 J male mice were fed with HFD for 21days and then separated into 3 weight-matched groups. One group continued on the HFD as obese-controls. Two groups were switched from HFD to normal fat level diet (NFD) and sham or W-LHIT treated. In experiment 2, 25-week-old obese mice, following 2weeks acclimatization, received either W-LHIT or sham treatment while maintained on HFD. In both sets of experiments, NFD fed, age matched normal weight mice served as normal controls. Body weight and food intake were recorded. Epididymal fat pad weight, serum glucose and cholesterol levels, as well as PPARγ and FABP4 gene expression in epididymal fat tissue were analyzed at the end of the experiment.

Results

In experiment 1, W-LHIT treated obese mice lost body weight 12.2 ± 3.8% whereas sham treated mice lost 5.5 ± 2.8% by day 10 after switching from the HFD to the NFD, without reduction of chow consumption. In experiment 2, W-LHIT treated obese mice maintained on the HFD had significantly lower body weight (8 fold less) than the sham treated mice. W-LHIT treatment also reduced epididymal fat pad weight, blood cholesterol and glucose levels versus sham treated mice without reduced chow consumption. In addition, significantly increased PPARγ (peroxisome proliferator activated receptor γ) and FABP4 (fatty acid binding protein 4) gene expression were found in epdidymal fat tissues. Liver and kidney function and hematology testing results of W-LHIT treated mice were within the normal range.

Conclusions

W-LHIT significantly and safely reduced body weight, normalized glucose and cholesterol levels in obese mice, without suppression of appetite, and increased adipocyte PPARγ and FABP4 gene expression.

Novel curcumin derivative CNB-001 mitigates obesity-associated insulin resistance

Type 2 diabetes is growing at epidemic proportions, and pharmacological interventions are being actively sought. This study examined the effect of a novel neuroprotective curcuminoid, CNB-001 [4-((1E)-2-(5-(4-hydroxy-3-methoxystyryl-)-1-phenyl-1H-pyrazoyl-3-yl)vinyl)-2-methoxy-phenol], on glucose intolerance and insulin signaling in high-fat diet (HFD)-fed mice. C57BL6 mice (5-6 weeks old) were randomly assigned to receive either a HFD (45% fat) or a low-fat diet (LFD, 10% fat) for 24 weeks, together with CNB-001 (40 mg/kg i.p. per day). Glucose tolerance test revealed that the area under the curve of postchallenge glucose concentration was elevated on HF-feeding, which was attenuated by CNB-001. CNB-001 attenuated body weight gain, serum triglycerides, and IL-6, and augmented insulin signaling [elevated phosphoprotein kinase B (p-Akt), and phosphoinsulin receptor (p-IR)β, lowered endoplasmic reticulum (ER) stress, protein-tyrosine phosphatase 1B (PTP1B)] and glucose uptake in gastrocnemius muscle of HFD-fed mice. Respiratory quotient, measured using a metabolic chamber, was elevated in HFD-fed mice, which was unaltered by CNB-001, although CNB-001 treatment resulted in higher energy expenditure. In cultured myotubes, CNB-001 reversed palmitate-induced impairment of insulin signaling and glucose uptake. Docking studies suggest a potential interaction between CNB-001 and PTP1B. Taken together, CNB-001 alleviates obesity-induced glucose intolerance and represents a potential candidate for further development as an antidiabetic agent.

Antidiabetic plants improving insulin sensitivity

BACKGROUND

Globally, the prevalence of diabetes mellitus is increasing at an alarming rate. This chronic pathology gravely troubled the human health and quality of life. Both insulin deficiency and insulin resistance are involved in the pathophysiology of diabetes mellitus. Moreover, insulin resistance is being diagnosed nowadays in a growing population of diabetic and obese patients, especially in industrialized societies. There are lots of conventional agents available to control and to treat diabetes, but total recovery from this disorder has not been reported up to this date. Plants provided a potential source of hypoglycemic drugs and are widely used in several traditional systems of medicine to prevent diabetes. A few reviews with less attention paid to mechanisms of action have been published on antidiabetic plants.

OBJECTIVES

The present review focuses on the various plants that have been reported to be effective in improving insulin sensitivity associated with diabetes.

KEY FINDINGS

In this work, an updated systematic review of the published literature has been conducted to review the antidiabetic plants improving insulin sensitivity and 111 medicinal plants have been reported to have a beneficial effect on insulin sensitivity using several in-vitro and in-vivo animal models of diabetes.

CONCLUSION

The different metabolic and cellular effects of the antidiabetic plants improving insulin sensitivity are reported indicating the important role of medicinal plants as potential alternative or complementary use in controlling insulin resistance associated with diabetes mellitus.

A novel proteoglycan from Ganoderma lucidum fruiting bodies protects kidney function and ameliorates diabetic nephropathy via its antioxidant activity in C57BL/6 db/db mice

Diabetic nephropathy (DN) is the major cause of morbidity among diabetic patients. Thus, antidiabetic drugs with protection potential in the kidneys would have a higher therapeutic value. The effects of a novel proteoglycan, named FYGL, isolated from G. lucidum fruiting bodies, on the kidney function were investigated systematically in present work. FYGL (250 mg/kg) not only dosedependently reduced the blood glucose concentration (23.5%, p<0.05), kidney/body weight ratio (23.6%, p<0.01), serum creatinine (33.1%, p<0.01), urea nitrogen (24.1%, p<0.01),urea acid contents (35.9%, p<0.01) and albuminuria (30.7%, p<0.01)of DN mice compared to the untreated DN mice but also increased the renal superoxide dismutase (75.3%, p<0.01), glutathione peroxidase (35.0%, p<0.01) and catalase activities (58.5%, p<0.01) compared to the untreated DN mice. The decreasing of renal malondialdehyde content (34.3%, p<0.01) and 8-hydroxy-2'-deoxyguanosine expression (2.5-fold, p<0.01) were also observed in FYGL-treated DN mice compared to the untreated DN mice, along with an amelioration of renal morphologic abnormalities. We conclude that FYGL confers protection against the renal functional and morphologic injuries by increasing activities of antioxidants and inhibiting accumulation of oxidation, suggesting a potential nutritional supplement for the prevention and therapy of DN.

Antidiabetic, antihyperlipidemic and antioxidant activities of a novel proteoglycan from ganoderma lucidum fruiting bodies on db/db mice and the possible mechanism

Previously, we screened a proteoglycan for anti-hyperglycemic, named FYGL, from Ganoderma Lucidum. For further research of the antidiabetic mechanisms of FYGL in vivo, the glucose homeostasis, activities of insulin-sensitive enzymes, glucose transporter expression and pancreatic function were analyzed using db/db mice as diabetic models in the present work. FYGL not only lead to a reduction in glycated hemoglobin level, but also an increase in insulin and C-peptide level, whereas a decrease in glucagons level and showed a potential for the remediation of pancreatic islets. FYGL also increased the glucokinase activities, and simultaneously lowered the phosphoenol pyruvate carboxykinase activities, accompanied by a reduction in the expression of hepatic glucose transporter protein 2, while the expression of adipose and skeletal glucose transporter protein 4 was increased. Moreover, the antioxidant enzyme activities were also increased by FYGL treatment. Thus, FYGL was an effective antidiabetic agent by enhancing insulin secretion and decreasing hepatic glucose output along with increase of adipose and skeletal muscle glucose disposal in the late stage of diabetes. Furthermore, FYGL is beneficial against oxidative stress, thereby being helpful in preventing the diabetic complications.

Animal models of diabetes mellitus for islet transplantation

Due to current improvements in techniques for islet isolation and transplantation and protocols for immunosuppressants, islet transplantation has become an effective treatment for severe diabetes patients. Many diabetic animal models have contributed to such improvements. In this paper, we focus on 3 types of models with different mechanisms for inducing diabetes mellitus (DM): models induced by drugs including streptozotocin (STZ), pancreatomized models, and spontaneous models due to autoimmunity. STZ-induced diabetes is one of the most commonly used experimental diabetic models and is employed using many specimens including rodents, pigs or monkeys. The management of STZ models is well established for islet studies. Pancreatomized models reveal different aspects compared to STZ-induced models in terms of loss of function in the increase and decrease of blood glucose and therefore are useful for evaluating the condition in total pancreatomized patients. Spontaneous models are useful for preclinical studies including the assessment of immunosuppressants because such models involve the same mechanisms as type 1 DM in the clinical setting. In conclusion, islet researchers should select suitable diabetic animal models according to the aim of the study.