Extracts of Rehmanniae radix, Ginseng radix and Scutellariae radix improve glucose-stimulated insulin secretion and beta-cell proliferation through IRS2 induction

Baicalin suppresses macrophage JNK-mediated adipose tissue inflammation to mitigate insulin resistance in obesity

ETHNOPHARMACOLOGICAL RELEVANCE

Radix scutellariae (the root of Scutellaria baicalensis Georgi) is a traditional Chinese medicine (TCM) used to treat a wide range of inflammation-related diseases, such as obesity, diabetes, diabetic kidney disease, and COVID-19-associated inflammatory states in the lung and kidney. Baicalin is the major anti-inflammatory component of Radix scutellariae and has shown the potential to inhibit inflammation in metabolic disorders. In this study, we explored the ability and underlying mechanisms of baicalin to modulate the macrophage to mitigate insulin resistance in obesity.

MATERIALS AND METHODS

Obese mice were administered baicalin (50 mg/kg/day) intraperitoneally for 3 weeks. RAW264.7 and BMDM cells were stimulated with LPS and treated with baicalin for 24 h, while 3T3-L1 and primary white adipocytes were treated with the supernatants from baicalin-treated RAW264.7 cells for 24 h.

RESULTS

The results showed that baicalin significantly improved glucose and insulin tolerance as well as decreased fat and adipose tissue macrophage levels in obese mice. Besides, baicalin significantly reduced serum and adipose tissue IL-1β, TNF-α and IL-6 levels in obese mice, as well as suppressed LPS-induced IL-1β, TNF-α and IL-6 expression and release in macrophages. Furthermore, treatment with the supernatant from baicalin-treated RAW264.7 cells increased the levels of PGC-1α, SIRT1, p-IRS-1 and p-AKT in adipocytes. Moreover, baicalin treatment dramatically downregulated macrophage p-p38, p-JNK, and Ac-p65Lys310 levels while increasing SIRT1 both in vivo and in vitro. Importantly, JNK inhibitor SP600125 blocked most of the effects of baicalin on SIRT1, Ac-p65Lys310 and pro-inflammatory factors in macrophages.

CONCLUSION

Therefore, these results demonstrated for the first time that baicalin exerts its anti-inflammatory effects in obese adipose tissue macrophages mainly through suppressing JNK/SIRT1/p65 signaling. These findings amplified the mechanisms of baicalin and its potential to attenuate insulin resistance.

Regeneration of Pancreatic Beta Cells by Modulation of Molecular Targets Using Plant-Derived Compounds: Pharmacological Mechanisms and Clinical Potential

Type 2 diabetes (T2D) is characterized by pancreatic beta-cell dysfunction, increased cell death and loss of beta-cell mass despite chronic treatment. Consequently, there has been growing interest in developing beta cell-centered therapies. Beta-cell regeneration is mediated by augmented beta-cell proliferation, transdifferentiation of other islet cell types to functional beta-like cells or the reprograming of beta-cell progenitors into fully differentiated beta cells. This mediation is orchestrated by beta-cell differentiation transcription factors and the regulation of the cell cycle machinery. This review investigates the beta-cell regenerative potential of antidiabetic plant extracts and phytochemicals. Various preclinical studies, including in vitro, in vivo and ex vivo studies, are highlighted. Further, the potential regenerative mechanisms and the intra and extracellular mediators that are of significance are discussed. Also, the potential of phytochemicals to translate into regenerative therapies for T2D patients is highlighted, and some suggestions regarding future perspectives are made.

Mesenchymal Stem Cells Secretions Enhanced ATP Generation on Isolated Islets during Transplantation

The success of islet transplantation in both basic research and clinical settings has proven that cell therapy has the potential to cure diabetes. Islets intended for transplantation are inevitably subjected to damage from a number of sources, including ischemic injury during removal and delivery of the donor pancreas, enzymatic digestion during islet isolation, and reperfusion injury after transplantation in the recipient. Here, we found that protein factors secreted by porcine adipose-tissue mesenchymal stem cells (AT-MSCs) were capable of activating preserved porcine islets. A conditioned medium was prepared from the supernatant obtained by culturing porcine AT-MSCs for 2 days in serum-free medium. Islets were preserved at 4°C in University of Wisconsin solution during transportation and then incubated at 37°C in RPMI-1620 medium with fractions of various molecular weights prepared from the conditioned medium. After treatment with certain fractions of the AT-MSC secretions, the intracellular ATP levels of the activated islets had increased to over 160% of their initial values after 4 days of incubation. Our novel system may be able to restore the condition of isolated islets after transportation or preservation and may help to improve the long-term outcome of islet transplantation.Abbreviations: AT-MSC, adipose-tissue mesenchymal stem cell; Cas-3, caspase-3; DAPI, 4,6-diamidino-2-phenylindole; DTZ, dithizone; ES cell, embryonic stem cell; FITC, fluorescein isothiocyanate; IEQ, islet equivalent; INS, insulin; iPS cell, induced pluripotent stem cell; Luc-Tg rat, luciferase-transgenic rat; PCNA, proliferating cell nuclear antigen; PDX1, pancreatic and duodenal homeobox protein-1; UW, University of Wisconsin; ZO1, zona occludens 1.

Hypoglycemic Effect and Experimental Validation of Scutellariae Radix based on Network Pharmacology and Molecular Docking

Scutellariae Radix (SR) is a well-known traditional herb that has good pharmacological effects against diabetes. However, the mechanism of SR against diabetes is not clear. In this study, the ingredient–target–pathway relationship and hypoglycemic effect of SR on diabetes were explored using network pharmacology, molecular docking and an animal experiment. The targets of SR and diabetes were mined. The selected targets were studied using Gene Ontology (GO) enrichment analysis and pathway enrichment analysis. The network of active components, targets and pathways was integrated to analyze the ingredient–target–pathway relationship. Then, the correspondence between the active components and targets was verified using molecular docking. Finally, an animal experiment was used to verify the hypoglycemic effect of SR. There were 52 components and 22 targets for the hypoglycemic effect of SR. We identified 18 biological processes, 9 cellular components, 15 molecular functions and 25 signaling pathways. Molecular docking results indicated that the targets of diabetes bound strongly to the main components. The animal experiments showed that SR could significantly decrease the blood glucose level of diabetic rats (p ≤ 0.05). This study explored the potential targets and signaling pathways of SR in diabetes, and the results may help to illustrate the hypoglycemic mechanism of SR.

Bioactive Phytochemicals Isolated from Akebia quinata Enhances Glucose-Stimulated Insulin Secretion by Inducing PDX-1

Chocolate vine (Akebia quinata) is consumed as a fruit and is also used in traditional medicine. In order to identify the bioactive components of A. quinata, a phytosterol glucoside stigmasterol-3-O-β-d-glucoside (1), three triterpenoids maslinic acid (2), scutellaric acid (3), and hederagenin (4), and three triterpenoidal saponins akebia saponin PA (5), hederacoside C (6), and hederacolchiside F (7) were isolated from a 70% EtOH extract of the fruits of A. quinata (AKQU). The chemical structures of isolates 1-7 were determined by analyzing the 1D and 2D nuclear magnetic resonance (NMR) spectroscopic data. Here, we evaluated the effects of AKQU and compounds 1-7 on insulin secretion using the INS-1 rat pancreatic β-cell line. Glucose-stimulated insulin secretion (GSIS) was evaluated in INS-1 cells using the GSIS assay. The expression levels of the proteins related to pancreatic β-cell function were detected by Western blotting. Among the isolates, stigmasterol-3-O-β-d-glucoside (1) exhibited strong GSIS activity and triggered the overexpression of pancreas/duodenum homeobox protein-1 (PDX-1), which is implicated in the regulation of pancreatic β-cell survival and function. Moreover, isolate 1 markedly induced the expression of extracellular signal-regulated protein kinases 1 and 2 (ERK1/2), insulin receptor substrate-2 (IRS-2), phosphoinositide 3-kinase (PI3K), and Akt, which regulate the transcription of PDX-1. The results of our experimental studies indicated that stigmasterol-3-O-β-d-glucoside (1) isolated from the fruits of A. quinata can potentially enhance insulin secretion, and might alleviate the reduction in GSIS during the development of T2DM.

Use of Traditional Chinese Medicine May Delay the Need for Insulin Treatment in Patients with Type 2 Diabetes: A Population-Based Cohort Study

Objectives: Traditional Chinese medicine (TCM) has been shown to reduce insulin resistance and improve beta cell function in previous studies. The aim of this study was to assess whether the use of TCM can delay the need for insulin therapy in patients with type 2 diabetes. Design: Data on patients with type 2 diabetes who received medical treatment for the first time between 2000 and 2003 were obtained from National Health Insurance Research Database (NHIRD) in Taiwan. Among these patients, those with a cumulative use of TCM of more than 28 days were defined as TCM users, and the others as non-users. Kaplan-Meier analysis was used to evaluate the cumulative risk of initiating insulin therapy. Cox proportional hazards models with and without competing risk events were used to evaluate the association between the use of TCM and insulin therapy. Settings/Location: Data were obtained from National Health Insurance Research Database (NHIRD) in Taiwan. Subjects: Patients with type 2 diabetes who received medical treatment for the first time between 2000 and 2003. Interventions: Among these patients, those with a cumulative use of TCM of more than 28 days were defined as TCM users, and the others as non-users. Outcome measures: After 1:1 propensity score matching, both groups were tracked until the initiation of insulin therapy, death, or the end of 2013. Results: We identified 6524 TCM users and 6524 non-users. The TCM users had a significantly lower risk of insulin initiation in a dose-dependent manner (log-rank test p < 0.001). This effect was consistent across subgroups with different severities of diabetes, and remained significant in competing risk analysis (for TCM users with 28 to 83 days cumulative use, HR 0.78 [0.70-0.87], p < 0.0001; for TCM users with ≥ 84 days cumulative use, HR 0.47 [0.42-0.53], p < 0.0001). Conclusions: The use of TCM in addition to standard diabetes treatment may delay the need for insulin treatment in patients who received medical treatment for type 2 diabetes for the first time. This benefit was strongly dose-dependent and applicable in patients with different severities of diabetes.

Ginseng for the treatment of diabetes and diabetes-related cardiovascular complications: a discussion of the evidence 1

Diabetes mellitus (DM) is a chronic metabolic disorder associated with elevated blood glucose levels due either to insufficient insulin production (type 1 DM) or to insulin resistance (type 2 DM). The incidence of DM around the world continues to rise dramatically with more than 400 million cases reported today. Among the most serious consequences of chronic DM are cardiovascular complications that can have deleterious effects. Although numerous treatment options are available, including both pharmacological and nonpharmacological, there is substantial emerging interest in the use of traditional medicines for the treatment of this condition and its complications. Among these is ginseng, a medicinal herb that belongs to the genus Panax and has been used for thousands of years as a medicinal agent especially in Asian cultures. There is emerging evidence from both animal and clinical studies that ginseng, ginseng constituents including ginsenosides, and ginseng-containing formulations can produce beneficial effects in terms of normalization of blood glucose levels and attenuation of cardiovascular complications through a multiplicity of mechanisms. Although more research is required, ginseng may offer a useful therapy for the treatment of diabetes as well as its complications.

Panax ginseng improves glucose metabolism in streptozotocin-induced diabetic rats through 5' adenosine monophosphate kinase up-regulation

5′ AMP-activated protein kinase (AMPK), insulin receptors and transporters are distorted in diabetes mellitus. In this study, the effect of Panax ginseng was assessed on glucose manipulating enzymes activities and gene expression of AMPK, IRA and GLUT2 in streptozotocin-induced diabetic male rats. Forty male albino rats were randomly divided to four groups 10 rats of each, group I, normal control group (received saline orally); group II, normal rats received 200 mg/kg of Panax ginseng orally; group III, Streptozotocin (STZ) –induced diabetic rats and group IV, STZ-induced diabetic rats received 200 mg/kg of Panax ginseng orally. The duration of experiment was 30 days. Results showed the ability of Panax ginseng to induce a significant decrease in the blood glucose and increase in the serum insulin levels, hepatic glucokinase (GK), and glycogen synthase (GS) activities with a modulation of lipid profile besides high expression levels of AMPK, insulin receptor A (IRA), glucose transporting protein-2 (GLUT-2) in liver of diabetic rats. In conclusion, the obtained results point to the ability of Panax ginseng to improve the glucose metabolism in diabetic models.

Can highly cited herbs in ancient Traditional Chinese medicine formulas and modern publications predict therapeutic targets for diabetes mellitus?

ETHNOPHARMACOLOGICAL RELEVANCE

The prevalence of diabetes among all age groups worldwide was estimated to be more than 382 million in 2013. Traditional Chinese medicine (TCM) has been practiced for thousands of years, and substantial valuable experience and prescriptions have been accumulated in the TCM system for the treatment of diabetes. In recent decades, a large amount of experimental and clinical data has been published on the use of herbal medicines related to these ancient TCM prescriptions.

AIM OF THE STUDY

This study aimed to discover a method for the investigation of potential antidiabetic herbs from the large amount of data in ancient TCM formulas and modern publications and to verify this method through an in vitro bioactivity study.

MATERIALS AND METHODS

In our review, the most frequently cited TCM herbs were selected as potential antidiabetic herb candidates on the basis of TCM philosophical theory (ancient TCM formulas) and Western medicine philosophical theory (modern publications). The ethanol and aqueous extracts of the selected herbs were screened for their α-glucosidase inhibitory, glucose-stimulated insulin secretion (GSIS), and intestinal glucose transport inhibitory effects.

RESULTS

Twelve herbs [Terminalia chebula Retz., fructus immaturus, dried; Poria cocos (Schw) Wolf., sclerotium, dried; Zea mays L., stigma, dried; Pueraria lobata (Willd.) Ohwi, radix, dried; Cucurbita moschata (Duch. ex Lam.) Duch. ex Poiret, fructus, dried; Lycium barbarum L., fructus, dried; Glycine max (L.) Merr., semen, fermented; Glycyrrhiza uralensis Fisch., radix and rhizoma, dried; Dioscorea opposita Thunb., rhizoma, dried; Morus alba L., folium, dried, Morus alba L., fructus, dried; and Polygonatum odoratum (Mill.) Druce, rhizoma, dried] were finally selected as candidates with potential glucose-lowering effects after a review was performed of herbs that are frequently cited in ancient TCM formulas and modern publications. The bioactive study results demonstrated that both the ethanol extracts and crude polysaccharides of M. alba L., fructus, dried, and M. alba L., folium, dried, and the crude polysaccharides of T. chebula Retz., fructus immaturus, dried, exhibited α-glucosidase inhibitory effects. Moreover, the crude polysaccharides of P. cocos (Schw) Wolf., sclerotium, dried; Z. mays L., stigma, dried; and T. chebula Retz., fructus immaturus, dried, exhibited favorable GSIS effects, and the ethanol extracts of P. odoratum (Mill.) Druce, rhizoma, dried; T. chebula Retz., fructus immaturus, dried; and G. uralensis Fisch., radix and rhizoma, dried, significantly decreased glucose transport across the cell monolayer.

CONCLUSIONS

Our review and the preliminary bioactive study revealed that 10 of the 12 recommended edible TCM herbs had favorable antidiabetic effects, demonstrating that TCM herbs with a high prescription and publication frequency may provide insights into the potential therapeutic targets of diabetes mellitus and may aid in the discovery of effective compounds complementary to currently used medicines. Such a literature and medicine review is a useful method of exploring potential antidiabetic herbs by using the wealth of information in ancient TCM formulas and modern publications.

Effects of Chinese herbal medicines on the occurrence of diabetic retinopathy in type 2 diabetes patients and protection of ARPE-19 retina cells by inhibiting oxidative stress

Diabetic retinopathy is a microvascular complication of type 2 diabetes and the leading cause of acquired blindness. In Taiwan, Chinese herbal medicine (CHM) is a popular adjunctive therapy. In this study, we investigated the CHM prescription patterns and their effects. We identified 23,701 subjects with type 2 diabetes in a database, and after matching for age and gender, 6,948 patients each were assigned to CHM and non-CHM groups. In the female subgroups, the cumulative retinopathy probability was lower for the CHM users than that for the CHM non-users (P < 0.001, log-rank test). Among the top 10 CHMs, Jia-Wei-Xiao-Yao-San (JWXYS; 52.9%), Shu-Jing-Huo-Xue-Tang (SJHXT; 45.1%), and Ge-Gen-Tang (GGT; 43.7%) were the most common herbal formulas. Yan-Hu-Suo (48.1%), Ge-Gen (42.1%), and Huang-Qin (HQin; 40.1%) were the most common single herbs. CHM network analysis showed that JWXYS was the core CHM of cluster 1. JWXYS, DS, XF, and SZRT exhibited both of the reductions of H₂O₂-induced phosphorylation of p38 MAPK and p44/42 MAPK (Erk1/2) in human ARPE-19 retina cells. In cluster 2, SJHXT was the core CHM. SJHXT and NX showed both of the phosphorylation reductions. In cluster 3, GGT was the core CHM, and it reduced the phosphorylation of both MAPKs. In cluster 4, HQin was the core CHM, and it also reduced the phosphorylation of both MAPKs. Our study suggests that adjunctive CHM therapy may reduce diabetic retinopathy via antioxidant activity of the herbs and provides information on core CHM treatments for further scientific investigations or therapeutic interventions.

Bridging Type 2 Diabetes and Alzheimer's Disease: Assembling the Puzzle Pieces in the Quest for the Molecules With Therapeutic and Preventive Potential

Type 2 diabetes (T2D) and Alzheimer's disease (AD) are two age-related amyloid diseases that affect millions of people worldwide. Broadly supported by epidemiological data, the higher incidence of AD among type 2 diabetic patients led to the recognition of T2D as a tangible risk factor for the development of AD. Indeed, there is now growing evidence on brain structural and functional abnormalities arising from brain insulin resistance and deficiency, ultimately highlighting the need for new approaches capable of preventing the development of AD in type 2 diabetic patients. This review provides an update on overlapping pathophysiological mechanisms and pathways in T2D and AD, such as amyloidogenic events, oxidative stress, endothelial dysfunction, aberrant enzymatic activity, and even shared genetic background. These events will be presented as puzzle pieces put together, thus establishing potential therapeutic targets for drug discovery and development against T2D and diabetes-induced cognitive decline-a heavyweight contributor to the increasing incidence of dementia in developed countries. Hoping to pave the way in this direction, we will present some of the most promising and well-studied drug leads with potential against both pathologies, including their respective bioactivity reports, mechanisms of action, and structure-activity relationships.

Metabolomics insights into diabetes nephropathy and protective effects of Radix Scutellariae on rats using ultra-high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry

UHPLC-Q-TOF-MS based metabolomics combined with multivariate statistical analysis for evaluating protective effects ofRadix Scutellariaeon DN rats.

Traditional medicine yanggyuksanhwa-tang inhibits adipogenesis and suppresses proliferator-activated receptor-gamma expression in 3T3-L1 cells

Background:

Yanggyuksanhwa-tang (YGSHT) is a specific traditional Korean herbal formula for Soyangin according to Sasang constitutional philosophy. Although its biological activities against inflammation and cerebral infarction have been reporting, there is no information about the adipogenic activity of YGSHT. In the present study, we investigated the anti-adipogenic activity of YGSHT to evaluate effects of YGSHT on adipogenesis in vitro.

Materials and Methods:

Using 3T3-L1 preadipocytes, we induced the cellular differentiation into adipocytes by adding insulin. Anti-adipogenic activity of YGSHT was measured by oil red O staining, triglyceride assay, glycerol-3-phosphate dehydrogenase (GPDH) activity test, and leptin assay.

Results:

YGSHT extract had no significant cytotoxicity in preadipocytes or differentiated adipocytes. YGSHT reduced the number of lipid droplets and content of triglyceride in adipose cells. YGSHT also significantly inhibited GPDH activity and decreased leptin production compared with control adipocytes. Down-regulation of peroxisome proliferator-activated receptor-gamma (PPAR-γ) expression at the messenger RNA level was observed in YGSHT-treated adipocytes.

Conclusion:

Taken together, our data suggest that YGSHT has potential as an anti-obesity drug candidate.

Cyanidin and malvidin in aqueous extracts of black carrots fermented with Aspergillus oryzae prevent the impairment of energy, lipid and glucose metabolism in estrogen-deficient rats by AMPK activation

Black carrots (Daucus carota L.) are rich in anthocyanins which contribute many health benefits, but are limited by bioavailability and instability when exposed to oxygen, heat and light. Fermenting black carrots may improve the stability, absorption and bioactivity of its anthocyanins. Here, we examined whether and by what mechanisms the long-term consumption of unfermented black carrot extract (BC) and its extracts fermented with Lactobacillus plantarum (BCLP) or Aspergillus oryzae (BCAO) might prevent menopausal symptoms including impaired energy, glucose and lipid metabolism in estrogen-deficient animals with diet-induced obesity. Ovariectomized (OVX) rats were fed four different high-fat diets containing 2 % dextrin (OVX-control), 2 % BC, 2 % BCLP, or 2 % BCAO for 12 weeks. Sham rats were fed high-fat diets containing 2 % dextrin. The contents of total anthocyanins increased in BCAO compared to BC and BCLP, whereas the contents of cyanidin-3-rutinosides, malvidin-3,5-diglycosides and delphine-3-glucoside were lower and cyanidin and malvidin were much higher in BCLP and BCAO than BC. Fat mass and weight gain were lower in descending order of OVX-control > BC and BCLP > BCAO due to increased energy expenditure and fat oxidation. However, BC, BCLP and especially BCAO all normalized HOMA-IR, an indicator of insulin resistance and glucose intolerance, in OVX rats. OVX increased serum total and LDL cholesterol and triglycerides, but BC, BCLP and BCAO significantly prevented the increases. BCAO markedly decreased hepatic triglyceride levels by increasing gene expressions of CPT-1 and PPAR-α, which are involved in fatty acid oxidation, and decreasing mRNA expressions of FAS and SREBP-1c, which are associated with fatty acid synthesis. This was related to increased pAMPK → pACC signaling and improved hepatic insulin signaling (pAkt → pFOXO-1). Cyanidin and malvidin markedly decreased fat accumulation in 3T3-L1 adipocytes by increasing CPT-1 and decreasing FAS and SREBP-1c expression in comparison with cyanidin-3-rutinoside and malvidin-3,5-diglycosides. In conclusion, with increasing cyanidin and malvidin, BCAO prevented the exacerbation of lipid and glucose metabolism by activating hepatic insulin signaling and AMPK activation by in OVX rats.

An 8-wk, randomized, double-blind, placebo-controlled clinical trial for the antidiabetic effects of hydrolyzed ginseng extract

BACKGROUND

To investigate the antidiabetic effects of hydrolyzed ginseng extract (HGE) for Korean participants in an 8-wk, randomized, double-blinded, placebo-controlled clinical trial.

METHODS

Impaired fasting glucose participants [fasting plasma glucose (FPG) ≥ 5.6mM or < 6.9mM] who had not been diagnosed with any disease and met the inclusion criteria were recruited for this study. The 23 participants were randomly divided into either the HGE (n = 12, 960 mg/d) or placebo (n = 11) group. Outcomes included measurements of efficacy (FPG, postprandial glucose, fasting plasma insulin, postprandial insulin, homeostatic model assessment-insulin resistance, and homeostatic model assessment-β) and safety (adverse events, laboratory tests, electrocardiogram, and vital signs).

RESULTS

After 8 wk of HGE supplementation, FPG and postprandial glucose were significantly decreased in the HGE group compared to the placebo group. No clinically significant changes in any safety parameter were observed. Our study revealed that HGE is a potent antidiabetic agent that does not produce noticeable adverse effects.

CONCLUSION

HGE supplementation may be effective for treating impaired fasting glucose individuals.

Comparative metabolism of Radix scutellariae extract by intestinal bacteria from normal and type 2 diabetic mice in vitro

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional Chinese medicine (TCM) has been used in clinical practice for several thousand years. TCM has played an indispensable role in the prevention and treatment of disease, especially the complicated and chronic ones. In TCMs, many ingredients which are known to have biological effects just pass through the gut, they do not get into the bloodstream. Study on interactions of these active ingredients with the intestinal bacteria is very helpful to unravel how TCM works. Radix scutellariae was widely used alone or in combination with other medicinal herbs to the treatment of type 2 diabetes mellitus for a long time in China even in Asia. Additionally, the incidence of type 2 diabetes is closely related to the changes of intestinal flora. In this paper, the metabolism of baicalin in Radix scutellariae extract by normal and type 2 diabetic mice intestinal bacteria were firstly investigated.

MATERIALS AND METHODS

Ultra performance liquid chromatography/quadrupole-time-of-flight mass spectrometry (UPLC/QTOF-MS) technique combined with Metabolynx(TM) software was used for analysis of the metabolic profile of baicalin in Radix scutellariae extracts by the intestinal bacteria from normal and type 2 diabetic mice.

RESULTS

The amount of baicalin׳s aglycone (baicalein) in type 2 diabetic mice samples were remarkably more than that in normal mice samples and oroxylin A only existed in type 2 diabetic mice samples. Intestinal bacteria produced not only a small amount of baicalein, but also some conjugates such as hydrogenated baicalin and methylated baicalin.

CONCLUSIONS

We proposed that β-d-glucuronidases contributed to the deglycosylation prior to absorption. Intestinal bacteria from pathological state mice produced more baicalein, which was well absorbed contributing to the treatment of type 2 diabetes. Additionally, the pharmacological effects of oroxylin A were associated with type 2 diabetes. Hence, the production of metabolites of baicalin might influence the effects of traditional medicines. Thus the study on the metabolism of baicalin by intestinal bacteria from normal and type 2 diabetic mice was of great importance to understanding the effects of traditional medicines. Furthermore, this work demonstrated the potential of the ultra performance liquid chromatography/quadrupole time-of-flight mass spectrometry approach with MetaboLynx for quite rapid, simple, reliable and automated identification of metabolites of natural products.

Phytotherapy in diabetes: Review on potential mechanistic perspectives

Diabetes mellitus (DM) is a widely spread epidemic disease that results from the absence of insulin, decreased secretion and/or impaired function. Since DM is a multi-factorial disease, the available pharmaceuticals, despite their sensible treatment, target mostly one pathway to control hyperglycemia and encounter several side effects. Therefore, new therapeutic paradigms aim to hit several pathways using only one agent. Traditionally, antidiabetic plants and/or their active constituents may fulfill this need. More than 200 species of plants possess antidiabetic properties which were evaluated mostly by screening tests without digging far for the exact mode of action. Searching among the different literature resources and various database and in view of the above aspects, the present article provides a comprehensive review on the available antidiabetic plants that have been approved by pharmacological and clinical evaluations, and which their mechanism(s) of action is assured. These plants are categorized according to their proved mode of action and are classified into those that act by inhibiting glucose absorption from intestine, increasing insulin secretion from the pancreas, inhibiting glucose production from hepatocytes, or enhancing glucose uptake by adipose and muscle tissues. The current review also highlights those that mimic in their action the new peptide analogs, such as exenatide, liraglutide and dipeptidylpeptidase-4 inhibitors that increase glucagon-like peptide-1 serum concentration and slow down the gastric emptying.

Use of Mesenchymal Stem Cell-Conditioned Medium to Activate Islets in Preservation Solution

Pancreatic islet transplantation has received widespread attention as a promising treatment for type 1 diabetes. However, islets for transplantation are subject to damage from a number of sources, including ischemic injury during removal and delivery of the donor pancreas, enzymatic digestion during islet isolation, and reperfusion injury after transplantation in the recipient. Here we found that protein fractions secreted by mesenchymal stem cells (MSCs) were capable of activating preserved islets. A conditioned medium from the supernatant obtained by culturing adipose tissue MSCs (derived from wild-type Lewis rats) was prepared for 2 days in serum-free medium. Luc-Tg rat islets to which an organ preservation solution was added were then incubated at 4°C with fractions of various molecular weights prepared from the conditioned medium. Under the treatment with some of the fractions, by 4 days the relative luminescence intensities (representative of the ATP levels of the cold-preserved islets) had increased to over 150% of their initial values. Our novel system may be able to restore isolated islets to the condition they were in before transport, culture, and transplantation.

Treating type 2 diabetes mellitus with traditional chinese and Indian medicinal herbs

Type II diabetes mellitus (T2DM) is a fast-growing epidemic affecting people globally. Furthermore, multiple complications and comorbidities are associated with T2DM. Lifestyle modifications along with pharmacotherapy and patient education are the mainstay of therapy for patients afflicted with T2DM. Western medications are frequently associated with severe adverse drug reactions and high costs of treatment. Herbal medications have long been used in the treatment and prevention of T2DM in both traditional Chinese medicine (TCM) and traditional Indian medicine (TIM). This review examines in vivo, in vitro, and clinical evidence supporting the use of various herbs used in TCM and TIM. The problems, challenges, and opportunities for the incorporation of herbal frequently used in TCM and TIM into Western therapy are presented and discussed.

Herbal medicines for the management of diabetes

Herbal medicines have been used in the management of diabetes in traditional medicine. This chapter reviews recent findings of the most popular herbs reported to treat diabetes through their relevant mechanistic pathways. These include increased insulin secretion, improvement in insulin sensitivity, enhanced glucose uptake by adipose and muscle tissues, inhibition of glucose absorption from intestine, inhibition of glucose production from hepatocytes and anti-inflammatory activities. The pharmacological activities have highlighted the potential efficacy of these herbal medicines in the management of diabetes.

GPR40: a therapeutic target for mediating insulin secretion (review)

G-protein-coupled receptor 40 (GPR40), known as free fatty acid receptor 1, is mainly expressed in pancreatic β-cells and activated by medium- and long-chain fatty acids. Increasing evidence indicates that the activation of GPR40 in cells causes insulin secretion, and GPR40 has become an attractive therapeutic target for type 2 diabetes. Recently, certain novel GPR40 agonists have been identified that regulate glucose-stimulated insulin secretion, leading to the development of new drugs for the treatment of type 2 diabetes. In this review, we focus on progress in the physiological role of GPR40 and potential drugs targeting GPR40 over the past decade.

Extracts from Radix Astragali and Radix Rehmanniae promote keratinocyte proliferation by regulating expression of growth factor receptors

Chinese herbal medicine has long been used as a treatment for wounds. However, the underlying cellular and molecular mechanisms remain largely unknown. In this study it was shown that the proliferation of keratinocytes, which is known to play an important role in wound healing as the major cell type in the epidermis, was promoted by three herbal extracts/natural compounds: NF3 (an extract from the mixture of Radix Astragali (RA) and Radix Rehmanniae (RR) in the ratio of 2:1), stachyose (an isolated compound from Radix Rehmanniae) and extract P2-2 (a sub-fraction from the extract of Radix Astragali). The effect of the herbal extracts/natural compounds on the growth of keratinocytes was not influenced by a high glucose level, a condition similar to diabetic patients who usually suffer from diabetic foot ulcers. Real time RT-PCR results showed that the expression of epidermal growth factor (EGF) receptor, but not transforming growth factor-β (TGF-β) receptor, was up-regulated by NF3. Moreover, treatments with the EGF receptor kinase inhibitor AG1478 and the MEK inhibitor U0126 resulted in the diminishment of the effect of the three herbal extracts/natural compounds on keratinocyte proliferation, indicating that EGF receptor might have a significant role in this action. This study has further elucidated the molecular mechanism under which herbal extracts/natural compounds exert their effects on the wound healing process.

Hypoglycemic effect of Rehmannie Radix Preparata (Sookjihwang) extract in streptozotocin-induced diabetic rats

Rhemannie Radix Preparata (RRP) has been previously employed in traditional oriental medicine as a treatment for diabetic thirst and improving blood flow. The aim of this study was to evaluate its hypoglycemic control by assaying the activities of key enzymes of carbohydrate metabolism in streptozotocin-(STZ)-induced diabetic rats. Further, RRP extracts were prepared in water (RRPW), in 50% ethanol (RRP50), and in 100% ethanol (RRP100), respectively, and compared for their actions in diabetic rats. The oral treatment of RRP (5 mg/kg b.w./d) to diabetic rats for 21 days resulted in a significant decline in blood glucose by 67% compared to diabetic control rats (P < 0.05). The altered activities of glucokinase, glucose-6-phosphate dehydrogenase (G6PD), 6-phosphogluconate dehydrogenase (6PGD), and acetyl CoA carboxylase (ACC) in the livers of diabetic rats were reversed significantly to near-normal levels by the administration of RRP (P < 0.05). Among the three RRP extracts, RRP100 was the most effective in terms of hypoglycemic action. However, the administration of RRP to diabetic rats did not improve insulin production. The modulatory effects of RRP100 on the attenuation of carbohydrate enzyme activities appear to hold promise for widespread use for the treatment of diabetes in the future.

Transcriptional changes associated with reduced spontaneous liver tumor incidence in mice chronically exposed to high dose arsenic

Exposure of male C3H mice in utero (from gestational days 8-18) to 85ppm sodium arsenite via the dams' drinking water has previously been shown to increase liver tumor incidence by 2 years of age. However, in our companion study (Ahlborn et al., 2009), continuous exposure to 85ppm sodium arsenic (from gestational day 8 to postnatal day 365) did not result in increased tumor incidence, but rather in a significant reduction (0% tumor incidence). The purpose of the present study was to examine the gene expression responses that may lead to the apparent protective effect of continuous arsenic exposure. Genes in many functional categories including cellular growth and proliferation, gene expression, cell death, oxidative stress, protein ubiquitination, and mitochondrial dysfunction were altered by continuous arsenic treatment. Many of these genes are known to be involved in liver cancer. One such gene associated with rodent hepatocarcinogenesis, Scd1, encodes stearoyl-CoA desaturase and was down-regulated by continuous arsenic treatment. An overlap between the genes in our study affected by continuous arsenic exposure and those from the literature affected by long-term caloric restriction suggests that reduction in the spontaneous tumor incidence under both conditions may involve similar gene pathways such as fatty acid metabolism, apoptosis, and stress response.