Ginsenoside Rb1 as an Anti-Diabetic Agent and Its Underlying Mechanism Analysis

Interactions Between Gut Microbiota, Host, and Herbal Medicines: A Review of New Insights Into the Pathogenesis and Treatment of Type 2 Diabetes

Herbal medicines (HMs) are a major subset of complementary and alternative medicine. They have been employed for the efficient clinical management of type 2 diabetes mellitus (T2DM) for centuries. However, the related underlying mechanisms still remain to be elucidated. It has been found out that microbiota is implicated in the pathogenesis and treatment of T2DM. An interplay between gut microbiota and host occurs mainly at the gastrointestinal mucosal barrier. The host movements influence the composition and abundance of gut microbiota, whereas gut microbiota in turn modulate the metabolic and immunological activities of the host. Intestinal dysbiosis, endotoxin-induced metabolic inflammation, immune response disorder, bacterial components and metabolites, and decreased production of short-chain fatty acids are considered significant pathogenic mechanisms underlying T2DM. The interaction between gut microbiota and HMs during T2DM treatment has been investigated in human, animal, and in vitro studies. HMs regulate the composition of beneficial and harmful bacteria and decrease the inflammation caused by gut microbiota. Furthermore, the metabolism of gut microbiota modulates HM biotransformation. In this review, we have summarized such research findings, with the aim to improve our understanding of the pathogenesis and potential therapeutic mechanisms of HMs in T2DM and to provide new insights into specific targeted HM-based therapies and drug discovery.

The Mechanism of Traditional Chinese Medicine for the Treatment of Obesity

Obesity is the lipid deposition caused by the imbalance between energy intake and consumption caused by a variety of factors. Obesity can lead to multiple systemic complications. At present, the treatment of obesity is mainly lifestyle intervention, drug weight loss, and weight loss surgery, but the curative effect is limited or the side effects are serious. Traditional Chinese medicine plays a unique role in the treatment of obesity. Existing studies have found that traditional Chinese medicine can treat obesity in a variety of ways, such as regulating intestinal microflora, enhancing hormone level, regulating fat metabolism, and so on. In this review, we will introduce and summarize the mechanism of traditional Chinese medicine in the treatment of obesity.

Ginsenoside-Rb1 Improved Diabetic Cardiomyopathy through Regulating Calcium Signaling by Alleviating Protein O-GlcNAcylation

Ginsenoside-Rb1 (Rb1), a major active component of ginseng, has many benefits for cardiovascular disease and diabetes mellitus (DM), but the effect and mechanism on diabetic cardiomyopathy are not clear. In the present study, we found that Rb1-feeding significantly improved cardiac dysfunction and abnormal cardiomyocytes calcium signaling caused by diabetes. This improved calcium signaling was because Rb1 reduced Ca²⁺ leakage caused by overactivated ryanodine receptor 2 (RyR2) and increased Ca²⁺ uptake by sarcoplasmic reticulum Ca²⁺-ATPase 2a (SERCA 2a). Furthermore, we found that Rb1 not only enhanced energy metabolism like metformin and eliminated O-GlcNAcylation of calcium handling proteins to regulate calcium signaling but also directly inhibited RyR2 activity to regulate calcium signaling. The present study indicated that as a health supplement or drug, Rb1 was a relatively effective auxiliary therapeutic substance for diabetic cardiomyopathy.

Sheng Mai San protects H9C2 cells against hyperglycemia-induced apoptosis

BACKGROUND

Sheng Mai San (SMS) has been proven to exhibit cardio-protective effects. This study aimed to explore the molecular mechanisms of SMS on hyperglycaemia (HG)-induced apoptosis in H9C2 cells.

METHODS

HG-induced H9C2 cells were established as the experimental model, and then treated with SMS at 25, 50, and 100 μg/mL. H9C2 cell viability and apoptosis were quantified using MTT and Annexin V-FITC assays, respectively. Furthermore, Bcl-2/Bax signalling pathway protein expression and Fas and FasL gene expression levels were quantified using western blotting and RT-PCR, respectively.

RESULTS

SMS treatments at 25, 50, 100 μg/mL significantly improved H9C2 cell viability and inhibited H9C2 cell apoptosis (p < 0.05). Compared to the HG group, SMS treatment at 25, 50, and 100 μg/mL significantly downregulated p53 and Bax expression and upregulated Bcl-2 expression (p < 0.05). Moreover, SMS treatment at 100 μg/mL significantly downregulated Fas and FasL expression level (p < 0.05) when compared to the HG group.

CONCLUSION

SMS protects H9C2 cells from HG-induced apoptosis probably by downregulating p53 expression and upregulating the Bcl-2/Bax ratio. It may also be associated with the inhibition of the Fas/FasL signalling pathway.

Black Ginseng and Ginsenoside Rb1 Promote Browning by Inducing UCP1 Expression in 3T3-L1 and Primary White Adipocytes

In this study, we investigated the effects of black ginseng (BG) and ginsenoside Rb1, which induced browning effects in 3T3-L1 and primary white adipocytes (PWATs) isolated from C57BL/6 mice. BG and Rb1 suppressed the expressions of CCAAT/enhancer-binding protein alpha (C/EBPα) and sterol regulatory element-binding transcription factor-1c (SREBP-1c), whereas the expression level of peroxisome proliferator-activated receptor gamma (PPARγ) was increased. Furthermore, BG and Rb1 enhanced the protein expressions of the brown-adipocyte-specific markers PR domain containing 16 (PRDM16), peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α), and uncoupling protein 1 (UCP1). These results were further supported by immunofluorescence images of mitochondrial biogenesis. In addition, BG and Rb1 induced expressions of brown-adipocyte-specific marker proteins by AMP-activated protein kinase (AMPK) activation. BG and Rb1 exert antiobesity effects by inducing browning in 3T3-L1 cells and PWATs through AMPK-mediated pathway activation. We suggest that BG and Rb1 act as potential functional antiobesity food agents.

Ginsenoside Rb1 mitigates oxidative stress and apoptosis induced by methylglyoxal in SH-SY5Y cells via the PI3K/Akt pathway

Diabetic encephalopathy is a severe diabetic complication characterized by cognitive dysfunction and neuropsychiatric disability. Methylglyoxal (MGO), a highly reactive metabolite of hyperglycemia, serves as a major precursor of advanced glycation end products that play key roles in diabetic complications. Ginsenoside Rb1 (abbreviated as Rb1) has received extensive attention due to its potential therapeutic effects on diabetes and neurodegeneration. Therefore, this study aimed to investigate the effects of Rb1 on MGO-induced damage in SH-SY5Y cells and the related mechanism. SH-SY5Y cells were pretreated with Rb1 for 8 h and then exposed to MGO (0.5 mM) for 24 h. Cell survival was assessed by the MTT assay. Cell apoptosis was assessed using Hoechst 33342/propidium iodide (PI) staining and an Annexin-V/PI kit. The activities of oxidative stress markers were examined using commercial kits. Reactive oxygen species (ROS) staining and JC-1 staining were used to evaluate mitochondria injury. In addition, protein levels were measured by Western blot analysis. As a result, Rb1 alleviated the injury induced by MGO by increasing the activities of superoxide dismutase, catalase and total glutathione, decreasing the level of malondialdehyde, and alleviating mitochondrial damage and ROS production. Furthermore, Rb1 could enhance the Bcl-2/Bax ratio, inhibit the expression of cleaved caspase-3 and cleaved caspase-9, and enhance the levels of phosphorylated Akt. Moreover, the protective effects of Rb1 against MGO-induced apoptosis were partly abolished by LY294002, a specific inhibitor of phosphatidylinositol 3-kinase (PI3K) phosphorylation. Our results demonstrated that Rb1 ameliorated MGO-induced oxidative stress and apoptosis in SH-SY5Y cells via activating the PI3K/Akt signaling pathway.

HMGB1-triggered inflammation inhibition of notoginseng leaf triterpenes against cerebral ischemia and reperfusion injury via MAPK and NF-κB signaling pathways

Ischemic stroke is a clinically common cerebrovascular disease whose main risks include necrosis, apoptosis and cerebral infarction, all caused by cerebral ischemia and reperfusion (I/R) injury. This process has particular significance for the treatment of stroke patients. Notoginseng leaf triterpenes (PNGL), as a valuable medicine, have been discovered to have neuroprotective effects. However, it was not confirmed that whether PNGL may possess neuroprotective effects against cerebral I/R injury. To explore the neuroprotective effects of PNGL and their underlying mechanisms, a middle cerebral artery occlusion/reperfusion (MCAO/R) model was established. In vivo results suggested that in MCAO/R model rats, PNGL pretreatment (73.0, 146, 292 mg/kg) remarkably decreased infarct volume, reduced brain water content, and improved neurological functions; moreover, PNGL (73.0, 146, 292 mg/kg) significantly alleviated blood-brain barrier (BBB) disruption and inhibited neuronal apoptosis and neuronal loss caused by cerebral I/R injury, while PNGL with a different concertation (146, 292 mg/kg) significantly reduced the concentrations of IL-6, TNF-α, IL-1 β, and HMGB1 in serums in a dose-dependent way, which indicated that inflammation inhibition could be involved in the neuroprotective effects of PNGL. The immunofluorescence and western blot analysis showed PNGL decreased HMGB1 expression, suppressed the HMGB1-triggered inflammation, and inhibited microglia activation (IBA1) in hippocampus and cortex, thus dose-dependently downregulating inflammatory cytokines including VCAM-1, MMP-9, MMP-2, and ICAM-1 concentrations in ischemic brains. Interestingly, PNGL administration (146 mg/kg) significantly downregulated the levels of p-P44/42, p-JNK1/2 and p-P38 MAPK, and also inhibited expressions of the total NF-κB and phosphorylated NF-κB in ischemic brains, which was the downstream pathway triggered by HMGB1. All of these results indicated that the protective effects of PNGL against cerebral I/R injury could be associated with inhibiting HMGB1-triggered inflammation, suppressing the activation of MAPKs and NF-κB, and thus improved cerebral I/R-induced neuropathological changes. This study may offer insight into discovering new active compounds for the treatment of ischemic stroke.

Chemical Structures and Pharmacological Profiles of Ginseng Saponins

Ginseng is a group of cosmopolitan plants with more than a dozen species belonging to the genus Panax in the family Araliaceae that has a long history of use in traditional Chinese medicine (TCM). Among the bioactive constituents extracted from ginseng, ginseng saponins are a group of natural steroid glycosides and triterpene saponins found exclusively throughout the plant. Studies have shown that these ginseng saponins play a significant role in exerting multiple therapeutic effects. This review covers their chemical structure and classification, as well as their pharmacological activities, including their regulatory effects on immunomodulation, their anticancer effects, and their functions in the central nervous and cardiovascular systems. The general benefits of ginseng saponins for boosting physical vitality and improving quality of life are also discussed. The review concludes with fruitful directions for future research in the use of ginseng saponins as effective therapeutic agents.