Centella asiatica (also known as Centella asiatica (L.) Urb. or Gotu kola) is a traditional Chinese medicine with extensive medicinal value, which is commonly used in Southeast Asian countries. This study aimed to summarize the effects of C. asiatica and its main components on neurological diseases, endocrine diseases, skin diseases, cardiovascular diseases, gastrointestinal diseases, immune diseases, and gynecological diseases, as well as potential molecular mechanisms, to study the pathological mechanism of these diseases based on the changes at the molecular level. The results showed that C. asiatica and its triterpenoids had extensive beneficial effects on neurological and skin diseases, which were confirmed through clinical studies. They exhibited anti-inflammatory, anti-oxidative stress, anti-apoptotic effects, and improvement in mitochondrial function. However, further clinical studies are urgently required due to the low level of evidence and lack of patients.

L-Citrulline (L-Cit), a free amino acid from watermelon, has effects on hypertension and anti-oxidization; however, there are few reports of effects related to obesity. This study investigated the effects and mechanism of L-Cit on anti-obesity in obese/diabetic KK-Ay mice and high-fat diet fed Sprague-Dawley (SD) rats. L-Cit induced significant reduction of food intake, body weight and fat tissue mass in obese/diabetic KK-Ay mice. Moreover, blood glucose level did not change but free fatty acid level and serum insulin level were significantly decreased by treatment with L-Cit, suggesting that L-Cit improved glucose and fatty metabolism in obesity model mice. As well as obese/diabetic KK-Ay mice, there was a significant decrease in food intake and a tendency of body weight to decrease in high-fat diet fed SD rats treated with L-Cit. Also, levels of proopiomelanocortin (POMC), a food intake suppression peptide, increased in the hypothalamus. Our study suggests that L-Cit improves metabolic syndrome through decreased body weight by appetite suppression.

Background: Isoquercitrin, a flavonoid compound that is widely distributed in medicinal and dietary plants, possesses many biological activities, including inhibition of adipocyte differentiation. In this study, we investigated the effect of isoquercitrin on lipid accumulation and its molecular mechanisms in rat hepatoma H4IIE cells. Methods: To investigate the effect of isoquercitrin on lipid accumulation, H4IIE cells were induced by FFA and the total lipid levels were detected by Oil Red O staining. Furthermore, The protein levels of AMPK and acetyl-CoA carboxylase (ACC), the gene expressions of transcriptional factor, lipogenic genes, and adiponectin receptor 1 (AdipoR1) were analyzed by Western blotting and quantitative real-time PCR. To further confirm the pathway of isoquercitrin-mediated hepatic lipid metabolism, H4IIE cells were treated with an AMPK inhibitor and AdipoR1 siRNA. Results: Isoquercitrin significantly enhances AMPK phosphorylation, downregulates sterol regulatory element binding protein transcription factor 1 (SREBP-1) and fatty acid synthase (FAS) gene expressions. Pretreatment with AMPK inhibitor, significantly decreased the AMPK phosphorylation and increased FAS expression stimulated by isoquercitrin. Isoquercitrin might also upregulate the expression of AdipoR1 dose-dependently via AMPK in the presence of an AMPK inhibitor and AdipoR1 siRNA. Conclusions: Isoquercitrin appears to regulate AMPK activation, thereby enhancing AdipoR1 expression, suppressing SREBP-1 and FAS expressions, and resulting in the regulation of lipid accumulation. These results suggest that isoquercitrin is a novel dietary compound that can be potentially be used to prevent lipid metabolic disorder and nonalcoholic fatty liver disease.

Background: Metabolic syndrome (MS) and type 2 diabetes mellitus (T2DM) have been associated with insulin-resistance; however, the effective therapies in improving insulin sensitivity are limited. This study is aimed at investigating the effect of Guava Leaf (GL) extracts on glucose tolerance and insulin resistance in SHRSP.Z-Leprfa/Izm rats (SHRSP/ZF), a model of spontaneously metabolic syndrome. Methods: Male rats at 7 weeks of age were administered with vehicle water or treated by gavage with 2 g/kg GL extracts daily for six weeks, and their body weights, water and food consumption, glucose tolerance, and insulin resistance were measured. Results: Compared with the controls, treatment with GL extracts did not modulate the amounts of water and food consumption, but significantly reduced the body weights at six weeks post treatment. Treatment with GL extracts did not alter the levels of fasting plasma glucose and insulin, but significantly reduced the levels of plasma glucose at 60 and 120 min post glucose challenge, also reduced the values of AUC and quantitative insulin sensitivity check index (QUICKI) at 42 days post treatment. Furthermore, treatment with GL extracts promoted IRS-1, AKT, PI3Kp85 expression, then IRS-1, AMKP, and AKT308, but not AKT473, phosphorylation, accompanied by increasing the ratios of membrane to total Glut 4 expression and adiponectin receptor 1 transcription in the skeletal muscles. Conclusions: These data indicated that GL extracts improved glucose metabolism and insulin sensitivity in the skeletal muscles of rats by modulating the insulin-related signaling.

Diabetes is caused by the lack of release or action of insulin. Some foods and supplements can compensate for this deficiency; thus, they can aid in the prevention or treatment of diabetes. The aim of this study was to investigate the effects of Cyclocarya paliurus extract (CPE) on insulin signaling and its capacity to correct hyperglycemia in the absence of insulin. To investigate the hypoglycemic effects of CPE, C2C12 cells were exposed to CPE (50 and 100 μg/mL). CPE promoted 2-(N-(7-Nitrobenz-2-oxa-1,3-diazol-4-yl)Amino)-2-Deoxyglucose (2NBDG) uptake into the cells via translocation of glucose transporter 4 (Glut4) to the plasma membrane. In addition, CPE enhanced tyrosine phosphorylation of insulin receptor substrate and activated phosphatidylinositol 3-kinase and protein kinase B (Akt) via sirtuin1 in C2C12 cells. Moreover, we found that oral administration of CPE (1 g/kg) to streptozotocin-induced hyperglycemic mice produced a progressive decrease in plasma glucose levels at 1 h after single dosing. At that point, CPE significantly increased the expression of skeletal muscle membrane Glut4 and enhanced the phosphorylation of Akt. These results suggest that CPE exerts antidiabetic effects similar to those of insulin, and may be an oral therapeutic alternative for the management of diabetes.