New dammarane triterpenoid saponins from the leaves of Cyclocarya paliurus
Abstract Three new dammarane triterpenoid saponins, cyclocariosides O-Q (1–3), were isolated from the ethanolic extracts of the leaves of Cyclocarya paliurus. The structures of these compounds were elucidated by spectroscopic methods.
Cyclocarya paliurus extract modulates adipokine expression and improves insulin sensitivity by inhibition of inflammation in mice.
ETHNOPHARMACOLOGICAL RELEVANCE
Cyclocarya paliurus Batal., a Chinese native plant, is the sole species in its genus and its leaves have been widely used as a remedy for diabetes in traditional folk medicine. The study was undertaken to evaluate the effects of Cyclocarya paliurus leaves extracts (CPE) on adipokine expression and insulin sensitivity in mice.


MATERIALS AND METHODS
Mice were stimulated with conditioned medium (prepared from activated macrophages, Mac-CM) to induce adipose dysfunction and insulin resistance. Then mice were treated with CPE (100, 200 and 500 mg/kg, ig.) or metformin (200 mg/kg, ig.), followed by glucose and insulin intolerance, adipokine expression, phosphorylation of insulin receptor substrate (IRS-1) and glucose consumption measurement.


RESULTS
CPE, as well as metformin effectively promoted glucose disposal in oral glucose tolerance test in normal mice. Mac-CM challenge induced glucose and insulin intolerance, but CPE reversed these alternations with increased glycogen content in muscle and liver, well demonstrating its beneficial effects on glucose homeostasis. RT-qPCR analysis showed that CPE inhibited TNF-a, IL-6, MCP-1 and resistin overexpression and effectively enhanced adiponectin expression in adipose tissue when mice were exposed to Mac-CM stimulation. Inflammation impaired insulin signaling in muscle, whereas CPE inhibited inflammation-induced serine phosphorylation of IRS-1 and effectively restored the phosphorylation of both IRS-1 at tyrosine residues and downstream Akt phosphorylation in response to insulin. Moreover, independently of insulin, CPE promoted glucose consumption in adipocytes under normal and inflammatory conditions.


CONCLUSION
Above-mentioned results demonstrated that CPE beneficially regulated adipokines expression and ameliorated insulin resistance through inhibition of inflammation in mice.
Red wine polyphenolics suppress the secretion of ApoB48 from human intestinal CaCo-2 cells.
Epidemiological studies suggest that the consumption of red wine lowers the risk of cardiovascular disease. Although the cardioprotective effect of red wine has been attributed to its polyphenolic content, presently, very little is known about the mechanisms by which these compounds benefit the cardiovascular system. Therefore, the aim of this study was to elucidate whether red wine polyphenolics attenuate the synthesis and secretion of proatherogenic chylomicrons from intestinal cells. Apolipoprotein B48 levels (marker of intestinal chylomicrons), quantitated by western blotting, were significantly reduced by 30% in cultured CaCo-2 cells and medium when cells were incubated with either dealcoholized red wine, alcoholized red wine, or atorvastatin compared with controls. Intracellular cholesterol availability was also attenuated in cells incubated with dealcoholized red wine (72.5%), alcoholized red wine (81.5%), and atorvastatin (83.5%) compared to control cells. Collectively, this study suggests that red wine polyphenolics downregulate the production of atherogenic chylomicrons from intestinal cells, which may explain the reduced CVD mortality rates following its consumption.