Liangli Lucy YU
Department of Nutrition and Food Science, University of Maryland
Gynostemma pentaphyllum (Chinese name: Jiaogulan) has been used as functional tea worldwide. Commercially used Jiaogulan are mostly diploids, whereas tetraploids have been cultivated and were commercially available. Our previous studies have shown significant differences in flavonoid and saponin compositions and bioactivities between the tetraploid Jiaogulan and its diploid counterpart. Jiaogulan showed several health benefits including anti-inflammatory and antiobesity activities, and its saponins were considered as the major health constituents. As a continuation of our Jiaogulan research, the chemical constituents of saponin-rich fraction in tetraploid Jiaogulan were investigated. Six new 21, 23-epoxydammar-24-ene saponins and two novel 21-nordammarane saponins were isolated and elucidated by HRESIMS, 1D and 2D NMR data, chemical degradation and electronic circular dichroism (ECD) spectra. All isolated saponins suppressed the expression of IL-1β, COX-2 and TNF-α mRNA in the lipopolysaccharide-induced RAW 264.7 mouse macrophage cells at the concentrations of 10 and 100 μg/mL, suggesting their remarkable anti-inflammatory effects. In addition, a saponin also showed significant anti-adipogenic activity through down-regulation the expression of major genes involved in the adipogenesis pathway and up-regulation the WNT/b-catenin pathway. The results may be used to promote the value-added utilization of Jiaogulan and its components in reducing the risk of chronic inflammation and obesity. |
