Picrotoxane-type sesquiterpenoids from Dendrobium improve insulin resistance and increase glucose-stimulated insulin secretion.

Twelve picrotoxane-type sesquiterpenoids were isolated from Dendrobium wardianum, of which dendrowardins K-N (1-4) are new compounds and dendrowardins O and P (9, 10) are new natural products. Notably, the structure of dendrowardin K contains the rarely observed 10,11-γ-lactone ring. The structural configurations of these compounds were determined through comprehensive 1D and 2D nuclear magnetic resonance (NMR), single-crystal X-ray diffraction, and other spectroscopic analyses.

Structure characterization and immunoactivity on dendritic cells of two neutral polysaccharides from Dictyophora rubrovalvata.

Dictyophora rubrovalvata is a valuable fungus homologous to food and medicine, and its polysaccharide have been gaining increasing attention because of its plentiful activity. However, the structure and activity of its homogeneous polysaccharide have not been studied enough. In this study, two polysaccharides DRP-I and DRP-II were purified from D.