Extraction and Crystal Structure of Physalin B

Physalin B (C28H32O9), a main active physalin of Physalis angulata L was isolated from the whole plant of Physalis angulata L, and characterized by X-ray diffraction analysis. It crystallizes in the monoclinic system, space group P2(1) with C28H32O9, a = 12.4996(2), b = 14.35620(10), c = 14.75190(10)Å, V = 2607.97(5)Å3, Z = 4,Dc = 1.382mg/cm3, Mr = 542.56, F(000) = 1152, and mi= 0.870 mm-1. The final R = 0.0389 and wR = 0.1037 for 47670 observed reflections (I 2 (I)). The rigid molecule consists of eight fused rings involving two lactones.. There are two C28H32O9 molecules in an symmetric unit, and the title compound is stacked into a 3D layer structure through hydrogen bonds.In the 5-20mimol/L range, physalin B can significantly inhibit the secretion of inflammatory cytokines TNF- and IL-6 on RAW264.7 cells. The results suggest that physalin B has anti-inflammatory activity in vitro.