Extraction and Crystal Structure of Physalin B

The title compound of 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 P21 with C28H32O9, a = 12.4996(2), b = 14.35620(10), c = 14.75190(10), V = 2607.97(5) 3, Z = 4, Dc = 1.382 mg/cm3, Mr = 542.56, F(000) = 1152, and μ = 0.870 mm-1. The final R = 0.0389 and wR = 0.1037 for 47670 observed reflections(I > 2σ(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 5～20 μmol/L range, physalin B can significantly inhibit the secretion of inflammatory cytokines TNF-α and IL-6 on RAW264.7 cells. The results suggest that physalin B has anti-inflammatory activity in vitro.