[The structure of versicolactone A from Aristolochia versicolar S.M. Hwang]

A novel sesquiterpene lactone, versicolactone A, with 12-carbon ring skeleton, was isolated from the roots of Aristolochia versicolar S. M. Hwang. Versicolactone A, C15H20O2, colorless prisms, mp 130-132 degrees C, [alpha]6D +486 degrees (c 0.1276, CHCl3). Its structure was established by spectroscopic methods, mainly 2D-NMR (1H-1H COSY, 1H-13C COSY, COLOC), HRMS and metastable ion measurement.