Bioassay guided purification of methanolic extract of the bark of the plant, Thespesia populnea yielded a naphthalene derivative, (+)-gossypol (1). The structure of compound, (+)-gossypol has been established based on its physical and spectral data (UV, IR, 1H & 13C NMR and Mass). The compound has been shown moderate elastase inhibition activity when compared with control compound, ursolic acid.
