Phytochemical characterisation of a cytotoxic stem bark extract of Steganotaenia araliacea and identification of a protoflavanone by LC–SPE–NMR

Abstract

A 80% ethanolic stem bark extract of Steganotaenia araliacea (Apiaceae) showed cytotoxic properties against MDA-MB-231 (breast), PANC-1 (pancreas) and HT-29 (colon) cancer cell lines. Phytochemical investigations by LC-SPE-NMR led to the identification of spiropreussomerin A, most probably produced by an endophytic fungus, the flavanonol conrauiflavonol / afzelin A, and a protoflavanone that has not been reported before and for which the name steganoprotoflavanone was adopted. Surprisingly none of the previously reported cytotoxic dibenzocyclo-octadiene lactone lignans was obtained as a major constituent of the cytotoxic extract.