Effect of 6α,7β-dihydroxyvouacapan-17β-oic acid and its lactone derivatives on the growth of human cancer cells

Abstract The furanditerpene 6 α ,7 β -dihydroxyvouacapan-17 β -oic acid ( 1 ) is a natural product biosynthesized by some species from the genus Pterodon (Leguminosae). This secondary metabolite has multiple biological activities that include anti-inflammatory, analgesic, plant growth regulatory, anti-edematogenic, photosystem II inhibitory and photosynthesis uncoupler, and antifungal properties. However, few studies on the antiproliferative profile of compound 1 and/or its derivatives have been reported up to date. Here, we describe the isolation of compound 1 from hexane extract of P. polygalaeflorus fruits as well as the semisynthesis of three lactone derivatives: 6 α -hydroxyvouacapan-7 β ,17 β -lactone ( 2 ), 6 α -acetoxyvouacapan-7 β ,17 β -lactone ( 3 ), and 6-oxovouacapan-7 β ,17 β -lactone ( 4 ). Additionally, antiproliferative activity of these compounds against nine human cancer cell lines was investigated. Our results revealed that 6 α -hydroxyvouacapan-7 β ,17 β -lactone ( 2 ) was the most potent furanditerpene against all cancer cell lines studied. The presence of non-substituted hydroxyl group at C-6 and the presence of 7 β ,17 β -lactone ring are important for the antiproliferative activity of these compounds.