Antitumor activity of flavonoids from Pteleopsis suberosa leaves

Pteleopsis suberosa Engl. et Diels (Combretaceae) is a tree widely distributed in the sahelian savanna, from Mali to Nigeria. In Malian folk medicine the decoction of the plant is used for the treatment of jaundice, asthenia, and disentery (1), while the decoction of the bark is popularly used especially for antiulcer properties, confirmed by pharmacological studies (2,3). In this work we describe the chemical and biological studies of the plant leaves. Sixteen flavonoids, including gallocatechin and flavonols having kaempferol, quercetin, and myricetin as aglycons, were isolated and identified. Among myricetin derivatives, myricetin 3-O-(4”-acetyl)-α-L-arabinopyranoside and myricetin 3-O-(3”-acetyl)-α-L-arabinopyranoside are now reported for the first time. The biological activity of the extracts and their active components was tested with androgen-insensitive prostate cancer cells (DU-145) testing cell viability (MTT assay), genomic DNA fragmentation (COMET assay) (4),and cell membrane integrity (LDH release) (4,5). The data obtained evidenced that the methanol extract of the leaves significantly (p<0.001) inhibited the growth of DU-145, probably triggering an apoptotic process.