Genista sessilifolia DC. and Genista tinctoria L. inhibit UV light and nitric oxide-induced DNA damage and human melanoma cell growth

Many Genista species (Leguminosae), containing isoflavones as biologically active substances, show interesting biological properties such as hypoglycemic, antiinflammatory, antiulcer, spasmolytic, antioxidant, estrogenic and cytotoxic activity against different human cancer cell lines. In this work, we describe the chemical composition of the methanolic extracts from aerial parts of Genista sessilifolia DC. and Genista tinctoria L., and their biological activity testing the effect on pBR322 DNA cleavage induced by hydroxyl radicals (OH), generated from UV-photolysis of hydrogen peroxide (H2O2) and by nitric oxide (NO). In addition, we investigated the growth inhibitory activity of these natural products against human melanoma cell line (M14). The extracts of G. sessilifolia and G. tinctoria, for their isoflavone components, showed a protective effect on UV light and nitric oxide-mediated plasmid DNA damage, and inhibited the growth of melanoma cells. The data of the present study also suggest that these natural products could trigger apoptotic death in M14 cells. In fact, a high DNA fragmentation (COMET assay) and a significant increase of caspase-3 activity, not correlated to LDH release, a marker of membrane breakdown, occurred in melanoma cells exposed to these extracts. The significant production of reactive oxygen species (ROS) evidenced in these experimental conditions could contribute to trigger the apoptosis cascades.