Antioxidant extracts of African medicinal plants induce cell cycle arrest and differentiation in B16F10 melanoma cells.

African ethnomedicine is essentially based on the traditional use of vegetal extracts. Since these natural drugs have shown health giving properties, in the present study we increased further the scientific basis supporting these data. We investigated the effects, on murine B16F10 melanoma cells, of plant extracts that were directly obtained by a Cameroon 'traditional healer'. After a preliminary study on the antioxidant functions of these compounds, already abundant in literature, Moringa oleifera Lam., Eremomastax speciosa (Hochst.) Cufod and Aframomum melegueta K. Schum extracts were individually analyzed. We performed laboratory assessments on these medicinal preparations in order to clearly demonstrate their antineoplastic features. All the treatments caused in tumor cells a great reduction in growth and proliferation rate, cell cycle arrest, increase of p53, p21WAF1/Cip1 and p27Kip1 protein levels and induction of differentiation. These results, on the bioactivity and the biochemical characteristics of African plant extracts, may increase the comprehension of indigenous therapeutic practices and represent the first step for the individuation of new inexpensive and natural drugs able to prevent and contrast cancer onset.