Apoptosis caused by triterpenes and phytosterols and antioxidant activity of an enriched flavonoid extract and from Passiflora mucronata.

The genus Passiflora is knew for food consumption mainly and it extracts present a variety of methabolites, including flavones, alkaloids and triterpenes usually correlated with their antioxidant and antitumoral activities. P. mucronata (Pm) is from Brazil South America and is characterized as "Maracujá de Restinga", being used in the folk medicine for treating insomnia and soothing. The present study evaluated in the first time, the antioxidant and cytotoxicity of the hydroalcoholic leaves extract and fractions from Pm. Their cytotoxic effects were against human prostate cancer (PC3) and mouse malignant melanoma (B16F10) cell lines, by the MTT and CV assays. β-Amyrin, oleanolic acid, β-sitosterol and stigmasterol were isolated as the main components of the most active hexane fraction. These substances were tested individually against the tumor cell lines, whereby β-sitosterol and stigmasterol showed the most relevant activity to PC3 in CV assay and, oleanolic acid to B16F10 by the MTT assay. In addition, these compounds were analysed to cell cycle arrest, and stigmasterol decreased the number of cells in B16F10 line in the G1/G0 phase and subsequently, increased the cell number in sub-G1 phase, presumably indicating apoptosis as possible mode of cell death.The antioxidant activity by the DPPH method showed that the hydroalcoholic extract from the leaves presented higher antioxidant activity (EC50= 133.3 µg/mL) compared to the flowers (EC50= 152.3 µg/mL) and fruits (EC50=207.9 µg/mL) extracts. By the HPLC-MS it was possible to identify the main flavones present in the leaf extract (isoschaftoside, schaftoside, isovitexin, vitexin, isoorientin, orientin).