Cytotoxic and antioxidant activities of Macfadyena unguis-cati L. aerial parts and bioguided isolation of the antitumor active components

Macfadyena unguis-cati L. (Bignoniaceae) is a perennial evergreen vine with a worldwide distribution and has been used in folk medicine. This study was to evaluate the phytochemical composition and potential bioactivity of the aerial parts of M. unguis-cati. Ethanol extract of M. unguis-cati was partitioned sequentially into PE, CHCl3, EtoAc, n- BuoH and H2O fractions. The EtoAc and n-BuoH fractions showed strong antioxidant activity on DPPH radical scavenging assay and ferric reducing power test, which were almost comparable to capacities of the positive controls vitamin C. The CHCl3 fraction exhibited the greatest cytotoxic activity on human hepatoma cells SMMC7721 and Be17402 by MIT assay with the IC50 values of 62.14 +/- 1.51 and 68.75 +/- 2.3 mu g(-1) mL(-1), respectively. Furthermore, bioassay-guided fractionation of CHCl3 fraction led to the isolation of five compounds, including decaffeoylacteoside (ML-1), lyoniresino1-3 alpha-O-beta-D-glucopyranside (ML-2), cirsimarin (ML-3), cirsimaritin (ML-4), ursolic acid (ML-5). Compounds ML-1, ML-2, and ML-5 were isolated firstly from this plant. Among the five compounds, ursolic acid displayed significant growth inhibition on cell proliferation of SMMC7721, HepG2 and Be17402 in a time and dose dependent manner with the IC50 value of 65.06 +/- 5.91, 149.47 +/- 31.97 and 73.16 +/- 0.31 mu M respectively. Cell cytotoxicity assays showed that ursolic acid was the most potent cytotoxic constituents in M unguis-cati. These results demonstrate that M. unguis-cati. extracts and active compounds can be potential pharmaceutical products, especially in antitumor and antioxidant agents.