Biflorin, an
ortho-naphthoquinone, is an active compound found in the roots of Capraria biflora L. It has been reported that
biflorin presents anticancer activity, inhibiting both tumor cell line growth in culture and
tumor development in mice. The aim of this study was to examine the effectiveness of
biflorin treatment using both in-vitro and in-vivo
melanoma models.
Biflorin displayed considerable cytotoxicity against all tested cell lines, with half maximal inhibitory concentration values ranging from 0.58 μg/ml in NCI H23 (human
lung adenocarcinoma) to 14.61 μg/ml in MDA-MB-231 (human
breast cancer) cell lines. In a second set of experiments using
B16 melanoma cells as a model,
biflorin reduced cell viability but did not cause significant increase in the number of nonviable cells. In addition, the
DNA synthesis was significantly inhibited. Flow cytometry analysis showed that
biflorin may lead to an apoptotic death in
melanoma cells, inducing DNA fragmentation and mitochondria depolarization, without affecting membrane integrity. In
B16 melanoma-bearing mice, administration of
biflorin (25mg/day) for 10 days inhibited
tumor growth, and also increased the mean survival rate from 33.3±0.9 days (control) to 44.5±3.4 days (treated). Our findings suggest that
biflorin may be considered as a promising lead compound for designing new drugs to be used in the treatment of
melanoma.