Antitumoural activity of Brazilian red propolis fraction enriched with xanthochymol and formononetin: An in vitro and in vivo study

In this study, ultra-high performance liquid chromatography-mass spectrometry and tandem mass spectrometry of selected ions were used to characterise the ethanolic extract of a sample of Brazilian red propolis (EEBRP) and an active fraction (BRP-IV) containing xanthochymol and formononetin. The antiproliferative effect of BRP-IV was assayed using melanoma tumour xenografts in mice and HL-60, K562, RPMI8226, B16F10 cell lines. This fraction inhibited growth of tumour cell lines with IC50 values of 20.5 ± 2.4 to 32.6 ± 2.6 µg/mL while EEBRP induced cytotoxic effect with IC50 values of 29.7 ± 1.5 to 42.1 ± 8.7 µg/mL. BRP-IV also inhibited the proliferation of B16F10 cells by blocking cell cycle progression in the G2/M phase and inducing apoptosis. Administration of 10 mg/kg/day BRP-IV suppressed the growth of B16F0 tumour xenografts in C57BL/6 mice with less general toxicity than control groups. Taken together, these results indicate that BRP-IV can be considered a promising anticancer drug for the treatment of human cancers.