In vitro anticancer screening of Colombian plants from Piper genus (Piperaceae)

Historically, knowledge of ethnobotany, which has revealed different phytochemical and pharmacological compounds from traditional plants, has formed the basis for new anticancer drug discovery. The use of some Piper species in traditional medicine against cancer, suggests that genus Piper is a promising source of new compounds with anticancer activity. A total of 28 ethanolic extracts were obtained from 16 different Piper spp., then in vitro cytotoxicity activity was performed with 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay in three certified human cancer cell lines (A549 lung, PC-3 prostate and MDAMB-231 breast). Seven ethanolic extracts obtained from different parts of Piper eriopodon, Piper cumanense and Piper bogotense showed promising anticancer effect with IC50 values below to 30 µg/mL. The most potent cytotoxic effect was found in the leaves ethanolic extract of P. eriopodon with an IC50 of 17.7 µg/mL for A549, 11.8 µg/mL for PC-3 and 20.7 µg/mL for MDAMB-231. Bioassay guided fractionation was performed for the most active extract and a highly cytotoxic compound was isolated and identified by spectroscopic means, mainly 1D and 2D RMN spectroscopy. The isolated compound identified as gibbilimbol B was shown to be a strong cytotoxic effect against cancer cell lines with IC50 values in the range of 11.4 and 41.9 µg/mL.  Key words: Piper, Piperaceae, alkenylphenols, cytotoxicity, anticancer, gibbilimbol B.