In vitro cytotoxicity assessment of phenolic extracts from grapevine bunch stem and cane by-products for their potential use as phytotherapeutic agents

Aim: In the present study, bunch stem and cane extracts (Vitis vinifera L. cv. Malbec) rich in phenolic compounds (PCs) like flavonoids, phenolic acids, and stilbenes are studied as potential anticancer candidates. Methods: Twenty-three PCs were quantified by liquid chromatography-diode array fluorescence detection (LC-DAD-FLD). In vitro cytotoxic activity of both extracts on healthy (HBL-100) and colorectal cancer (HCT-116) human cell lines was assessed by 3-(4,5-di-methylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) reduction assay. Results: Cane extract did not show cytotoxic effect for the tested lines, which can be considered as an advantage for its application in the pharmaceutical industry. Conversely, the bunch stem extract showed a dose-dependent cytotoxic effect on HCT-116 and an IC50 of 680 µg/mL after 48 h of incubation; but not reported cytotoxic activity on the healthy cell line, evidencing a beneficial selective activity. The reported results encourage further investigation of these extracts as potential preventive and/or therapeutic drugs, or their combined use with chemotherapeutic treatments that lead to a potential dose reduction. Conclusions: The results preliminarily demonstrated that the extracts have potential anticancer properties or do not cause damage at the cellular level, encouraging their application as functional/nutraceutical or phytotherapeutic agents.