engleski

Biological activity of a grape pomace extracts in vitro

Colorectal cancer is the second most fatal and the third most diagnosed type of cancer worldwide [1]. Although having multifactorial causes, most colorectal carcinoma are mainly determined by dietary factors. Indeed, polyphenols have been reported to interfere with cancer initiation, promotion, and progression, acting as chemo preventive agents [1]. The aim of this study is to evaluate biological activity – inhibition of cell growth and cell cycle on two colorectal tumor cell lines in vitro of grape pomace (GP) extracts rich with polyphenolic compounds. Extracts were obtained from biologically untreated (PP) and treated GP (Cabernet Sauvignon) with white-rot fungi Phanerochaete chrysosporium (PC) and Trametes gibbosa (TG) cultivated in solid-state conditions. Polyphenolic profile in GP extracts was determined by UHPLC. Antiproliferative activity of tested extracts was evaluated by MTT test on solid tumor cell lines (SW620, CaCo-2) in triplicate in three independent experiments (0.25-2.5 mg/ml). Cell cycle analysis was done by BD FACScanto II flow cytometer. Experiments were carried out in duplicate at the IC50 concentration. Data were evaluated by Mann Whitney U test (p<0.05). A total of 19 phenolic compounds (Gallic acid, p-Hydroxybenzoic acid, Syringic acid, Epicatechin, Caffeic acid, Catechin, Ferulic acid, Vanillic acid, p-Coumaric acid, Quercetin, Procyanidin B1, Procyanidin B2, Resveratrol, Kaempferol, Ellagic acid, Epicatechin gallate, Gallocatechin gallate, 3, 4-Dihydroxybenzoic acid, o-Coumaric acid) in GP extracts obtained from the PP sample were identified and quantified by UHPLC. According to MTT assay IC50 value (mg/ml) was determined as follow: SW620 (PP – 1.45 ; TG – 1.16 ; PC – 0.98), CaCo-2 (PP – 1.13 ; TG – 0.91 ; PC – 1.08). Cell cycle analysis showed that untreated GP extracts (PP) at IC50 concentration after 48 hours arrested SW620 (1.45 mg/ml) and CaCo-2 (1.13 mg/ml) at G2/M phase together with reduced percentage of cells in G1 phase by 19.4% (SW620) and 13.8% (CaCo-2). Extracts from samples TG and PC at IC50 concentrations express different effect on these two cell lines with minor differences compare to control. Obtained results indicate that polyphenols from GP extracts are effective agents against colorectal carcinoma tumor cell lines while biological treatment of GP by used white-rot fungi (PC, TG) do not provoke better biological polyphenolic activity.

polyphenols, grape pomace, UHPLC, antiproliferative activity, cell cycle

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