In vitro anticancer activity of ethanolic extracts of Piper nigrum against colorectal carcinoma cell lines.
Palabras clave
Abstracto
BACKGROUND
Piper nigrum (PN) is well known for its cytotoxic and pharmacological benefits. However, there is minimal documented evidence about its cytotoxic efficacy against colorectal carcinoma. We therefore sought to procure a precisely quantitative and qualitative result, pertaining the efficacy of an ethanolic extract of PN (EEPN) against colorectal carcinoma.
METHODS
EEPN was prepared by subjecting dried PN seeds to gradient ethanol fractionation. The total phenol content (TPC), antioxidant activity (AOA), and anti-inflammatory activity (AIA) were determined using Folin-Ciocalteu assay, ferric reducing ability of plasma and 2, 2-diphenyl-1-picrylhydrazyl methods, and human red blood cells membrane stabilizing assay, respectively. Colorectal carcinoma cell lines (HCT-116, HCT-15, and HT-29) were procured from National Centre for Cell Science, Pune, and were cultured in Dulbecco's modified eagle media supplemented with 10% fetal bovine serum and 1 mM L-glutamine. Cells were seeded into a 96-well plate, followed by treatment with increasing concentrations of EEPN. The cytotoxic efficacy was evaluated based on percentage inhibition of cells, using sulforhodamine-B assay. The IC-50 values were calculated using Prism software (Prism from GraphPad software, Inc. CA, USA).
RESULTS
Biochemical analysis revealed that 50% EEPN exhibited higher TPC, AOA, and AIA when compared to 70% and 100% EEPN at any given concentration (P = 0.041). Cytotoxic analysis revealed a dose-dependent response with maximum cellular inhibition at TPC of 6 and 3 μg/ml, using 50% EEPN. However, 50% inhibition of cellular growth using 50% EEPN was seen with TPC of 3.2, 2.9, and 1.9 μg/ml at 24, 48, and 72 h, respectively, in HCT-15 cells. Hence, time- and dose-dependent increase in the cytotoxic efficacy of 50% EEPN against colorectal carcinoma cell lines were noted (P < 0.001).
CONCLUSIONS
Given the significantly positive correlations exhibited between the biochemical and the cytotoxic properties evaluated in our study, we hereby conclude PN as a novel therapeutic spice for the treatment of colorectal carcinoma.
