Anticancer properties of black seed (Nigella sativa L.) seedling and/or callus extract against human breast adenocarcinoma and colon cancer cell lines

Callus was initiated from leaf explants of Nigella sativa on MS media supplemented with different plant growth regulator (PGRs) after five weeks. To improve callus growth, fresh callus was subcultured on MS media supplemented with different concentrations of TDZ [(Thidiazuron), 1-Phenyl-3-(1,2,3,-thiadiazol-5-yl) urea], BAP (6-benzylaminopurine), and NAA (alpha-Naphthalene Acetic Acid) separately or in combinations. All callus treatments were subcultured for three successive subcultures every five weeks in the dark, 10 and 20 mu mol m(-2) s(-1) light intensity condition. The maximum callus biomass (fresh and dry) was obtained with 2 mg L-1 TDZ, and it seemed that the increase in light intensity synergized the effect of TDZ, but the rate of growth declined with repeated subculturing. The potential of callus to synthesize thymol could be proved by high performance liquid chromatography (HPLC) analysis. Data revealed that thymol content in callus obtained on MS media supplemented with 2 mg L-1 TDZ reached up to 118.73 mu g g(-1) dry weight. In an experiment to investigate the cytotoxic activity of seedling and callus methanol extract of N. sativa using MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide) assay, the seedling extract gave higher cytotoxic activity against human breast adenocarcinoma (MCF-7), while the callus extract exhibited promising cytotoxic properties against human colon cancer (Caco-2) cell lines. The data presented in this study may represent additional evidence of the promising role that in vitro plant cell cultures could play in the production of valuable phytopharmaceutics.