In Vitro Callus Induction and Antimicrobial Activities of Callus and Seeds Extracts of Nigella sativa L.

Abstract

Abstract: In this study, extracts of Nigella sativa seeds and its induced callus were investigated for their antimicrobial activities against four standard bacteria (Bacillus subtilus , Staphylococcus aureus , Escherichia coli and Pseudomonas aeruginosa) and two fungi (Candida albicans and Aspergillus niger) by using agar diffusion method. To induce callus, hypocotyls and cotyledons explants from N. sativa were cultured in MS medium supplemented with different types and different concentrations of growth regulators. Explants of N. sativa showed a rapid rate of initiation of callus after two weeks when grown in MS media supplemented with NAA at 1.0 mg/l and 5.0 mg/l of NAA respectively, while a slow rate of induction of callus observed when the hypocotyls grown in MS media supplemented with 5.0 mg/l 2,4-D and 0.5 mg/l 2,4-D, when the explants were cotyledons. The NAA in this study was found to be the suitable hormone regulator for N. sativa for both types of explants used. Methanolic extracts of seeds and callus of N. sativa showed activity against Escherichia coli with inhibition zone (21mm)&(23mm) respectively and no antifungal activity was observed for both seeds and callus extracts.

The antibacterial activity of Penicillin and Gentamicin were determined against the tested bacteria and compared with the antibacterial activity of the tested extracts of N. sativa seeds and callus. Methanolic extracts show antimicrobial activity against E. coli higher than that of Gentamicin and Penicillin at 10μg/disc. Phytochemical screening for the seeds and callus extracts indicated the presence of secondary metabolites such as alkaloids, flavonoids and tannins which may be responsible for the antimicrobial activity of the tested extracts.