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Abstract

In this study, extracts of Nigella sativa (Ranunculaceae) and its induced callus were investigated for their antimicrobial activities against four bacteria (Bacillus subtilus, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa) and two fungi (Candida albicans and Aspergillus niger) by using agar diffusion method. In order to induce callus hypocotyls and cotyledons explants from N. sativa were cultured in MS media supplemented with different types and different concentrations of growth regulators. Hypocotyls and cotyledons explants of N. sativa showed a rapid rate of initiation of callus after two weeks when grown on 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 on 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 (23 mm) inhibition zone 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. N. sativa seeds and callus methanolic extracts show antimicrobial activity against E. coli higher than Gentamicin and Penicillin at 10 �¼g per disc. Preliminary phytochemical screening for the plant 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.

Biography

Mawahib El Amin Mohamed El Nour has completed her PhD from University of Khartoum and Postdoctoral studies from University of Bayreuth, Germany. She is the Dean Faculty of Science & Technology, University of Al Neelain, Sudan. She has published more than 20 papers in reputed journals. She is an Associate Professor of Biotechnology. Her current research fi elds are phytochemical screening of medicinal plants for natural products, tissue culture of economically important plants, biotechnology (fermented food), production of secondary metabolites by cultured cells and tissue and stress physiology (drought, salinity and temperature).

Email: elnourmawahib@gmail.com