Antimicrobial activity of aqueous and methanolic extracts of two medicinal plants from the algerian Sahara
Larbi Zakaria Nabti, Rachid Belhattab
The antimicrobial activity of several extracts of two medicinal plants from the algerian Sahara, which known by their various therapeutic properties, Randonia africana Coss. and Oudneya africana R.Br. was investigated using the disc diffusion method. The aqueous and methanolic extracts of the two plants were obtained by decoction of the aerial parts (leaves and stems) and maceration in 80 % (v/v) methanolic solution respectively. The four extracts were tested against seven reference microorganisms; two Gram-positive bacteria (Staphylococcus aureus ATCC 25923, Bacillus subtilis ATCC 6633), two Gram-negative bacteria (Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853), two molds (Aspergillus flavus NRRL 391, Aspergillus Niger 2CA 936) and one yeast (Candida albicans ATCC 1024). Neither the aqueous extracts of the two species studied nor the methanolic ones showed any antibacterial activity against the Gram-negative bacteria and A.flavus. However, the methanolic extract of O.africana and the aqueous extract of R.africana were the most active among all the four extracts tested, mainly against Gram-positive bacteria and C.albicans.