Preliminary phytochemical screening and antibacterial activity of ethanolic and aqueous extracts of Sudanese medicinal plant Ziziphus spina-christi L leaves

Abstract

In the current work ethanolic and aqueous extracts of Ziziphus spina-christi leaves were investigated for their phytochemical and antibacterial activity. Phytochemical screening was conducted using standard qualitative methods and the antibacterial activity was investigated using disc diffusion method. The microorganisms employed were six pathogenic bacteria; three Gram-positive: Staphylococcus aureus (ATCC1026), Bacillus subtilis (ATCC19659) and Enterococcus faecalis (ATCC29212); and three Gram-negative: Salmonella typhi (ATCC14038), Pseudomonas aeruginosa (ATCC15442) and Escherichia coli (ATCC10536). Phytochemical analyses revealed the presence of alkaloids, flavonoids, saponins, phenolics, terpenoids and tanins in ethanol extratct. Aqueous extract showed the presence of alkaloids, flavonoids, saponins and tanins. Both extracts demonstrated varying levels of activity against Gram-positive bacteria, whereas all Gram-negative bacteria completely resistance to the extracts. Ethanol extract dominated aqueous extract in inhibiting the growth of the pathogenic bacteria under study. Highest antibacterial activity was observed with ethanol extract against S. aureus (18.1 mm), while minimum activity was observed with aqueous extract against B. subtilis (13.3 mm). The findings of this study indicated that the leaves of Z. spina-christi possess various secondary metabolites having the potential for the developing pharmaceutical drugs, especially antibacterial ones.

Keywords

• ziziphus spina-christi, phytochemical screening, antibacterial activity