Biological activity of extracts from Capparis decidua L. twigs

Capparis decidua L. (family Capparaceae) is widely used in Sudan for curing variety of ailments. The objective of this study was to evaluate the antimicrobial, antigiardial, antimalarial, antioxidant activities and cytotoxicity of plant extracts from the twigs of C. decidua. Extracts were evaluated for their effectiveness against four bacterial strains including both Gram-positive (Bacillus subtilis and Staphylococcus aureus) and Gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria as well as fungal species (Candida albicans and Aspergillus niger) using disc diffusion method. Antibacterial effects of twigs extracts showed different degrees of inhibition profiles against tested bacteria. The ethyl acetate extract showed the highest activity against S. aureus (21 mm), B. subtilis (20 mm) and P. pneumoniae (18 mm) while the n-butanol extract displayed best inhibition against P. pneumoniae (18 mm) and E. coli (16 mm). All extracts showed high antifungal activity against A. niger and C. albicans with inhibition zone ranged from 17 to 22 mm. Antimalarial activity assay showed that all extracts were less potent than chloroquine drug against P. falciparum. Antigiardial activity was determined against Giardia lamblia where the chloroform and ethyl acetate extracts possessed potent antigiardial activity after 24 h at concentration 500 μg/ml with respectively 91 and 89% mortality comparable to that exhibited by metronidazole drug (89%). The antioxidant potential of extracts was determined on the basis of their scavenging activity of the stable 1, 1-diphenyl-2-picryl hydrazyl (DPPH) free radical and ferric-reducing antioxidant power (FRAP). The petroleum ether and n-butanol extracts showed moderate DPPH scavenging activity, while the ethyl acetate and chloroform extracts showed low activity. All extracts were inactive in the FRAP assay. All extracts were nontoxic against brine shrimps and vero cell lines suggesting that they were safe for traditional use. Key words: Capparis decidua, antimicrobial activity, antigiardial activity, antimalarial activity, antioxidant activity, cytotoxicity.