Chemical profile and antibacterial activity of crude fractions and essential oils of Capparis ovata Desf. and Capparis spinosa L. (Capparaceae)

Crude extract fractions and essential oils obtained from Capparis ovata Desf. var. palaestina and C. spinosa L. var. aravensis from Jordan were examined for their chemical ingredients and antibacterial activity. Phytochemical screening of the crude fractions obtained from these two plants revealed the presence of different classes of compounds. Terpenes were detected in the hexane and aqueous methanol fractions. Butanol, aqueous methanol, and water fractions contained flavonoids. Tannins and alkaloids were detected in the butanol fractions only. Water fractions contained reducing sugars. GC/MS analysis of essential oils revealed a complex mixture of compounds. Oils of C. ovata and C. spinosa were dominated by nitrogen- and sulfur-containing compounds (63.39%, 77.03%, respectively) as represented by methyl isothiocyanate (31.81%) in C. ovata and isopropyl isothiocyanate (28.92%) in C. spinosa. Antibacterial activities of extract fractions were evaluated in vitro against a variety of Gram-positive and Gram-negative bacteria by agar well diffusion. The butanol fraction showed the broadest range of antibacterial efficacy, while the hexane fraction showed the narrowest. The butanol fraction of C. ovata showed a marked inhibitory effect against Streptococcus faecalis (MIC= 24 ?/mL). Escherichia coli was sensitive only to the butanol fractions. Antibacterial activity tests of essential oils showed that they were antibacterial, and highest activities were found against Micrococcus luteus. Findings of this study augment enrichment of the studied Capparis varieties with beneficial secondary metabolites which possess potential applications in microbial chemotherapy, and nutrition.