Phytochemical Profiling, Antimicrobial Activity and Brine Shrimps Lethality of Croton zambesicus Seeds and Leaves Extracts

Abstract

It is a well known medicinal plant in Sudan with different traditional uses. To date there are no chemical or biological records reported on C. zambesicus seeds. Air dried ground seeds and leaves of C. zambesicus were extracted using 80% methanol. The methanolic extract was sequentially fractionated with petroleum ether, chloroform and ethyl acetate. The obtained extracts of C. zambesicus seeds leaves were screened antimicrobial activities against four standard bacteria (Bacillus subtitles, Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and two fungi (Aspergillus niger and Candida albicans) using in vitro agar diffusion method. The cytotoxicity evaluation of the bioactive fractions was carried out in vitro using brine shrimp lethality assay. The MIC of the seeds crude extract was 12 mg/ml against B. subtitles, E. coli, and P.aeruginosa. After fractionation of the seeds methanolic extract the antibacterial activity was mainly accumulated in the ethyl acetate phase with an MIC of 50 mg/ml against Bacillus subtitles. The MIC of the leaves crude extract was 6.25 mg/ml against S. aureus, Escherichia coli, and Pseudomonas aeruginosa. After fractionation of the leaves methanolic extract the antibacterial activity was mainly accumulated in the chloroform phase with an MIC of 12.5 mg/ml against Bacillus subtitles. Terpenoids were mainly detected in the petroleum ether fraction in addition to four compounds which were suggested to be phenolics. Phenolic acids and flavonoids were detected in the ethyl acetate fraction giving typical blue, yellow and orange colours with NPR at 366 nm. Terpenoids and polyphenols, mainly flavonoids, detected in C. zambesicus active extracts were believed to be responsible of the antimicrobial and antioxidant activities mentioned above. All extracts were quite safe in brine shrimp lethality assay. These results justify the traditional use of C. zambesicus seeds and leaves.