Evaluation of the anticancer activity and fatty acids composition of “Handal” (Citrullus colocynthis L.) seed oil, a desert plant from south Jordan

Background The chemical composition of Handal (Citrullus colocynthis L.) seed oil cultivated in Jordan deserts was characterized, and its bioactivity was evaluated. Methods The oil was extracted from the grinded seeds in 500 ml Soxhlet extractor for 24 hr using n-hexane, and the recovered fatty acids were methylated with methanolic-HCL. The fatty acid methyl esters (FAMEs) composition was analyzed using GC-MS and GC-FID. The anticancer activity associated with the oil was assessed against colon cancer cell lines (Caco-2 and HCT-116) and compared to its cytotoxicity on the human skin fibroblast. Multivariate analysis was used to determine relationship of the fatty acid composition with that of the anticancer activity. Results The results demonstrated that fatty acid composition of Citrullus colocynthis seed oil chiefly contains Linoleic acid, denoted as C18:2n6 (75%), followed by Palmitic acid C16:0 (8%), Stearic acid C18:0 (5%), and Oleic acid C18:1n9 (9%). It is demonstrated as an excellent source of essential fatty acids omega-6 (e.g., Linoleic acid), whereas omega-3 (e.g., α-Linolenic acid) and hydroxy polyunsaturated fatty acids are found at small level. Interestingly, the oil exhibited reasonable anticancer effects against colorectal cancer cell lines with IC50 values varying between 4 and 7 mg/ml. The correlation test revealed a relationship between the fatty acid composition and the effectiveness on treatments. Conclusions Handal plant from Jordan appears to have very high level of Linoleic acid compared to other oils measured in different geographic locations and that there appears to be some anticancer activities associated with the fatty acid content of Handal seed oil.