Antibacterial studies, physicochemical properties and fatty acid composition of fixed oil from Citrullus lanatus seed cultivated in South-South Nigeria

Abstract

Citrullus lanatus seed oil was extracted from its powered seeds in a Soxhlet apparatus using diethyl ether. Physicochemical, fatty acid and antibacterial analyses of the oil was carried out using standard methods. Extraction yielded 50 % oil characterised with a light yellow colour, an agreeable odour, specific gravity of 0.89 and refractive index of 1.48+0.02. The iodine, peroxide, saponification and acid values were found to be 59.01+0.05, 5.17+0.05, 352.54+0.05, and 6.45+0.05 respectively. The results of the fatty acid analysis showed that the oil contains linoleic acid (56.85%), oleic acid (14.79%), palmitic acid (13.95%) and stearic acid (9.17%) among other acids. Antibacterial evaluation revealed that the oil was active against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis and Staphylococcus aureus with the diameters of zone of inhibition ranging from 12-20 mm wide, the oil was however not active against Enterorbacter aerogenes, Klebsiella pneumonia and Proteus mirabilis. Moreover, these experimental findings support the ethnomedical usage of the oil in treatment of certain skin infections and rich source of polyunsaturated fatty acids (parent fatty acids of omega 6- series), which has ample health benefits.