Phytochemical Studies on the Antibacterial Extracts of Citrullus colocynthis and Cucurbita maxima Seeds

Abstract

Two cucurbits were selected for the present study: Cirrullus colocynrhis and Cucurbita maxima. The ethanolic extracts of the seeds of the two Sudanese species were screened phytochemically for detection of their secondary metabolites. Sterols, triterpencs, saponins, coumarins were present in the seeds of the two species, but falvonoids were detected only in C. co/ocynlhis. The petroleum ether, chloroform and methanol extracts of the seeds of the two species were screened against five bacterial species: Bacillus subtilis, Staphylococcus auerous, Eschericlzia coli, Proteus vulgaris and Pseudomonas aeruginosa. The extracts exhibited variable antimicrobial activity and the chloroform extract of the seeds of C. colocynthis was selected for further studies, Biological monitoring of the antibacterial activity enabled the isolation of eight pure compounds by fractionation of the chloroform extract in a silica gel column and elution with pet ether, chloroform and methanol followed by the usual work-up by analytical and preparative TLC. The eight compounds were further investigated by UV-and IR- spectroscopy and interpretation of data gave grounds to suggest that they were most probably oxygenated saturated and unsaturated aliphatic hydrocarbons such as keto alcohols, fatty acids and their esters.