Antibacterial ferulates from Jatropha dhofarica

Abstract

The growing world health burden caused by emergence and spreading of resistant strains as well as appearance of new infectious diseases creates an urgent need for continuous search of new and more effective anti-infective metabolites. One of the major sources of new drugs are natural products isolated from terrestrial plants reported to have ethnomedical history. This paper reports isolation of antibacterial compounds from an endemic medicinal plant, Jatropha dhofarica growing in Oman. Dichloromethane extract obtained from stem bark of J. dhofarica was subjected to chromatographic techniques to give pure compounds that were tested against strains of Staphylococcus aureus, Escherichia coli, and Haemophilus influenza in disc diffusion method to evaluate their antibacterial activity. Elucidation of structures of isolated compounds was accomplished via NMR and MS experiments. Two major compounds including ferulic acid and tetratriacontyl ferulate were afforded from dichloromethane extract. Ferulic acid displayed high antibacterial activity against strains of E. coli and S. aureus, (IZ = 9 and 13.5mm, respectively). Its activity against S. aureus was comparable to that of a standard drug, amoxicillin. Tetratriacontyl ferulate showed only moderate activity against strains of the tested bacteria species (IZ = 6–9 mm). The present observations might justify the local use of this plant species as anti-infective agent. It also suggests a need to standardize the use of this plant in herbal remedies as well as develop ferulates as new antimicrobial agents.