Development of an ointment from ethanolic extracts of Azadirachta indica and Curcuma longa against methicillin resistant Staphylococcus aureus

Abstract

Background: Methicillin resistant Staphylococcus aureus (MRSA) is one of the leading causes of cutaneous infections all over the world. Increasing patterns of antibiotic resistance have led to the search for remedies in herbal medicines as cheaper and more available alternatives. The antibacterial activity of Azadirachta indica and Curcuma longa on MRSA has been shown in various studies, however no study had been done to evaluate the antibacterial efficacy of the combination of extracts from the two plants on MRSA. Objective: This study aimed to develop an ointment against cutaneous infections caused by MRSA from ethanolic extracts of Azadirachta indica leaves and ethanolic extracts of Curcuma longa rhizomes. Method Azadirachta indica and Curcuma longa were collected fresh, washed with clean running water, dried, ground and extracted by maceration using 75% ethanol as a solvent. Test solutions of 1000mg/ml, 500mg/ml, 250mg/ml and 125mg/ml for each of the ethanolic extracts was tested for anti-MRSA activity to determine the lowest concentration that gave the greatest zone of inhibition. A combination of the two plants was then tested for anti- MRSA activity. Results: Azadirachta indica extracts showed antibacterial activity that decreased with dilution and had an MIC of 114.208mg/ml. Curcuma longa extracts also showed antibacterial activity that decreased with dilution and had an MIC of 86.3774mg/ml. The combination of the two ethanolic extracts exhibited antibacterial activity against MRSA that increased with increase in concentration and had an MIC of 46.1530mg/ml. The ointment formulated from this combination recorded no erythema or edema when applied to the skin of albino rats. Conclusion: Ethanolic extracts of Azadirachta indica leaves and Curcuma longa rhizomes both have individual antibacterial activity against MRSA and combination of the two ethanolic plant extracts has improved antibacterial activity against MRSA. An ointment formulated from this combination is safe for topical application.