Comparative analysis of the antimicrobial potential of stem and fruit extracts of Calotropis procera

Abstract

Background: The dramatic rise in antimicrobial resistance continues to threaten the effective management and treatment of emerging and re-emerging infectious diseases. Medicinal plants offer excellent therapeutic alternative especially due to their plethora bioactive constituents and low resistance development to them. Purpose: The comparative analysis of the antimicrobial potential of the stem and fruit extracts of Calotropis procera was investigated. Materials and Methods: Using different extracts of the plant, the phytochemical screening was determined alongside their antimicrobial properties with agar-disc diffusion assay. The antimicrobial potency of the plant extracts (200 mg/ml) was evaluated and compared by their inhibition zone (IZ), activity index (AI), percentage specific activity (PSA), and percentage total activity (PTA) values. Results: The highest antibacterial activity (IZ = 15 ± 0.5 mm) was displayed by the stem hot aqueous extract against Staphylococcus aureus, while the maximum antifungal effect was exerted by both the stem cold and hot aqueous extracts (P > 0.05). The overall antimicrobial AI (AI = 1.56) was displayed by the stem cold aqueous extract against Candida albicans. The stem's hot and ethanolic extracts exhibited the highest achievable PSA of 100'. Furthermore, the stem extracts displayed the PTA of 83.3' compared to 25' by the fruit extracts, thus confirming the greater antimicrobial potency of the plant's stem extracts. Conclusion: This study suggests that while the stem extracts of C. procera could have displayed better antimicrobial activity, the overall effects elicited by the plant could be attributed to the presence of phytochemicals as revealed by the result of the phytochemical screening. Further studies focusing on complete characterization and evaluation of the mechanism of antimicrobial action of bioactive constituents of the extracts is underway.