Phytochemical Components and Antimicrobial Activity of Ethanolic Extracts From Different Parts Of Calotropis gigantea (L.) Dryand.

Objective: The present study aimed to determine the antimicrobial activity and phytochemicals of different parts of C. gigantea. Material and Methods: The flower, leaf, stem bark, and latex of C. gigantea were extracted using 50%, 70%, and 95% ethanol. Phenolic and flavonoid content were measured using colorimetric assays. The disc diffusion method was used to evaluate antimicrobial activity against a panel of microorganisms.Results: The ethanolic extracts of C. gigantea (2 mg/disc) from the tested parts contained total phenolic and flavonoid contents ranging from 13-38 mg GAE/ g extract and 1-175 mg RTE/ g extract. Extracts from the flower, leaf, and stem bark showed similar inhibitory effects against Pseudomonas aeruginosa TISTR 1467. Additionally, extracts from the flower and leaf demonstrated inhibition zones against Candida tropicalis TISTR 5136. No inhibitory activity was observed against Staphylococcus aureus ATCC 6538, Acinetobacter baumannii ATCC 19606, Candida albicans TISTR 5554, and Candida krusei TISTR 5351 from any of the tested samples. Conclusion: The ethanolic extracts from various parts of C. gigantea contained a high amount of phenolics and flavonoids, and exhibited antimicrobial activity, particularly against P. aeruginosa and C. tropicalis. These findings suggest that C. gigantea may be a promising natural source for further isolation and purification, which could enable the discovery of new antimicrobial agents.