Assessment of Annona reticulata Linn. leaves fractions for invitro antioxidative effect and antimicrobial potential against standard human pathogenic strains

Abstract

Since from long time the plant, Annona reticulata Linn. is known for its beneficial effects. Leaves of A. reticulata were screened for phytochemicals and in vitro antioxidant, antibacterial and antifungal activity. The shade dried leaves were extracted with methanol and aqueous methanolic extract was partitioned successively with n butanol, chloroform and acetone solvents. Methanolic extract was subjected to antioxidant screening using DPPH free radical scavenging activity and H₂O₂ scavenging activity. Antibacterial and antifungal activity of extract and fractions were analyzed on eight different clinical bacterial and fungal strains using agar well diffusion method and broth dilution method (MIC and MMC determination). The antioxidant activity showed that the extracts exhibited scavenging effect in concentration-dependent manner. The extract showed potent inhibitory effect against Bacillus subtilis and Escherichia coli bacterial strains while in case of fungal strains the maximum effect was observed against Candida blanki. The maximum zone of inhibition of n-butanol, chloroform and acetone fractions was observed against B. subtilis, and E. coli respectively while all fractions exhibited potent inhibitory effect against C. blanki. MIC and MBC values were determined for active samples, methanol extract and chloroform fraction against Staphylococcus aureus, B. subtilis, E. coli and Pseudomonas aeruginosa which revealed lower MIC and MBC values. The fungal strains Candida albicans, Saccharomyces cerevisiae and C. blanki were used to calculate MIC and MFC values for methanol extract and acetone fraction which  demonstrated lower MIC and MFC values. The results provided evidence that the plant is richly supplied with numerous phytoconstituents that might indeed be potential sources of natural antioxidant, antimicrobial agents and supplementary food.

Keywords: Annona reticulata; Antioxidant activity; Antimicrobial activity; Phenolic compounds; DPPH