Exploring the bioactivities of Annona muricata seeds and peels: in vitro assessment of antimicrobial, anti-inflammatory, and antioxidant effects

Abstract

Annona muricata L. (soursop, graviola, or guanabana) is widely used in traditional medicine for treating various ailments. This study evaluates the antioxidant, anti-inflammatory, and antimicrobial activities of its seed and peel extracts prepared by cold maceration using 80% aqueous ethanol and 100 % water. Anti-inflammatory activity was assessed by human red blood cell (HRBC) membrane stabilization and albumin denaturation inhibition methods; antioxidant activity by DPPH and FRAP assays; and antimicrobial activity by agar well diffusion and minimum inhibitory concentration (MIC) tests. The aqueous ethanol seed extract (AME2) produced the highest yield (35.9%), while aqueous extracts (AME3 and AME4) yielded less than 1 %. In the HRBC assay, AME3 showed the highest heat-induced membrane stabilization (20%), and AME4 the greatest hypotonic-induced effect (21%), slightly below indomethacin (36%). AME4 also gave the strongest albumin denaturation inhibition (86.67% at 1000 µg/mL). Antioxidant activity increased with concentration: AME3 had the highest FRAP inhibition (25.70% at 1000 µg/mL) and AME4 the highest DPPH scavenging (52.60%), though both were weaker than ascorbic acid. Antimicrobial screening showed inhibition zones up to 20 mm for AME3 and AME4, with corresponding low MICs (0.63 mg/mL). In general, the results show that the seeds and peels of A. muricata, especially the aqueous seed extract, have good anti-inflammatory and antioxidant effects, and moderate antimicrobial activity. These findings support the traditional use of the plant and suggest it could be useful as a natural source of medicine.