PHYTOCHEMICAL SCREENING AND ANTIMICROBIAL ACTIVITIES OF FRUIT PULP, SEED AND LEAF EXTRACTS OF SOURSOP (Annona muricata L.)

Abstract

Annona muricata is a species of the Annonaceae family that has therapeutic potential. Thus, the objective of the study was to assess phytochemical and antimicrobial activity of A.muricata fruit pulp, seed and leaf extracts. The experiment was arranged as 3 x 3 x 1 x 6 (3 source extracts at 3 concentration levels, 1 Methanol and 6 test pathogenic microbes) factorial design in three replications. ANOVA was carried out using SAS software. The phytochemical composition of methanolic extract of A. muricata fruit pulp, seed and leaf revealed the presence of bioactive components including tannins, saponins, flavonoids, steroids, terpenoids and alkaloids while, Phlobatannins were absent in all. The disc diffusion method was used to measure diameter of inhibition zone of methanolic extracts of A. muricata fruit pulp, seed and leaf. The highest concentration of the methanolic extract recorded the strongest antibacterial activity with maximum zone of inhibition (17.83mm) observed for fruit pulp extract against Staphylococcus aureus. The highest concentration of the extract revealed maximum antifungal activity with the highest zone of inhibition (14.00mm) recorded for methanolic pulp extract against Aspergillus versicolor. Broth dilution methods were used to determine minimum inhibitory concentration, minimum bactericidal concentration and minimum fungicidal concentration. The methanolic extract from A. muricata fruit pulp presented strongest antibacterial activity with MIC (3.125mg/ml) and corresponding MBC (6.25mg/ml) against S.aureus. The weakest bacterial activity with MIC (50mg/ml) and corresponding MBC (50mg/ml) was observed for methanolic leaf extract against E. coli. The strongest antifungal activity with MIC (12.5mg/ml) and corresponding MFC (25mg/ml) was recorded for methanolic extract of A. muricata fruit pulp against A. versicolor where as the weakest antifungal activity with MIC (50mg/ml) and corresponding MFC (100mg/ml) was observed for methanolic leaf extract against C. albican. A. muricata fruit pulp possessed both strongest antibacterial and antifungal potential while methanolic leaf extract revealed the least potential. E. coli more resistant to extracts while S. aureus has was most susceptible. C. albicans was made the most resistant to extracts While, A.versicolor was most susceptible