Antimicrobial Activity of Terpenoids Extracted from Annona muricata Seeds and its Endophytic Aspergillus niger Strain SH3 Either Singly or in Combination

Background: Annona muricata (Soursop) has an antimicrobial activity toward various pathogenic microorganisms which support its ethnomedicinal for the treatment of many infectious diseases.

Aim: Aim of the present study to evaluate the relation between antimicrobial activities of terpenoids extracted from different soursop parts with the isolated endophytic fungi.

Methods: Endophytic fungal species of pulp and peel of Annona fruit along with those of seeds were isolated. Salkowski test was used for qualitative screening of terpenoids in plant and the isolated endophytic Aspergillus niger strain SH3.

Results: Endophytic A. niger strain SH3 and Annona seed extract showed high terpenoid content indicated by the high intensity of reddish-brown colour. GC/Mass analysis revealed six compounds of terpenoids from endophytic A. niger strain SH3 extract and four compounds from seed extract with different retention times. The antimicrobial assay was performed using A. niger strain SH3 extract and Annona seed extract singly or in combinations against S. aureus, P. aeruginosa, E. coli and C. albicans.

Conclusion: The results revealed the significant antimicrobial activity of both extracts. However, the combined extract showed some reduction in antimicrobial activity which could be attributed to the antagonistic effect exhibited by their constituents.