Antimicrobial Potentials of Secondary Metabolites of Endophytic Fungi Isolated from Synclisia scabrida Miers

The increase in the development of multi-drug resistance among pathogens calls for the development of novel therapeutic agents with better effectiveness and low toxicity. The plant-associated endophytic fungi are producers of bioactive secondary metabolites with enormous potential. The study aimed to isolate, identify, and characterize the secondary metabolites of endophytic fungi isolated from different non-diseased plant parts (leaf, stem, and root bark) of Synclisia. scabrida Miers. The isolation of endophytic fungi was carried out using standard protocols and identified by molecular techniques. The bioactive secondary metabolites were extracted using ethyl acetate. The quantitative phytochemical screening of the fungal metabolites was carried out using Gas chromatography. The antimicrobial activities of ethyl acetate extracts of the isolates were analyzed via agar well diffusion technique and the minimum inhibitory concentrations (MICs) were determined by broth dilution method. The different endophytic fungal metabolites exhibited a good presence of different phytochemical compounds. The fungal metabolites showed antimicrobial activities against several of the six tested human pathogenic bacteria or fungi. Among these metabolites, L1, R1 and R2 metabolites were the most potent, exhibiting significant activities against the test organisms. L1 and R1 metabolites showed the lowest MIC of 0.53±0.13 and 0.70±0.07 mg/ml against A. niger and C. albicans respectively. A total of five endophytic fungi were isolated from the leaf, stem, and root bark of S. scabrida Miers, and three different fungal species were identified using molecular techniques. The plant, S. scabrida Miers harbors endophytic fungi yielding bioactive metabolites with potent antimicrobial activities against pathogenic microorganisms.