Biosynthetic Potentials by Co-culture Approach for Enhanced Production of Bioactive Molecules

Aims: Endophytic fungi are producers of important bioactive compounds with several biological activities. Endophytic fungi are known to reside within the internal tissues of plants. Hyptis suaveolens is a medicinal plant cultivated in Nigeria for its therapeutic potential. Study Design: In the present study, endophytic fungi were isolated from the leaf blade and midrib of a healthy leaf of Hyptis suaveolens and identified using internal transcribed spacer (ITS-rDNA) sequence analysis and subjected to modulation studies Methodology: The biosynthetic gene clusters of the pure fungi were subjected to modulation by adopting the co-culture technique and fermentation on local rice. The secondary metabolites were extracted using ethyl acetate, and the fungal crude extracts were subjected to antioxidant and antimicrobial activities adopting the diphenyl picrylhydrazyl and agar well diffusion techniques, respectively. The biosynthesized secondary metabolites were monitored using phytochemical analysis. Results: The endophytic fungus was identified as Aspergillus aflatoxiformans. At various concentrations, all the modulated fungal extracts showed interesting microbial growth inhibition, observed to be concentration dependent as well as broad-spectrum in action. The minimum inhibitory concentrations and inhibition zones ranged between 0.25 and 2 mg/mL and 2 to 13 mm, respectively. Escherichia coli and Staphylococcus aureus were the two most susceptible bacteria isolates. Also, all the modulated extracts showed potent antioxidant capacities at 80µg/mL. The presence of flavonoids and terpenoid in the modulated extracts may be responsible for the observed activities. Conclusion: The data obtained from this study highlight the presence and induction of biosynthetic gene clusters present in Aspergillus aflatoxiformans needed for drug development.