Metabolite profiling and bioactivity assessment of diverse endophytic fungi from the endangered plant, Nilgirianthus ciliatus

Endophytic fungi are potential sources of bioactive compounds with therapeutic properties. This study investigated the fungal endophytes associated with Nilgirianthus ciliatus, an endangered medicinal plant, to discover its secondary metabolites and bioactivities. Molecular analysis revealed the prominent species to be Aspergillus niger, Didymella sp., Trichoderma viride, Bipolaris zeicola and Nigrospora sphaerica. Alkaloids, flavonoids, phenolics, terpenes and saponins were detected in ethyl acetate extracts employing phytochemical screening. Didymella sp. has showed the highest level of antioxidant activity, demonstrating strong DPPH radical scavenging and reduction capability. T. viride had strong antibacterial action against Klebsiella pneumoniae and Escherichia coli, meanwhile Didymella sp. and N. sphaerica were most effective against E. coli. GC-MS analysis uncovered many bioactive chemicals, including trans-farnesol and pentadecanoic acid, which are renowned for their antibacterial and antioxidant properties. These findings highlight the presence of the rich variety of diverse endophytic fungi harboring such medicinal plants, which offer promising applications in medicine, biotechnology and agriculture as sources of novel bioactive compounds. Further exploration and characterization of these strains could unlock valuable sustainable resources for various industries.