Genome-Informed Natural Product Discovery from Endophytic Fungi of Garcinia kola (Bitter Kola) in South West Nigeria: Bioinformatics and Bioactivity Integration

Endophytic microorganisms inhabiting the tissues of medicinal plants represent an underexplored reservoir of pharmacologically active secondary metabolites. Garcinia kola, a species of immense ethnopharmacological significance in South West Nigeria, harbours a diversity of endophytic fungi whose biosynthetic gene clusters and associated natural products are entirely uncharacterised. This study integrates genome-sequencing-based biosynthetic gene cluster (BGC) analysis with in vitro bioactivity profiling to drive natural product discovery from Garcinia kola endophytes. Endophytic fungi were isolated from healthy G. kola seeds and stem tissues collected from Osun and Ondo States. Morphological identification and ITS rDNA sequencing characterised the isolated strains. Whole genome sequencing of five selected isolates was performed on the Illumina NovaSeq platform. AntiSMASH 7.0 was used to predict BGCs encoding polyketides, non-ribosomal peptides, terpenoids, and indole alkaloids. Selected strains were cultured in six media for secondary metabolite induction. Ethyl acetate extracts were profiled by UHPLC-HRMS and evaluated for antimicrobial, anticancer, and antioxidant activities. Three novel polyketide scaffolds and two terpenoid natural products were prioritised through dereplication and bioassay-guided analysis. One novel compound demonstrated MIC of 0.98 ug/mL against MRSA and selective cytotoxicity against HeLa cells (IC50 12.3 uM). This genome-to-bioactivity pipeline establishes a replicable framework for endophyte-derived drug discovery from Nigerian medicinal plants. Keywords: endophytic fungi, Garcinia kola, biosynthetic gene clusters, natural product discovery, antimicrobial