Endophytic Fungi Isolated from the Medicinal Plants Kigelia africana and Warburgia salutaris

Background: Medicinal plants play an important role in the search for bioactive strains of endophytic fungi. Objective: The aim of the study was to isolate and identify the endophytic fungi associated with Kigelia africana and Warburgia salutaris and evaluate their bioactivity. Methods: Endophytic fungi were isolated from the stem and leaf tissues of Kigelia africana and Warburgia salutaris and identified by rDNA sequencing of the ITS region. Crude extracts were screened for antimicrobial activity using the agar diffusion method and evaluated for total antioxidant activity using a commercial kit. The metabolites present in the extracts were predicted using Gas Chromatography-Mass Spectrometry (GC-MS). Results: Eleven endophytic fungi identified as Penicillium chloroleucon, Alternaria solani, Coprinellus micaceus, Cryptococcus cf. taibaiensis, Vishniacozyma victoriae, Alternaria alternata and Cystobasidium larynges were isolated from Warburgia salutaris. Seven more endophytic fungi identified as Penicillium chloroleucon, Myrothecium gramineum, Phomopsis sp., Alternaria brassicae, Cercospora chrysanthemi, Cladosporium uredinicola, and Aureobasidium leucospermi were isolated from Kigelia africana. The isolate Cladosporium uredinicola from Kigelia africana was shown to have both antioxidant (175.42±2.53 μM copper reducing equivalents) and antimicrobial activity (against E. coli ATCC1056). The main constituents in the crude ethyl acetate extract of the isolate Vishniacozyma victoriae from Warburgia salutaris were identified as N- hydroxymethylacetamide (33.14%), 26- hydroxycholesterol (8.21%), formic acid, butyl ester (1.14%), cyclotetracosane (0.70%), 1-heptacosanol (0.66%), benzo [h] quinolone, 2, 4-dimethyl (0.57%), and pyrrolo[1,2-a] pyrazine-1,4-dione, hexahydro- 3-(9-phenylmethyl) – (0.50%) through GC-MS spectra analysis. Conclusion: The isolate Cladosporium uredinicola has potential as a source of antimicrobial and antioxidant bioactive compounds and the isolate Vishniacozyma victoriae produces a diverse range of metabolites.