Screening of metabolites from endophytic fungi of some Nigerian medicinal plants for antimicrobial activities

Abstract

Endophytic fungi associated with Nigerian plants have recently generated significant interest in drug discovery programmes due to their immense potential to contribute to the discovery of new bioactive compounds. This study was carried out to investigate the secondary metabolites of endophytic fungi isolated from leaves of Newbouldia laevis, Ocimum gratissimum, and Carica papaya The plants were collected from Agulu, Anambra State, South-East Nigeria. Endophytic fungal isolation, fungal fermentation; and extraction of secondary metabolites were carried out using standard methods. The crude extracts were screened for antimicrobial activities using the agar well diffusion method, and were also subjected to high performance liquid chromatography (HPLC) analysis to identify their constituents. A total of five endophytic fungi was isolated, two from N. laevis (NL-L1 and NL-L2), one from O. gratissimum (SL-L1), and two from C. papaya (PPL-LAC and PPL-LE2). In the antimicrobial assay, the extracts of NL-L2, SL-L1, and PPL-LE2 displayed mild antibacterial activity against both Gram negative and Gram positive test bacteria. PPL-LAC extract showed mild activity only against S. aureus, while no antimicrobial activity was recorded for NL-L1 extract. All the endophytic fungal extracts showed no activity against the test fungi C. albicans and A. fumigatus HPLC analysis of the fungal extracts revealed the presence of ethyl 4-hydroxyphenyl acetate and ferulic acid in NL-L1; ruspolinone in NL-L2; protocatechuic acid, scytalone, and cladosporin in SL-L1; indole-3-acetic acid and indole-3-carbaldehyde in PPL-LE2; and indole-3-acetic acid in PPL-LAC. The findings of this study revealed the potentials possessed by these plants as source of endophytes that express biological active compounds. These endophytes hold key of possibilities to the discovery of novel molecules for pharmaceutical, agricultural and industrial applications.

Antibacterial potential of some Cameroonian ornamental plants and their isolated endophytic fungi

“…The fungi isolated from the plants as well as their extracts showed some of them with good antibacterial activities. These results corroborate those found by the investigations of Eze et al (2019) who showed that several endophytic fungi isolated from ornamental plants were endowed with antibacterial properties.…”

Isolation and Characterization of Fungal Endophytes Isolated from Medicinal Plant Ephedra pachyclada as Plant Growth-Promoting

“…Similarly, Manganyi et al [ 49 ] reported that among 133 endophytic fungi isolated from healthy roots and leaves of medicinal plant Pelargonium sidoides , only the crude extract of sixteen fungal strains showed antibacterial activity against Bacillus cereus, Enterococcus faecium, E. coli , and Enterococcus gallinarum . Moreover, the ethyl acetate extract of five endophytic fungal strains isolated from Nigerian plants Ocimum gratissimum, Newbouldia laevis, and Carica papaya displayed antibacterial activity against Gram-positive and Gram-negative bacteria, while they did not exhibit any antifungal activity against Candida albicans and Aspergillus fumigatus [ 50 ].…”

Susceptibility Studies of Vancomycin Resistant Staphylococcus aureus (VRSA), Extended ?-lactamase Producing Escherichia coli and P. falciparum to Ethylacetate Extract of Endophytic Fungal Metabolites from Annona senegalensis

“…The organism was susceptible to all the concentrations of the extract. Similarly, Eze et al 33 reported high susceptibility of both Gram positive and Gram negative test bacteria to their endophytic fungal extracts. However, vancomycin resistant Staphylococcus aureus did not show any form of sensitivity to all the tested concentrations of the bioactive compounds in RT3.…”