Aim: This study tries to find new antimicrobial agents using some Nigerian
Background: Antimicrobial compounds from fungi endophytes have shown great
promise in mitigating the threats of resistant pathogens.
Objective: The study evaluated the in vitro antimicrobial property of secondary metabolites
of endophytic fungi isolated from Newbouldia laevis and Cassia tora leaves.
Methods: Ten endophytic fungi were isolated from the two plants’ leaves and later fermented
on local rice for 21 days. Thereafter, their secondary metabolites were extracted
using ethyl acetate. The antibacterial activity of the extracts on the test organisms were
determined using agar diffusion and agar dilution methods, while the bioactive constituents
were identified using high performance liquid chromatography coupled to diode
Results: Nine of the crude extracts (NL1, NL3, NL6, NL10, NL12, CT2, CT7, CT9 and
CT10) of the fungi isolates inhibited at least one of the microorganisms studied with maximum
and minimum inhibition-zone-diameter of 14 mm and 2 mm, respectively while
CT1 did not inhibit any of the tested microorganisms at tested concentrations. The extracts
exhibited good antifungal activity, inhibiting the growth of both C. albicans and
Trichophyton tested with an inhibition-zone-diameter ranging between 4-8 mm and 7-14
mm, respectively. The endophytic fungi extracts-CT2 and NL1-exhibited the best antimicrobial
activity, inhibiting most of the tested microorganisms. HPLC-DAD analysis of
the endophytic fungal extracts identified some classes of compounds such as catechin
derivatives, benzoic acid derivatives and apigenin, which were previously reported to
have antimicrobial potentials.
Conclusion: Newbouldia laevis and Cassia tora leaves house endophytic fungi capable
of yielding secondary metabolites with potential as anti-infective agents.