Abstract:
Scientists are exploring the potential of fungal endophytes to create new medications, recognizing
their high bioactive content and potential for treating various diseases. The current study aimed
to identify and isolate endophytic fungi from Adenanthera pavonina, a plant that belongs to the
family Fabaceae and to evaluate their antibacterial activity. A. pavonina leaf segments were
pretreated by cleaning and air-drying, then stored at 4 °C. Healthy, younger leaves were selected
and cut under aseptic conditions. The segments were then sterilized in 70% ethanol, rinsed with
distilled water, and dried with a sterile cotton cloth and incubated on Potato Dextrose Agar plates,
followed by subculturing to isolate pure fungal strains. Two distinct fungal species were identified
using cotton blue staining and microscopic screening from plant tissues. They had two different
hyphal types: one with a cotton texture and quick growth, and the other with a cloudy texture
with slow fungal growth. The two fungal isolates were cultured separately on Sabouraud Dextrose
Broth. The fungal biomass was separated, and metabolites were extracted into an ethyl acetate
phase. Crude extracts of each fungal strain were collected, dried, and dissolved in ethyl acetate for
disk diffusion assay. Four bacterial strains were used for antimicrobial assays: Escherichia coli,
Pseudomonas aeruginosa, Staphylococcus aureus, and Enterococcus faecalis by preparing streak
plates using stock cultures. The turbidity of these suspensions was adjusted to the McFarland 0.5
solution. Once the correct turbidity was obtained, 100 μL of each microbial suspension was placed
on Mueller Hinton Agar and prepared spread plates. The assay utilized a fungal extract as the test
solution, with tetracycline antibiotic (0.02 g/mL) serving as the positive control and ethyl acetate
as the negative control. Aseptically prepared antimicrobial disks were obtained, and each disk was
loaded with 25 μL of the positive controller, negative controller, and test solutions. The experiment
showed a clear zone of inhibition with tetracycline as the positive control, while ethyl acetate showed
no antimicrobial effect in any plate. In contrast, the inhibition zone was not evident in the test
samples. The fungal extract was found to be ineffective in inhibiting the bacterial strains.
