Antimicrobial and immunomodulatory activities of secondary metabolites of an endophytic fungus isolated from Ageratum conyzoides

Main Authors: Ujam, Nonye T., Eze, Peter M., Chukwunwejim, Chidimma R., Okoye, Festus B. C., Esimone, Charles O.
Format: Article Journal
Terbitan: , 2019
Subjects:
Online Access: https://zenodo.org/record/3240604
Daftar Isi:
  • Endophytes have proven to be the promising sources of biologically active products which are of interest for specific medicinal applications. In this study, secondary metabolites of an endophytic fungus isolated from fresh leaves of Ageratum conyzoides was investigated for antimicrobial and immunomodulatory properties. Isolation of the endophytic fungus, fermentation and extraction of the fungal secondary metabolites were carried out using standard procedures. The extract was evaluated for antimicrobial activity using the agar well diffusion and agar dilution methods. Also, the immunomodulatory activity of the extract was evaluated using cyclophosphamide‐induced immunosuppression assay. The crude fungal extract was subjected to High Performance Liquid Chromatography-Diode Array Detector (HPLC-DAD) analysis to identify the chemical constituents. The endophytic fungal extract at 1 mg/ml, exhibited antimicrobial activity against Pseudomonas aeruginosa, Salmonella Typhi, Candida albicans and Aspergillus niger with inhibition zone diameters of 8, 5, 3 and 2 mm respectively. Also, the minimum inhibitory concentrations of the extract against the test organisms ranged from 0.03-1 mg/ml. The extract at 100 and 200 mg/kg, showed immune-stimulatory activity in a dose related manner with a significant increase in the total white blood cells and neutrophil levels. The extract also exhibited immune-protective properties by inhibiting the immune-suppressive activity of cyclophosphamide. HPLC-DAD revealed the presence of xanthorrhizol, orsellinic acid, p-hydroxybenzoic acid, scalarolide reported previously to have antimicrobial and immunomodulatory properties. The secondary metabolites of the endophytic fungus isolated from A. conyzoides displayed both antimicrobial and immunomodulatory activities.