The anti-pseudomonal potentials of metabolites from some endophytic fungi isolated from Garcinia kola leaves

Chinedu Joseph Ikem ,David Chinemerem Nwobodo ,Festus Basden Chiedu Okoye ,Chibueze Peter Ihekwereme

doi:10.21608/nrmj.2020.95326

Abstract

The morbidity and mortality rates from Pseudomonas aeruginosa infections are increasing, due to the development of drug-resistant strains. This study aimed to explore the secondary metabolites of endophytic fungi of Garcinia kola for their antibacterial activities against P. aeruginosa. The endophytic fungi associated with healthy leaves of G. kola were isolated using the standard methods. These fungi were subjected to solid-state fermentation on rice media at 28oC for 21 d. The fungal secondary metabolites were extracted using ethyl acetate, and then concentrated under vacuum. The fungal crude extracts were screened for their antibacterial activities against clinical and laboratory strains of P. aeruginosa, using the agar diffusion method. The bioactive components of the fungal extracts were identified using High-Performance Liquid Chromatography-Diode Array Detector (HPLC-DAD) analysis. Three endophytic fungi mainly; Aspergillus sp., Fusarium sp. and Colletotrichum sp. were isolated. At concentration of 1 mg/ml, extracts of the three fungi displayed anti-pseudomonal activities against all the isolates, except for a P. aeruginosa isolate recovered from urine. Results of the HPLC-DAD analysis revealed the presence of several active compounds such as; indole-3-acetic acid, p-hydroxybenzoic acid, and protocatechuic acid, among others in the fungal extracts. These compounds have been previously reported to have significant antimicrobial properties. This study reveals that endophytic fungi associated with G. kola leaves possess promising anti-pseudomonal potential.

Highlights

Pseudomonas aeruginosa is a major etiological agent of healthcare-associated bacterial infections and is responsible for 11% of the hospital-acquired infections, which results in high mortality and morbidity rates (Haque et al, 2018)
Considering the numerous therapeutic potentials of this plant, as well as the eco-friendly properties of the endophytic fungi drug discovery approach, the objective of this study was to screen for the in-vitro anti-pseudomonal potency of the endophytic fungal extracts of G. kola, against the clinical and laboratory strains of P. aeruginosa
A total of three endophytic fungi were isolated from the leaf segments of G. kola plant, and labeled as: Gc1-3

Summary

Introduction

Pseudomonas aeruginosa is a major etiological agent of healthcare-associated bacterial infections and is responsible for 11% of the hospital-acquired infections, which results in high mortality and morbidity rates (Haque et al, 2018). P. aeruginosa is susceptible to a limited number of antibacterial agents, suggesting that the high mortality rate associated with this bacterium could be attributed to its virulence, and to the administration of ineffective empirical antibacterial therapy. The morbidity and mortality from P. aeruginosa infections are increasing, due to these drug-resistant strains. Several previous studies of Ozer et al, (2009); Marilyn et al, (2012); Egbujor et al, (2020) reported that resistance development in P. aeruginosa is multifactorial, with mutations in several genes contributing for resistance to β-lactams, carbapenems, aminoglycosides, fluoro-quinolones and sulphonamides.

Objectives

Methods

Results

Conclusion