Antimicrobial activities of secondary metabolites of endophytic fungi isolated from Catharanthus roseus

Abstract

Introduction: Recently, several endophytes have been shown to possess the potentials to synthesize novel bioactive compounds that have found use for drug discovery. We isolated endophytic fungi associated with Catharanthus roseus collected from the river banks of Amassoma in Southern Nigeria, and identified some of their bioactive secondary metabolites. Methods: The fungi were subjected to solid-state fermentation on rice medium and the metabolites were extracted using ethyl acetate. The fungal crude extracts were screened for antimicrobial activity and were also subjected to high-performance liquid chromatography-diode-array detection (HPLC-DAD) analysis for the identification of the bioactive compounds. Results: The fungal extracts showed both antibacterial and antifungal activities with minimum inhibitory concentrations ranging from 0.0625 to 1 mg/mL. The HPLC-DAD analysis of the extracts suggested the presence of citreoisocoumarin, citreoisocoumarinol, questinol, hydroxyemodin, acropyrone, methyl 2-(4-hydroxyphenyl) acetate, nigricinol, and cladosporin. Conclusion: The results of this study suggest that endophytic fungi associated with C. roseus could be a promising source of novel bioactive compounds with pharmaceutical and industrial importance.

Keywords

• Catharanthus roseus
• Endophytic fungi
• Secondary metabolites
• HPLC-DAD analysis