Investigating Antimicrobial Properties of Endophytic fungi Associated with Salvadora oleoides Decne

Seema      Dhankhar; Sandeep      Dhankhar; Jaya      P. Yadav

doi:10.2174/22113626130106

Abstract

Virtually all fungal endophytes produce a variety of bioactive molecule, which is currently attracting worldwide scientific attention towards isolation and exploration of their biotechnological promise. In the present study, 17 endophytic fungi (identified by way of morphological and/or sequence based molecular methods) were screened for antimicrobial activity against pathogenic strains of six bacteria and three Aspergilli sp. The seventeen culturable fungi extracted with three solvents in increasing polarity; acetone, methanol and water were examined for antimicrobial activity in crude extracts using microbroth dilution assay. Tetracycline and Amphotericin B were used as positive controls against different bacterial strains and Aspergilli respectively. The crude extracts of Aspergillus sp. JPY1, Aspergillus sp. JPY2, Aspergillus niger and an unidentified sp. exhibited the maximum activity against three pathogenic Aspergilli sp. Their in vitro minimum inhibitory concentrations (MICs) against Aspergilli were found to be 0.387 -12.50 mg/ml by microbroth dilution. In disc diffusion assay, only eleven out of fifty-one fungal extracts were found to be endowed with antimicrobial activity at a preset concentration of 50 µg/ disc which could be the potential source to develop new antimicrobial agents. The work on study of cytotoxicity and phytochemical screening (preliminary and GC-MS) of crude extracts endowed with antimicrobial properties is reported here. It is the first report of Salvadora oleoides associated endophytic fungi with antimicrobial activity, which could be an essential source of bioactive compounds useful for developing better antifungal or antibacterial drugs with good therapeutic index value.

Keywords: Antimicrobial, crude extracts, cytotoxicity, endophytic fungi, minimum inhibitory concentrations, Salvadora oleoides.