Abstract

ANTIMICROBIAL PROPERTIES OF EXTRACTS OF ENDOPHYTIC FUNGI ISOLATED FROM THE LEAVES OF SPONDIAS MOMBIN IN NIGERIA

Roseline Ngozi. Asomugha*, Augustina Ifeyinwa Ijomah, Ugochukwu Moses Okezie*, Moses Nkechukwu Ikegbunam, Festus Basden Chiedu Okoye and Azuoma Lasbrey Asomugha

Abstract

Drug resistant infections have become a very disturbing and challenging aspect of clinical practice necessitating the need to explore new frontiers of drug development. In the present study, four endophytic fungi (MR1, MR2, LB1 and LB2) were isolated from healthy leaves of the medicinal plant Spondias mombin using standard procedures. These fungi were fermented on local rice for twenty one days thereafter extracts of MR1, MR2, LB1 and LB2 were obtained using ethyl acetate and concentrated using a rotary evaporator at a reduced temperature. The fungal crude extracts were subjected to antimicrobial activity screening as well as phytochemical analysis in order to identify the secondary metabolites produced by each fungus. The results showed that MR1, LB1 and LB2 were the only active fungal extracts. At 1 mg/mL, MR1 extract was observed to be the most active inhibiting all the bacteria test organisms. The active fungal extracts exhibited good antibacterial activity against the bacterial isolates, the activity was observed to be broad-spectrum in action, inhibiting the growth of both the gram positive and gram negative test isolates at tested concentrations. The inhibition zones of the potent fungal extracts as well as their MICs ranged between 2 to 6 mm and 0.5 – 1 mg mL-1 respectively. The secondary metabolites detected in the fungal extracts included Alkaloid, flavonoids and terpenoids previously established to be active against different bacteria isolates. The activities demonstrated by these fungal extracts may be attributed to the presence of the bioactive metabolites present in them. As a result of the remarkable anti-bacterial activity demonstrated by MR1 in comparison to other fungal extracts in this work, MR1 was further identified to be Fusarium equiseti combining macroscopic, microscopic as well as standard molecular techniques. Thus, this work clearly indicates that F. equiseti is a potential source of bioactive drug like molecules for development of new antibiotics.

Keywords: Resistance, Endophyte, Fusarium equiseti, Spondias mombin, Antimicrobial, Secondary metabolites.