Abstract

EFFICACY AND MECHANISM OF ESSENTIAL OILS ON INHIBITION OF ASPERGILLUS NIGER ISOLATED FROM ZEA MAYS

Suresh Kumar C., Aathiya Vanekar, Pratibha K. Y. and Marhoob Banu*

ABSTRACT

The present study was conducted with the main purpose to evaluate antifungal activity of six essential oils viz., Cinnamon oil (Cinnamomum zeylanicum), Clove oil (Syzygium aromaticum), Camphor oil (Cinnamomum camphora), Eucalyptus oil (Eucalyptus globulus), Neem oil (Azadirachta indica) and Rose oil (Rosa rubiginosa) at concentrations of 20%, 40%, 60%, 80% and 100% respectively on Aspergillus niger by poisoned food technique. Screening of fungi on Zea mays (maize) was done by agar plate method and the fungi studied was Aspergillus niger. Potato dextrose agar was prepared and well grown colony of Aspergillus niger was inoculated. Pure culture of Aspergillus niger was obtained by subculturing the previous culture and incubated at 27 ± 2 °C for 48 h. Aspergillus niger was suspended in sterile distilled water and adjusted to a standard inoculum size to 1-2 x 106 CFU/mL. Five different concentrations of essential oils were added to sterile potato dextrose agar at concentration of 500 ppm in the hood of laminar air flow and 0.1 ml of fungal suspension was used to inoculate treated PDA petriplates with a sterile non-toxic cotton swab. Acetone at 500 ppm was added as control. The treated plates with essential oils and control were incubated at 27 ± 2 °C for 7 days. After incubation the treated plates were observed for zone of inhibition around wells and also for complete inhibition. It was observed that rose oil, cinnamon oil and clove oil were effective in completely inhibiting the growth of Aspergillus niger while eucalyptus oil and camphor oil showed zone of inhibition and neem oil was not effective against Aspergillus niger. Zone of inhibition was measured and recorded in millimetres (mm).

Keywords: Agar plate method, Antifungal activity, Aspergillus niger, Poisoned food technique, Zea mays.