EVALUATION OF ANTIFUNGAL ACTIVITY OF ESSENTIAL OILS AGAINST TOXIGENIC ISOLATES OF ASPERGILLUS FLAVUS

Abstract

The genus Aspergillus comprised of round about 150 species and worldwide the most common environmental molds. Aspergillus flavus is reported in environment and present naturally in postharvest infestation of grains, feed, food and nuts. Main route of infection is inhalation of conidia from environment. These conidia can be the source of infection in hospital air and enter in wounds during surgery. Drugs presently used against aspergillosis aren’t responding. Resistance is big issue now-a-days. So, alternatives like essential oil can be a good option in growth inhibition of Aspergilli. Essential oils have ability to inhibit the growth of toxigenic Aspergilli. Essential oils have potential to be used as preservative in feed to restrict proliferation of toxin producing fungi. Toxigenic isolates of A. flavus (n=10) are identified by macroscopic characters and microscopic characters by cellophane tape method and slide culture method. A. flavus is screened for their toxin production by thin layer chromatography (TLC). Disk diffusion test is used for antifungal susceptibility testing. Antifungal activity of essential oils is determined by log reduction method. MIC of the essential oil Syzygium aromaticum (long), Elettaria cardamomum (Elaichi), Ferula asafetida (Hing) and Curcum longa (Huldi) is determined by using MTT (3[4, 5-dimethylthiazol-2-yl]-2,5diphynyl tetrazolium bromide) assay. Essential oil of Syzygium aromaticum (long) exhibited most noticeable antifungal activity against toxin producing isolates of A. flavus in comparison to other three oils Curcum longa (Huldi), Elettaria cardamomum (Iaychi) and Ferula asafetida (Hing). Minimum inhibitory concentration of Syzygium aromaticum (long) was from (0.0307±0.001µL/mL) to (0.07±0.00µL/mL). Cytotoxic effect of Syzygium aromaticum (long) evaluated by MTT assay that showed percentage livability from 50% to 77.3% at concentration 100 µL/mL to 0.19 µL/mL. Mycotoxin production is one of the most burning issues in poultry sector. A. flavus is one of the major mycotoxin producer in poultry feed and animal rations as well as causes economic losses by infecting crops. This study suggests that essential oil of Syzygium aromaticum (long) if mixed in below cytotoxic level in feed, animal rations and grains. Antifungal property of essential oil will inhibit the growth of toxigenic fungi ultimately no mycotoxin production.