Antifungal and Antiaflatoxinogenic Effects of Cymbopogon citratus, Cymbopogon nardus, and Cymbopogon schoenanthus Essential Oils Alone and in Combination

Abstract

The antifungal and antiaflatoxinogenic activities of the essential oils (EOs) from the leaves of <i>Cymbopogon schoenanthus</i>, <i>Cymbopogon citratus</i>, <i>Cymbopogon nardus</i>, and their pair combinations were investigated. Antifungal susceptibility and the efficacy of paired combinations of EOs were assessed using agar microdilution and checkerboard methods, respectively. Identification and quantification of chemical components of the EOs were carried out by gas chromatography-mass spectrometry and gas chromatography-flame ionization detector (GC-MS and GC-FID), respectively. Aflatoxins were separated and identified by High-Performance Liquid Chromatography (HPLC) and then quantified by spectrofluorescence. The EO of <i>C. nardus</i> exhibited the highest inhibitory activity against <i>Aspergillus flavus</i> and <i>Aspergillus parasiticus</i>. The combination of <i>C. citratus</i> and <i>C. nardus</i> and that of <i>C. nardus</i> and <i>C. schoenanthus</i> exhibited a synergistic effect against <i>Aspergillus flavus</i> and <i>Aspergillus</i>, respectively. Both <i>C. citratus</i> and <i>C. schoenanthus</i> EOs totally inhibited the synthesis of aflatoxin B1 at 1 µL/mL. <i>C. citratus</i> blocked the production of aflatoxins B2 and G2 at 0.5 µL/mL. Both <i>C. citratus</i> and <i>C. schoenanthus</i> totally hampered the production of the aflatoxin G1 at 0.75 µL/mL. The combination of <i>C. citratus</i> and <i>C. schoenanthus</i> completely inhibited the production of the four aflatoxins. The study shows that the combinations can be used to improve their antifungal and antiaflatoxinogenic activities.