In vitro and in vivo antifungal activity of Cuminum cyminum essential oil against Aspergillus aculeatus causing bunch rot of postharvest grapes

Abstract

Bunch rot in grapes is an aggressive disease and needs to be controlled during the postharvest period. We investigate the antifungal potential ofZanthoxylum bungeanumMaxim.,Zanthoxylum rhetsa,Cuminum cyminum,Coriandrum sativum, andZingiber montanum(J. Koenig) Link ex A. Dietr. essential oils againstAspergillus aculeatusthat cause bunch rot disease on postharvest grapes.C.cyminumessential oil exhibited stronger significantly inhibition percentage of 95.08% than other treatments inin vitroassay. Cumin aldehyde (33.94%) and α-terpinen-7-al (32.20%) were identified as major volatile compounds inC.cyminumoil. Antifungal potential ofC.cyminumoil was then tested in conidia germination andin vitrotests compared to cumin aldehyde and α-terpinen-7-al. Their EC50values against the conidial germination were also estimated. Significant reduction of conidia germination was also detected inC.cyminumessential oil and cumin aldehyde at a concentration of 1,000 and 100 μg/mL, respectively. EC50values of theC.cyminumessential oil, cumin aldehyde, and α-terpinen-7-al were 67.28 μg/mL, 9.31 μg/mL, and 13.23 μg/mL, respectively.In vivoassay, the decrease of the disease severity (0.69%) and incidence (1.48%) percentage ofA.aculeatuson grape berries treated at 1,000 μg/mL ofC.cyminumessential oil was significantly greater than that obtained from other treatments after 10 days incubation. In addition, grape berries treated withC.cyminumessential oil decreased weight loss and retained fruit firmness. The changing of total soluble solids, total phenolic content, and antioxidant activity are also delayed in treated fruits. Therefore, essential oil ofC.cyminummay be applied as a biological antifungal agent to controlA.aculeatusin postharvest grapes without any negative effects on its quality.