Inhibitory Mechanism of Oregano Essential Oil Emulsion Against Colletotrichum gloeosporioides in Mangoes and Its Regulatory Effects on Postharvest Quality

In response to the growing need for sustainable and safe postharvest strategies, plant essential oils have emerged as promising natural alternatives to synthetic fungicides. Mango (<i>Mangifera indica</i> L.), as a vital tropical fruit, suffers significant postharvest losses due to anthracnose caused by <i>Colletotrichum gloeosporioides</i>. This study investigated the antifungal efficacy of oregano essential oil (OEO) against <i>C. gloeosporioides</i> and its regulatory effects on the postharvest quality of mango fruit. The potent antifungal activity of OEO is demonstrated by its low MIC (0.005%) and MFC (0.01%) against <i>C. gloeosporioides</i>. The antifungal mechanism was primarily attributed to the disruption of plasma membrane integrity of <i>C. gloeosporioides</i>, as indicated by increased propidium iodide uptake, elevated extracellular conductivity, and leakage of cellular proteins. The OEO treatment inhibited peel color transformation, reduced weight loss, maintained firmness, and slowed the increase in the soluble solids content to acidity ratio. Furthermore, OEO enhanced the fruit's antioxidant capacity by sustaining higher superoxide dismutase activity and suppressing the activities of polyphenol oxidase and peroxidase, leading to a marked reduction in malondialdehyde accumulation. These findings comprehensively demonstrate the dual functionality of OEO as a direct fungicidal agent and a systemic physiological regulator that delays senescence and preserves mango quality. This study underscores the potential of OEO as a sustainable alternative for integrated postharvest management of mango anthracnose, offering insights for its practical application in the fruit industry.