Exogenous melatonin preserves mango fruit quality and reduces anthracnose disease progression by enhancing antioxidative defense mechanisms

• Melatonin (MT) treatment reduced anthracnose and maintained mango fruit firmness • MT regulated respiration and preserved total soluble solids and titratable acidity • MT maintained higher phenolic, flavonoid content, and antioxidant activity • MT inhibited anthracnose in vitro and in vivo by boosting defense responses • Principal component analysis confirmed MT enhances mango resistance to anthracnose Mango ( Mangifera indica L.) is highly perishable, with anthracnose, caused by Colletotrichum gloeosporioides, significantly impacting its postharvest quality. Melatonin (MT) is reported to control chilling injury and postharvest disease in some fruits. Therefore, this study planned to investigate the effects of exogenous MT on anthracnose disease incidence and antioxidant enzymatic activity in mango fruit during postharvest storage. It further seeks to identify the optimal concentration of exogenous MT for lowering anthracnose severity and evaluate its impact on antioxidant enzyme activity and overall fruit quality during storage. An optimized dose of 1600 μM MT treatment for 2 h effectively delayed fruit softening, reduced disease incidence, and preserved firmness, titratable acidity, and weight. MT-treated fruit maintained higher phenolic and flavonoid content, enhanced antioxidant activity, and showed lower malondialdehyde accumulation. Increased superoxide dismutase and catalase activity contributed to improved defense mechanisms. Additionally, MT inhibited in vitro and in vivo anthracnose development, as confirmed by principal component analysis. These findings highlight MT’s role in enhancing mango resistance to C. gloeosporioides by modulating antioxidant defense, preserving structural integrity, and delaying ripening, making it a promising postharvest treatment.