Impact of Storage Condition on Chemical Composition and Antifungal Activity of Pomelo Extract against Colletotrichum gloeosporioides and Anthracnose in Post-harvest Mango

Abstract

Anthracnose caused by <i>Colletotrichum</i> leads to a tremendous post-harvest mango loss. While chemical fungicides are applied to control anthracnose, natural alternatives are preferred due to food safety and environmental concerns. Pomelo extract (PE) exhibits a broad spectrum of antimicrobial activities; however, its effect against anthracnose is unknown. Here we investigated the chemical profile of PE using GC-MS and the anti-anthracnose activity of PE using in vitro and in vivo assays. We also evaluated the impact of storage temperature (0°, 5°, 10°, 20°, -20°, and -80 °C) and light conditions on the composition and antifungal activity of PE. We found that PE inhibited <i>C. gloeosporioides</i> in vitro with an IC₅₀ of 3.2 mL L^-1. Applying chitosan-based coating incorporated with 20 mL L^-1 PE significantly suppressed anthracnose in post-harvest 'Keitt' mango. A storage temperature below 5 °C substantially preserved major compounds and the antifungal activity of PE after 6 m of storage. Finally, we showed that applying <i>d</i>-limonene, the key constituent of PE, inhibited <i>C. gloeosporioides</i> in vitro (IC₅₀: 10.9 mM) and suppressed anthracnose in vivo. In conclusion, we demonstrated that the application of PE and <i>d</i>-limonene are sustainable methods for anthracnose control in post-harvest crops and established the preservation protocol for PE.