In vitro antifungal potential of peel essential oils from different citrus species on Alternaria alternata

The essential oil extraction from Citrus peels constitutes an effectual approach for the valorization of Citrus fruit waste. Citrus peel essential oils can have an antifungal activity. The peel essential oils of seven species of Citrus, namely clementine, pummelo, tangelo, sweet orange, sour orange, tangerine and lemon, were extracted by steam distillation and subjected to chemical analysis to identify and evaluate the chemical constituents. Tangerine exhibited the highest yield (1.23%) followed by lemon (0.66%), clementine (0.56%), sweet orange (0.55%), tangelo (0.50%) and sour orange (0.47%). The lowest yield was obtained in pummelo (0.16%). The main compound in all Citrus essential oils was limonene with 62.1% for tangerine, 69.7% for lemon, 72.2% for tangelo, 76.4% for clementine, 89.8% for pummelo, 92.8% for sour orange and 94.1% for sweet orange. All these Citrus essential oils had a weak antifungal activity (MIC = 8000-12000 μg/mL) against Alternaria alternata strain.