Antifungal activity in vitro of ethanol and aqueous extracts of leaves and branches of Flourensia spp. against postharvest fungi

Abstract

Fusarium and Rhizopus rots occur in stored fruits and cause high post-harvest losses. The most common fruit affected by these fungi is tomato, which is the principal exportation product of Mexico. Chemical treatment is one of the postharvest techniques that are normally used to prolong shelf life and reduce food spoilage. However, the indiscriminate use of pesticides in horticultural products allows the resistance of plagues and also affects human health. The use of natural products, such as plant extracts for the management of fungal diseases in plants, is considered an alternative method to synthetic fungicides. The objectives of this research were to evaluate the antifungal activity in vitro of ethanol and aqueous extracts of leaves and branches of Flourensia cernua, F. microphylla and F. retinophylla against Fusarium oxysporum and Rhizopus stolonifer, which cause diseases in postharvest fruits and high economic losses in tomato; and to obtain information on the chemical composition of the bioactive components of the extracts. The chemical profile identified in ethanol extracts of leaves and branches of F. cernua, F. microphylla and F. retinophylla, was: 17 and 10 compounds; 7 and 9 compounds and 7 compounds in both tissues, respectively. Flourensia spp. ethanol extracts showed high effectiveness in the inhibition of mycelial growth of F. oxysporum and R. stolonifer. F. cernua inhibited F. oxysporum at MIC90 of 2163mg/L for leaves ethanol extract and 4240mg/L for branches ethanol extract. Also, F. cernua inhibited R. stolonifer at MIC90 of 1692 for both tissues. Flourensia spp. ethanol extracts represent an alternative to be used as a botanical fungicide, which could replace the use of synthetic fungicides.