Polvos, extractos y fracciones de hojas de Cestrum nocturnum L. y su actividad antifúngica en dos aislamientos de Fusarium spp

One of the main causes that originate considerable postharvest loses during handling and storage of fruits and vegetables is the infection by Fusarium. One possible alternative to control postharvest disease originated by fungi in fruits and vegetables is the application of powders and extracts from botanical species with fungicidal properties. The genus Cestrum is composed by a great diversity of botanical species with different applications in the traditional medicine, associated with pesticidal and fungicidal activities. The objectives of this research were to obtain aqueous, ethanolic, metanolic, chlorophormic, dichloromethanic and acetonic extracts, evaluating their antifungal activity. Fractions obtained by column chromatography (CC) were evaluated on germination of two isolations of Fusarium from fruits of papaya and red mombin. The fungicidal potential of powders of C. nocturnum at concentrations each 0.5, 1.0, 1.5 and 2.0 g mL-1 and aqueous, methanol, acetone, dichloromethane, chloroform-methanol-water, and ethanol extracts at concentrations each of 12, 25 y 50 mg mL-1 were also evaluated on this two isolations. The parameters evaluated were: mycelial growth, sporulation, germination and also rate of growth. Results showed significative differences in the amount and number mixture of compounds obtained depending on dissolvent applied, time of extraction (24 and 48 h), sterilized and non-sterilized and type of isolation. The greatest number of mixture of compounds (16) was obtained with the acetonic extract. This alsoshowed the greatest number of inhibitory zone of germination in TLC and fractions of CC on Fusarium. The fungicidal activity was different in relation to isolate and treatment applied. Powders stimulated sporulation and germination in both isolates; however, they did inhibit micelial growth in red mombin isolate. For both isolates, only the methanol extract of C. nocturnum at 25 mg mL-1 inhibited micelial growth and sporulation. Rate of growth was higher in red mombin isolate.