RESUMO Objetivou-se neste estudo avaliar a atividade antifúngica do extrato metanólico e frações das folhas de Randia nitida (Kunth) DC. sobre Colletotrichum truncatum (Schw.) Andrus & Moore, Rhizoctonia solani Kühn e Sclerotinia sclerotiorum (Lib.) de Bary e realizar análise química e atividade antioxidante. O extrato metanólico bruto (EBM) e frações (hexânica= FHX, diclorometano= FDM e acetato de etila= FAE) foram submetidas a análise fitoquímica clássica e determinado os fenóis totais, flavonoides e atividade antioxidante. As amostras foram incorporadas, individualmente, ao meio de cultura BDA (batata-dextrose-ágar) nas concentrações de: 10, 20, 40, 80 e 160 µg mL-1 de extrato ou fração. O crescimento micelial foi avaliado quando a testemunha alcançou a borda da placa. Os resultados fitoquímicos indicaram que os flavonoides, esteroides e triterpenos são os constituintes químicos majoritários no EBM e nas frações. O teor de fenóis totais, flavonoides e a atividade antioxidante foi maior para a fração FAE e extrato EBM, seguido da fração FDM e da FHX, contudo a fração hexânica apresentou maior conteúdo de esteroides e triterpenos em relação as demais frações. Para os três fungos, as frações eficientes foram as frações FAE, FDM e FHX, respectivamente, todas na maior concentração estudada (160 µg mL-1). A maior porcentagem de inibição foi observada frente ao patógeno S. sclerotiorum, chegando a 93,75%. Conclui-se que todas as frações apresentam atividade antifúngica sobre os fitopatógenos e a fração FHX foi a mais ativa frente a Sclerotinia sclerotiorum, provavelmente pela presença de esteroides e triterpenos. | ABSTRACT This study aimed to evaluate the antifungal activity of methanol extract and fractions of leaves of Randia nitida (Kunth) DC on Colletotrichum truncatum (Schw.) Andrus & Moore, Rhizoctonia solani Kühn and Sclerotinia sclerotiorum (Lib.) De Bary and perform chemical and antioxidant activity tests. Crude methanol extract (EBM) and fractions (hexane = FHX, dichloromethane = FDM and ethyl acetate = FAE) underwent classical phytochemical analysis and determination of total phenols, flavonoids and antioxidant activity. Samples were individually incorporated into PDA culture mediums (potato-dextrose-agar) at concentrations of 10, 20, 40, 80 and 160 µg mL-1 of extract or fraction. Mycelial growth was evaluated when control reached the edge of the plate. Phytochemical results indicated that flavonoids, steroids and triterpenoids are the major chemical constituents in both EBM and fractions. Total phenols, flavonoids and antioxidant activity were higher for FAE and EBM, followed by FDM and FHX; however, the latter showed higher content of steroids and triterpenoids compared to the other fractions. For C. truncatum, R. solani and S. sclerotiorum, the most efficient fractions were respectively FAE, FDM and FHX, all of them in the highest concentration (160 µg mL-1). The highest inhibition rate was observed against S. sclerotiorum, reaching 93.75%. We concluded that all fractions have antifungal activity on the plant pathogens, being FHX the most active against S. sclerotiorum, which might have been due to the presence of steroids and triterpenes.

ABSTRACT The biological control, thinking about the integrated management, has been inserted with other management techniques to disease control, such as soybean anthracnose. The aims of this work were to verify the action of Trichoderma and Bacillus isolates in the induction of soybean resistance mechanisms to anthracnose as a function of seed treatment. The statistical design was entirely randomised, in a 5 x 2 (agent species x sampling times) factorial scheme with five replicates. Soybean seeds were treated with Bacillus amyloliquefaciens BV03, B. subtilis BV02, Trichoderma asperellum BV10, Carbendazim + Thiram and distilled water (control). Seven days after seedling emergence, 2 μL of 1 x 10−4 Colletotrichum truncatum spores were inoculated on the cotyledons. Catalase (CAT), peroxidase (POX), phenylalanine ammonia lyase (PAL) and glyceollin (GLY) activities before and after pathogen inoculation, as well as the diameter of the anthracnose lesion on the cotyledons, were evaluated. Data were submitted to analysis of variance and, when significant, the mean values were compared by Fisher’s test (p < 0.05). The treatments did not influence the first sampling time before inoculation. Trichoderma asperellum BV10 increased POX and PAL activities up to 173%, while B. amyloliquefaciens BV03 increased POX activity. Glyceollin was not influenced by the treatments. The T. asperellum BV10 reduces the diameter of the anthracnose lesion by up to 61%. Thus, T. asperellum BV10 has the potential to control soybean anthracnose, improved the response defense against C. truncatum, when performed on seed treatment.