Chemical composition of the essential oil of Psidium guajava leaves and its toxicity against Sclerotinia sclerotiorum

Abstract

Globally, the fungus Sclerotinia sclerotiorum is considered as one of the most important phytopathogens, since it affects the production of several economically important crops. Further, it is difficult to control, thus increasing the use of pesticides. Therefore, the search for new substances, especially those extracted from plants, has received special attention to control this plant pathogen. The objective of the present study was to evaluate the yield and chemical composition of the essential oil extracted from the fresh leaves of guava collected during the rainy and dry seasons, and also to evaluate its toxicity against S. sclerotiorum. The experiment was a completely randomized design with five treatments and six replicates. The essential oil was extracted by hydrodistillation of the leaves and analyzed by gas chromatography-flame ionization detector and gas chromatography-mass spectrometry. The main compounds identified in the essential oil were trans-caryophyllene and ?-humulene. The essential oil at a concentration of 300 ?L exhibited 90% inhibition of the mycelial growth of S. sclerotiorum. This confirmed the antifungal potential of the essential oil of the guava leaves during both the sampling seasons.

Perfil químico e atividades antioxidante e antifúngica dos óleos essenciais de Raulinoreitzia crenulata (Spreng.) R. M. King & H. Rob

“…Após solidificação do meio, em câmara de fluxo laminar, 1 disco de micélio para cada cepa de S. sclerotiorum, C. gloeosporioides e C. acutatum com 9 mm de diâmetro, foi depositado no centro da placa de Petri de 9 cm de diâmetro. Em seguida, foram incubadas à temperatura de 20, 23 e 25 °C, com fotoperíodo de 12 horas, para S. sclerotiorum, C. acutatum e C. gloeosporioides respectivamente, conforme descrito por Silva et al (2018), Cunico et al (2002) e Celoto et al (2008) adaptado. A avaliação consistiu em medições diárias do diâmetro das colônias, por meio de um paquímetro digital (Digimess) com resolução de 0,01 mm/.0005'', iniciadas após 24 horas do início da incubação e encerradas, quando as colônias fúngicas, do tratamento testemunha, atingiram completamente a área interna da placa.…”

“…Inúmeras espécies fúngicas vêm se adaptando as doses aplicadas nas lavouras, levando o aparecimento de espécies resistentes, isso promove a produção ou mesmo o aumento das doses lançadas durante a cultura (Carmona & Sautua, 2017). Em especial o mofo-branco (Sclerotinia sclerotiorum), e as diversas formas de antracnose, sendo o Colletotrichum gloeosporioides e Colletotrichum acutatum exemplos de agentes fitopatogênicos que todos os anos causam exponencial perdas na agricultura e no armazenamento de grãos (soja, milho, sorgo, grão-debico), bem como durante o transporte de frutas como morango, manga, mamão, abacate e banana (Martinazzo et al, 2019;Silva et al, 2018;Bagherabadi et al, 2018;Freddo et al, 2016;Amaike & Keller, 2011 ). O trabalho teve por objetivo avaliar os óleos essenciais dos galhos, folhas e flores de Raulinoreitzia crenulata, quanto ao perfil químico e suas atividades antioxidantes na redução do radical livre DPPH e antifúngica frente à Sclerotinia sclerotiorum, Colletotrichum gloeosporioides e Colletotrichum acutatum em diferentes concentrações.…”

Effects of Solvent to Feed Ratio and Microwave Power on Extraction of Essential Oil from Red Guava Leaves (Psidium guajava l.) Using Microwave Hydro Distillation Method

“…The composition of guava leaf essential oil compound is caryophyllene, β-Selinene, and Caryophyllene Oxide with the percentage of 13.44%, 11.65%, and 2.16% [6]. Table 1…”

“…Red guava leaves has many phytochemical compounds containing flavonoids, tannins (17.4%), phenolics (575.3 mg/g) and essential oils [5]. The main components of guava leaves essential oil are ɑ-humulene, transcaryophilene, and 1,8-cineol [6]. The specific aroma arising from essential oils are the volatile compounds that easily to evaporate [7].…”

AVANÇOS METODOLÓGICOS NA DATAÇÃO POR TRAÇOS DE FISSÃO E U-Pb EM ZIRCÃO

“…The isolate of fungi was provided by the Embrapa Arroz e Feijão, whose headquarters is in Santo Antônio de Goiás, GO, Brazil. Assays were carried out in the agricultural microbiology lab at IF Goiano -Campus Rio Verde, in agreement with the methodology described bySilva et al (2018) [11]. In vitro antifungal activity of ML-EO and MF-EO was evaluated against Cladosporium cladosporioides, Colletotrichum gloeosporioides, Fusarium solani and Rhizopus stolonifer.…”