Óleos essenciais e vegetais no controle in vitro de Colletotrichum gloeosporioides

Abstract

RESUMO:O objetivo deste trabalho foi avaliar a atividade antifúngica de óleos essenciais e vegetais no controle in vitro de Colletotrichum gloeosporioides, agente causal da antracnose em pós-colheita de frutíferas. Treze óleos essenciais foram utilizados em concentrações de 0,00%, 0,40%, 0,80%, 1,70%, 3,20%, 6,25%, 12,50%, 25,00%, 50,00% e 100,00%, e uma linhagem padrão de Colletotrichum gloeosporioides. Foram avaliadas a concentração inibitória mínima e a concentração mínima fungicida a fim de caracterizar o potencial de cada um dos óleos essenciais avaliados. Verificou-se que os óleos utilizados apresentaram atividade fungicida em diferentes concentrações, as quais variaram de 0,80% (melaleuca), 3,20%, (eucalipto), 6,25% (limão, capim limão, cravo da índia, canela e nim), 12,5% (hortelã e citronela), 25% (copaíba), 50% (coco e gengibre) e 100% (manjericão). O óleo de nim apresentou maior redução da carga microbiana em função do tempo de exposição, sendo necessários 30 minutos para anulação da contagem microbiana. O efeito antifúngico dos óleos essenciais, para controle de Colletotrichum gloeosporioides, depende da planta e da concentração empregada.Palavras-chave: antracnose, frutíferas, antifúngicos, plantas medicinais.ABSTRACT: Essential and vegetal oils in the in vitro control of Colletotrichum gloeosporioides. This study aimed to evaluate the antifungal effect of essential and vegetal oils in the in vitro control of Colletotrichum gloeosporioides, a causal agent of anthracnose in fruit postharvest. Thirteen essential oils were used at concentrations of 0.00%, 0.40%, 0.80%, 1.70%, 3.20%, 6.25%, 12.50%, 25.00%, 50.00%, and 100.00%, and also a standard strain of Colletotrichum gloeosporioides, The minimum inhibitory concentration and minimum fungicidal concentration were assessed to characterize the potential of each of the essential oils tested. We found that used oils showed fungicidal activity at different concentrations, which varied in 0.80% (Melaleuca alternifólia), 3.20%, (Eucalyptus globulus), 6.25% (Citrus limonium, Cymbopogon citratus, Syzygium aromaticum, Cinnamomum zeylanicum, and Azadirachta indica), 12.5% (Mentha piperita and Cymbopogon winterianus), 25% (Copaifera langsdorfii), 50% (Cocos nucifera and Zingiber officinale), and 100% (Ocimum basilicum). The Azadirachta indica oil showed greater reduction of microbial load because of the exposure time, and took 30 minutes for annulment of microbial count. The antifungal effect of essential oils to control Colletotrichum gloeosporioides depends on the plant and quantity of concentration. INTRODUÇÃOA principal preocupação dos agricultores na produção de frutas está relacionada com a manifestação de doenças na fase de pós-colheita, entre elas, a antracnose, que é causada pelo fungo Colletotrichum gloeosporioides Penz. (Silva et al., 2009).A antracnose é a doença de pós-colheita de maior ocorrência nas regiões tropicais e subtropicais do mundo, podendo atingir frutas como o mamão (Carica papaya L.), a manga (Mangifera indica L.), a banana (Musa spp.)...

In vitro Antifungal Activity of Plant Extracts, Hydrolates and Essential Oils of Some Medicinal Plants and Control of Cucumber Anthracnose

“…The essential oils of all species of medicinal plants evaluated, with the exception of saffron, were 100% effective at all concentrations against all fungi. Ramos et al [5], found similar results in a study where the total inhibition of the mycelial growth of C. gloeosporioides by the essential oils of C. citratus and C. citriodora was observed in the concentrations of 6.25% and 3.2%, respectively. The antifungal activity of citral, the major constituent of the essential oil of C. citratus, may cause rupture of the cell membrane integrity and extravasation of the cellular components of the microorganisms.…”

“…For the study and validation of these alternative methods, researches have been carried out in vitro to assess the potential of medicinal plants for the control of phytopathogenic fungi using essential oils and aqueous extracts [4,5]. In addition, researches in vivo have been developed in order to verify the resistanceinducing activity of such products.…”

http://www.conhecer.org.br/enciclop/2019a/agrar/uso%20de%20oleos.pdf

“…Andrade e Vieira (2016) efeito sobre a germinação de conídios, in vitro e in vivo. Ramos et al (2016) observaram que o óleo essencial de cravo da índia na concentração de 6,25% foi eficiente no controle de Colletotichum gloesporioides, ainda ressaltaram que para um efeito satisfatório é necessário empregar uma concentração adequada a cada microrganismo. Resultados similares ao encontrado por Fialhio et al 2015que determinaram o efeito fungicida do óleo essencial de canela a campo na redução da severidade de Phakopsora euvitis.…”

Control of Some Phytopathogenic Fungi Using Clove Essential Oil (Syzygium aromaticum L.)

“…A decrease in the growth rate was observed with oil concentration increased until the growth of phytopathogens was stopped when submitted to their respective MICobs (See Table 1), there was a significant difference in the negative controls that showed the highest growth According to literature, the phenolic compound Eugenol is the major constituent of clove essential oil, in addition to other chemical compounds such as β-caryophyllene, αhumulene, caryophyllene oxide and eugenyl acetate in lower concentrations [21,22,34,35]. The fungitoxicity of eugenol and other compounds has been reported in some studies [26,35,36,37]. The mechanism of action of clove essential oil is associated with its hydrophobicity, which provides interaction with the wall and lipids of the cell membrane and mitochondria, altering cellular permeability and causing disturbances in its structures.…”