Isolamento de fungos da própolis, síntese e biotransformação de clovanos com fungos e avaliação da atividade biológica 

• Ano de defesa: 2012
• Autor(a) principal: Giovanni Gontijo de Souza
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: Biotransformação; Atividade biológica; Clovanos; Fungos; Propólis; Própole; Química orgânica; Química; Biotransformação (Metabolismo)
• Link de acesso: http://hdl.handle.net/1843/SFSA-8UTVH2

In this work it has been isolated 22 strains of fungi exposed to ultravioletradiation using propolis as substrate. In the process of fungal identification it was possible to achieve genera and species for 12 strains. The isolated fungi were evaluated according to their viability for use in biotransformation reactions. Compounds with a clovane backbone were synthesized starting from caryophyllene oxide. Among them, 2B -methoxyclovan-9A-ol was used as the substrate for bioransformation reactions which employ UV radiation exposed fungi Pestalotiopsis palustris and Penicillium citrinum, and also the soil fungi Penicillium janczewskii and Penicillium minioluteum. Hydroxylation anddemethylation products have been obtained as well as products resulted from the rearrangement of the carbon backbone. The higher yields were obtained for P. minioluteum, therefore, deeper studies concerning the metabolism of clovane derivatives 2B-propoxyclovan-9Aol, 2B-penthoxyclovan-9A-ol and 2B -(2-(4- nitrophenoxy)ethoxy)clovan-9A-ol obtained from these fungi have been performed. It was noted that the increasing of the side chain size bounded to the clovane backbone influences the interaction between the microorganismenzymes and this class of substrates, since only 2B -propoxyclovan-9A-ol was biotransformed by P. minioluteum. It was observed from an assay that the acetylation at C-9 of 2B-methoxyclovan-9A-ol does not allow thebiotransformation of this compound by the fungus. The chemoenzymaticsynthesis of rumphellclovane A by the action of P. minioluteum over(1S,2S,5S,8R)-8,9-Seco-8-hydroxy-2-methoxyclovan-9-lactone, synthesized from the oxidation of 2B -methoxyclovan-9A-ol, has also been accomplished in this work. The compounds 2 -methoxyclovan-9A-ol, 2B -ethoxyclovan-9A-ol, 2B-propoxyclovan-9A-ol, 2B -buthoxyclovan-9A-ol, 2B -penthoxyclovan-9A-ol, (2S,9R)-2-methoxyclovano-9,15-diol, clovan-2 -9A-diol, clovan-2B -9A -diol and rumphellclovane A were evaluated in bioassays for protein kinase C (PKC) activation. The first five compounds have also been evaluated as fungistatic agents against the phytopathogen Botrytis cinerea and as agents for germination and growth of Lactuca sativa