ESTUDO FITOQUÍMICO, ALELOPÁTICO E ANTIMICROBIANO DE Acacia longifolia Andr. (Willd.)

Acacia longifolia Andr.( Willd.), e uma especie nativa da Australia, utilizada como ornamento e fixadora de dunas. Por meio de CLAE semi-preparativa realizada com a gracao de acetato de etila das flores foi isolada uma aurona. Esta foi identificada por metodos espectroscopicos de UV e RMN de 1H e 13C, como aureusidina-4-O-galactosideo. Para diferenciar este composto de aureusidina-4- O- glucosideo, foi realizada uma hidrolise, seguida de CCD comamostras autenticas dos acucares. O estudo da atividade alelopatica demonstrou que a fracao cloroformio das flores apresentou elevada inibicao sobre a germinacao das sementes e o crescimento da radicula e do hipocotilo de Lactuca sativa. O estudo da atividade antimicrobiana revelou que o extrato bruto etanolico, a fracao de acetato de etila, e o extrato hidroalcoolico remanescente das folhas, nas concentracoes de 1000 mg apresentaram acao antibacteriana sobre o crescimento de Saphylococcus aureus. A fracao acetato de etila das flores na concentracao de 1000 ppm demonstrou moderada inibicao sobre o crescimento micelial de Fusarium oxysporum e um efeito menos pronunciado sobre Cylindrocladium spathulatum. PHYTOCHEMISTRY, ALLELOPATHIC AND ANTI-MICROBIAL STUDY OF Acacia longifolia Andr. (Willd.) Abstract Acacia longifolia (Andr.) Willd., is native from Australia usually used for garden decoration or to fix sand hills. Through semi-preparative HPLC applied to ethyl acetate fraction obtained froman ethanolic extract of its flowers is was isolated an aurone which was identified as auteusidin-4-galactoside, using UV, 1H and 13C NMR. To distinguish this compound fromcernuoside (aureusidin-4-glucoside) a hydrolysis followed by TLC with authentic samples of sugars was performed. It was also found an allelopathic activity of the choroform fraction obtained from the same ethanolic extract of flowers. The effect found was a high inhibition of the germination of the seeds and of the radicle and hypocotyl growing of Lactuca sativa. In other study it was found anti microbial activity against Saphylococcus aureus. The activity was found with 1000 mg of the ethanolic extract from leaves, its ethyl acetate fraction and the hydro-ethanolic ending fraction. Studying fungi toxic activity against Fusarium oxysporum and Cylindrocladium spathulatum it was found moderate inhibitor activity of the mycelia growing of the first and lower activity against the second.