, Brazil, where nine constituents were isolated: a mixture of α-and β-amyrin, lupeol, a mixture of flavonols ramnocitrin and eupalitin, acacetin, 3-prenyl-4-hydroxycinnamic acid, 3,5-diprenyl-4-hydroxycinnamic acid the new compound, the (E)-3-[4-(3-phenylpropanoiloxy)]-3,5-diprenil-cinnamic acid. The structures of the isolated compounds were characterized by 1D-and 2D-NMR experiments, MS and IR spectrometry, and comparison with data described in the literature.Keywords: propolis; (E)-3-[4-(3-phenylpropanoiloxy)]-3,5-diprenyl-cinnamic acid; cinnamic acid derivatives. INTRODUÇÃOO termo própolis significa defesa da cidade ou da colmeia (pro "em defesa de" e polis "cidade"). 1,2 As abelhas, de fato, usam esta substância para protegê-las contra insetos e micro-organismos empregando-a em finas camadas nas paredes internas das colmeias, para vedar aberturas e rachaduras, reparar e fortalecer os favos de mel, no preparo de locais assépticos para a postura da abelha rainha e na mumificação de insetos invasores. 3 A própolis é conhecida e utilizada pelo homem desde os tempos mais remotos; os sacerdotes do antigo Egito a utilizavam frequentemente como substância medicinal e como parte integrante dos unguentos e cremes para embalsamar; persas, romanos e incas também fizeram uso da própolis para tratamento de infecções. 4 Dependendo da flora de origem e da idade, sua coloração varia do marrom escuro, passando a uma tonalidade esverdeada até o marrom avermelhado e seu odor é variável de uma amostra para outra. 1,5 Particularmente, sob a forma de extratos hidroetanólicos, a pró-polis vem se destacando tanto pelas suas propriedades terapêuticas, tais como atividades antimicrobiana, anti-inflamatória, cicatrizante, anestésica, anticancerígena e fotoprotetora, 6 quanto pela possibilidade de aplicação em indústrias farmacêutica e alimentícia, na forma de alimentos funcionais. 7,8 A própolis verde, produzida em Minas Gerais principalmente a partir de Baccharis dracunculifolia DC (Asteraceae), tem sido relatada na literatura como potencializadora da resposta imunológica, 9 como anti-inflamatória, 10,11 inibidora do crescimento tumoral 11 e hepatoprotetora. 12 Seu constituinte majoritário é o ácido 3,5-diprenil-4-hidroxicinâmico (artepilina), 11 sendo também fonte de outros derivados prenilados do ácido p-cumárico, e de grande quantidade de flavonoides, muitos dos quais não estão presentes na própolis da Europa, América do Norte e Ásia. 7 Amostras de própolis de outras regiões do Brasil também têm sido estudadas quanto a sua constituição química e à influência da sazonalidade em atividades biológicas e na composição fenólica. 13 Este trabalho focalizou uma reinvestigação fitoquímica de uma amostra de própolis verde, obtida na cidade de Passa Quatro (Minas Gerais). Do extrato etanólico foram isolados e caracterizados a mistura de α-e β-amirinas (1a e 1b), o lupeol (2), a mistura dos flavonóis ramnocitrina (3a) e eupalitina (3b), acacetina (4) e os ácidos 3-prenil-4-hidroxicinâmico (5), artepilina (6) e a nova substância caracterizada ...
Acetophenone is a component of castoreum, the exudate from the castor sacs of the mature beaver [1]. Linum usitatissimum L. (Linaceae), known as flax or linseed, is a good source of oil and meal, which is rich in fiber, protein, and fat. Its oil is arguably one of the richest source of polyunsaturated fatty acids, used in food and in the prevention of cardiovascular diseases [2,3].The use of natural catalysts offers a clean way to perform chemical process under mild reaction conditions with less or no usage of organic solvents, a high degree of selectivity due to the high chemo-, regio-and enantioselectivity of enzymes, while working under mild and environmental friendly conditions linked to the principles of green chemistry [4][5][6][7][8]. Thus, the biocatalysts can be an interesting alternative to prepare chiral alcohols and can also act as chiral auxiliaries in asymmetric synthesis of chiral molecules, and as a result the production of single enantiomers of molecules has become increasingly important in the food, cosmetic, and pharmaceutical industries, from the corresponding prochiral ketones [6,[9][10][11][12][13]. Therefore, researchers have strived to find solutions for the replacement of conventional chemical routes by application of enzymes.Reports in the literature describe the use of different plant species for biotransformation, with several advantages such as their disposal after use, their biodegrability, as well as their wide availability at low cost [6,[8][9][10][11][14][15][16][17].In particular, the potential source of enzymes from Brazilian northwestern plants and their use as biocatalysts in bioreduction reactions have been related [10,11,14,17,18]. In order to contribute to the study of vegetables as natural catalyst, this paper reports the use of whole plant cell of seeds of L. usitatissimum as a biocatalyst for the reduction reactions of aromatic ketones.The enzymatic reduction of acetophenone (1) as standard substrate prochiral ketone and derivatives 2-14 using L. usitatissimum as biocatalyst is reported. All reactions were carried out using 50 mg of substrate and 20 g of biocatalyst in a buffer solution (Na 2 HPO 4 -KH 2 PO 4 ), pH 6.0, over a period of 72 h at 25qC without a co-solvent which are the optimal reaction conditions among the tested parameters.The bioreduction pattern of acetophenone (1) by L. usitatissimum occurred with a bioconversion value of 70.4%, a very good enantioselectivity (93.7% ee), and a satisfactory yield of (S)-alcohol. The study of reduction enzymatic reaction of acetophenone 1 and other prochiral ketones derived from acetophenones 2 to 12, including D-tetralone 13 and 1-acetonaphthone 14, was performed (Scheme 1).The results showed that L. usitatissimum exhibited a broad spectrum of enantionselectivity among the acetophenones and their derivatives, with a very good enantioselectivity (>75% ee) for acetophenone (1) and its derivatives 2, 6, 8, 9, and 10 (Table 1). It was observed that the best enantiomeric excess (ee) compared with acetophenone (1) was obtaine...
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