Biotransformation of Benzaldehyde-Type and Acetophenone-Type Derivatives by Pharbitis nil Hairy Roots
作者:Hideki Kanho、Sayaka Yaoya、Nobuo Kawahara、Takahisa Nakane、Yoichi Takase、Kazuo Masuda、Masanori Kuroyanagi
DOI:10.1248/cpb.53.361
日期:——
The glucosylation of some coumarin and flavone derivatives on incubation with the hairy roots of morning glory (Pharbitis nil) was previously reported. We further studied the biotransformation of benzaldehyde- and acetophenone-type derivatives. Vanillin and isovanillin were reduced to alcoholic derivatives and glucosylated at the phenolic and the alcoholic hydroxyl groups. In the case of 3,4-dihydroxybenzaldehyde, the formyl group was reduced and the 3-hydroxyl or 4-hydroxyl groups were glucosylated to give monoglucosides. The 3-hydroxyl group was predominantly glucosylated to the 4-hydroxyl group. 4-β-D-Glucopyranosyloxy-3-methoxybenzylalcohol was obtained in low yield. In time-course experiments with vanillin, it was found that the high-level reduction of the formyl group and glucosylation of the phenolic hydroxyl group occurred, and finally 4-O-β-D-glucopyranosylvanillylalcohol was obtained as the main product. In the case of 3,4-dimethoxybenzaldehyde, 3,4,5-trimethoxybenzaldehyde, and salicylaldehyde, the formyl groups were reduced, and then the hydroxyl groups at the benyl position were glucosylated to give alcoholic glucosides in relatively high yields. In 4-hydroxy-3-methoxyacetophenone, the 4-hydroxyl group was glucosylated and two dimerized glucosides, biphenyl and biphenylether types, were obtained in low yields. In acetophenone, 1-β-D-glucopyranosyloxy-1-phenylethane and 2-β-D-glucopyranosyloxyacetophenone were obtained. As mentioned above P. nil hairy roots showed various biotransformative activities including glucosylation of phenolic and benzylic hydroxyl groups, reduction of the formyl group near the benzene ring, and phenol oxidation dimerization. The glucosylation reaction was especially interesting for the production of valuable glucosides.
之前已有研究报告显示,某些香豆素和黄酮衍生物在与牵牛花毛根(Pharbitis nil)孵育时发生了葡萄糖化反应。我们进一步研究了苯甲醛和乙酰苯酮类衍生物的生物转化。香草醛和异香草醛被还原为醇类衍生物,并分别在酚羟基和醇羟基上发生了葡萄糖化。在3,4-二羟基苯甲醛的情况下,甲醛基被还原,而3-羟基或4-羟基则被葡萄糖化,从而生成单糖苷。3-羟基主要葡萄糖化为4-羟基。4-β-D-葡萄糖吡喃酯氧基-3-甲氧基苄醇的产率较低。在与香草醛的时间过程实验中,发现甲醛基的高水平还原和酚羟基的葡萄糖化同时发生,最终获得了4-O-β-D-葡萄糖吡喃醇香草醇作为主要产物。在3,4-二甲氧基苯甲醛、3,4,5-三甲氧基苯甲醛和水杨醛的情况下,甲醛基被还原后,苄位的羟基被葡萄糖化,生成的醇类葡萄糖苷的产率相对较高。在4-羟基-3-甲氧基乙酰苯酮中,4-羟基被葡萄糖化,并生成了两种二聚葡萄糖苷,即联苯和联苯醚类,产率较低。在乙酰苯酮中,得到1-β-D-葡萄糖吡喃酯氧基-1-苯乙烯和2-β-D-葡萄糖吡喃酯氧基乙酰苯酮。如上所述,P. nil毛根显示了多种生物转化活性,包括酚羟基和苄羟基的葡萄糖化、苯环附近甲醛基的还原以及酚氧化二聚化。葡萄糖化反应尤其值得关注,因为它能够产生有价值的葡萄糖苷。