摘要
芳香族化合物在反刍动物瘤胃的厌氧微生物作用下,通过水解、还原等反应,发生生物转化和矿化。不同的芳香族和脂环族化合物具有各自的代谢特点与途径:羟基桂皮酸经微生物氢化形成的羟基-3-苯丙酸,再经O-脱甲基作用和脱羟基作用转变为3-苯基丙酸;羟基苯甲酸经脱羧和脱甲氧基作用转化为简单酚类;消化道内的微生物对环己烷羧酸转化为苯甲酸的芳香化过程不起作用,仅对奎尼酸和莽草酸转化为环已烷羧酸的过程起作用;氨基酸通过瘤胃微生物降解的可能途径主要是Stickland反应,即氨基酸通过氧化还原机理脱氨;香豆素可能不是哺乳动物体内苯甲酸的前体物质,瘤胃微生物对类黄酮降解的方式与大肠微生物不同;不同类型的单宁降解不同:水解单宁的尿代谢物一般与五倍子酸的分解产物一样,如果缩合单宁单体间稳定耦合链被断裂,那么其代谢途径可能与简单类黄酮的代谢过程类似;木质素单体很容易被生物转化,但木质素低聚体能经受一定程度的解聚作用。
Under anaerobic condition in the rumen,aromatic compounds are partial degraded(biotransformantion) and completely degraded(mineralisation) by microorganisms through recations such as hydrolysis and reduction.However,individual xenobiotic has specific metabolizing process and form:hydroxycyclohexanecarboxylic acids converted to hydroxy-3-phenylpropionic acids by microbial hydrogenation;hydroxybenzoic acids are metabolized into simple phenols through microbial decarboxylation and dehydroxylation;gut microorganisms are only responsible for the convertion of quimic acid and shikimic acid to hydroxyclohexanecarboxylic acids(CHCA)but not for the aromatisation of CHCA to benzoin acid;pairs of aromatic amino acids are deaminated by mechanisms of oxidation and reduction by Stickland reactions;coumarins and flavonoids seems not to be precursors of benzoic acid in mammals;for two groups of tannins,one differs from another in metabolizing,hydrolysable tannins give rise to the same urinary metabolites as those from gallic acid while condensed tannins follow similar pathways as flavonoids when the very stable linkages between monomers were cleaved;lignin-related monomers can be readily biotransformed and in some circumstances mineralized while lignin polymers can suffer to a certain extent depolymerisation.
出处
《动物营养学报》
CAS
CSCD
2004年第3期13-19,共7页
CHINESE JOURNAL OF ANIMAL NUTRITION
基金
中国科学院"百人计划"
高等学校优秀青年教师教学科研奖励计划资助(TRAPOYT)。
