Division of Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan.
Planta Med. 2011 Jul;77(11):1110-5. doi: 10.1055/s-0030-1270749. Epub 2011 Feb 3.
Different types of ellagitannins are reported to have various biological activities, such as antioxidant, antiviral, and antitumor activities. However, there are few definitive studies on the absorption and metabolism of ellagitannins. This review compares the absorption and metabolism of ellagitannins, and the antioxidant properties of their metabolites in rats, with those of intact ellagitannins by means of IN VITRO and IN VIVO assays. We isolated 7 urinary and intestinal microbial metabolites in rats after the ingestion of geraniin, which is a typical ellagitannin isolated from GERANIUM THUNBERGII, an antidiarrheic remedy in Japan. The structures of these metabolites were determined to be dibenzopyran derivatives ( 1- 7), using NMR and mass spectroscopic data. Four major metabolites ( 1- 4) prepared by chemical synthesis were evaluated for their antioxidant activities by using 2,2-diphenyl-1-picrylhydrazyl radical scavenging and oxygen radical absorbance capacity (ORAC) methods. The metabolites exhibited more potent antioxidant activities in the ORAC assay than intact ellagitannins, such as geraniin and corilagin. Furthermore, plasma ORAC scores increased with increases in the plasma concentration of the metabolites after the oral administration of geraniin to rats. These findings suggest that these metabolites may contribute to the health benefits of ellagitannins as antioxidants in the body.
不同类型的鞣花单宁据称具有多种生物活性，如抗氧化、抗病毒和抗肿瘤活性。然而，关于鞣花单宁的吸收和代谢的明确研究很少。本综述通过体外和体内试验比较了鞣花单宁及其代谢物在大鼠体内的吸收和代谢，以及抗氧化特性，与完整鞣花单宁进行了比较。我们从日本一种抗腹泻药物天竺葵中分离出的典型鞣花单宁棓儿茶素，在大鼠摄入后分离出 7 种尿和肠道微生物代谢物。这些代谢物的结构通过 NMR 和质谱数据确定为二苯并吡喃衍生物（1-7）。通过化学合成制备的 4 种主要代谢物（1-4）通过 2,2-二苯基-1-苦基肼自由基清除和氧自由基吸收能力（ORAC）方法评估其抗氧化活性。与完整的鞣花单宁，如棓儿茶素和柯里拉京相比，这些代谢物在 ORAC 试验中表现出更强的抗氧化活性。此外，在大鼠口服棓儿茶素后，随着代谢物在血浆中的浓度增加，血浆 ORAC 评分也随之增加。这些发现表明，这些代谢物可能有助于鞣花单宁作为体内抗氧化剂的健康益处。
