藏、蒙、维等民族用药中常富含鞣质，如民族药复方中出现频率最高的诃子含有大量可水解鞣质，特色民族药材文冠木和锁阳则含有大量缩合鞣质(分别为黄烷醇以A-和B-型连接的聚合物)。随着其复杂结构的解明，鞣质类的药效也日益受到重视。近年美国FDA通过的两个植物组分药均为小分子鞣质(绿茶的儿茶素组分Veregen和秘鲁巴豆的黄烷醇低聚体Fulyzaq)。前期研究显示锁阳鞣质易被半胱氨酸降解，生成的小分子黄烷-半胱氨酸加成物对α-葡萄糖苷酶的抑制活性更强；文冠木粉末给药后，不能被溶剂提取的大分子鞣质在体内降解为活性小分子。然而，鞣质的体内转化物尚有大量结构和活性没有解明。本课题拟以文冠木及锁阳为例，按民族用药习惯粉末给药后，研究血清中鞣质的代谢及与其他物质结合后的生物活性产物（代谢活性化产物）。确定这些代谢活性化产物的化学结构和生物活性，为展现民族医药科学精髓和基于民族药的新药发现提供科学数据。

Tibetan, Mongolian, and Uygur medicinal systems frequently use tannin-rich medicinal herbs, such as the fruits of Terminalia chebula Retz, which is the most frequently used herbal drug in ethnic medicinal prescription and contains high amounts of hydrolyzable tannins. Other common ethnomedicinal and food materials, such as the woods of Xanthoceras sorbifolia Bunge and the stems of Cynomorium songaricum Rupr, harbor many condensed tannins with A- and B-type flavanol linkages, respectively. With their complex structures being solved gradually, the therapeutic effects of tannins are attracting more attention. For example, 2 small molecular tannins have been approved by the FDA as botanical drugs in recent years: Veregen (green tea catechins) and Fulyzaq (the oligomeric proanthocyanidin from Croton lechleri). Previous studies have shown that Cynomorium tannins are degraded easily by cysteine to form small molecular flavanol-cysteine conjugates that have increased inhibition against α-glucosidase. After administration of the wood powder of Xanthoceras sorbifolia, the large molecular tannins that were nonextractable by solvents were degraded into bioactive small molecules in vivo. However, the structures and bioactivities of many other compounds that are produced through biotransformation or conjugation with other molecules (bio-activation products) in vivo are unknown. This project intends to investigate the structures and bioactivities of the tannin bio-activation products in serum, after X. sorbifolia wood and C. songaricum stems have been administered in their traditional powder forms. This research will increase our understanding of ethnomedicines and guide the discovery of new drugs that are based on natural medicines.