外排转运体影响中药酚性物质磺酸化代谢及作用机制研究

The phenolic compounds are widely distributed in traditional Chinese medicines (TCM) and possess many pharmacological activities, such as anti-inflammatory, anti-oxidant and anti-cancer effects. However, their effective forms and mechanisms of action in vivo have remained to be uncertern. Therefore, it is necessary to elucidate the metabolism and disposition of these compounds. In our preliminary study, we have uncovered that sulfotransferase rapidly metabolize these phenolic compounds, thus limit their oral absorption, resulting in exceedingly low exposure. In addition, we have discovered that efflux transporters mediate the efflux transport of sulfates and regulate cellular sulfonation of phenolic compounds. Furthermore, sulfates of phenolic compounds could be hydrolyzed to generate aglycon, which was catalyzed by the sulfatase family of enzymes. On the basis of previous work, this project will class phenolic compounds by Biopharmaceutics Drug Disposition Classification System (BDDCS) according to the permeability of these compounds evaluated in vitro, elucidate the contribution of efflux transporter on sulfates excretion and determine the role of sulfatase in the sulfonation-transport interplay of phenolic compounds. Ultimate clarification of the key influence factors involved in phenolic compounds sulfonation will contribute to predict the disposition of these compounds in vivo exactly, and will also contribute to elucidate the effective forms and mechanisms of action of phenolic compounds in vivo.

酚性物质广泛存在于各种中药，具有抗炎、抗氧化和抗肿瘤等多种活性。然而，该类物质体内显效形式和机制尚不明确。因此，明确中药酚性物质体内代谢及处置过程极为重要。我们前期研究发现，中药酚性物质易于发生磺酸化代谢（简称“SULT代谢”），在体内主要以代谢物的形式存在、原型暴露低。外排转运体【如乳腺癌耐药蛋白（BCRP）和多药耐药相关蛋白（MRPs）】介导酚性物质SULT代谢物的胞外转运，并能显著改变该类物质的胞内代谢程度。此外，SULT代谢物在细胞内能发生水解反应生成原型药。本项目拟在前期工作基础上，测定中药酚性物质的渗透性、按生物药剂分类系统（BDDCS）进行分类，进一步明确外排转运体对SULT代谢中药酚性物质的影响，并探讨磺酸苷水解酶在外排调控代谢中的作用。明确影响SULT代谢中药酚性物质的关键因素及机制，将为准确预测该类物质体内SULT代谢、阐明其体内中药药效物质基础和作用机理提供科学依据。

代谢物外排是机体通过磺酸化代谢（SULT代谢）清除药物的关键步骤。我们前期研究发现，中药酚性物质易于发生SULT代谢，在体内主要以代谢物的形式存在、原型暴露低。外排转运体【如乳腺癌耐药蛋白（BCRP）和多药耐药相关蛋白（MRPs）】活性抑制，可显著降低代谢物外排速率、增加其胞内蓄积，说明代谢物外排具有调控中药酚性物质SULT代谢、改变药物/代谢物体内处置的作用。然而外排调控SULT代谢的作用机制尚不明确。本项目在前期工作基础上，围绕中药酚性物质SULT代谢及代谢物外排之间相互作用关系开展研究。测定了中药酚性物质的渗透性和SULT代谢特性，并按生物药剂分类系统（BDDCS）进行分类，进一步明确了外排转运体对中药酚性物质体内药动学的影响。此外，我们利用单一细胞模型（只表达SULT1A3的HEK293细胞模型）及动物模型，采用各分子生物学手段，明确了外排转运体与中药酚性物质SULT代谢的相关性，并确定了磺酸苷水解酶（arylsulfatase B, ARSB）在外排调控代谢中的关键作用。明确影响SULT代谢中药酚性物质的关键因素及机制，将为明确转运蛋白影响药动学、药效学、准确预测该类物质体内SULT代谢提供科学依据。