Background: Flavonoid compounds are one kind of active ingredients isolated from a traditional Chinese herb Zizyphi spinosae semen (ZSS). Studies have shown that ZSS flavonoids have significant antioxidant effects.

Methods: In this study, the Caco-2 cell monolayer model was constructed to investigate the intestinal absorption characteristics and mechanism of Isovitexin (IV), Swertisin (ST), Isovitexin-2''-O-β-D-glucopyranoside (IVG), Spinosin (S), 6'''-p-coumaroylspinosin (6-CS) and 6'''-feruloylspinosin (6-FS).

Results: The results of the bidirectional transport assay showed that the six flavonoids have good intestinal absorption in a near-neutral and 37°C environment, and the absorbability in descending order was 6-FS>6- CS>IVG>S>IV>ST. The results of carrier inhibition experiments and transport kinetics indicated that the absorption mechanism of six flavonoids was energy-dependent monocarboxylate transporter (MCT)-mediated active transport. In particular, the para-cellular pathway also participated in the transport of IV, ST, IVG and S. Furthermore, the efflux process of six flavonoids was mediated by P-glycoprotein (P-gp) and multidrug resistance protein (MRP), which may result in a decrease of bioavailability.

Conclusion: Our findings provide significant information for revealing the relationship between the intestinal absorption mechanism of flavonoids and its structure as well as laying a basis for the research of flavonoid preparations.

背景：黄酮类化合物是从传统中草药刺槐（ZSS）中分离得到的一种活性成分。研究表明，ZSS类黄酮具有显着的抗氧化作用。

方法：本研究通过构建Caco-2细胞单层模型，研究了Isovitexin（IV）、Swertisin（ST）、Isovitexin-2''-O-β-D-吡喃葡萄糖苷（IVG）的肠道吸收特性和机制。 , 多杀菌素 (S)、6'''-p-香豆酰多糖苷 (6-CS) 和 6'''-阿魏酰多糖苷 (6-FS)。

结果：双向转运试验结果表明，6种黄酮类化合物在近中性、37℃环境下均具有良好的肠道吸收性，吸收性从高到低依次为6-FS>6-CS>IVG>S>IV>英石。载体抑制实验和转运动力学结果表明，六种黄酮类化合物的吸收机制是能量依赖性单羧酸转运蛋白（MCT）介导的主动转运。特别是，细胞旁通路还参与了 IV、ST、IVG 和 S 的转运。此外，6 种黄酮类化合物的外排过程是由 P-糖蛋白 (P-gp) 和多药耐药蛋白 (MRP) 介导的。可能导致生物利用度降低。

结论：本研究结果为揭示黄酮类化合物的肠道吸收机制与其结构之间的关系提供了重要信息，为黄酮类制剂的研究奠定了基础。