School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing, 102488, China.
J Ethnopharmacol. 2021 Apr 24;270:113785. doi: 10.1016/j.jep.2021.113785. Epub 2021 Jan 7.
The Scutellariae Radix (SR) and Coptidis Rhizoma (CR) herb couple is widely used in traditional Chinese medicine prescriptions for the treatment of diabetes mellitus due to its interaction and synergistic effect compared to either herb alone, but the underlying mechanism of interaction between these herbs is unclear. This study aimed to investigate the effects of CR on the metabolism and absorption of SR.
After rats were treated with normal saline (NS group) or the CR extract (CR-treated group) for seven consecutive days, the intestinal flora was extracted from rat faeces for a co-incubation with the SR extract to investigate the metabolism of SR flavonoids, and a non-everted gut sac was prepared in vitro to evaluate the intestinal absorption of the SR extract. The components of the SR extract, the metabolites of the SR extract that was co-incubated with intestinal flora, and the dialysate acquired from non-everted gut sacs were identified and determined by an HPLC-MS/MS method. The absorption rate constant (K) and the apparent permeability (P) of each compound were calculated, and the effects of CR on the metabolism and absorption of flavonoids in SR were evaluated, by comparison the K and P between two groups using Student's t-test.
Twenty-nine flavonoids were detected and identified in the SR extract, including 16 glycosides and 13 aglycones. In the co-incubation with the intestinal flora, differences in metabolite classes were not observed between the NS group and CR-treated group; however, the metabolic rates of 17 flavonoids in the CR-treated group were significantly higher than the NS group. The P of 11 compounds (4 glycosides and 7 aglycones) across the gut sac were greater than 2 × 10 cm/s in both groups, while the P values of 7 compounds including wogonoside (WG) and other aglycones were significantly decreased in the CR-treated group.
Based on these results, CR decreased the metabolism and absorption of SR flavonoids, and exerted much greater inhibitory effects on aglycones than glycosides, which may be one of the potential mechanisms underlying the therapeutic effects of the combination of SR and CR on diabetes mellitus.
黄芩（SR）和黄连（CR）草药组合在传统中药方剂中被广泛用于治疗糖尿病，因为与单独使用任何一种草药相比，它们具有相互作用和协同作用，但这些草药相互作用的潜在机制尚不清楚。本研究旨在探讨 CR 对 SR 代谢和吸收的影响。
大鼠连续 7 天用生理盐水（NS 组）或 CR 提取物（CR 处理组）处理后，从大鼠粪便中提取肠道菌群，与 SR 提取物共孵育，以研究 SR 类黄酮的代谢，并且在体外制备非翻转肠囊，以评估 SR 提取物的肠吸收。采用 HPLC-MS/MS 法鉴定和测定 SR 提取物的成分、与肠道菌群共孵育的 SR 提取物的代谢产物和非翻转肠囊的透析液。通过学生 t 检验比较两组之间的吸收速率常数（K）和表观渗透系数（P），评估 CR 对 SR 中类黄酮代谢和吸收的影响。
在 SR 提取物中检测并鉴定了 29 种类黄酮，包括 16 种糖苷和 13 种苷元。在与肠道菌群共孵育时，NS 组和 CR 处理组之间未观察到代谢产物类别的差异；然而，CR 处理组中 17 种类黄酮的代谢率明显高于 NS 组。两组中 11 种化合物（4 种糖苷和 7 种苷元）的 P 值均大于 2×10cm/s，而在 CR 处理组中，7 种化合物（包括黄芩苷和其他苷元）的 P 值显著降低。
基于这些结果，CR 降低了 SR 类黄酮的代谢和吸收，对苷元的抑制作用比对糖苷更强，这可能是 SR 和 CR 组合治疗糖尿病的潜在机制之一。
