Li Wenlan, Nan Lili, Ji Yubin, Sun Xiangming, Sun Zhi
Engineering Research Center of Natural Anticancer Drugs, Ministry of Education, Harbin University of Commerce, Harbin, China.
Zhongguo Zhong Yao Za Zhi. 2009 Oct;34(20):2627-32.
To investigate the absorption of gnsenoside Rg1 and Rb1 in Radix Gngseng at different intestine segments of rats and the influence of the drug solution concentration, pH, P-gp inhibitor.
The intestine cannulation was performed for in situ recirculation. Gnsenoside Rg1, Rb1 and phenol red concentration in the flux were separately measured by the reversed phase HPLC and UV.
When the concentration was raised from 0.075-0.75 g L(-1) and 0.03-0.3 g L(-1), the uptake of ginsenoside Rg1 and Rb1 was separately linearly increased (r >0.999), and no changes of K(a) absorption fraction and t(1/2) are found. The pH of flux has no effect on drug absorption. Ginsenoside Rg1 can be absorbed in the whole intestine and no changes of K(a), absorption fraction and t(1/2) refound and all the parameters of ginsenoside Rb1 at jejunum are higher than that at ileum and duodenum (P <0. 5). Further more, P-gp inhibitor verapamil has obvious effect on the intestinal absorption of ginsenoside Rb1 (P <0.5) while it has no effect on ginsenoside Rg1.
The absorption of ginsenoside Rg1 and Rb1 in intestine of rat are first-order kinetics, the absorption mechanism is infered the passive diffusion. Ginsenoside Rg1 has no specific absorption locus in intestine of rat and ginsenoside Rb1 has specific absorption locus of jejunum. Meanwhile, ginsenoside Rb1 is the P-gp substrate, and could increase its fraction of bioavailability by corporation with P-gp inhibitor.
研究大鼠不同肠段对人参中人参皂苷Rg1和Rb1的吸收以及药液浓度、pH值、P-糖蛋白抑制剂的影响。
采用肠插管法进行原位循环。通过反相高效液相色谱法和紫外分光光度法分别测定流出液中人参皂苷Rg1、Rb1和酚红的浓度。
当浓度从0.075 - 0.75 g·L⁻¹和0.03 - 0.3 g·L⁻¹升高时，人参皂苷Rg1和Rb1的摄取量分别呈线性增加（r >0.999），且吸收速率常数（Ka）、吸收分数和半衰期（t₁/₂）无变化。流出液的pH值对药物吸收无影响。人参皂苷Rg1可在整个肠道吸收，且Ka、吸收分数和t₁/₂无变化，人参皂苷Rb1在空肠的所有参数均高于回肠和十二指肠（P <0.05）。此外，P-糖蛋白抑制剂维拉帕米对人参皂苷Rb1的肠道吸收有明显影响（P <0.05），而对人参皂苷Rg1无影响。
大鼠肠道对人参皂苷Rg1和Rb1的吸收符合一级动力学，吸收机制推测为被动扩散。人参皂苷Rg1在大鼠肠道无特定吸收部位，人参皂苷Rb1有特定的空肠吸收部位。同时，人参皂苷Rb1是P-糖蛋白底物，与P-糖蛋白抑制剂合用可提高其生物利用度。
