Department of Pharmaceutical Sciences, Faculty of Science, Tshwane University of Technology, Pretoria, South Africa.
Phytomedicine. 2011 Jun 15;18(8-9):783-7. doi: 10.1016/j.phymed.2011.01.017. Epub 2011 Feb 25.
Hoodia gordonii was traditionally used by the Khoisan people as a thirst and appetite suppressant and is currently commercially available as a popular weight-loss supplement. The perceived active ingredient isolated from this plant is a steroidal glycoside named P57. This study aimed at investigating the in vitro transport of P57 across excised porcine intestinal and buccal mucosa in a Sweetana-Grass diffusion apparatus. For both the intestinal and buccal experiments, the transport of pure P57 was compared to that obtained from a crude plant extract. Bi-directional transport experiments were conducted across the intestinal tissue in two different media namely Krebs-Ringer bicarbonate buffer and simulated intestinal fluid. Apical-to-basolateral transport experiments were conducted across the buccal tissue in two different media namely Krebs-Ringer bicarbonate buffer and artificial saliva. Apparent permeability coefficient (P(app)) and flux values were calculated and analysed by means of a one-way repeated analysis of variance (ANOVA) to determine if differences were significant (p≤0.05). The transport of pure P57 across intestinal tissue was significantly higher in the secretory direction than in the absorptive direction indicating efflux by membrane transporters. Much higher intestinal transport was obtained for P57 in both directions when applied in the form of a crude extract, possibly due to inhibition of efflux as indicated by lower secretory transport compared to absorptive transport. For the buccal tissue, no transport was obtained for the pure P57, while relatively high transport was obtained when applied in the form of a crude extract. Furthermore, the intestinal transport of P57 was significantly decreased when the crude extract was prepared in simulated intestinal fluid compared to when it was prepared in buffer. On the other hand, buccal transport was higher in artificial saliva than in buffer. It is therefore evident that the transport of P57 across mucosal tissues is significantly affected on exposure to conditions simulating the in vivo situation.
霍多利亚（Hoodia gordonii）过去一直被科伊桑人（Khoisan people）用作止渴和抑制食欲的药物，目前作为一种流行的减肥补充剂在商业上可获得。从这种植物中分离出来的被认为是活性成分的是一种名为 P57 的甾体糖苷。本研究旨在使用 Sweetana-Grass 扩散装置研究 P57 在离体猪肠和口腔黏膜中的转运情况。对于肠和口腔实验，比较了纯 P57 的转运情况和从粗提植物提取物中获得的转运情况。在两种不同的介质，即 Krebs-Ringer 碳酸氢盐缓冲液和模拟肠液中，进行了跨肠组织的双向转运实验。在两种不同的介质，即 Krebs-Ringer 碳酸氢盐缓冲液和人工唾液中，进行了跨口腔组织的顶-底向转运实验。通过单向重复方差分析（ANOVA）计算和分析表观渗透系数（P(app)）和通量值，以确定差异是否显著（p≤0.05）。纯 P57 在肠组织中的转运在分泌方向上明显高于吸收方向，表明膜转运蛋白的外排。当以粗提物的形式应用时，P57 在两个方向上都获得了更高的肠内转运，这可能是由于外排抑制，与吸收转运相比，分泌转运较低。对于口腔组织，纯 P57 没有转运，而当以粗提物的形式应用时，获得了相对较高的转运。此外，当粗提取物在模拟肠液中制备时，P57 的肠内转运明显降低，而当在缓冲液中制备时则降低。另一方面，口腔转运在人工唾液中比在缓冲液中更高。因此，显然 P57 跨黏膜组织的转运在暴露于模拟体内情况的条件下会受到显著影响。
