Feng-Ying Zheng, Shun-Xing Li, Lu-Xiu Lin
Department of Chemistry and Environmental Science, Zhangzhou Teachers College, Zhangzhou, Fujian 363000, PR China.
J Trace Elem Med Biol. 2007;21(2):77-83. doi: 10.1016/j.jtemb.2006.12.004. Epub 2007 Mar 6.
Since n-octanol, a long-chain alkanol, presents a configuration similar to that of carbohydrates and lipids, the lipophilicity and absorptivity of organic medicines may be assessed from their distribution coefficients between octanol and water. n-octanol is used as a model of biomembrane. This strategy has been used in order to define the species of iron in two phytomedicines and to study the distribution of iron in decoctions of phytomedicines in the stomach and the intestine. The concentrations of iron in the original herbal materials and in n-octanol- and water-soluble species were determined by flame atomic spectrometry following mixed acid digestion. The acidities of digestive and absorptive juices (saliva, gastric juice, bile and intestine), the phytomedical composition and the compatibility of phytomedicines, i.e., the combination ratio of single phytomedicines, greatly affected the iron complexing ligands and determined the species and bioavailability of iron. The concentration of octanol-soluble iron could be used for the bioavailability assessment of iron in phytomedicines. The dosage of iron in phytomedicines could be designed according to the level of the octanol-soluble iron and the reference daily intakes for iron (18 mg/d). Risk assessment could be examined through the comparison between the level of the octanol-soluble iron and the tolerable upper intake level for iron (45 mg iron/d).
由于正辛醇（一种长链烷醇）的结构与碳水化合物和脂质相似，有机药物的亲脂性和吸收性可以通过它们在正辛醇和水之间的分配系数来评估。正辛醇被用作生物膜的模型。该策略已被用于确定两种植物药中铁的种类，并研究植物药煎剂在胃和肠道中铁的分布。通过混合酸消解后，采用火焰原子光谱法测定了原始草药材料以及正辛醇溶性和水溶性物种中铁的浓度。消化液和吸收液（唾液、胃液、胆汁和肠液）的酸度、植物药的成分以及植物药的配伍，即单一植物药的组合比例，极大地影响了铁的络合配体，并决定了铁的种类和生物利用度。正辛醇溶性铁的浓度可用于评估植物药中铁的生物利用度。植物药中铁的剂量可以根据正辛醇溶性铁的水平和铁的每日参考摄入量（18毫克/天）来设计。通过比较正辛醇溶性铁的水平和铁的可耐受最高摄入量（45毫克铁/天），可以进行风险评估。
