Comparison of the pharmacokinetics of hawthorn phenolics in extract versus individual pure compound

The pharmacokinetics of an active herbal substance may be different when administered in an extract form as compared to that when administered as a pure compound. This study investigated the pharmacokinetics of 4 active compounds of hawthorn fruits--namely, (-)-epicatechin, chlorogenic acid, hyperoside, and isoquercitrin--following administration of an extract formulation (as hawthorn phenolic extract, which contained the active compounds) or equivalent doses of individual pure compound in male Sprague-Dawley rats (n = 5 per group). The hawthorn phenolic extract or pure compounds were administered both orally and intravenously. Following administration, multiple plasma samples were obtained, and the plasma concentrations were determined by high-performance liquid chromatography. After the intravenous injection of hawthorn phenolic extract, higher plasma drug concentration, larger area under the plasma concentration-time curve from 0 to infinity, longer terminal elimination half-life, smaller apparent volume of distribution, lower total body clearance, and higher urinary excretion of each compound were obtained when compared to that after the pure compound. Following the oral administration of either hawthorn phenolic extract or pure compound, only epicatechin was absorbed, and their pharmacokinetics were generally not significantly different between these 2 formulations. The differences in the pharmacokinetics of the 2 formulations following intravenous but not oral administration may be attributable to the existence of other co-occurring components in the hawthorn phonolic extract (which may be present in the body after intravenous but not oral administration). The results showed that an herbal extract formulation, when administered intravenously, could potentially alter the pharmacokinetics of its active ingredients.