| Firstly, the present study characterized the antioxidative components in hawthorn fruits, and found that hawthorn fruits are an excellent source of antioxidants. Eleven compounds were isolated from the fruits of a Chinese hawthorn (Crataegus pinnatifida Bge. var. major N.E. Br.). Among them, eucomic acid 4-methyl ester, a new compound, was elucidated by various spectral methods and by X-ray crystallography. Others were identified as (−)-epicatechin (EC), procyanidin B2 (PC-B2), hyperoside (HP), isoquercitrin (IQ), quercetin, rutin, chlorogenic acid (ChA), protocatechuic acid, eucomic acid and ursolic acid.; Secondly, the storage stability of the five major active phenolics (EC, PC-B2, HP, IQ and ChA) in hawthorn fruits and a hawthorn drink were investigated at three temperatures (4, 23, 40°C). The results indicated that all studied phenolics were stable during the 6 months storage period at 4°C but very unstable at 40°C in both the fruits and the drink. EC and PC-B2 degraded almost completely after 6 months storage at 40°C. Low-temperature storage is recommended for maintaining the quality of hawthorn and hawthorn preparations.; Thirdly, the pharmacokinetics of the four major active phenolics (EC, ChA, HP and IQ) were studied in rat after intravenous administration of a hawthorn phenolic extract (220 mg/kg containing 34.8, 7.5, 6.0 and 4.5 mg of EC, ChA, HP and IQ, respectively).; Finally, oral absorption and elimination of the four phenolics were investigated in rats by giving the same doses and same dosage forms as by intravenous route. The results demonstrated that EC and IQ could be absorbed in unchanged form with bioavailabilities of 34.23 and 61.00% (calculated by given in the pure form) respectively, while ChA and HP could not. The results also greatly suggest that absorption of flavonoid glycosides (such as IQ) might depend on the type of sugar moiety attached to the aglycone. In addition, from the bioavailability point of view, the present study also suggests that EC and IQ can serve as bioavailable marker compounds for the quality control of hawthorn herbs and their various preparations. (Abstract shortened by UMI.)... |
