The active constituents of Rhodola rosea extract SHR-S of the popular plant adaptogen Rhodiola. rosea are tyrosol, rhodioloside and rosavin. Validated capillary electrophoretic methods for the determination of these components in the blood was developed and used for a pharmacokinetic study in rats and human (n=16) volunteers. Rhodioloside was found to be quickly and completely absorbed into the blood of rats (bioauailability-75-90Eo), distributed within org&ns and tissues, and rapidly metabolised to tyrosol
following oral administration of SHR-5 at doses of 20 and 50 mg /hg. Many of the measured pharmacokinetic parameters of rhodioloside were significantly different when the pure compound was administered rather
than the extract. The basal leuel of tyrosol in blood plasma of rats increased following administration of SHR-S as a result both of absorption of free tyrosol present in the extract and of biotransformation of rhodioloside into
tyrosol, which occurred within the first 2 h. The pharmacohinetics and the rate of biotransformation of rhodioloside were essentially the same following single or multiple regimes of administration of SHR-S. Rosauin has low bioavailability (20-267oa) nd was quickly eliminated from the blood of rats that haue been administered SHR-5. The results of the study in humans showed that 16 healthy volunteers, after oral administration of two tablets of Rosenroot, reached a maximum concentration of rhodioloside and rosavin in blood plasma after 2 h, where the absorption rate constant was equal in both components. Although, in contrast to rhodioloside, rosavin was not detected in blood plasma at 0.5 h and t h after oral administration of two tablets of Rosenroot. The maximum concentration and elimination half-life of rhodioloside was 2-3 x higher than in rosavin. The AUC, -C *,and AUC-, values of rhodioloside were 3.5, 2.2 and 3.I-fold higher than in rosavin. Thus, the elimination of rhodioloside from the blood was 1.8 fold longer than the elimination time of rosavin.
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