Sensitive analysis and simultaneous assessment of pharmacokinetic properties of crocin and crocetin after oral administration in rats

Crocin and crocetin in rat plasma were simultaneously analysed using ultra-performance liquid chromatography tandem mass spectroscopy (UPLC–MS/MS), and method was fully validated. For the first time, levels of both crocin and crocetin in plasma were profiled after oral administration of crocin, and this UPLC–MS/MS approach was applied to evaluate pharmacokinetics and relative bioavailability of crocin and crocetin in rats. It was shown that crocin transformed into crocetin quickly in the gastrointestinal tract, and crocetin was 56–81 fold higher exposed in rat plasma than crocin after oral administration of crocin. A comparison study revealed that an oral administration of equal molar crocin achieved higher exposure of crocetin in rat plasma than that of crocetin. It was suggested that oral administration of crocin has the advantages over crocetin, and crocetin may be the active component potentially responsible for the pharmacological effect of crocin.