Development and application of an UHPLC-MS method for comparative pharmacokinetic study of phenolic components from dragon's blood in rats under simulated microgravity environment

Dragon's blood is a commonly used Chinese herbal medicine shown to have protective effects in simulated microgravity in rats and mice. The current study aimed to develop an ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS) method for simultaneous determination of four phenolic components from the herb: loureirin A, loureirin C, 7,4'-dihydroxyflavone and pterostilbene in rats, and use the method for comparative study on the pharmacokinetics (PK) and excretion of these components in rats after oral dosage of dragon's blood under simulated microgravity environments. The results showed the developed UHPLC-MS method was sensitive and rapid. The comparative pharmacokinetic study in rats showed loureirin A, loureirin C and 7,4-dihydroxyflavone had decreased C_max and AUC and increased V_d and CL in simulated microgravity environment; but pterostilbene had the opposite changes. The four phenolic components also showed increased or decreased excretions in simulated microgravity rats. These results indicate the chemical structure and physicochemical property, as well as physiological conditions may have an impact on the absorption and excretion of phenolic components in simulated microgravity environment. It also implies that different drug may behave differently in the same spaceflight condition leading to an increase or a reduction in pharmacodynamic outcomes.