Pharmacokinetics and tissue distribution of eighteen major alkaloids of Aconitum carmichaelii in rats by UHPLC-QQQ-MS.

Aconitum carmichaelii Debeaux is a widely used herbal medicine, which has anti-inflammatory and analgesic activities. However, due to its high toxicity, poisoning incidents often occur all over the world. To systematically understand the pharmacokinetics (PK) and tissue distribution of A. carmichaelii, 18 representative alkaloids, including 8 amine- (ADA), 4 monoester- (MDA) and 6 diester-type (DDA) diterpenoid alkaloids, were simultaneously quantified by ultra-high performance liquid chromatography-triple quadrupole mass spectrometry (UHPLC-QQQ-MS) with dynamic multiple reaction monitoring (MRM) mode. PK results suggested that benzoylmesaconine, mesaconitine, 10-OH-aconitine and aconitine had lower bioavailability, which might relate to the substitution at C-3. In tissue distribution, alkaloids present higher concentrations in the liver, kidney, and only songorine, neoline and benzoyldeoxyaconine were detected in the brain. Moreover, the concentrations of extremely toxic DDAs in high-dose group were much higher than that of low-dose group, indicating that these DDAs might be the main reason for the toxicity of Aconitum. The results also suggested that benzoyldeoxyaconine and deoxyaconitine should be determined for the quality control of A. carmichaelii due to their high concentrations in both herbal extract and tissues. The systematic investigation into these 18 representative alkaloids could basically illuminate the PK and distribution of A. carmichaelii in rats, and provide some information for clinical studies.