A systematic review of pharmacokinetic studies on herbal drug Fuzi: Implications for Fuzi as personalized medicine

Background: Fuzi, which is the processed lateral roots of Aconitum carmichaeli Debx. (Ranunculaceae), is a traditional herbal medicine that is well known for its excellent pharmacological effects and acute toxicity. Aconitum alkaloids are responsible for its pharmacological activity and toxicity. Although a large number of studies on Fuzi have been reported, no comprehensive review on its pharmacokinetics has yet been published.

Purpose: This paper seeks to present a comprehensive review regarding the phytochemistry, pharmacokinetic features and toxicity of Fuzi. The regulation of drug-metabolizing enzymes (DMEs) and efflux transporters (ETs) by Fuzi is also concluded. Additionally, the use of Fuzi as a personalized medicine based on the bioavailability barrier (BB), which mainly comprises DMEs and ETs, is discussed.

Methods: All available information on Fuzi was collected by searching for key words in PubMed, ScienceDirect, CNKI, Google Scholar, Baidu Scholar, and Web of Science.

Results: Aconitum alkaloids, which mainly include diester-diterpene alkaloids (DDAs), monoester-diterpene alkaloids (MDAs) and unesterified-diterpene alkaloids (UDAs), could be detected after Fuzi ingestion in vivo. The Aconitum alkaloids are rapidly absorbed in the intestine and extensively distributed in the body. DMEs, especially CYP3A4/5, are responsible for various types of metabolic reactions of the Aconitum alkaloids. ETs, including P-glycoprotein (P-gp), multidrug resistance-associated protein 2 (MRP2), and breast cancer resistance protein (BCRP), are involved in the efflux of the DDAs and MDAs. The kidney is the most important organ involved in the excretion of the Aconitum alkaloids. DDAs are the main toxic compounds present in Fuzi, and their acute toxicity is mainly due to their effects on the voltage-dependent sodium channels. Furthermore, Fuzi can substantially regulate DMEs and ETs.

Conclusions: The toxicity of DDAs is acute. However, further investigations are necessary to determine the exact toxicological mechanisms. The significant impact of Fuzi on DMEs and ETs suggests that the co-administration of Fuzi with drugs that are substrates of DMEs and/or ETs may cause herb-drug interactions (HDIs). The BB network controlled exposure to the Aconitum alkaloids in vivo. Polymorphisms of DMEs and ETs in different individuals contribute to the differences in the efficacy and toxicity of Fuzi ingestion. In the future, the use of Fuzi as personalized medicine based on the BB network is necessary and practical to achieve ideal therapeutic efficacy with minimal toxicity.