The AAPS Journal

, Volume 18, Issue 5, pp 1273–1288 | Cite as

Metabolic Profile of 3-Acetyl-11-Keto-β-Boswellic Acid and 11-Keto-β-Boswellic Acid in Human Preparations In Vitro, Species Differences, and Bioactivity Variation

  • Yonglei Cui
  • Xiangge Tian
  • Jing Ning
  • Chao WangEmail author
  • Zhenlong Yu
  • Yan Wang
  • Xiaokui Huo
  • Lingling Jin
  • Sa Deng
  • Baojing Zhang
  • Xiaochi MaEmail author
Research Article


3-Acetyl-11-keto-β-boswellic acid (AKBA) and 11-keto-β-boswellic acid (KBA) are widely used in the clinic as anti-inflammatory drugs. However, these drugs have the poor bioavailability, which may be caused by their extensive metabolism. In this study, we systemically characterized both phase I and II metabolism of AKBA and KBA in vitro. In total, four major metabolites were firstly biosynthesized and identified using 1D and 2D NMR spectroscopy. Among them, three metabolites were novel. The kinetic parameters (K m , V max , CL int, and K i ) were also analyzed systematically in various biological samples. Finally, the deacetylation of AKBA and hydroxylation of KBA were confirmed to be the major metabolic pathways based on their large CL int and the high amounts of KBA (46.7%) and hydroxylated KBA (50.8%) along with a low amount of AKBA (2.50%) in human primary hepatocytes. Carboxylesterase 2 (CE2) selectively catalyzed the deacetylation of AKBA to form KBA. Although CYP3A4, CYP3A5, and CYP3A7 catalyzed the metabolism of KBA, CYP3A4 played a predominant role in the hydroxylation reaction of KBA in human. Notably, deacetylation and regioselective hydroxylation exhibited considerable species differences. Deacetylation was only observed in human liver microsomes and primary human hepatocytes; 21- and 20-mono-hydroxylation of KBA were primarily observed in human, monkey, and dog; and 16- and 30-mono-hydroxylation were observed in other species. More importantly, all four mono-hydroxylation metabolites exhibited a moderate anti-inflammatory activity. The 21- and 20-hydroxylation metabolites inhibited the expression of iNOS, the LPS-induced activation of IkBα and p65 phosphorylation, and suppressed p65 nuclear translocation in RAW264.7 cells.


acetyl-11-keto-β-boswellic acid anti-inflammatory CYP3A4 metabolism profiles species difference 



3-Acetyl-11-keto-β-boswellic acid


11-Keto-β-boswellic acid


Human liver microsomes


Human intestine microsomes


Monkey liver microsomes


SD rat liver microsomes






Human serum albumin


Rat serum albumin


Pig liver microsomes


Dog liver microsomes


Mouse liver microsomes


Rabbit liver microsomes


Guinea pig liver microsomes




β-Nicotinamide adenine dinucleotide phosphate disodium salt


21β-Hydroxy-11-keto-β-boswellic acid


16β-Hydroxy-11-keto-β-boswellic acid


30-Hydroxy-11-keto-β-boswellic acid


20β-Hydroxy-11-keto-β-boswellic acid


Huperzine A




Bis-p-nitrophenyl phosphate









This study was supported by the National Natural Science Foundation of China (Nos. 81274047, 81473334, and 81503201), the Distinguished Professor of Liaoning Province, Dalian Outstanding Youth Science and Technology Talent program (2014J11JH132 and 2015J12JH201), and the Liaoning Bai Qian Wan Talent Program and Innovation Team of Dalian Medical University.

Author Contributions

Xiaochi Ma, Yonglei Cui, and Xiangge Tian designed the experiments. Yonglei Cui and Jing Ning performed the experiments. Chao Wang, Zhenlong Yu, and Yan Wang analyzed the data. Xiaokui Huo, Lingling Jin, Sa Deng, and Baojing Zhang prepared the figures. Yonglei Cui and Xiangge Tian wrote the main text. All authors reviewed the manuscript.

Compliance with Ethical Standards

Conflict of Interest

The authors declare that they have no conflict of interest.

Supplementary material

12248_2016_9945_MOESM1_ESM.docx (1.4 mb)
ESM 1 (DOCX 1430 kb)


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Copyright information

© American Association of Pharmaceutical Scientists 2016

Authors and Affiliations

  • Yonglei Cui
    • 1
  • Xiangge Tian
    • 2
  • Jing Ning
    • 1
  • Chao Wang
    • 1
    Email author
  • Zhenlong Yu
    • 1
  • Yan Wang
    • 1
  • Xiaokui Huo
    • 1
  • Lingling Jin
    • 1
  • Sa Deng
    • 1
  • Baojing Zhang
    • 1
  • Xiaochi Ma
    • 1
    Email author
  1. 1.College of Pharmacy, Academy of Integrative MedicineDalian Medical UniversityDalianChina
  2. 2.College of Basic Medical ScienceDalian Medical UniversityDalianChina

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