An alkaloid-rich phytopharmaceutical prepared from Qing Dai against IL-17A-induced psoriasis

Chia Lin Lee*, Chien Ming Wang, Ying Chyi Song, Chuan Teng Liu, Mei Yun Chu, Hung Rong Yen*

*Corresponding author for this work

Research output: Contribution to journalJournal Article peer-review


Ethnopharmacological relevance: Psoriasis is a chronic inflammatory disease due to immune dysregulation that cannot be cured. The skin conditions of psoriasis negatively impact patients’ quality of life worldwide. Qing Dai (Indigo Naturalis), a traditional Chinese medicine (TCM) processed from Strobilanthes cusia is a clinical medicine used for psoriasis patient in Taiwan and the gene overexpression of interleukin (IL)-17A could be notably reduced in skin lesions after using Qing Dai ointment and its alkaloid ingredients. Aim of the study: To develop a potential anti-psoriatic phytopharmaceutical, an alkaloid-rich fraction named INM-A was prepared from Qing Dai. The chemical profile and anti-psoriatic activity of INM-A were analyzed and evaluated to define its in vitro mechanism and in vivo efficacy for psoriasis therapy. Materials and methods: Dowex® 50WX4 hydrogen form resin was used for column chromatography to prepare INM-A. To track alkaloids, INM-A was conducted with Dragendorff's, Mayer's, and Wagner's reagents. HPLC and UV–Vis spectrophotometer were applied to analyze the chemical profile and relative total alkaloid content in INM-A. A psoriatic mouse model induced by imiquimod (IMQ) was performed to verify in vivo efficacy of INM-A. IL-17A-dominated cellular oxygen consumption rate, oxidative stress, and cytokines in keratinocytes were measured to clarify in vitro mechanism of INM-A. Results: An alkaloid-rich fraction, INM-A, consisted of seven active alkaloid compounds 1–7 was obtained from Qing Dai. INM-A improved the skin condition severities in IMQ-induced psoriatic mice and decreased IL-17A in not only psoriatic mice but also polarized Th17 cells. In addition, INM-A targeted IL-17A to inhibit inflammation and OXPHOS-driven oxidative stress in human keratinocytes. Conclusion: Accordingly, INM-A manufactured from Qing Dai may be a promising lead phytopharmaceutical for further IL-17A-related inflammatory disease studies such as psoriasis.

Original languageEnglish
Article number116924
Pages (from-to)116924
JournalJournal of Ethnopharmacology
Issue numberPt A
StatePublished - 10 01 2024
Externally publishedYes

Bibliographical note

Copyright © 2023 Elsevier B.V. All rights reserved.


  • Alkaloid-rich phytopharmaceutical (INM-A)
  • Anti-OXPHOS-driven oxidative stress
  • Anti-inflammation
  • IL-17A inhibition
  • Psoriasis
  • Qing Dai (Indigo Naturalis)
  • Keratinocytes/pathology
  • Imiquimod
  • Humans
  • Psoriasis/chemically induced
  • Antineoplastic Agents/therapeutic use
  • Skin/pathology
  • Animals
  • Quality of Life
  • Mice
  • Mice, Inbred BALB C
  • Interleukin-17
  • Alkaloids/adverse effects
  • Disease Models, Animal


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