Kaemtakols A-D, highly oxidized pimarane diterpenoids with potent anti-inflammatory activity from Kaempferia takensis

Orawan Jongsomjainuk; Jutatip Boonsombat; Sanit Thongnest; Hunsa Prawat; Paratchata Batsomboon; Sitthivut Charoensutthivarakul; Saroj Ruchisansakun; Kittipong Chainok; Jitnapa Sirirak; Chulabhorn Mahidol; Somsak Ruchirawat

doi:10.1007/s13659-023-00420-0

Kaemtakols A-D, highly oxidized pimarane diterpenoids with potent anti-inflammatory activity from Kaempferia takensis

Nat Prod Bioprospect. 2023 Dec 1;13(1):55. doi: 10.1007/s13659-023-00420-0.

Authors

Orawan Jongsomjainuk¹, Jutatip Boonsombat^{1

2}, Sanit Thongnest^{3

4}, Hunsa Prawat^{1

2}, Paratchata Batsomboon⁵, Sitthivut Charoensutthivarakul⁶, Saroj Ruchisansakun⁷, Kittipong Chainok⁸, Jitnapa Sirirak⁹, Chulabhorn Mahidol^{1

10}, Somsak Ruchirawat^{5

10

2}

Affiliations

¹ Laboratory of Natural Products, Chulabhorn Research Institute, Bangkok, Thailand.
² Center of Excellence on Environmental Health and Toxicology (EHT), OPS, MHESI, Bangkok, Thailand.
³ Laboratory of Natural Products, Chulabhorn Research Institute, Bangkok, Thailand. sanit@cri.or.th.
⁴ Center of Excellence on Environmental Health and Toxicology (EHT), OPS, MHESI, Bangkok, Thailand. sanit@cri.or.th.
⁵ Laboratory of Medicinal Chemistry, Chulabhorn Research Institute, Bangkok, Thailand.
⁶ Excellent Center for Drug Discovery (ECDD), School of Bioinnovation and Bio-Based Product Intelligence, and Center for Neuroscience, Faculty of Science, Mahidol University, Bangkok, Thailand.
⁷ Department of Plant Science, Faculty of Science, Mahidol University, Bangkok, Thailand.
⁸ Thammasat University Research Unit in Multifunctional Crystalline Materials and Applications (TU-MCMA), Faculty of Science and Technology, Thammasat University, Pathum Thani, Thailand.
⁹ Department of Chemistry, Faculty of Science, Silpakorn University, Nakhon Pathom, Thailand.
¹⁰ Program in Chemical Sciences, Chulabhorn Graduate Institute, Chulabhorn Royal Academy, Bangkok, Thailand.

Abstract

Four highly oxidized pimarane diterpenoids were isolated from Kaempferia takensis rhizomes. Kaemtakols A-C possess a tetracyclic ring with either a fused tetrahydropyran or tetrahydrofuran motif. Kaemtakol D has an unusual rearranged A/B ring spiro-bridged pimarane framework with a C-10 spirocyclic junction and an adjacent 1-methyltricyclo[3.2.1.0^2,7]octene ring. Structural characterization was achieved using spectroscopic analysis, DP4 + and ECD calculations, as well as X-ray crystallography, and their putative biosynthetic pathways have been proposed. Kaemtakol B showed significant potency in inhibiting nitric oxide production with an IC₅₀ value of 0.69 μM. Molecular docking provided some perspectives on the action of kaemtakol B on iNOS protein.

Keywords: Anti-inflammatory; DP4+; Diterpenoid; Kaempferia takensis; Molecular docking; Structure elucidation.

Abstract

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