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Open AccessArticle

Bioactive Capnosanes and Cembranes from the Soft Coral Klyxum flaccidum

Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung 804, Taiwan
Department of Pharmacognosy, College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia
Department of Pharmacognosy, Faculty of Pharmacy, Mansoura University, Mansoura 35516, Egypt
Graduate Institute of Natural Products, College of Medicine, Chang Gung University, Taoyuan 333, Taiwan
Research Center for Chinese Herbal Medicine, Research Center for Food and Cosmetic Safety, and Graduate Institute of Health Industry Technology, College of Human Ecology, Chang Gung University of Science and Technology, Taoyuan 333, Taiwan
Department of Anesthesiology, Chang Gung Memorial Hospital, Taoyuan 333, Taiwan
Institute of Oceanography, National Taiwan University, Taipei 112, Taiwan
Frontier Center for Ocean Science and Technology, National Sun Yat-sen University, Kaohsiung 804, Taiwan
Graduate Institute of Natural Products, Kaohsiung Medical University, Kaohsiung 807, Taiwan
Department of Medical Research, China Medical University Hospital, China Medical University, Taichung 404, Taiwan
Author to whom correspondence should be addressed.
These authors contributed equally to this work.
Mar. Drugs 2019, 17(8), 461;
Received: 15 July 2019 / Revised: 2 August 2019 / Accepted: 4 August 2019 / Published: 7 August 2019
(This article belongs to the Special Issue Marine Natural Products Discovery: In Honor of Late Prof. Tatsuo Higa)
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Two new capnosane-based diterpenoids, flaccidenol A (1) and 7-epi-pavidolide D (2), two new cembranoids, flaccidodioxide (3) and flaccidodiol (4), and three known compounds 5 to 7 were characterized from the marine soft coral Klyxum flaccidum, collected off the coast of the island of Pratas. The structures of the new compounds were determined by extensive spectroscopic analyses, including 1D and 2D nuclear magnetic resonance (NMR) spectroscopy, and spectroscopic data comparison with related structures. The rare capnosane diterpenoids were isolated herein from the genus Klyxum for the first time. The cytotoxicity of compounds 1 to 7 against the proliferation of a limited panel of cancer cell lines was assayed. The isolated diterpenoids also exhibited anti-inflammatory activity through suppression of superoxide anion generation and elastase release in the N-formyl-methionyl-leucyl-phenylalanine/cytochalasin B (fMLF/CB)-stimulated human neutrophils. Furthermore, 1 and 7 also exhibited cytotoxicity toward the tested cancer cells, and 7 could effectively inhibit elastase release. It is worth noting that the biological activities of 7 are reported for the first time in this paper. View Full-Text
Keywords: soft coral; Klyxum flaccidum; capnosane; cembrane; cytotoxic activity; anti-inflammatory activity soft coral; Klyxum flaccidum; capnosane; cembrane; cytotoxic activity; anti-inflammatory activity

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This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

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Tseng, W.-R.; Ahmed, A.F.; Huang, C.-Y.; Tsai, Y.-Y.; Tai, C.-J.; Orfali, R.S.; Hwang, T.-L.; Wang, Y.-H.; Dai, C.-F.; Sheu, J.-H. Bioactive Capnosanes and Cembranes from the Soft Coral Klyxum flaccidum. Mar. Drugs 2019, 17, 461.

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