The Invasive Anemone Condylactis sp. of the Coral Reef as a Source of Sulfur- and Nitrogen-Containing Metabolites and Cytotoxic 5,8-Epidioxy Steroids

Atallah F Ahmed; Chang-Feng Dai; Yao-Haur Kuo; Jyh-Horng Sheu

doi:10.3390/metabo13030392

The Invasive Anemone Condylactis sp. of the Coral Reef as a Source of Sulfur- and Nitrogen-Containing Metabolites and Cytotoxic 5,8-Epidioxy Steroids

Metabolites. 2023 Mar 7;13(3):392. doi: 10.3390/metabo13030392.

Authors

Atallah F Ahmed^{1

2

3}, Chang-Feng Dai⁴, Yao-Haur Kuo⁵, Jyh-Horng Sheu^{1

6

7

8

9}

Affiliations

¹ Department of Marine Resources, National Sun Yat-sen University, Kaohsiung 804, Taiwan.
² Department of Pharmacognosy, College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia.
³ Department of Pharmacognosy, Faculty of Pharmacy, Mansoura University, Mansoura 35516, Egypt.
⁴ Institute of Oceanography, National Taiwan University, Taipei 106, Taiwan.
⁵ Division of Herbal Drugs and Natural Products, National Research Institute of Chinese Medicine, Taipei 112, Taiwan.
⁶ Institute of Natural Products, Kaohsiung Medical University, Kaohsiung 807, Taiwan.
⁷ Department of Medical Research, China Medical University Hospital, China Medical University, Taichung 404, Taiwan.
⁸ Frontier Center for Ocean Science and Technology, National Sun Yat-sen University, Kaohsiung 804, Taiwan.
⁹ Doctoral Degree Program in Marine Biotechnology, National Sun Yat-sen University, Kaohsiung 804, Taiwan.

Abstract

The Condylactis-genus anemones were examined for their proteinaceous poisons over 50 years ago. On the other hand, the current research focuses on isolating and describing the non-proteinaceous secondary metabolites from the invasive Condylactis anemones, which help take advantage of their population outbreak as a new source of chemical candidates and potential drug leads. From an organic extract of Condylactis sp., a 1,2,4-thiadiazole-based alkaloid, identified as 3,5-bis(3-pyridinyl)-1,2,4-thiadiazole (1), was found to be a new natural alkaloid despite being previously synthesized. The full assignment of NMR data of compound 1, based on the analysis of 2D NMR correlations, is reported herein for the first time. The proposed biosynthetic precursor thionicotinamide (2) was also isolated for the first time from nature along with nicotinamide (3), uridine (5), hypoxanthine (6), and four 5,8-epidioxysteroids (7-10). A major secondary metabolite (-)-betonicine (4) was isolated from Condylactis sp. and found for the first time in marine invertebrates. The four 5,8-epidioxysteroids, among other metabolites, exhibited cytotoxicity (IC₅₀ 3.5-9.0 μg/mL) toward five cancer cell lines.

Keywords: 5,8-epidioxysteroids; Condylactis sp.; anemone; cytotoxicity; ecological impact; marine alkaloids; natural 1,2,4-thiadiazole; thioniacinamide.

Abstract

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