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Tan YS, Ng MP, Tan CH, Tang WK, Sim KS, Yong KT, Krishnan P, Lim KH, Lim SH, Low YY. Quinoline, Indole, and Isogranatanine Alkaloids from Malayan Leuconotis eugeniifolia. JOURNAL OF NATURAL PRODUCTS 2024; 87:286-296. [PMID: 38284153 DOI: 10.1021/acs.jnatprod.3c00960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2024]
Abstract
Nine new alkaloids, eugeniinalines A-H (1-8) and (+)-eburnamenine N-oxide (9), comprising one quinoline, six indole, and two isogranatanine alkaloids, were isolated from the stem-bark extract of the Malayan Leuconotis eugeniifolia. The structures and absolute configurations of these alkaloids were established based on the analysis of the spectroscopic data, GIAO NMR calculations, DP4+ probability analysis, TDDFT-ECD method, and X-ray diffraction analysis. Eugeniinaline A (1) represents a new pentacyclic quinoline alkaloid with a 6/6/5/6/7 ring system. Eugeniinaline G (7) and its seco-derivative, eugeniinaline H (8), were the first isogranatanine alkaloids isolated as natural products. The known alkaloids leucolusine (10) and melokhanine A (11) were found to be the same compound, based on comparison of the spectroscopic data of both compounds, with the absolute configuration of (7R, 20R, 21S). Eugeniinalines A and G (1 and 7) showed cytotoxic activity against the HT-29 cancer cell line with IC50 values of 7.1 and 7.2 μM, respectively.
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Affiliation(s)
- Yi-Sheng Tan
- Department of Chemistry, Faculty of Science, Universiti Malaya, 50603 Kuala Lumpur, Malaysia
| | - Min-Phin Ng
- Institute of Biological Sciences, Faculty of Science, Universiti Malaya, 50603 Kuala Lumpur, Malaysia
| | - Chun-Hoe Tan
- Department of Biotechnology, Faculty of Applied Science, Lincoln University College, 47301 Petaling Jaya, Selangor, Malaysia
| | - Wai-Kit Tang
- Department of Chemistry, Faculty of Science, Universiti Malaya, 50603 Kuala Lumpur, Malaysia
| | - Kae-Shin Sim
- Institute of Biological Sciences, Faculty of Science, Universiti Malaya, 50603 Kuala Lumpur, Malaysia
| | - Kien-Thai Yong
- Institute of Biological Sciences, Faculty of Science, Universiti Malaya, 50603 Kuala Lumpur, Malaysia
| | - Premanand Krishnan
- Foundation in Science, University of Nottingham Malaysia, Jalan Broga, 43500 Semenyih, Selangor, Malaysia
| | - Kuan-Hon Lim
- School of Pharmacy, University of Nottingham Malaysia, Jalan Broga, 43500 Semenyih, Selangor, Malaysia
| | - Siew-Huah Lim
- Department of Chemistry, Faculty of Science, Universiti Malaya, 50603 Kuala Lumpur, Malaysia
| | - Yun-Yee Low
- Department of Chemistry, Faculty of Science, Universiti Malaya, 50603 Kuala Lumpur, Malaysia
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