Antiplasmodial Triterpenoids from Ekebergia capensis

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• 作者：Toshihiro Murata ; Toshio Miyase ; Francis Wamakima Muregi ; Yasuko Naoshima-Ishibashi ; Kaoru Umehara ; Tsutomu Warashina ; Shigeyuki Kanou ; Gerald M. Mkoji ; Mamoru Terada ; Akira Ishih
• 刊名：Journal of Natural Products
• 出版年：2008
• 出版时间：February 2008
• 年：2008
• 卷：71
• 期：2
• 页码：167 - 174
• 全文大小：118K
• 年卷期：v.71,no.2(February 2008)
• ISSN：1520-6025

文摘

From the stem bark of Ekebergia capensis, 10 new triterpenoid compounds, ekeberins A (1), B (2), C₁ (3), C₂ (4), C₃ (5), D₁ (6), D₂ (7), D₃ (8), D₄ (9), and D₅ (10), were isolated together with 17 known compounds. The structures of these new compounds were elucidated on the basis of the results of spectroscopic analysis, and the absolute configuration of compounds 6−10 were determined by partial synthesis from known compounds and using the Mosher ester method. Several of these compounds were screened in vitro against both chloroquine (CQ)-sensitive and -resistant Plasmodium falciparum isolates and were found to exhibit moderate antiplasmodial activity, with compounds 20 (7-deacetoxy-7-oxogedunin) and 27 (2-hydroxymethyl-2,3,22,23-tetrahydroxy-2,6,10,15,19,23-hexamethyl-6,10,14,18-tetracosatetraene) showing IC₅₀ values of 6 and 7 µM, respectively. Compound 27 at a dose of 500 mg/kg showed moderate parasitemia suppression of 52.9% against P. berghei NK 65 in a mouse model.