Title
Limonoids Containing a C1–O–C29 Moiety: Isolation, Structural Modification, and Antiviral Activity
Author
Jing-Ling Ren, Xiao-Peng Zou, Wan-Shan Li, Li Shen, Jun Wu
Year
2018
Journal
Marine Drugs
Abstract
Five new limonoids named thaigranatins A–E (1–5), containing a C1–O–C29 moiety, were isolated from seeds of the Thai Xylocarpus granatum, collected at the mangrove swamp of Trang Province, together with the known limonoid, granatumin L (6). The structures of these compounds were established by HR-ESIMS and extensive NMR spectroscopic data. The absolute configuration of 1 was unequivocally determined by single-crystal X-ray diffraction analysis, conducted with Cu Kα radiation; whereas that of 2 or 6 was established to be the same as that of 1 by the similarity of their electronic circular dichroism (ECD) spectra. In view of the marked antiviral activity of 6, its structure was modified via hydrolysis with alkaline KOH, esterification with diazomethane and various organic acids, and oximization with hydroxyamine. Finally, 18 derivatives, viz. 7–10, 8a–8i, 9a–9b, and 10a–10c, were obtained. In vitro antiviral activities of these derivatives against human immunodeficiency virus 1 (HIV-1) and influenza A virus (IAV) were evaluated. Most notably, 8i exhibited marked inhibitory activity against HIV-1 with an IC50 value of 15.98 ± 6.87 μM and a CC50 value greater than 100.0 μM; whereas 10b showed significant inhibitory activity against IAV with an IC50value of 14.02 ± 3.54 μM and a CC50 value greater than 100.0 μM.
Full Article
Instrument
J-810
Keywords
Circular dichroism, Absolute configuration, Cotton effect, Pharmaceutical, Natural products