Studies on three species of Mongolian medicinal plants Phytochemical investigations and anti-parasitic activities of Oxytropis lanata and Bergenia crassifolia, and the effects of Astragalus mongholicus on uterus

平成29年

Trypanocidal Activity of 2,5-Diphenyloxazoles Isolated from the Roots of <i>Oxytropis lanata</i>

Eleven 2,5-diphenyloxazole derivatives (<b>1</b>–<b>11</b>), together with six known isoflavonoid derivatives, were isolated from the roots of <i>Oxytropis lanata</i>. The 2,5-diphenyloxazole (<b>1</b>) obtained proved to be identical to a standard sample used as a scintillator and liquid laser dye. The other oxazole derivatives isolated were found to have one to four hydroxy and/or <i>O</i>-methyl groups in their phenyl rings. Seven of the oxazole derivatives obtained are new (<b>3</b>–<b>9</b>). The inhibitory activity of the isolated compounds was evaluated against <i>Trypanosoma congolense</i>, the causative agent of African trypanosomosis in animals. Oxazoles with di- and trihydroxy groups showed trypanocidal activity, and 2-(2′,3′-dihydroxyphenyl)-5-(2″-hydroxyphenyl)­oxazole (<b>4</b>) exhibited the most potent inhibitory activity (IC₅₀ 1.0 μM)