Yamada H, Nagai T, Takemoto N, Endoh H, Kiyohara H, Kawamura H, Otsuka Y
Oriental Medicine Research Center, Kitasato Institute, Tokyo, Japan.
Biochem Biophys Res Commun. 1989 Dec 29;165(3):1292-8. doi: 10.1016/0006-291x(89)92743-5.
A hot-water extract from the seed of Plantago asiatica showed a potent inhibitory activity against jack bean alpha-mannosidase, and a flavanone glucoside, plantagoside, was isolated as the inhibitor. Plantagoside was a specific inhibitor for jack bean alpha-mannosidase (IC50 at 5 microM) and appeared to be a non-competitive inhibitor of the enzyme. Whereas, negligible or weak inhibitory activities were observed for beta-mannosidase, beta-glucosidase, and sialidase tested. Plantagoside also inhibited alpha-mannosidase activities in mouse liver lysosomal and microsomal fractions, and the enzyme inhibitory activity in microsomal fraction was enhanced in the presence of glucosidase inhibitor, castanospermine. Plantagoside suppressed antibody response to sheep red blood cells and concanavalin A induced lymphocyte proliferation which was measured by [3H]thymidine incorporation.
车前草种子的热水提取物对刀豆α-甘露糖苷酶显示出强大的抑制活性，一种黄烷酮糖苷——车前糖苷被分离出来作为抑制剂。车前糖苷是刀豆α-甘露糖苷酶的特异性抑制剂（IC50为5微摩尔），似乎是该酶的非竞争性抑制剂。然而，对于所测试的β-甘露糖苷酶、β-葡萄糖苷酶和唾液酸酶，观察到的抑制活性可忽略不计或较弱。车前糖苷还抑制小鼠肝脏溶酶体和微粒体部分中的α-甘露糖苷酶活性，并且在存在葡萄糖苷酶抑制剂栗精胺的情况下，微粒体部分中的酶抑制活性增强。车前糖苷抑制对绵羊红细胞的抗体反应以及伴刀豆球蛋白A诱导的淋巴细胞增殖，后者通过[3H]胸腺嘧啶核苷掺入来测定。
