Food R&D Center, Japan Tobacco Inc., 5-14 Haneda-asahi-cho, Ota-ku, Tokyo 144-0042, Japan.
Biomed Pharmacother. 2009 Dec;63(10):710-6. doi: 10.1016/j.biopha.2009.01.006. Epub 2009 Feb 4.
Conophylline, a vinca alkaloid from Ervatamia microphylla, is known to induce the differentiation of pancreatic precursor cells to insulin-producing cells. In the present research we examined the antidiabetic effects of this alkaloid in vivo by oral administration. Crude conophylline preparations were prepared from the leaves of Tabernaemontana divaricata collected in Okinawa Prefecture, Japan. Conophylline was orally absorbed and showed an increase in its plasma level in both normal and streptozotocin-induced diabetic Sprague-Dawley rats. The plasma conophylline concentration reached its maximum from 1.5 to 3h after a single oral administration and gradually decreased in 24h. The alkaloid decreased the blood glucose level and increased the plasma insulin level in streptozotocin-induced diabetic rats after repetitive administration for 15 days. Fasting blood glucose levels in rats treated orally with conophylline at 0.11 and 0.46 mg/kg/day were 411+/-47 and 381+/-65 mg/dl, respectively; whereas the glucose level of the control rats was 435+/-46 mg/dl. Conophylline also decreased the fasting blood glucose level in Goto-Kakizaki rats in a dose-dependent manner after repetitive administration for 42 days. These results suggest that the extract from conophylline-containing leaves may be useful as a functional food for the treatment of type 2 diabetes mellitus.
从 Ervatamia microphylla 中提取的长春酰胺生物碱，已知能诱导胰腺前体细胞向胰岛素产生细胞分化。在本研究中，我们通过口服给药在体内研究了这种生物碱的抗糖尿病作用。从日本冲绳县采集的 Tabernaemontana divaricata 叶片中制备了粗长春酰胺制剂。长春酰胺被口服吸收，并在正常和链脲佐菌素诱导的糖尿病 Sprague-Dawley 大鼠中显示其血浆水平增加。单次口服后，血浆长春酰胺浓度在 1.5 至 3 小时达到最大值，并在 24 小时内逐渐下降。该生物碱在重复给药 15 天后降低了链脲佐菌素诱导的糖尿病大鼠的血糖水平并增加了其血浆胰岛素水平。每天以 0.11 和 0.46 mg/kg 剂量口服长春酰胺的大鼠的空腹血糖水平分别为 411+/-47 和 381+/-65 mg/dl；而对照组大鼠的血糖水平为 435+/-46 mg/dl。长春酰胺在重复给药 42 天后也以剂量依赖性方式降低了 Goto-Kakizaki 大鼠的空腹血糖水平。这些结果表明，含长春酰胺的叶片提取物可能可作为治疗 2 型糖尿病的功能性食品。
