School of Pharmaceutical Sciences, Universiti Sains Malaysia, 11800, Penang, Malaysia.
Molecules. 2011 May 4;16(5):3787-801. doi: 10.3390/molecules16053787.
Preliminary investigations were carried out to evaluate the antidiabetic effects of the leaves of O. stamineus extracted serially with solvents of increasing polarity (petroleum ether, chloroform, methanol and water); bioassay-guided purification of plant extracts using the subcutaneous glucose tolerance test (SbGTT) was also carried out. Only the chloroform extract, given at 1 g/kg body weight (b.w.), significantly reduced (P < 0.05) the blood glucose level of rats loaded subcutaneously with 150 mg/kg (b.w.) glucose. The active chloroform extract of O. stamineus was separated into five fractions using a dry flash column chromatography method. Out of the five fractions tested, only chloroform fraction 2 (Cƒ2), at the dose of 1 g/kg (b.w.) significantly inhibited (P < 0.05) blood glucose levels in SbGTT. Active Cƒ2 was split into two sub-fractions Cƒ2-A and Cƒ2-B, using a dry flash column chromatography method. The activities Cƒ2-A and Cƒ2-B were investigated using SbGTT, and the active sub-fraction was then further studied for anti-diabetic effects in a streptozotocin-induced diabetic rat model. The results clearly indicate that Cƒ2-B fraction exhibited a blood glucose lowering effect in fasted treated normal rats after glucose-loading of 150 mg/kg (b.w.). In the acute streptozotocin-induced diabetic rat model, Cƒ2-B did not exhibit a hypoglycemic effect on blood glucose levels up to 7 hours after treatment. Thus, it appears that Cƒ2-B functions similarly to metformin, which has no hypoglycemic effect but demonstrates an antihyperglycemic effect only in normogycemic models. The effect of Cƒ2-B may have no direct stimulatory effects on insulin secretion or on blood glucose levels in diabetic animal models. Verification of the active compound(s) within the active fraction (Cƒ2-B) indicated the presence of terpenoids and, flavonoids, including sinensitin.
初步研究评估了 O. stamineus 叶用溶剂（石油醚、氯仿、甲醇和水）依次提取的抗糖尿病作用；还使用皮下葡萄糖耐量试验（SbGTT）对植物提取物进行了生物测定指导的纯化。只有在 1 g/kg 体重（bw）时，氯仿提取物显著降低了皮下给予 150 mg/kg（bw）葡萄糖的大鼠的血糖水平（P < 0.05）。用干法闪式柱色谱法将 O. stamineus 的活性氯仿提取物分离成五个馏分。在测试的五个馏分中，只有氯仿馏分 2（Cƒ2）在 1 g/kg（bw）剂量下显著抑制了 SbGTT 中的血糖水平（P < 0.05）。氯仿馏分 2 用干法闪式柱色谱法分为两个亚馏分 Cƒ2-A 和 Cƒ2-B。使用 SbGTT 研究了 Cƒ2-A 和 Cƒ2-B 的活性，然后在链脲佐菌素诱导的糖尿病大鼠模型中进一步研究了活性亚馏分的抗糖尿病作用。结果清楚地表明，Cƒ2-B 馏分在 150 mg/kg（bw）葡萄糖负荷后，空腹治疗正常大鼠的血糖降低。在急性链脲佐菌素诱导的糖尿病大鼠模型中，Cƒ2-B 处理后 7 小时内对血糖水平没有降低作用。因此，Cƒ2-B 的作用似乎类似于二甲双胍，二甲双胍没有降血糖作用，但仅在正常血糖模型中表现出抗高血糖作用。Cƒ2-B 的作用可能对糖尿病动物模型中的胰岛素分泌或血糖水平没有直接的刺激作用。活性馏分（Cƒ2-B）中活性化合物的验证表明存在萜类化合物和类黄酮，包括辛斯廷。
