短果杜鹃组培快繁及其种质试管保存培养基的筛选

以短果杜鹃新生嫩芽为外植体,应用均匀设计法筛选其基部直接再生芽苗、生根及其试管苗保存培养基,结果表明,最适合的基部直接再生芽苗诱导培养基为:DR+2-ip 2.75 mg·L-1+IAA0.07 mg·L-1;生根培养基:1/2MS(大量元素)+IAA0.1 mg·L-1+NAA0.05 mg·L-1+Kt0.2mg·L-1;试管苗保存培养基:1/SMS+根皮苷5.0mg·L-1.短果杜鹃组织培养的不同阶段需要不同的培养基,常温条件下,利用"低营养延缓生长"的方法在试管内保存其种质.     

Inhibition of glucose intestinal absorption by kaempferol 3-O-α-rhamnoside purified from Bauhinia megalandra leaves

Glucose intestinal absorption (GIA) is one of the factors that increase glycemia. Its reduction could be an important factor in decreasing hyperglycemia in diabetic patients. It has been shown that the aqueous extract of Bauhinia megalandra leaves inhibits GIA. In the present study we identified a compound present in the extract of B. megalandra responsible for the biological effect. The methanol extract of B. megalandra leaves was fractionated using different solvents, and high-speed counter-current chromatography yielding two pure compounds identified by ¹H NMR and ¹³C NMR as kaempferol 3-O-α-rhamnoside and quercetin 3-O-α-rhamnoside. The first one increased the K_M without changes in the V_MAX of GIA. In addition it exerted an additive inhibitory effect, on GIA, when combined with phlorizin. We suggest that kaempferol 3-O-α-rhamnoside is a competitive inhibitor of intestinal SGLT1 cotransporter.     

超声波辅助提取苹果叶多酚及其抗氧化性研究

研究了超声波辅助提取苹果叶多酚的最佳工艺及其抗氧化性。结果表明,超声波辅助提取苹果叶多酚的最佳条件为:乙醇体积分数20%,液料比40∶1(mL∶g),提取温度75℃,提取时间20 min,超声波功率600 W,提取两次,在此条件下多酚的得率为4.22%;苹果叶提取物有较好的抗氧化活性,对.OH和O2-.的清除能力比茶多酚强;HPLC分析表明苹果叶中根皮苷的含量为2.45%,苹果叶提取物中根皮苷的含量为6.18%,占提取物中多酚量的61.36%。     

苹果多酚及其活性单体的提取·分离纯化及降脂效果研究

[目的]分离并分析苹果多酚组分及活性单体纯度,并评价了它们的降脂活性。[方法]利用乙醇提取苹果多酚,并分离纯化了4种(绿原酸、儿茶素、根皮苷、槲皮素)活性单体,采用高效液相色谱与质谱联用分析多酚组分及活性单体纯度,建立小鼠糖尿病模型。[结果]苹果多酚中绿原酸的含量是35.207%、儿茶素3.991%、根皮苷15.662%、槲皮素0.274%。4个活性单体成分(绿原酸、儿茶素、根皮苷、槲皮素),经过液相质谱分析,绿原酸的纯度是99.298%、儿茶素99.426%、根皮苷99.857%、槲皮素99.317%。动物试验表明,苹果多酚、绿原酸、儿茶素、根皮苷、槲皮素均能有效降低糖尿病鼠血总胆固醇(TG)、甘油三脂(TC)、低密度脂蛋白(LDL-c)水平,增加血高密度脂蛋白(HDL-c)水平。相比较苹果多酚,4种单体(绿原酸、儿茶素、根皮苷、槲皮素)均显示了更好的降脂活性。其中,根皮苷的降脂效果最好。[结论]苹果多酚及活性单体有着较好的降脂活性。