超声波纤维素酶法提取紫苏叶活性物质及其抗氧化活性

对比了超声波法、纤维素酶法、先超声波后纤维素酶法、先纤维素酶后超声波法以及超声波纤维素酶同步法5 种提取方式对紫苏叶黄酮、多酚、迷迭香酸提取效果的影响并评价了其提取液的抗氧化能力。结果表明,超声波纤维素酶同步法提取紫苏叶可获得最大含量的黄酮、多酚及迷迭香酸,分别为32.74、20.91、2.42 mg/g,其提取液的DPPH自由基清除能力及铁还原能力最强,分别为614.24、3 277.72 μmol Trolox/L。其抗氧化能力与多酚的含量呈显著正相关,多酚含量与铁还原能力及DPPH自由基清除能力相关系数分别为0.878、0.804,均为极显著（P＜0.01）。     

反相高效液相色谱法测定白苏子和白苏子油中迷迭香酸的含量

采用反相高效液相色谱法测定了白苏子及其油中迷迭香酸的含量.使用KromasilC18(250mm×4.6mm,5μm)色谱柱,流动相为甲醇-0.1%磷酸水溶液(40 : 60),光电二极管阵列检测器,检测波长331nm,流速0.8mL/min,柱温28℃.迷迭香酸进样量在0.204.00μg时呈现良好的线性关系,线性回归方程为Y=3.02×105X-3.50×103,r=0.9999,平均加样回收率为97.3%,RSD为2.1%.白苏子中迷迭香酸的含量为0.2475mg/g,约为白苏子油中迷迭香酸含量0.0794mg/g的3.12倍.白苏子采用压榨法生产白苏子油时,活性成分迷迭香酸大部分残留在油粕中.方法灵敏、准确,重现性好,适用于白苏子和白苏子油中迷迭香酸的定量检测分析.     

RP-HPLC法测定紫苏子、白苏子中乌索酸和齐墩果酸含量

采用反相高效液相色谱法测定紫苏子和白苏子中乌索酸和齐墩果酸含量,色谱柱为Kromasil C18柱(250 mm×4.6 mm,5μm),流动相为甲醇—水(87:13),光电二极管阵列检测器,检测波长210 nm,流速0.8 ml/min,柱温28℃。乌索酸进样量在0.10～4.00μg,齐墩果酸进样量在0.05～2.00μg时呈现良好线性关系,平均加样回收率分别为100.6%和98.7%,RSD分别为1.6%和1.2%。方法灵敏、准确,重现性好,可用于乌索酸与齐墩果酸含量测定。     

高效液相色谱法测定绿苏叶提取液中紫苏醛的含量

利用高效液相色谱法分析绿苏叶提取液中的紫苏醛含量,采用乙腈水(体积为乙腈∶水=75∶25,流速为0.5mL/min)为流动相。结果表明:相对标准偏差仅为0.36%,回收率为97.2%～106.4%。与文献报道的甲醇水(体积比为甲醇∶水=72∶28,流速为1.3mL/min)作流动相相比,该方法快速,精度高,试剂耗用的成本相当。     

Effects of flavonoid-rich extract from seeds of Eugenia jambolana (L.) on carbohydrate and lipid metabolism in diabetic mice

Eugenia jambolana (EJ) is long known for its antidiabetic activities in traditional medicines. The aim of this study was to determine the probable mechanism of action of a flavonoid-rich extract from seeds of EJ on streptozotocin-induced diabetic mice. Various biochemical parameters, e.g. glucose tolerance, lipid profile, glycogen biosynthesis, glucose uptake and insulin release in vivo and in vitro, were significantly improved in the extract-treated diabetic mice. Similarly, differential regulation and expression of glucose homeostatic enzymes, e.g. glucose-6-phosphatase and hexokinase, were also changed significantly in response to the flavonoid-rich extract, which clearly demonstrated the hypoglycemic and hypolipidemic effects in treated animals. Further, analysis of the extract using HPLC, demonstrated the presence of different flavonoids and their derivatives which are known for their antidiabetic and antioxidant potential. The data showed that this flavonoid-rich seed extract has a remarkable dual hypoglycemic and hypolipidemic effect.