Comparison of Antioxidant Properties of Water and Ethanol Extracts Obtained from Dried Boxthorn (<i>Lycium chinensis</i>) Fruit

Antioxidant activities of W and E extracts obtained from dried boxthorn (Lycium chinensis) fruit were measured based on DPPH radical scavenging and reducing powers, and their relationships with total phenolics, flavonoid content, and antioxidant activity were investigated. A linear correlation among antioxidant activity, total phenolics, and flavonoid content was observed in concentration-dependent mode. Both extracts showed > 95% DPPH radical-scavenging activity and the higher reducing power of 3200 ppm at the same concentration. The antioxidant potential of both extracts were compared with those of commercial antioxidants such as BHA, BHT, TBHQ, ferulic acid, and α-tocopherol using H2O2 scavenging activity, inhibition of linoleic acid peroxidation, inhibition of hemolysis of rat erythrocyte induced by peroxyl radicals, and inhibition of Fe2+-induced lipid peroxidation using rat brain tissue. In the H2O2 scavenging activity, E extract showed a comparable significant antioxidant power, comparable to commercial antioxidants, and no signifi-cant difference (P > 0.05) was found between W and E extracts on inhibition of the linoleic acid peroxidation. Whereas W extract exhibited a significant power in the hemolysis of rat erythrocytes, none was observed in E extract. In the Fe-induced lipid peroxidation using rat brain tissue, no significant difference (P > 0.05) was found between both ex-tracts, showing a comparable activity with those of synthetic antioxidants. Both W and E extracts of dried boxthorn (Lycium chinensis) fruit may have a potential as natural antioxidants to replace synthetic antioxidants.

枸杞子极性溶剂提取物的自由基淬灭性质

根据我国食用枸杞子的习惯,对其水、50%和95%乙醇提取物的自由基淬灭能力进行了比较。水提物和50%醇提物中总黄酮的含量相近,分别为1154±89mg/kg和1207±66mg/kg,95%醇提物中含有更多的黄酮物质(1497±70mg/kg)。黄酮物质高效液相色谱分析结果说明,水提物中主要是芦丁和绿原酸,50%醇提物中主要是芦丁和原儿茶酸,95%醇提物中主要是芦丁。在DPPH·自由基反应体系中,所有提取物都表现为慢反应动力学,提取物的自由基淬灭能力随溶剂极性降低而提高。

枸杞叶中粗黄酮的超声法提取及抑菌活性

以枸杞叶为原料,采用单因素和正交试验设计研究枸杞叶中黄酮的超声法提取工艺,并研究提取液抑菌活性。结果表明:优化后的提取工艺条件是乙醇浓度(A)80%(体积分数)、料液比(B)1∶30(g/mL)、超声提取时间(C)35 min和超声功率(D)270 W,此时枸杞叶黄酮提取率为5.62%,各因素对黄酮提取率的影响大小顺序依次为A>C>B>D;枸杞叶黄酮提取液对黑曲霉、面包酵母无抑制作用,但其能抑制大肠杆菌(G^-)、金黄色葡萄球菌(G^+)及青霉的生长,最小抑菌浓度分别为10.3、20.6、41.2 mg/g。

佛手和枸杞提取物对小鼠皮肤胶原蛋白、SOD含量及毛发生长的影响

目的 :研究佛手和枸杞提取物对小鼠皮肤和毛发生长的作用。方法 :将佛手和枸杞提取液涂抹于小鼠脱毛皮肤部位 ,观察涂抹部位毛发生长情况 ,42d后取涂抹部位皮肤 ,测定超氧化物歧化酶SOD活性、胶原蛋白和丙二醛的含量。结果 :与空白对照组比较 ,佛手和枸杞提取液都能显著提高小鼠皮肤中SOD的活性 (P <0 .0 5) ,增加皮肤中胶原蛋白的含量 (P <0 .0 0 1 ) ,明显减少脂质过氧化产物丙二醛的含量 (P <0 .0 5) ,促进毛发的生长 (P <0 .0 0 1 )。结论

枸杞叶中总黄酮及芦丁提取工艺的研究

考察超声提取(1 h)、回流提取(1 h)、煮沸提取(1 h)3种不同提取方式,以及采用95%乙醇、75%乙醇、70%乙醇、60%乙醇、50%乙醇、热水等溶剂为提取试剂的提取方法,采用分光光度法测定总黄酮的含量,采用HPLC法测定芦丁的含量。结果表明采用回流提取方式以75%乙醇作为提取溶剂提取的提取方式效率最高。

不同方法制备枸杞籽油微乳的比较研究

目的:优选枸杞籽油微乳的处方组成,比较枸杞籽油微乳的3种制备方法。方法:以枸杞籽油自身作为油相,利用外观、乳滴粒径、三元相图和伪三元相图等评价指标,优选枸杞籽油微乳的制剂处方;以乳滴粒径和粒度分布为指标,比较超声乳化法、高压乳匀法和自乳化法制备枸杞籽油微乳的不同特点。结果:优选的处方为1%枸杞籽油、1%吐温80、2%甘油;超声乳化法的工艺参数为超声功率480W,工作-间歇时间为10s-5s,超声时间25min,制得微乳的平均粒径为(74.6±45.3)nm(多分散系数(P.I)=0.368);高压乳匀法的工艺参数为均质压力500bar循环3次,制得微乳平均粒径为(69.0±31.5)nm(P.I=0.378);在相同处方比例下,自乳化法无法自发形成微乳,而当枸杞籽油:吐温80:甘油=1:7:2时,可自发形成微乳。结论:不同方法均能制得粒径小而均匀、外观透明有乳光的枸杞籽油微乳,但各法适用范围和特点不同。