Antioxidant activity of Japanese pepper (Zanthoxylum piperitum DC.) fruit

Antioxidants were extracted from Japanese pepper (Zanthoxylum piperitum DC.) fruit and characterized. The antioxidant activity of the methanol extract from Japanese pepper fruit was found to be equal to that of α-tocopherol and stable under heat treatment. The main compounds that gave a significant antioxidant activity from the methanol extract were identified to be hyperoside (quercetin-3-O-galactoside) and quercitrin (quercetin-3-O-rhamnoside) as determined by HPLC, mass spectrometry, UV/Vis spectroscopy, and TLC. Radical-scavenging activities of hyperoside and quercitrin from Japanese pepper fruit were evaluated using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) method. As a result, hyperoside and quercitrin scavenged DPPH radical strongly with IC₅₀ values of 16 and 18 μM, respectively. These observations show the presence of strong antioxidants, namely hyperoside and quercitrin in Japanese pepper fruit.     

Neuronal cell protective and antioxidant effects of phenolics obtained from Zanthoxylum piperitum leaf using in vitro model system

In order to obtain basic data for the utilisation of Zanthoxylum piperitum leaf as a functional substance in the food industry, the antioxidative and neuronal cell protective effects of silica-gel open column chromatographic fractions, obtained from Z. piperitum leaf, were examined. ABTS and FRAP assays indicated that the ZP4 fraction (eluted with methanol/chloroform, 1:4, v/v) of Z. piperitum leaf was a more potent radical-scavenger and reducing agent than the other five fractions. The ZP4 fraction also presented protective effects against H₂O₂-induced neurotoxicity in a dose-dependent manner. Therefore, our study verified that the ZP4 fraction has strong antioxidative and neuronal protective effects which are correlated with its high level of phenolics, particularly quercitrin, afzelin, and hyperoside. These phenolics of Z. piperitum leaf can be utilised as effective and safe functional food substances, i.e., natural antioxidants, and may reduce the risk of neurodegenerative disorders.     

天然槲皮苷的棉、丝绸与羊毛染色试验

进行了槲皮苷提取及对棉布、丝绸和羊毛的染色试验。结果证明槲皮苷在酸性条件下媒染丝绸和羊毛,经预皂洗,皂洗牢度可达4级;且丝绸皂洗后颜色加深;铁盐媒染三种织物,皂洗牢度都可达4级。说明槲皮苷是一种好的媒染染料。     

高效液相色谱法及紫外可见分光光度法测定侧柏叶中黄酮含量的比较

目的 :通过对高效液相色谱法 (HPLC)及紫外可见分光光度法测定侧柏叶黄酮进行比较 ,寻找一种较准确、简单的测定侧柏叶黄酮的方法。方法 :HPLC法 :流动相由乙晴∶ 0 .0 1mol/ L KH2 PO4 ∶乙酸 (2 8∶ 72∶ 1.5 ,V/ V)组成 ;流速 1.0 m L·min- 1 ;检测波长为2 60 nm,以槲皮甙为参照品。紫外 /可见分光光度法 :以芦丁为参照品 ,410 nm波长测定黄酮含量。结果 :两种方法都有较好的精密度 ,但测定的结果有较大差异 ,紫外 /可见分光光度法测得的结果比 HPLC法高。结论 :以槲皮甙为定量指标更能准确地反映侧柏叶的内在质量 ,HPLC法是一种较理想的测定方法