橐吾属植物挥发油成分分析及活性研究

目的:对同一产区5种橐吾属植物的挥发油进行成分分析及活性研究。方法:利用水蒸气蒸馏法制备挥发油,结合GC-MS分析对比5种橐吾属植物挥发油成分的异同,并采用DPPH·和MTT法对5种挥发油的抗氧化和抑菌活性进行筛选。结果:5种橐吾属植物挥发油在测试浓度下对DPPH·均有一定的抑制率。抑菌试验结果显示,富含脂肪类成分的黄帚橐吾挥发油和富含芳香类成分的南川橐吾挥发油对绿脓杆菌具有一定的抑制活性。结论:该实验结果为科学评价橐吾属药用植物的活性部位和活性成分,及合理地开发和利用该属植物资源奠定基础。

Factors Influencing the Effects of Theabrownin in Pu-erh Tea on Scavenging DPPH Radicals

[Objective] This study aimed to explore factors influencing the effects of theabrownin in Pu-erh tea on scavenging DPPH radicals. [Method] Taking Pu-erh tea as main research object, theabrownin in Pu-erh tea from tea piles with different times of mixture, stored for different years and processed by both the old and new techniques were extracted and isolated. And DPPH method was used to study the effects of theabrownin solution and tea liquor on scavenging radicals and their antioxidant activity. [Result] The result showed that the theabrownin content in Pu-erh tea from tea piles with one to four times of mixture revealed a first declining and subsequently rising trend. Under different pH conditions, the rates of DPPH radical scavenging of 1 mg/ml theabrownin solution made from tea piles with different times of mixture decreased gradually with the increase of pH, and all the rates were lower than that of the control vitamin C solution; the rates of DPPH radical scavenging of theabrownin from tea samples stored for different years and produced by different techniques dropped slowly within pH range 3.0-6.0; when pH was higher than 6.0, the rates of DPPH radical scavenging of theabrownin from tea samples produced by both new and traditional techniques in 2001 declined obviously, while the declining trend was not obvious in either the black tea or the Pu-erh tea produced by new technique in 2005. Under different theabrownin concentrations, the rates of DPPH radical scavenging of theabrownin solution made from tea piles with different times of mixture ascended as the concentration increased and the highest rate occurred in tea pile with four times of mixture, reaching up to 46.56%±0.88%; for tea samples stored for different years and produced by different techniques, the rates of DPPH radical scavenging of theabrownin rose gradually with the increase of the theabrownin concentration; the rate of radical scavenging of theabrownin in the black tea ascended obviously and that in Pu-erh tea was decreasing within the concentration range of 0.04 -0.06 mg/ml. At pH6.0, the DPPH radical scavenging ability of theabrownin in 0.1 mg/ml theabrownin solution and tea liquor containing 0.1mg/ml theabrownin from tea piles with different times of mixture ascended with the time of mixture; solution made from tea samples produced by different techniques in different years, the DPPH radical scavenging ability of theabrownin solution and tea liquor followed： Pu-erh tea produced by the new technique in 2001 ﹥ Pu-erh tea produced by the old technique in 2001﹥ Pu-erh tea produced by the new technique in 2005. And the DPPH radical scavenging ability of theabrownin in tea liquor containing 0.1 mg/ml theabrownin was higher than that in 0.1 mg/ml theabrownin Solution made from tea samples either with different times of mixture or produced by different techniques in different years. The above results indicated that many factor influenced the effects of theabrownin on eliminating DPPH radicals, including the time of fermentation, fermentation technique, years of storage, concentration and pH all had great influence on the effects of theabrownin on eliminating radicals. To ensure a good effect on scavenging radicals, it is better to prepare theabrownin at pH6.0 with concentration between 0.08 and 0.1 mg/ml for drinking. [Conclusion] Results of this study provide a basis for developing functional products of theabrownin from Pu-erh tea in the future.

不同酶水解泥鳅蛋白的特性研究

采用Alcalase 2.4 L、Protamex、Papain、PTN6.0 S、Flavorzyme500 MG水解泥鳅蛋白,探讨了各种酶的酶解特性、产物营养组成和清除DPPH.活性的差异。结果表明,PTN6.0 S和Papain酶解产物的蛋白质利用率、肽得率和水解度均较高。各酶解产物的谷氨酸、色氨酸、天冬氨酸的含量都很高;酶解产物中的氨基酸组成较原料泥鳅蛋白更接近FAO/WHO推荐的成人模式。各种酶均能降解泥鳅蛋白中分子量大于3000 Da的片断,产物中以分子量小于500 Da的肽段为主。Alacalase 2.4 L的酶解产物清除DPPH.的能力最强,其次为PTN6.0 S酶解产物、Protamex酶解产物,而Flavorzyme 500 MG酶解产物清除DPPH.的能力最弱。

Antioxidant phenanthrenes and lignans from Dendrobium nobile

To study the antioxidant constituents from the stems of Dendrobium nobile, and to discuss theft structure-activity relationship. Compounds were isolated from a 60% ethanolic extract by various chromatographic techniques and were identified by spectral analysis. The antioxidant activities of compounds were evaluated by DPPH free radical scavenging assay. Five phenanthrenes and four lignans were obtained from the active fractions ofD. nobile. Their structures were identified as fimbriatone （1）, confusarin （2）, flavanthrinin （3）, 2,5-dihydroxy-4,9-dimethoxyphenanthrene （4）, 3,7-dihydroxy-2,4-dimethoxyphenanthrene （5）, syringaresinol （6）, pinoresinol （7）, medioresinol （8） and lirioresinol-A （9）, respectively. Compounds 2 and 6 exhibited more potent DPPH scavenging activities than vitamin C. All the above compounds were reported from this plant for the first time, and compounds 3, 4 and 9 were reported for the first time from the genus of Dendrobiurn. For all phenanthrenes and lignans, an electron-donating methoxyl group in the ortho position to the phenolic hydroxyl group exhibits enhanced antioxidant activities.

Antioxidant Activity of Ethanol Extract of Pomegranate Seed

In this study, the ethanol extract of pomegranate seed was prepared and its antioxidant activities were investigated. It was found the total phenolic content in the extract was as high as 41.791 mg GAE/g. And the extract showed high antioxidant activity measured as scavenging of DPPH radicals, hydroxyl radicals. It also exhibited strong antioxidant activity in reducing power and Rancimat test. These results demonstrated Pomegranate seeds could serve as a new source of natural antioxidant.

Total Phenolic Content and Antioxidative Activity in Seasoning Protein Hydrolysate as Affected by Pasteurization and Storage

Protein hydrolysate prepared from fish and shrimp by-products were used to prepare a seasoning protein hydrolysate （SPH）. The effects of pasteurization and storage on total phenolic content （TPC）, DPPH radical scavenging activity, reducing power, and color of the SPH were investigated. Pasteurization at 90 ℃ for 10 minutes led to a reduction of TPC and DPPH radical scavenging activity and an increase of reducing power of solid fraction of SPH by about 30%, 99%, and 100%, respectively. Consequently it increased TPC DPPH radical scavenging activity, and reducing power of the liquid phase by about 32%, 600%, and 100%, respectively. Storage at 28, 35, or 45 ℃ for 12 weeks altered color values and increased brownness intensity （OD420）. The storage led to an apparent increase of the TPC and antioxidative activity of the product. The results indicate the possibility of producing healthy appetizers from protein hydrolysate prepared from by-products of the seafood industry.

Studies on the Antioxidant Potential of Extracts from Unripe Fruit of Carica papaya

The antioxidant activities of the ethyl acetate fraction and aqueous extract of unripe fruit of Carica papaya were compared and investigated in vitro using thiobarbituric reactive species （TBARS） assay, total phenol content, evaluation of reactive oxygen species （ROS） in liver mitochondria, Fe2＋ chelating and 2,2-diphenyl-lpicrylhydrazyl （DPPH） scavenging activities. Both extracts had high antioxidant properties and could inhibit FeE＋ and sodium nitroprusside lipid peroxidation in the liver. Total phenol content of ethyl acetate fraction and aqueous extract were 4.50 ±2.26 and 1.21±3.12 mg/g, respectively. Both extracts had a maximal effect at the lowest concentrations tested （15 μg/mL for ethyl acetate and 150 μg/mL for the aqueous）. Ethyl acetate fraction showed that the highest values of antioxidant activity is probably associated with its high phenolic content, Fe2＋ chelating and DPPH scavenging activities. It is therefore concluded that ethyl acetate fraction and to a less extent the aqueous fractions are potent inhibitor of lipid peroxidation.

Efficiency of Antioxidant Compounds from Macro Edible Algae

Antioxidant efficiency was studied in fresh edible algae： Cladophora, Microspara and Nostochopsis spp. from Nan River, Nan province. The samples were collected from Pua and Tha-Wang-Pha district, studied antioxidant activity and compared the antioxidant efficacy of the extracts from the three fresh edible algae with a standard solution, 3-tert-butyl-4-hydroxyanisole （BHA）. This study found that an extract ofNostochopsis spp. was the highest antioxidant activity to DPPH free radical between 32.1 and 87.5, the highest amount of beta-carotene was 4.71-7.09 mg/g and the highest amount of phenol in fresh edible algae extracts from Microspora was between 9.37 and 37.02 mg/g. The highest vitamin C in Microspora was between 110.41-138.53 mg/100 g.

Non-alkaloid constituents of Vinca major

The present study was designed to investigate the non-alkaloid compounds from the leaves and stems of Vinca major cultivated in Yunnan Province, China. The compounds were isolated using chromatographic techniques. The structures were elucidated by 1D- and 2D-NMR spectroscopic methods in combination with UV, IR, and MS analyses. The 1, 1-diphenyl-2-picrylhydrazyl （DPPH）-scavenging activity of Compounds 1-7 were evaluated. One new iridoid glycoside （compound 1）, together with 11 known compounds, were isolated from Vinca major. Compounds 1, 5, and 6 showed moderate DPPH-scavenging activity, with IC50 values being 70.6, 32.8, and 62.2μmaol·L 1, respectively. In conclusion, compound 1 is a newly identified iridoid glycoside with moderate antioxidant activity.