桑叶乙醇提取物的体外抗氧化与抑菌活性

采用索氏提取法对干桑叶进行提取,得到乙醇提取物,并对提取物的组分以及体外抗氧化活性和抑菌活性进行了测定。研究结果表明：桑叶乙醇提取物中含有多种有机物,主要包括酯类(82.85%)、烷烃类(6.31%)、芳烃类(1.62%)和醇类(0.21%)。桑叶乙醇提取物总还原力与浓度有显著的线性关系;对DPPH自由基和OH自由基都有良好的清除能力,半数抑制浓度(IC₅₀)分别为73.07和104.52 mg/L。桑叶乙醇提取物对枯草芽孢杆菌、金黄色葡萄球菌和大肠杆菌均具有一定的抑制作用,抑制效果为枯草芽孢杆菌＞金黄色葡萄球菌＞大肠杆菌,IC₅₀分别为4.824、6.806和14.382 g/L。桑叶乙醇提取物的抗氧化活性和抑菌活性随样品浓度的增大而增大。     

Phenolics and Antioxidant Activity of Mulberry Leaves Depend on Cultivar and Harvest Month in Southern China

To elucidate the effects of cultivar and harvest month on the phenolic content and antioxidant activity of mulberry leaves, four major phenolics, including chlorogenic acid (ChA), benzoic acid (BeA), rutin (Rut) and astragalin (Ast), were quantified using an HPLC-UV method. Leaves from six mulberry cultivars, collected from April to October, were analyzed. The antioxidant activity of mulberry leaves was assessed by ferric reducing antioxidant power (FRAP), hydroxyl radical scavenging activity (HSA) and superoxide radical scavenging activity (SSA) assays. The results showed that the total values of the four phenolic compounds ranged from 2.3 dry weight (DW) to 4.2 mg/g DW, with ChA being the major compound. The mean total phenol (TP) content of the six cultivars ranged from 30.4 equivalents (GAE) mg/g DW to 44.7 GAE mg/g DW. Mulberry leaves harvested in May had the highest TP content. Moreover, the antioxidant activities of mulberry leaves harvested from April to October differed noticeably. In general, Kq 10 and May were considered to be a better cultivar and harvest month concerning phenolic content and antioxidant activity, respectively.     

Fatty Acid Composition of the Oil from Developing Seeds of Different Varieties of Safflower (Carthamus tinctorius L.)

Fatty acid composition and moisture and oil content were determined for Montola-2001 and Centennial safflower varieties at three different harvest dates from flowering to maturity, which were grown as autumn and spring crops in two different locations in 2001–2002 and 2002–2003. The experiment was carried out using split–split plots in a randomized complete block design with three replicates. Sowing dates affected oil content and fatty acid compositions significantly (P < 0.01), whereas moisture content in both years was not significantly affected. Moisture content declined 15 days from flowering period to maturity, while oil content increased. The rate of the palmitic acid formation decreased in both varieties 15 days from flowering period to maturity, whereas formation rates of the oleic and linoleic acids increased in Montola-2001 and Centennial varieties, respectively.     

Seasonal Variations of the Antioxidant Composition in Ground Bamboo Sasa argenteastriatus Leaves

Sasa argenteastriatus, with abundant active compounds and high antioxidant activity in leaves, is a new leafy bamboo grove suitable for exploitation. To utilize it more effectively and scientifically, we investigate the seasonal variations of antioxidant composition in its leaves and antioxidant activity. The leaves of Sasa argenteastriatus were collected on the 5th day of each month in three same-sized sample plots from May 2009 to May 2011. The total flavonoids (TF): phenolics (TP) and triterpenoid (TT) of bamboo leaves were extracted and the contents analyzed by UV-spectrophotometer. Our data showed that all exhibited variations with the changing seasons, with the highest levels appearing in November to March. Antioxidant activity was measured using DPPH and FRAP methods. The highest antioxidant activity appeared in December with the lowest in May. Correlation analyses demonstrated that TP and TF exhibited high correlation with bamboo antioxidant activity. Eight bamboo characteristic compounds (orientin, isoorientin, vitexin, homovitexin and p-coumaric acid, chlorogenic acid, caffeic acid, ferulic acid) were determined by RP-HPLC synchronously. We found that chlorogenic acid, isoorientin and vitexin are the main compounds in Sasa argenteastriatus leaves and the content of isovitexin and chlorogenic acid showed a similar seasonal variation with the TF, TP and TT. Our results suggested that the optimum season for harvesting Sasa argenteastriatus leaves is between autumn and winter.     

Chemical Composition and Antioxidant Activities of Three Polysaccharide Fractions from Pine Cones

The traditional method of gas chromatography-mass spectrometry for monosaccharide component analysis with pretreatment of acetylation is described with slight modifications and verified in detail in this paper. It was then successfully applied to the quantitative analysis of component monosaccharides in polysaccharides extracted from the pine cones. The results demonstrated that the three pine cone polysaccharides all consisted of ribose, rhamnose, arabinose, xylose, mannose, glucose and galactose in different molar ratios. According to the recovery experiment, the described method was proved accurate and practical for the analysis of pine cone polysaccharides, meeting the need in the field of chemical analysis of Pinus plants. Furthermore; the chemical characteristics, such as neutral sugar, uronic acids, amino acids, molecular weights, and antioxidant activities of the polysaccharides were investigated by chemical and instrumental methods. The results showed that the chemical compositions of the polysaccharides differed from each other, especially in the content of neutral sugar and uronic acid. In the antioxidant assays, the polysaccharide fractions exhibited effective scavenging activities on ABTS radical and hydroxyl radical, with their antioxidant capabilities decreasing in the order of PKP > PAP > PSP. Therefore, although the polysaccharide fractions had little effect on superoxide radical scavenging, they still have potential to be developed as natural antioxidant agents in functional foods or medicine.     

油茶叶多糖的闪式提取工艺优化及其抗氧化活性

在单因素试验基础上用响应面法对油茶叶多糖的闪式提取工艺进行优化,并对较优条件下提取的多糖的抗氧化活性进行测试.研究结果表明:油茶叶多糖闪式提取的较佳工艺条件为料液比1:30 (g:mL),提取温度81℃,提取时间75 s,此条件下,油茶叶多糖得率为8.43％.油茶叶多糖对DPPH·、·ABTS+、OH·都有很强的清除能...     

海南蒲桃叶黄酮的提取及抗氧化性研究

采用正交试验法研究了海南蒲桃叶黄酮提取条件对黄酮得率的影响,确定了最佳提取条件为:乙醇体积分数70%,料液比1:20(g:mL),提取温度80℃提取3 h,此条件下黄酮得率为6.06%。利用体外试验检测不同浓度海南蒲桃叶黄酮对二苯基苦基苯肼DPPH·的清除作用。结果表明海南蒲桃叶黄酮是一种有效的自由基清除剂,对DPPH·有显著的清除作用。黄酮溶液质量浓度在31.25～250m g/L范围内,清除率随质量浓度增大而增大,最高可达93.04%。     

Evaluation of Antioxidant Properties and Mineral Composition of Purslane (Portulaca oleracea L.) at Different Growth Stages

The main objective of this research was to appraise the changes in mineral content and antioxidant attributes of Portulaca oleracea over different growth stages. The antioxidant activity was measured using 1,1-diphenyl-2-picrylhydrazyl (DPPH), ferric-reducing antioxidant power (FRAP) assays. The iodine titration method was used to determine the ascorbic acid content (AAC). DPPH scavenging (IC(50)) capacity ranged from 1.30 ± 0.04 to 1.71 ± 0.04 mg/mL, while the ascorbic acid equivalent antioxidant activity (AEAC) values were 229.5 ± 7.9 to 319.3 ± 8.7 mg AA/100 g, total phenol content (TPC) varied from 174.5 ± 8.5 to 348.5 ± 7.9 mg GAE/100 g. AAC 60.5 ± 2.1 to 86.5 ± 3.9 mg/100 g and FRAP 1.8 ± 0.1 to 4.3 ± 0.1 mg GAE/g. There was good correlation between the results of TPC and AEAC, and between IC(50) and FRAP assays (r(2) > 0.9). The concentrations of Ca, Mg, K, Fe and Zn increased with plant maturity. Calcium (Ca) was negatively correlated with sodium (Na) and chloride (Cl), but positively correlated with magnesium (Mg), potassium (K), iron (Fe) and zinc (Zn). Portulaca olerecea cultivars could be used as a source of minerals and antioxidants, especially for functional food and nutraceutical applications.     

荷叶总生物碱清除氧自由基作用的研究

应用微弱化学发光法考察荷叶总生物碱对氧自由基的清除作用,并与荷叶水提液、荷叶醇提液及维生素C进行比较.结果表明,荷叶总生物碱对3种氧自由基O-2·、·OH、H2O2的IC50分别为305 μg·mL-1、50 μg·mL-1、3700μg· mL-1,其清除·OH的能力最强,显示了较强的抗氧化活性;荷叶水提液、荷叶醇提...     

Ameliorating Effects of Exogenously Applied Proline on Seed Composition,Seed Oil Quality and Oil Antioxidant Activity of Maize (Zea mays L.) under Drought Stress

This study was carried out to appraise whether or not the exogenous application of a potential osmoprotectant, proline, could ameliorate the adverse effects of drought stress on maize seed and seed oil composition, as well as oil antioxidant activity. Water stress reduced the kernel sugar, oil, protein and moisture contents and most of the seed macro- and micro-elements analyzed in both maize cultivars but it increased the contents of seed fiber and ash. Water stress increased the oil oleic acid content with a subsequent decrease in the amount of linoleic acid, resulting in an increased oil oleic/linoleic ratio for both maize cultivars. However, no variation was observed in oil stearic and palmitic acids content due to water stress. A considerable drought induced an increase in seed oil α-, γ-, δ- and total tocopherols and flavonoids were observed in both maize cultivars. However, oil phenolic and carotenoid content as well as 1,1-diphenyl-2-picryl-hydrazyl (DPPH) free radical scavenging activity decreased. Foliar-applied proline significantly increased the content of seed sugar, oil, protein, moisture, fiber and ash in both maize cultivars under well irrigated and water deficit conditions. Furthermore, exogenous application of proline increased the oil oleic and linoleic acid contents. The concentrations of antioxidant compounds namely phenolics, carotenoids, flavonoids and tocopherols estimated in the seed oil increased due to foliar-applied proline under water deficit conditions that was positively correlated with the enhanced oil DPPH free radical scavenging activity. Moreover, the increase in the contents of these antioxidant compounds and oil antioxidant activity due to the foliar application of proline was noted to be more pronounced under water deficit conditions.     

饿蚂蝗中黄酮类化合物的抗氧化活性的研究

提取了饿蚂蝗中的黄酮化合物,并研究了其含量及与体外抗氧化活性关系。用体积分数为75%的乙醇提取饿蚂蝗全草黄酮化合物,并采用HPD-100大孔树脂对粗提液进行精制,利用NaNO2-Al（ NO3）3-NaOH显色法和可见分光光度法测定精制黄酮的含量。采用DPPH和ABTS自由基测定法,对饿蚂蝗黄酮化合物的抗氧化活性进行评价。结果表明：在自由基清除实验中,精制饿蚂蝗黄酮类化合物自由基清除能力高于未精制的乙醇提取物。饿蚂蝗黄酮类化合物的体外抗氧化活性与黄酮含量呈正相关性。     

灰绿藜叶总黄酮提取及抗氧化活性

通过紫外-可见分光光度法,结合方法学研究,得到优化的灰绿藜叶总黄酮含量测定方法。采用单因素和响应面实验优化微波提取灰绿藜叶黄酮的工艺条件,同时研究了灰绿藜叶黄酮对.OH及O2-.的清除效果。结果表明,以质量分数3%AlCl3在273.5 nm测定的灰绿藜叶总黄酮含量的方法是最合适的。该法的稳定性、重复性、精确度、回收率均较好,其RSD分别为:1.42%、1.83%、0.86%和0.60%。微波提取灰绿藜叶黄酮的最佳提取条件为:乙醇体积分数57%,液料比(即每克固体料加入溶剂的体积量,mL/g,下同)20∶1,微波功率500 W,微波时间7.8 min,在该工艺条件下,灰绿藜叶黄酮得率为3.292%。灰绿藜叶黄酮对.OH及O2-.具有较好的清除作用。     

Screening the Antioxidant and Antimicrobial Properties of the Extracts from Plantain (Plantago Major L.) Leaves

Abstract

Antioxidant and antimicrobial activities of the extracts obtained by classical (maceration) and ultrasonic (40 kHz) extraction from dry Plantago major leaves were compared. The antioxidant activities of extracts obtained by ultrasonic and classical extraction were 0.87±0.02 and 0.85±0.02 µg/µg DPPH, respectively. Ultrasound positively affected the extractive substance yield and the kinetics of extraction, but the extract obtained by classical extraction contained higher total contents of phenolic compounds and flavonoids than that obtained by ultrasonic extraction. Extracts of P. major showed better antimicrobial activity against the yeasts than against the bacteria.     

Phenolic Compounds from Halimodendron halodendron (Pall.) Voss and Their Antimicrobial and Antioxidant Activities

Halimodendron halodendron has been used as forage in northwestern China for a long time. Its young leaves and flowers are edible and favored by indigenous people. In this study, eleven phenolic compounds were bioassay-guided and isolated from the aerial parts of H. halodendron for the first time. They were identified by means of physicochemical and spectrometric analysis as quercetin (1), 3,5,7,8,4′-pentahydroxy-3′-methoxy flavone (2), 3-O-methylquercetin (3), 3,3′-di-O-methylquercetin (4), 3,3′-di-O-methylquercetin-7-O-β-d-glucopyranoside (5), isorhamentin-3-O-β-d-rutinoside (6), 8-O-methylretusin (7), 8-O-methylretusin-7-O-β-d-glucopyranoside (8), salicylic acid (9), p-hydroxybenzoic acid (ferulic acid) (10), and 4-hydroxy-3-methoxy cinnamic acid (11). They were sorted as flavonols (1–6), soflavones (7 and 8), and phenolic acids (9–11). Among the compounds, flanools 1–4 revealed a strong antibacterial activity with minimum inhibitory concentration (MIC) values of 50–150 μg/mL, and median inhibitory concentration (IC₅₀) values of 26.8–125.1 μg/mL. The two isoflavones (7 and 8) showed moderate inhibitory activity on the test bacteria. Three phenolic acids (9, 10 and 11) showed strong antibacterial activity with IC₅₀ values of 28.1–149.7 μg/mL. Antifungal activities of the compounds were similar to their antibacterial activities. All these phenolic compounds showed significant antimicrobial activity with a broad spectrum as well as antioxidant activity based on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging and β-carotene-linoleic acid bleaching assays. In general, the flavonol aglycones with relatively low polarity exhibited stronger activities than the glycosides. The results suggest the potential of this plant as a source of functional food ingredients and provide support data for its utilization as forage as well.     

Pereskia aculeata Muller (Cactaceae) Leaves: Chemical Composition and Biological Activities

The aims of this work were to study the chemical composition of the essential oil from the leaves of Pereskia aculeata and to evaluate some biological activities of three leaf extracts. The phenolic content, antioxidant activity, and in vitro antimicrobial and antifungal activities were determined. The methanol extract showed antioxidant activity (EC₅₀ 7.09 mg/mL) and high polyphenols content (15.04 ± 0.31 mg gallic acid equivalents (GAE)/g). The petroleum ether extract exhibited potent antibacterial activity against Escherichia coli, whereas the chloroform extract showed inhibitory activity against Bacillus cereus and Staphylococcus aureus. The petroleum ether and methanol extracts were more effective in inhibiting the growth of Aspergillus versicolor. The possible cytotoxicity of extracts on neuroblastoma SH-SY5Y cancer cell line and the influence on adenylate cyclase (ADCY) expression was also studied. P. aculeata chloroform extract showed antiproliferative activity with an IC₅₀ value of 262.83 µg/mL. Treatments of SH-SY5Y neuroblastoma cells with 100 µg/mL of methanol extract significantly reduced ADCY1 expression.     

响应面法优化闪式提取罗汉松总黄酮及抗氧化活性研究

本研究对罗汉松总黄酮提取工艺及其抗氧化活性进行了研究,采用闪式提取法提取罗汉松总黄酮,并通过单因素法和响应面优化方法,同时考察了罗汉松总黄酮对DPPH•、O2-•和•OH自由基清除作用。结果表明,闪式提取罗汉松总黄酮最佳工艺条件为：乙醇浓度71 %、料液比1:36 (g·mL-1)、提取时间53 s、提取电压为75 V时,罗汉松总黄酮提取率为8.147 %。罗汉松总黄酮对DPPH•、O2-•和•OH具有明显的清除能力,最大清除率分别达到87.13%、58.24%和67.56%,为罗汉松的综合开发利用提供了参考。     

Polyphenolic Contents and Antioxidant Potential of Stem Bark Extracts from Jatropha curcas (Linn)

We assessed the polyphenolic contents and antioxidant potential of the aqueous, ethanol and methanol stem bark extracts of Jatropha curcas. The total phenol, flavonoids, flavonols and proanthocyanidin contents of the extracts were evaluated to determine their effect on the antioxidant property of this plant, using standard phytochemical methods. The antioxidant and free radical scavenging activity of ethanol, methanol and aqueous extracts of the plant were also assessed against 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), ferric reducing, nitric oxide (NO), superoxide anion, (O(2) (-)) and hydrogen peroxide (H(2)O(2)) using spectroscopic methods and results were compared with that of butylated hydroxyl toluene (BHT) and ascorbic acid as standards. The concentrations of different classes of phenolic compounds were higher in methanol and ethanol extracts compared to aqueous extracts. There was correlation between total phenol, total flavonoids, total flavonol and total proanthocyanidins (r = 0.996, 0.978, 0.908, and 0.985) respectively. There was correlations between the amount of phenolic compounds and percentage inhibition of DPPH radicals scavenging activity of the extract (r = 0.98). Findings from the present study indicated that J. curcas is a potential source of natural antioxidants and may be a good candidate for pharmaceutical plant based products.