连香树水提物和乙醇提取物的体外抗氧化研究

为了探究连香树水提物和乙醇提取物的主要成分和抗氧化作用,该研究采用水提和醇提两种方法提取连香树叶片中的代谢物并测定其主要成分,通过体外抗氧化实验,即清除羟自由基(·OH)、DPPH自由基(DPPH·)、超氧阴离子(O_2~-·)和还原铁离子(Fe~(3+))的能力等四个指标来评价其抗氧化作用。结果表明:连香树水提物和乙醇提取物中均含有山萘酚。此外,水提物中还含有苜蓿素和异槲皮苷等黄酮类物质;乙醇提取物中还含有柚皮素和槲皮素3-O-β-D-葡萄糖苷等黄酮类物质。水提物和乙醇提取物均有清除羟自由基、DPPH自由基、超氧阴离子及还原三价铁离子的能力。抗氧化的作用随提取物浓度的增大而增强,其中清除超氧阴离子(IC50值分别为0.092、0.002 mg·mL~(-1))的能力强于阳性对照Vc(IC_(50)值为0.241 mg·mL~(-1))且铁离子还原力的IC_(50)值(水提物为0.014 mg·mL~(-1),乙醇提取物为0.001 mg·mL~(-1))相对较小,说明其总抗氧化活性较强。由此可见,连香树水提物和乙醇提取物均具有良好的抗氧化作用,可作为一种潜在的天然抗氧化剂。     

金缕半枫荷多酚提取及其抗氧化抗菌活性研究

为进一步开发和利用金缕半枫荷,该研究以超声时间、液料比、乙醇体积分数和超声温度为考察因素,用金缕半枫荷总多酚提取率作为评价指标,采用单因素和正交试验优化提取工艺确定最佳工艺,并以最佳工艺制备金缕半枫荷多酚;进一步采用DPPH·和羟自由基清除法评价金缕半枫荷多酚的抗氧化能力,以抑菌圈和最小抑菌浓度(MIC)为指标,采用牛津杯和肉汤稀释法考察其抗菌活性。结果表明:最佳提取工艺为乙醇浓度70%,料液比为1∶16,提取时间为60 min,提取温度为60℃。金缕半枫荷多酚清除DPPH·自由基的IC_(50)为5.22μg·mL~(-1),与阳性对照维生素C的IC_(50)值4.31μg·mL~(-1)无显著差异,羟自由基清除率IC_(50)为105μg·mL~(-1),显著低于维生素C的IC_(50)值(180μg·mL~(-1))。对金黄色葡萄球菌和大肠杆菌具有抑制作用,抑菌圈直径分别为(13.7±1.2) mm和(10.0±1.3) mm,MIC分别为0.393和0.785 mg·mL~(-1)。这表明金缕半枫荷多酚具有抗菌和显著抗氧化能力,为开发利用金缕半枫荷资源提供了理论依据。     

羊肚菌多糖提取及其抗氧化活性研究

为了探讨碱法提取羊肚菌多糖的工艺条件并测定其抗氧化活性,该研究以四川北川羊肚菌为原料,采用碱法提取羊肚菌多糖,利用苯酚-硫酸法对羊肚菌多糖得率进行测定,并通过单因素探讨提取温度(70、80、90、100℃)、提取时间(2、4、6、8 h)、碱液浓度(0.4、0.6、0.8、1.0 mol·L~(-1))、料液比(1∶15、1∶20、1∶25、1∶30 g·mL~(-1))对羊肚菌多糖得率的影响,同时采用正交试验优化提取工艺,对其抗氧化活性进行测定。结果表明:在提取温度90℃、提取时间5 h、碱液浓度0.7 mol·L~(-1)、料液比1∶20(g·mL~(-1))条件下得到的羊肚菌多糖得率为5.39%。羊肚菌多糖具有较强的清除DPPH自由基、羟自由基、超氧阴离子的能力和较好的还原能力,其IC50分别为0.468、0.208、0.022、0.014 mg·mL~(-1),抗氧化能力依次为还原能力超氧阴离子清除能力羟自由基清除能力DPPH自由基清除能力。优化后的羊肚菌多糖提取工艺合理、可行,且羊肚菌多糖具有较强的抗氧化活性。     

肠浒苔多糖的羧甲基化修饰及其抗氧化活性研究

该研究采用氢氧化钠-氯乙酸的化学反应体系制备羧甲基化肠浒苔多糖,以获得不同取代度的羧甲基化肠浒苔多糖,取代度的大小受氢氧化钠浓度、反应温度和反应时间的影响。结果表明:(1)当氢氧化钠浓度20%、反应温度60℃、反应时间3 h时,得到羧甲基化的最大取代度为0.781。(2)通过体外抗氧化来评价不同羧甲基化肠浒苔多糖的抗氧化活性。(3)当羧甲基化肠浒苔多糖的浓度为1.6 mg·mL~(-1)时,羧甲基化肠浒苔多糖清除羟基自由基、超氧阴离子自由基的能力分别为44.45%、51.98%,其清除DPPH自由基清除率和还原能力分别为16.75%、0.457 6。(4)与修饰前的相比,羟基自由基、超氧阴离子的清除能力均有较大幅度提高,羧甲基化修饰对肠浒苔多糖的DPPH自由基和还原力有减弱作用。以上结果表明,羧甲基化修饰引起的肠浒苔多糖的结构变化可以提高其抗氧化活性。     

红冬蛇菰提取物抗氧化及抑制亚硝化作用研究

对红冬蛇菰不同溶剂提取物的抗氧化活性及抑制亚硝化作用进行比较研究。采用DPPH法、ABTS法和普鲁士蓝法分别测定各提取物的自由基清除能力和铁离子还原力,以评价红冬蛇菰的抗氧化能力;采用盐酸萘乙二胺法和α-萘胺法分别测定红冬蛇菰各提取物对亚硝酸盐的清除率和对亚硝胺合成的阻断率,以评价红冬蛇菰的抑制亚硝化作用。实验结果表明,红冬蛇菰各提取物中乙酸乙酯提取物清除DPPH自由基(IC_(50)=0.06±0.001 mg/mL)和ABTS自由基(IC_(50)=0.07±0.001 mg/mL)能力以及对铁离子还原能力最强,并显著强于其他提取物(P0.01),其中清除ABTS自由基的能力显著高于Vc(IC_(50)=0.10±0.002 mg/mL)(P0.01);在模拟人体胃液的条件下(pH 3.0,温度37℃),各提取物能有效地清除亚硝酸盐以及阻断亚硝胺合成,并随着反应质量浓度增加清除率和阻断率增大最后趋于平缓,其中乙酸乙酯提取物对亚硝酸盐的清除能力(IC_(50)=1.91±0.022 mg/mL)和亚硝胺合成的阻断能力(IC_(50)=8.44±0.091 mg/mL)均显著强于其他提取物(P0.01)。红冬蛇菰提取物属天然产物,具有较好的抗氧化活性和抑制亚硝化作用,因此在抗氧化剂的研究方面具有潜在的开发利用价值,同时极有可能是一种新的防癌抗癌天然保健品。     

荸荠皮多糖体外清除自由基活性的研究

采用DPPH自由基法、邻苯三酚自氧化法和水杨酸法分别表征了荸荠皮多糖清除DPPH自由基(DPPH.)、超氧阴离子自由基(O2-.)和羟基自由基(.OH)的能力。结果显示,脱蛋白和未脱蛋白荸荠皮多糖具有清除自由基的活性,但该活性明显低于茶多酚。脱蛋白多糖清除DPPH.的能力高于未脱蛋白多糖,其清除50%DPPH.的作用质量浓度(EC50)分别为50.26 mg.L-1和76.22 mg.L-1。两种多糖清除.OH和O2-.的能力相当,其EC50(g.L-1)分别为0.118和0.124以及10.87和9.53。     

栽培辣蓼提取物清除DPPH反应体系的优化及抗氧化能力评价

本研究目的是优化辣蓼提取物清除DPPH(1,1-二苯基-2-三硝基苯)的反应体系,研究栽培辣蓼提取物的抗氧化能力,更好地利用栽培辣蓼资源。本研究首先优化DPPH工作及保存参数,筛选辣蓼提取物清除DPPH体系;进而测定辣蓼提取物DPPH清除率。结果显示DPPH溶液应用无水乙醇现用现配,4℃保存,工作浓度应在36.3~121μmol/L之间;辣蓼提取物清除DPPH的反应时间为30 min,室温(27℃)避光。辣蓼提取物的IC_(50)为334 mg/L。优化DPPH清除反应体系后,测定的辣蓼提取物清除DPPH活性准确可信,可更好的评价栽培辣蓼提取物的抗氧化能力。     

电子顺磁共振对五种中草药抗氧化活性的研究

采用电子顺磁共振(EPR)技术,通过大黄、香青兰、香茅草、懈寄生和骆驼蓬子五种中草药对1,1-二苯基-2-苦基肼自由基(DPPH)、羟基自由基(·OH)和超氧阴离子自由基(O-·2)3种自由基清除能力大小的比较,研究了大黄等五种中草药抗氧化活性能力。这五种中草药对3种自由基均有一定的清除作用,其中大黄清除DPPH和超氧阴离子自由基的IC50小于0.5 mg/mL,清除羟基自由基的IC50=1.892 mg/mL。结果表明五种中草药中大黄的抗氧化活性能力最强,为中草药用于生物体的抗氧化应激研究提供依据。     

红树植物桐花树叶片多酚提取物对酪氨酸酶活性抑制及抗自由基和抗菌活性分析

采用超声波辅助-乙酸乙酯提取方法获得桐花树〔Aegiceras corniculatum(Linn.)Blanco〕叶片多酚提取物,研究了该提取物对酪氨酸酶活性的抑制作用及其动力学特征,并分析了该提取物对DPPH·自由基的清除作用及其抗菌活性。结果显示:多酚提取物得率约为(122.0±31.4)mg·g-1,提取物中多酚含量约为(521.8±17.2)mg·g-1。该提取物对酪氨酸酶活性的抑制作用呈明显正相关的量效关系,IC50为0.650 g·L-1,与阳性对照槲皮素对酪氨酸酶活性的抑制能力相近;该提取物通过降低酶活性实现对酪氨酸酶活性的抑制,且该抑制作用具有可逆性;随提取物质量浓度的提高酶促反应Km值增大、vm值减小,其动力学特征符合混合Ⅰ型抑制类型;对游离酶的抑制常数Ki为0.833 g·L-1,对酶-底物络合物的抑制常数Kis为1.823 g·L-1,表明该提取物与游离酶的亲和力大于其与酶-底物络合物的亲和力。随质量浓度提高,该提取物对DPPH·自由基的清除率逐渐增大并在0.000~0.600 g·L-1范围内呈明显量效关系,且IC50为0.304 g·L-1,与0.036 g·L-1槲皮素等效,显示该多酚提取物对自由基的清除能力较强。随质量浓度提高,该提取物对大肠杆菌(Escherichia coli)、金黄色葡萄球菌(Staphylococcus aureus)和枯草芽孢杆菌(Bacillus subtilis)的抑菌圈直径均逐渐增大,显示该提取物对3种供试菌均有抑菌作用,最小抑菌浓度均为25 g·L-1。结果表明:通过深入的开发研究,桐花树叶片多酚提取物可作为兼具辅助防腐抑菌功能的新型酪氨酸酶抑制剂。     

黑豆多肽分离及其抗氧化活性的研究

采用凝胶柱层析法分离具有抗氧化活性的黑豆多肽,并分析其分子量分布;同时还采用DPPH·清除法研究各分离肽段的抗氧化活性,对抗氧化活性最佳的肽段进行动力学分析.结果表明:黑豆多肽经分离后得到3个片段,黑豆小分子肽BSP3对DPPH·自由基具有最强清除作用,其半清除浓度(HSC50)为0.664 mg/mL.所以,分子量小于1000 Da的黑豆小分子肽具有很好的抗氧化活性.     

Antioxidant activities of sulfated polysaccharides from brown and red seaweeds

The in vitro antioxidant activities of the following six sulfated polysaccharides were investigated: iota, kappa and lambda carrageenans, which are widely used in the food industry, fucoidan (homofucan) from the edible seaweed Fucus vesiculosus and fucans (heterofucans) F0.5 and F1.1 from the seaweed Padina gymnospora. With respect to the inhibition of superoxide radical formation, fucoidan had an IC₅₀ (the half maximal inhibitory concentration) of 0.058 mg·mL⁻¹, while the IC₅₀ for the kappa, iota and lambda carrageenans were 0.112, 0.332 and 0.046 mg·mL⁻¹, respectively. All of the samples had an inhibitory effect on the formation of hydroxyl radicals. The results of peroxidation tests showed that fucoidan had an IC₅₀ of 1.250 mg·mL⁻¹ and that the kappa, iota and lambda carrageenans had an IC₅₀ of 2.753 and 2.338 and 0.323 mg·mL⁻¹, respectively. Fucan fractions showed low antioxidant activity relative to fucoidan. These results clearly indicate the beneficial effect of algal polysaccharides as antioxidants.     

不同炮制方法对玉竹提取物得率及体外抗氧化作用的影响

以多糖、总黄酮、醇溶物和水溶物的得率及体外抗氧化活性为考察指标,研究了酒蒸和蜜蒸两种炮制方法对玉竹品质的影响。结果表明：酒蒸炮制玉竹的多糖、醇溶物得率最高,蜜蒸炮制玉竹总黄酮、水溶物的得率最高,比未炮制的玉竹（生品玉竹）中相应成分的得率分别提高了43.86%、29.53%、49.46%和34.66%。将多糖、水溶性浸出物、醇溶性浸出物及总黄酮四者得率相加的和进行比较,蜜蒸最好,蜜蒸为111.069%,酒蒸为107.309%,生品玉竹为80.926%。酒蒸炮制玉竹的多糖、水溶物对DPPH自由基的清除率均高于蜜蒸玉竹和生品玉竹,其DPPH_IC50分别为0.345±0.019和0.441±0.022 mg·mL^-1;蜜蒸炮制玉竹的总黄酮、醇溶物对DPPH自由基的清除率均高于酒蒸玉竹和生品玉竹,其DPPH_IC50分别为0.047±0.011和0.199±0.036 mg·mL^-1;在浓度为1 mg·mL^-1时,蜜蒸玉竹总黄酮对DPPH自由基的清除率最大,为90.29%,超过了浓度为0.05 mg·mL^-1的芦丁和槲皮素标品对DPPH自由基的清除率。两种炮制方法均提高了多糖、水溶物、总黄酮3种提取物的还原能力,但是降低了醇溶物的还原能力。     

火棘花挥发油化学成分的GC-MS分析及抗氧化活性研究

采用水蒸气蒸馏法提取火棘花挥发油,利用气相色谱—质谱联用技术(GC-MS)分析其化学成分。使用维生素C和BHT为阳性对照,以DPPH自由基、亚硝酸钠清除作用为指标评价挥发油的抗氧化活性。从挥发油中鉴定了77个化合物,占挥发油总量的83.77%,含有多种生物活性成分,以萜类及其含氧衍生物(50.31%)、烷烃(18.52%)、醛(5.54%)为主;挥发油对DPPH自由基、亚硝酸钠有明显的清除作用,清除率为50%时,其体积分别为43.51、79.48μL,样品量与清除率间呈量效关系;挥发油对DPPH自由基的清除效果略低于1 mg·mL-1维生素C,对亚硝酸钠的清除效果优于1 mg·mL-1的BHT。     

Polyphenol Characterization,Antioxidant and Skin Whitening Properties of Alnus cordata Stem Bark

In this study, we investigated the phenolic composition of the crude extract (MeOH 80 %) of Alnus cordata (Loisel .) Duby stem bark (ACE) and its antioxidant and skin whitening properties. RP‐LC‐DAD analysis showed a high content of hydroxycinnamic acids (47.64 %), flavanones (26.74 %) and diarylheptanoids (17.69 %). Furthermore, ACE exhibited a dose‐dependent antioxidant and free‐radical scavenging activity, expressed as half‐maximal inhibitory concentration (IC₅₀): Oxygen radical absorbance capacity (ORAC, IC₅₀ 1.78 μg mL^?1)>Trolox equivalent antioxidant capacity (TEAC, IC₅₀ 3.47 μg mL^?1)>2,2‐Diphenyl‐1‐picrylhydrazyl (DPPH, IC₅₀ 5.83 μg mL^?1)>β‐carotene bleaching (IC₅₀ 11.58 μg mL^?1)>Ferric reducing antioxidant power (FRAP, IC₅₀ 17.28 μg mL^?1). Moreover, ACE was able to inhibit in vitro tyrosinase activity (IC₅₀ 77.44 μg mL^?1), l ‐DOPA auto‐oxidation (IC₅₀ 39.58 μg mL^?1) and in an in vivo model it exhibited bleaching effects on the pigmentation of zebrafish embryos (72 h post fertilization) without affecting their development and survival. In conclusion, results show that A. cordata stem bark may be considered a potential source of agents for the treatment of skin disorders due to its bleaching properties and favorable safety profiles, associated to a good antioxidant power.     

Fatty acid composition and biological activities of Isochrysis galbana T-ISO,Tetraselmis sp. and Scenedesmus sp.: possible application in the pharmaceutical and functional food industries

Organic and water extracts of Isochrysis galbana T-ISO (=Tisochrysis lutea), Tetraselmis sp. and Scenedesmus sp. were evaluated for their antioxidant activity, acetylcholinesterase (AChE) inhibition, cytotoxicity against tumour cell lines, and fatty acids and total phenolic content (TPC). I. galbana T-ISO had the highest TPC (3.18 mg GAE g^?1) and radical scavenging activity, with an IC₅₀ value of 1.9 mg mL^?1 on the acetone extract. The extracts exhibited a higher ability to chelate Fe²⁺ than Cu²⁺, and the maximum Fe²⁺ chelating capacity was observed in the hexane extract of Scenedesmus sp. (IC₅₀=0.73 mg mL^?1) and Scenedesmus sp. (IC₅₀?=?0.73 mg mL^?1). The highest ability to inhibit AChE was observed in the water and ether extracts of Scenedesmus sp., with IC₅₀ values of 0.11 and 0.15 mg mL^?1, respectively, and in the water extract of I. galbana (IC₅₀?=?0.16 mg mL^?1). The acetone extract of I. galbana T-ISO significantly reduced the viability of human hepatic carcinoma HepG2 cells (IC₅₀?=?81.3 μg mL^?1) as compared to the non-tumour murine stromal S17 cell line, and displayed a selectivity index of 3.1 at the highest concentration tested (125 μg mL^?1). All species presented a highly unsaturated fatty acids profile. Results suggest that these microalgae, particularly I. galbana T-ISO, could be a source of biomolecules for the pharmaceutical industry and the production of functional food ingredients and can be considered as an advantageous alternative to several currently produced microalgae.     

Evaluation of antioxidant capacities of green microalgae

Three strains of green microalgae, Chlorococcum sp.C53, Chlorella sp. E53, and Chlorella sp.ED53 were studied for their antioxidant activities. Crude extracts of these microalgae in hot water and in ethanol were examined for their total phenolic contents and for their antioxidant capacities. In order to determine their phenolic contents, the Folin–Ciocalteu method was used. As for the determination of their antioxidant capacities, four different assays were used: (1) total antioxidant capacity determination; (2) DPPH radical scavenging assay; (3) ferrous ion chelating ability assay; and (4) inhibition of lipid peroxidation (using thiobarbituric acid reactive substance). For all the strains we have studied, their ethanolic extract showed more antioxidant activities than their hot water extract. Categorically, the ethanolic extract of Chlorella sp.E53 exhibited both the highest total phenolic content of 35.5?±?0.14 mg gallic acid equivalent (GAE) g^?1 dry weight and the highest DPPH radical scavenging of 68.18?±?0.38 % at 1.4 mg mL^?1 (IC₅₀ 0.81 mg mL^?1), whereas Chlorella sp.ED53 showed both the highest ferrous ion chelation activity of 42.78?±?1.48 % at 1 mg mL^?1 (IC₅₀ 1.23 mg mL^?1) and the highest inhibition of lipid peroxidation of 87.96?±?0.59 % at 4 mg mL^?1. This high level of inhibition is comparable to 94.42?±?1.39 % of butylated hydroxytoluene, a commercial synthetic antioxidant, at the same concentration.     

雪松不同部位中原花青素的含量测定及其清除DPPH自由基的活性

雪松(Cedrus deodara)是松科(Pianaceae)雪松属(Cedrus)树种的泛称,为广泛分布于喜马拉雅山脉的常绿树种,包括雪松(C.deodara)、黎巴嫩雪松(C.libani)、短叶雪松(C.brevifolia)和北非雪松(C.atlantica)等。雪松的针叶药用历史悠久,主要化学成分为黄酮类、苯丙素类、有机酸类、三萜类、甾体类、多糖及针叶胶等,具有抗肿瘤、抗氧化、改善记忆、抗菌及抗病毒等多种功效。为了测定雪松不同部位中原花青素的含量,并考察其清除DPPH自由基活性的能力,该研究以Fe3+离子为催化剂,用正丁醇-盐酸法分别测定雪松松针、花序、小枝、木质部、树皮中原花青素的含量,并对不同部位提取液清除DPPH自由基的能力进行测定。结果表明:松针、花序、木质部、树皮、小枝中原花青素的含量分别为12.93%、12.93%、6.41%、12.00%、3.37%,在质量浓度(以生药计)为0.8 mg·m L-1时,其对DPPH自由基的清除率均达到或接近90%。该研究结果提示雪松各个部位的原花青素含量丰富,其提取液的体外抗氧化活性很高,这为雪松的进一步开发利用提供了很好的参考价值。     

Chemical characteristics,antioxidant and anticancer potential of sulfated polysaccharides from <Emphasis Type="Italic">Chlamydomonas reinhardtii</Emphasis>

The sulfated polysaccharides (SPs) from Chlamydomonas reinhardtii (Cr) were isolated by hot water method using 80% alcohol and semi purified by anion-exchange column chromatography. The chemical analysis of the extract showed 78% carbohydrates, 18% reducing sugars, 60% non-reducing sugars, 2% protein, 33% sulfate, 39% uronic acid, and 4% ash. The elemental analysis of this C. reinhardtii sulfated polysaccharide-enriched extract (Cr-SPs) showed 53% carbon, 8% hydrogen, and 6% nitrogen. FTIR analysis of Cr-SPs showed characteristic bands of sulfated polysaccharides. Further, the Cr-SPs showed significant hydroxyl radical scavenging activity of 22.29–80.9% at 0.01–1 mg mL^?1, 38–77% of DPPH radical scavenging activity at 0.01–1 mg mL^?1, 9.8–81% ABTS radical scavenging activity, 34.5–67.6% of ferrous chelating ability, and 11.62–75% of total antioxidant capacity. Cr-SPs also showed efficient in vitro anticancer activity. Specifically, they inhibited triple-negative breast cancer cell (MDA-MB-231) proliferation with an IC₅₀ of 172 μg mL^?1. Concentration-dependent reduction in the number of colonies formed by MDA-MB-231 cells suggested their potential to inhibit the clonal expansion of the cancer cells. Higher concentrations of crude extract were found to disrupt the microtubule networks in these cells. The cells treated with Cr-SPs eventually underwent apoptosis as evidenced by the formation of characteristic DNA ladder. These results indicate that Cr-SPs find promising opportunities for cancer treatment.     

In vitro antioxidant activity of silymarin

Silymarin, a known standardized extract obtained from seeds of Silybum marianum is widely used in treatment of several diseases of varying origin. In the present paper, we clarified the antioxidant activity of silymarin by employing various in vitro antioxidant assay such as 1,1-diphenyl-2-picryl-hydrazyl free radical (DPPH·) scavenging, 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging activity, total antioxidant activity determination by ferric thiocyanate, total reducing ability determination by Fe³⁺ ? Fe²⁺ transformation method and Cuprac assay, superoxide anion radical scavenging by riboflavin/methionine/illuminate system, hydrogen peroxide scavenging and ferrous ions (Fe²⁺) chelating activities. Silymarin inhibited 82.7% lipid peroxidation of linoleic acid emulsion at 30 μg/mL concentration; butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), α-tocopherol and trolox indicated inhibition of 83.3, 82.1, 68.1 and 81.3% on peroxidation of linoleic acid emulsion at the same concentration, respectively. In addition, silymarin had an effective DPPH· scavenging, ABTS^√+ scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, ferric ions (Fe³⁺) reducing power by Fe³⁺ ? Fe²⁺ transformation, cupric ions (Cu²⁺) reducing ability by Cuprac method, and ferrous ions (Fe²⁺) chelating activities. Also, BHA, BHT, α-tocopherol and trolox, were used as the reference antioxidant and radical scavenger compounds. Moreover, this study, which clarifies antioxidant mechanism of silymarin, brings new information on the antioxidant properties of silymarin. According to the present study, silymarin had effective in vitro antioxidant and radical scavenging activity. It could be used in the pharmacological and food industry because of its antioxidant properties.     

4种珍稀食用菌水提物的抗氧化活性研究

用DPPH自由基清除法、羟基自由基清除法和超氧阴离子自由基清除法对4种珍稀食用菌灵芝、云芝、茶树菇、松茸的水提物进行抗氧化活性评价,为更好评价其抗氧化活性,以维生素C作为阳性对照。实验结果显示：4种食用菌水提物具有不同程度的抗氧化活性。云芝对DPPH自由基的清除能力最强,其IC₅₀值为1.46 mg/mL,维生素C清除DPPH自由基的IC₅₀为0.046 mg/mL;茶树菇对清除羟基自由基的清除能力最强,其IC₅₀值为1.41 mg/mL,云芝和松茸也有较强清除羟自由基能力,其IC₅₀值分别为1.56、1.57 mg/mL,三者的清除能力均明显优于阳性对照样品,维生素C清除羟自由基的IC₅₀为2.41 mg/mL;灵芝和云芝有较强清除超氧阴离子自由基能力,其IC₅₀值分别为124.48、138.28 mg/mL。