灵芝抗氧化清除自由基作用的研究

文中综述了灵芝的抗氧化清除自由基作用。灵芝对各种因素引起的脑、心脏、胰腺、肝脏、胃肠道、肾脏和其他重要脏器的脂质过氧化损伤具有明显的保护作用。灵芝可显著减少脂质过氧化产物丙二醛(MDA)的含量,增强抗氧化酶如超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-PX)以及其他抗氧化酶的活性。稹灵芝对体外培养的巨噬细胞(小鼠)、胰岛细胞(小鼠)、大脑皮层细胞(大鼠)、嗜铬细胞瘤细胞(大鼠)、血管内皮细胞(大鼠、人)和皮肤角质细胞(人)的氧化损伤具有明显保护作用。灵芝在体内外对不同动物模型和细胞模型的抗氧化清除自由基作用可能与其免疫调节、抗肿瘤、降血压、降血糖、保肝、心血管保护和抗衰老作用的机制有关。     

红花的化学成分及DPPH自由基清除活性研究

从红花中分离得到14个化合物,通过波谱数据和理化性质分别鉴定为:异光黄素(1)、(2S)-4',5,6,7-四羟基二氢黄酮-6-O-β-D-葡萄糖苷(2)、新红花苷(3)、山柰酚(4)、山柰酚-3-O-β-D-葡萄糖苷(5)、山柰酚-3-O-β-芸香糖苷(6)、6-羟基山柰酚(7)、6-羟基山柰酚-3-O-β-D-葡萄糖苷(8)、槲皮素(9)、对羟基苯甲酸(10)、对羟基桂皮酸(11)、尿嘧啶(12)、腺嘌呤(13)、β-谷甾醇(14),其中化合物1首次从红花属植物中分离得到。采用TLC-DPPH生物自显影法筛选单体化合物及红花醇提物各萃取部位的自由基清除活性,结果表明乙酸乙酯萃取物及化合物4、9、11具有明显的DPPH自由基清除活性。     

灵芝液体发酵清除自由基活性产物发酵条件的优化

以红灵芝(Ganoderma.lucidum)为实验菌株,对其液体发酵活性产物清除自由基的发酵条件进行了研究。实验考察了培养基成分对灵芝液体发酵所产生的有效产物清除自由基能力的影响。结果表明,葡萄糖、酵母粉分别为灵芝发酵活性产物清除自由基效果较合适的碳源、氮源,最佳质量浓度分别为40 g.L-1和3 g.L-1,清除自由基的能力分别为55.7%、40.8%和66.5%、50.6%;铁离子对灵芝发酵产物清除超氧阴离子具有明显的效果,适宜质量分数为70×10-6;清除超氧阴离子的能力为54.6%,而硒离子对灵芝发酵产物抑制羟自由基有明显的促进作用,最适的质量分数为90×10-6清除羟自由基的能力为67.7%。油酸能促进灵芝发酵产物的清除超氧阴离子和羟自由基的能力,适宜的质量分数为0.1%,清除两种自由基的能力分别为:73.7%,53%。     

怀山药醇提取物抗DPPH自由基活性研究

将怀山药乙醇提取物采用溶剂萃取的方法,分成极性不同的五个部分,并首次用DPPH(2,2-diphenyl-1-picrylhydrazyl)方法测定各部分的抗自由基活性,发现乙酸乙酯萃取部分活性最强,氯仿萃取部分次之,再其次是正丁醇和水溶性部分。乙酸乙酯和氯仿萃取部分较强的抗自由基活性主要归因于其中所含的多酚类成分。同时利用薄层层析(TLC)、紫外光谱(UV)、^13C核磁共振(NMR)技术及显色反应对酚性成分进行了定性检验,并用Folin-Denis法测定了各萃取部位中酚性成分含量,发现抗自由基活性与萃取物中多酚性成分含量有一定的相关性。因而在评价怀山药质量时,其中所含的酚性成分不应忽视。     

蔷薇科一些植物鲜叶提取物清除DPPH自由基活性的研究

用二苯基苦基苯肼自由基酶标仪法,对业热带蔷薇科常见的50种木本植物鲜叶的自由基清除活性进行了比较,发现不同属、不同种树木鲜叶的80%甲醇提取物的自由基清除活性有很大差异,其中苹果属5种植物在相当于鲜叶浓度为0.5mg/mL于37℃下孵育20min时,对0.5mmol·L-1DPPH自由基平均清除率达62.4%,而绣线菊属3种植物的平均自由基清除率仅11.6%.尖嘴林檎、棣棠、木瓜、三叶海棠、湖北海棠、木香花、小果蔷薇和黄山花楸等鲜叶有较强的自由基清除活性,它们在浓度为0.5mg/mL时的自由基清除率分别可达85.0%、75.8%、70.7%、69.6%、64.5%、62.5%、61.8%和61.3%,显示其有较大的开发潜力.     

细脚拟青霉不同菌株清除DPPH自由基活性研究

在初筛基础上选择不同地理来源的10株细脚拟青霉,用二苯基苦基苯肼自由基酶标仪法比较了不同提取部位的DPPH自由基清除率。结果表明在所有供试菌株中细脚拟青霉的两个菌株清除自由基活性均较高。10株细脚拟青霉间的清除自由基活性少数相似,多数差异显著;发酵液和菌丝体提取物清除自由基活性不同;菌丝体不同溶剂先后提取所得物清除率也不同,其中氯仿提后甲醇提取物无论提取量,还是活性均较高,5分钟时的清除率最少也有66.0%(Pt02菌株),最高是Pt69菌株达到93.5%,Pt57菌株的清除率为92.8%;氯仿提取量极少,活性也不高;经氯仿和甲醇提取后的水提物,得率只有甲醇的一半左右,而活性与氯仿提取物相当,在14.11%~45.3%之间。     

一些单子叶木本植物鲜叶提取物清除DPPH自由基活性初探

研究用二苯基苦基苯肼自由基酶标仪法,对常见的三十余种单子叶木本植物鲜叶的自由基清除活性进行了比较,发现不同科属、不同种植物鲜叶的80％甲醇提取物对DPPH自由基的清除活性有很大差异,其中供试的棕榈科7种植物鲜叶提取物,在相当于鲜叶浓度为2．5mg／ml于37℃下孵育20min时,对0．5mmol／L DPPH自由基清除率平均可达40．0％,而龙舌兰科5种植物平均仅为7．2％;刺葵、棕竹、筋头竹、蒲葵和棕榈等鲜叶有较强的自由基清除活性,它们在相当于鲜叶浓度为2．5mg/ml时的自由基清除率分别可达83．1％、79．2％、64．9％、60．5％和51．3％。这些树种有一定的开发潜力。     

用清除有机自由基DPPH法评价植物抗氧化能力

几种抗氧化剂的浓度与其清除1,1-二苯基苦基苯肼(DPPH)能力呈显著的线性相关.不同抗氧化剂清除DPPH能力差异明显.抗坏血酸与DPPH反应的灵敏性高于其抑制肾上腺素氧化的能力.用DPPH法和亚油酸氧化法同时测定了生长在不同光强下植物叶片抗氧化能力的变化,两种方法所得结论相一致.结果表明清除有机自由基法是一种快速、简便、灵敏的评估植物抗氧化能力的可行方法.     

黑柄炭角菌产生的DPPH自由基捕捉成分

对黑柄炭角菌深层发酵制品中的DPPH自由基捕捉成分进行研究。经硅胶柱层析、中压液相色谱顺相和反相分离、制备型高压液相色谱分离等一系列步骤 ,共获得相对纯度在85%以上 ,收量在 2mg以上的自由基捕捉物质 2 0个 ,对其中的B4 1 6进行了质谱、1H NMR、13C NMR、1H 13CHMBC、红外光谱等的测定 ,测得分子式为C10 H10 O4 ,推断它为 5,8二羟基 3 甲基 3,4二氢异香豆素。在 2 0 μmol L时 ,它的DPPH自由基捕捉活性为维生素C的 1 67倍 ,维生素E的 2 1倍。     

咪唑类氮氧自由基的合成及其DPPH清除能力的研究

目的:合成8种新型咪唑类氮氧自由基(4a~4h),并探讨其对1,1-二苯基-2-三硝基苯肼自由基(DPPH)的清除作用。方法:本文以2-硝基丙烷为原料,经烷基化、还原、缩合及氧化反应等步骤,合成8种新型咪唑类氮氧自由基(4a~4h)。将4a~4h分别与DPPH作用,使用紫外-可见分光光度法测定其中DPPH的浓度,考察4a~4h对DPPH自由基的清除作用,以四甲基哌啶氮氧自由基(Tempol)作为阳性对照。结果:合成中间体及终产物经~1H NMR、HRMS、EPR等光谱数据确证了结构。通过DPPH自由基清除实验,结果显示所合成的8种新型咪唑类氮氧自由基对DPPH均有清除作用。结论:合成了新型咪唑类氮氧自由基,并对其合成方法进行了重要改进。在对DPPH自由基清除能力方面,8种化合物在一定浓度范围(0.01μmol/mL-2.4μmol/mL)内,清除作用与浓度成依赖性增长关系。其中,4b与Tempol相当,4a优于阳性对照Tempol,具有进一步开发研究的潜在价值。     

芦丁-锗配合物及其自由基清除活性研究

芦丁是存在于多种植物中的天然多羟基黄酮苷,能与多种金属离子形成配合物。本文采用紫外分光度法考察了芦丁与锗离子的配位作用,并研究了芦丁-锗配合物清除超氧自由基和DPPH自由基的作用。结果显示在KH2PO4-NaOH(pH6．70)的缓冲液中,芦丁与锗离子能形成1：1的配合物,其K稳=10^7.46,同时配合物显示有较好的自由基清除活性。     

Analysis of the monosaccharide composition of purified polysaccharides in Ganoderma atrum by capillary gas chromatography

Introduction – Ganoderma, one of the best‐known traditional Chinese medicines, has attracted considerable attention owing to the fact that dozens of polysaccharides isolated from it have shown diverse and potentially significant pharmacological activities. However, no work has been reported on the analysis of monosaccharide composition of polysaccharide isolated from the aqueous extract of Ganoderma atrum yet. Objective – To develop a simple and sensitive GC‐based method for the analysis of monosaccharide composition of purified polysaccharides in Ganoderma atrum. Methodology – The polysaccharide was first hydrolysed to give the constituent monosaccharides, which were subsequently derived into acetylated aldononitriles and analysed by gas chromatography using a capillary column packed with a (5%phenyl) methylpolysiloxane stationary phase with the addition of acetyl inositol as the inner standard. High‐performance liquid chromatography was also used for comparison. Results – The stable derivatives of the most common monosaccharides could be separated and reproducibly determined with high sensitivity. The limits of detection and quantification were 0.013 and 0.043 mg/mL, respectively. The intermediary precision values (expressed as the RSD) were less than 10%. The mean recovery of the method was 100 ± 3%, with RSD values of less than 5%. The results obtained from GC and HPLC methods were found to be close to each other within acceptable error ranges. Conclusion – This study demonstrated that the developed method could be applied as an accurate method for the compositional analysis of monosaccharides in the field of biological and biochemical study. Copyright © 2009 John Wiley & Sons, Ltd.     

Ganoderma atrum polysaccharide induces anti-tumor activity via the mitochondrial apoptotic pathway related to activation of host immune response

Ganoderma atrum polysaccharide (PSG-1), the major active ingredient isolated from Ganoderma atrum, has been suggested as a candidate for cancer therapy. The aim of this study was to investigate the anti-tumor effect of PSG-1 using sarcoma 180 (S-180) transplanted mice and further to examine the molecular mechanisms of PSG-1-induced anti-tumor effect. Results showed that PSG-1 significantly inhibited tumor growth in S-180-bearing mice. PSG-1-induced tumor apoptosis was associated with the alteration of Bcl-2 family proteins, increase of reactive oxygen species generation, loss of mitochondrial membrane potential (Δψ(m) ), release of cytochrome c from the mitochondria into cytosol, and activation of caspase-3 and -9. Elevation of immune function was also shown during PSG-1-induced tumor apoptosis, as evidenced by increase of spleen and thymus indexes, lymphocyte proliferation, concentrations of tumor necrosis factor (TNF)-α, and interleukin-2 in serum. Furthermore, the combined treatment of PSG-1 and cyclophosphamide (CTX) results in an enhancement of the anti-tumor effect of CTX alone via increased host immune response. These results suggested that PSG-1 had a potent anti-tumor activity by induction of tumor apoptosis through mitochondrial pathways, and immunoenhancement effect of PSG-1 was related to its anti-tumor effect. In addition, PSG-1 enhanced CTX-induced anti-tumor activity in S-180-bearing mice.     

Ganoderma atrum polysaccharide protects cardiomyocytes against anoxia/reoxygenation‐induced oxidative stress by mitochondrial pathway

It is now well established that oxidative stress plays a causative role in the pathogenesis of anoxia/reoxygenation (A/R) injury. Ganoderma atrum polysaccharide (PSG‐1), the most abundant component isolated from G. atrum, has been shown to possess potent antioxidant activity. The goals of this study were to investigate the effect of PSG‐1 against oxidative stress induced by A/R injury and the possible mechanisms in cardiomyocytes. In this work, primary cultures of neonatal rat cardiomyocytes pretreated with PSG‐1 were subjected to A/R and subsequently monitored for cell viability by the 3‐(4,5‐dimethyl‐2‐thiazolyl)‐2,5‐diphenyl‐2H‐tetrazolium bromide (MTT) assay. The levels of intracellular reactive oxygen species (ROS), apoptosis, and mitochondrial membrane potential (Δψ_m) were determined by flow cytometry. Western blot analysis was used to measure the expression of cytochrome c, Bcl‐2 family, and manganese superoxide dismutase (MnSOD) proteins, and the activities of caspase‐3 and caspase‐9 were determined by a colorimetric method. The results showed that PSG‐1 protected against cell death caused by A/R injury in cardiomyocytes. PSG‐1 reduced the A/R‐induced ROS generation, the loss of mitochondrial membrane potential (Δψ_m), and the release of cytochrome c from the mitochondria into cytosol. PSG‐1 inhibited the A/R‐stimulated activation of caspase‐9 and caspase‐3 and alteration of Bcl‐2 family proteins. Moreover, PSG‐1 significantly increased the protein expression of MnSOD in cardiomyocytes. These findings suggest that PSG‐1 significantly attenuates A/R‐induced oxidative stress and improves cell survival in cardiomyocytes through mitochondrial pathway. J. Cell. Biochem. 110: 191–200, 2010. © 2010 Wiley‐Liss, Inc.     

New Phenylpropanoid Glycosides from Illicium majus and Their Radical Scavenging Activities

Chemical investigation of the ethanol extract of the branch and leaves of Illicium majus resulted in the isolation of four new phenylpropanoid glycosides ( 1 – 4 ) and one new phenolic glycoside ( 9 ), along with 13 known ones. Spectroscopic techniques were used to elucidate the structures of the new isolates such as 3-[(2R,3S)-7-hydroxy-2-(4-hydroxy-3-methoxyphenyl)-3-(hydroxymethyl)-2,3-dihydro-1-benzofuran-5-yl]propyl β-D-glucopyranoside ( 1 ), [(2R,3S)-7-hydroxy-2-(4-hydroxy-3-methoxyphenyl)-5-(3-hydroxypropyl)-2,3-dihydro-1-benzofuran-3-yl]methyl 2-O-α-L-rhamnopyranosyl-β-D-glucopyranoside ( 2 ), [(2R,3S)-7-hydroxy-2-(4-hydroxy-3-methoxyphenyl)-5-(3-hydroxypropyl)-2,3-dihydro-1-benzofuran-3-yl]methyl 2-O-α-L-rhamnopyranosyl-β-D-xylopyranoside ( 3 ), 3-[(2R,3S)-3-({[2-O-(4-O-acetyl-α-L-rhamnopyranosyl)-β-D-xylopyranosyl]oxy}methyl)-7-hydroxy-2-(4-hydroxy-3-methoxyphenyl)-2,3-dihydro-1-benzofuran-5-yl]propyl acetate ( 4 ), and 4-(2-hydroxyethyl)phenyl 3-O-β-D-glucopyranosyl-β-D-glucopyranoside ( 9 ). Free radical scavenging activities of the isolates were elucidated through the DPPH assay method. The most active compounds, 1-O-caffeoyl-β-D-glucopyranose ( 17 ) and soulieana acid 1 ( 18 ), exhibited moderate radical scavenging activities (IC₅₀=37.7±4.4 μM and IC₅₀=97.2±3.4 μM, respectively). The antibacterial activities of the isolates against Staphylococcus aureus and Escherichia coli were also assessed, and no activity was shown at the measured concentration (<32 μg/mL).     

荸荠皮提取物对DPPH自由基清除活性

采用70%丙酮溶液对荸荠皮中抗氧化物质进行提取,得到红棕色浸膏。通过定性及定量方法分析了荸荠皮提取物中可能存在的具有抗氧化活性的物质;采用DPPH自由基法测定了荸荠皮提取物对DPPH自由基的清除能力。结果显示,荸荠皮提取物中含有多酚类和黄酮类等化合物,其多酚含量为3.31%(w/w,以干物质计)。DPPH自由基法显示,荸荠皮提取物具有一定的清除DPPH自由基能力,其清除能力与提取物浓度之间显示出良好的剂量-效应关系。该提取物(IC50值为130.37 ppm)对DPPH自由基清除能力略低于BHT(IC50值为94.16 ppm)。