杨桃提取物体外清除氧自由基作用

从杨桃果中提取得到三种提取物为匀浆提取物、蛋白提取物和多糖提取物。采用化学发光法测定这三种提取物清除氧自由基的活性,实验结果:匀浆提取物清除羟自由基(·OH)和H2O2的活性大小相近,而清除超氧阴离子自由基(O2–·)的活性较小,其IC50约为前两者的4倍。蛋白提取物清除O2–·和·OH的活性大小相近,而清除H2O2的活性明显小于前两者,IC50约为前两者的9倍。多糖提取物清除.OH的活性明显大于清除O2–·和H2O2的活性,其IC50约为O2–·的1/22,约为H2O2的1/65。结果表明,杨桃果具有清除O2–·、·OH和H2O2的作用,不同提取物对这些活性氧自由基的清除能力有所不同。     

沱茶中抗自由基化学成分的研究

对沱茶(Camellia sinensis var．assamica)的水提取物、50％甲醇提取物、甲醇提取物进行了DPPH自由基清除作用的研究,实验结果表明,水提取物和50％甲醇提取物均具有较强的清除自由基作用,其半数抑制率(IC50)分别为6．07μg／mL和5．01μg／mL,而甲醇提取物清除自由基作用的活性则较弱,其半数抑制率(IC50)为39．63μg/mL。利用层析等手段分别从抗自由基活性较强的水提取物的甲醇可溶部分分离获得了20种化合物,其中,10种化合物(2、5、6、11、12、13、16、17、18、19)为首次从该植物中得到的化合物;DPPH自由基清除活性研究结果表明,其中化合物(1、4、7、9、10、12、14、18)的活性强于阳性对照品抗坏血酸和咖啡酸。比较分析化合物的结构与其活性的关系,发现结构中苯环上有邻位羟基的化合物其清除自由基的活性较强,而且羟基越多活性越强。     

香榧假种皮提取物的体外抗氧化活性研究

测定了香榧假种皮提取物中的总酚含量,并采用DPPH自由基清除法、β-胡萝卜素漂白法、硫代巴比妥酸法等3种方法评价了香榧假种皮提取物的体外抗氧化活性。结果表明:香榧假种皮提取物中总酚含量为(76.67±2.06)mg/g。香榧假种皮提取物具有一定的抗氧化活性,且在一定浓度范围内呈剂量效应关系,但是其抗氧化活性低于BHT和抗坏血酸。DPPH自由基清除法、硫代巴比妥法、β-胡萝卜素漂白法等3种方法测定香榧假种皮提取物体外抗氧化活性的IC50值分别为1.55 mg/m L、2.02 mg/m L、0.58 mg/m L。     

安徽长江滩地杨树人工林个体生长与水淹状况的关系

通过对长江滩地连续7年的水文动态以及滩地杨树人工林年轮生长序列的研究,分析杨树人工林个体生长与水淹时间、水淹深度以及气候因子的相应关系,建立相关模型.结果表明,林分个体胸径分布格局与滩地的高程具显著的相关性,水淹深度对直径生长的影响大于水淹的时间,而当年的径向生长与前一年8、9月水淹情况以及气候因子的关系明显.在滩地营造杨树人工林,以丰产为目的宜选择水淹深度小于2m的地域造林,淹水深度超过2m的地域宜适当密植,以培养小径材为主.     

黄芪和党参提取物的抗氧化活性研究

采用分光光度法测定不同产地黄芪、党参醇提取物的抗氧化性,并对它们清除自由基能力进行比较.结果显示,甘肃渭源、陇西、吉林舒兰、山西浑源黄芪醇提取物的DPPH自由基清除率依次为:21.38%、13.53%、35.09%和20.18%,表明不同产地的黄芪的抗氧化活性差异明显;陕西凤县、南郑、山西陵川党参醇提取物的DPPH自由基清除率依次为:17.56%、9.87%和8.03%,表明不同产区的党参抗氧化活性存在一定的差异;黄芪、党参提取物清除DPPH自由基的IC50分别是0.24和0.85 mg·mL-1,即黄芪提取物清除自由基能力大于党参提取物.     

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)。     

4种地衣提取物抗氧化和抗肿瘤活性研究

本研究初步评估了4种药用地衣(太白茶、金刷把、黑石耳、红石耳)不同溶剂提取物的抗氧化活性及其粗多糖的抗肿瘤活性。通过测定清除DPPH自由基、羟基自由基和还原能力,对4种地衣不同溶剂提取物进行体外抗氧化活性评价,结果表明,金刷把和黑石耳的甲醇提取相清除DPPH自由基能力高于其它溶剂提取相,其IC50值(半抑制浓度)分别为0.7847 mg/mL和0.5595 mg/mL;黑石耳甲醇提取相(IC50=0.5747 mg/mL)清除羟基自由基能力优于阳性对照物Vc(IC50=0.6126 mg/mL);黑石耳氯仿提取相、金刷把乙酸乙酯提取相和太白茶甲醇提取相清除羟基自由基能力与Vc相当;4种地衣甲醇提取相还原能力均较强,且与其浓度呈较好的量效关系。利用MTT法分析4种地衣多糖对HeLa、A375和Hep G2细胞体外生长增殖的抑制作用,结果显示黑石耳粗多糖对Hep G2细胞的抑制作用较为突出(IC50=0.2567 mg/mL),而金刷把抑制HeLa细胞的生长增殖作用最强,其IC50值为0.4332 mg/mL。     

李氏块菌提取物抗氧化活性的研究

对李氏块菌Tuber liyuanum子实体的不同提取物,包括甲醇提取物(ME)、乙醇提取物(EE)、丙酮提取物(AE)、正丁醇提取物(BAE)和乙酸乙酯提取物(EAE),进行清除DPPH自由基、羟基自由基、超氧阴离子自由基、铁离子螯合能力、还原力以及总酚含量的测定和研究,发现ME对DPPH自由基、超氧阴离子自由基清除及还原力活性最高,EC50值分别为23.37mg/m L、11.65mg/m L和24.47mg/m L;EE对羟基自由基清除和铁离子螯合能力活性最高,EC50值分别为7.24mg/m L和小于0.5mg/m L;ME的总酚含量最高(3.08mg GAE/g提取物),其次是EE(1.34mg GAE/g提取物),提取物总酚含量与抗氧化活性呈现出一定的正相关性。     

枸骨叶提取物对酪氨酸酶的抑制与抗氧化作用

本实验以枸骨叶为研究对象,经75%乙醇浸提,用极性递增的溶剂分离制备获得枸骨叶提取物,测定了枸骨叶提取物对酪氨酸酶的抑制作用,并使用1,1-二苯基-2-三硝基苯肼(1,1-Diphenyl-2-picrylhydrazyl,DPPH)自由基清除的方法检测了枸骨叶提取物抗氧化能力。实验结果表明:枸骨叶三氯甲烷和正丁醇提取物对酪氨酸酶具有较强的抑制作用,IC50值分别达到0.414 mg/m L和0.667 mg/m L,均为混合型可逆抑制类型。同时,二者均具有一定的清除DPPH自由基的能力,IC50值分别为0.132 mg/m L和0.039 mg/m L,表明枸骨叶提取物同时具有抑制酪氨酸酶活性和抗氧化的功效,在美容、药物及食品等行业具有潜在的应用价值。     

球孢白僵菌不同菌株清除自由基活性评价

选择不同来源的12株球孢白僵菌,分别测定菌丝体2种溶剂提取物在不同抗氧化模型中的抗氧化作用。结果表明,不同溶剂提取物对二苯基苦味酰基苯肼自由基(DPPH)和羟自由基(.OH)均有清除作用,但是清除自由基的活性不同,乙酸乙酯提取物对.OH的清除作用最为显著,活性较高,最高清除率达到71.54%。甲醇提取物活性均较低,30 min时甲醇提取物对DPPH和.OH清除率最高分别为36%和38.96%,12株白僵菌间的清除自由基活性有较大的差异。     

安徽长江滩地杨树人工林个体生长与水淹状况的关系

通过对长江滩地连续７年的水文动态以及滩地杨树人工林年轮生长序列的研究,分析杨树人工林个体生长与水淹时间、水淹深度以及气候因子的相应关系,建立相关模型。结果表明,林分个体胸径分布格局与滩地的高程具显著的相关性,水淹深度对直径生长的影响大于水淹的时间,而当年的径向生长与前一年８、９月水淹情况以及气候因子的关系明显。在滩地营造杨树人工林,以丰产为目的宜选择深度小于２ｍ的地域造林,淹水深度超过２ｍ的地域宜     

灰树花提取物清除氧自由基的研究

采用化学发光法比较了灰树花各提取物对超氧阴离子自由基、羟基自由基的清除效果。研究结果表明,灰树花子实体和菌丝体的提取物对羟基自由基均有很好的清除作用,灰树花菌丝体水提物(GFME)、灰树花子实体水提物(GFE)、灰树花子实体水提多糖(GFP)、灰树花子实体碱提多糖(GFAP)清除羟基自由基的IC50均小于1.0 mg/mL,其他提取物清除羟基自由基的IC50也均小于3.0 mg/mL。而对超氧阴离子自由基仅GFME、GFMP、GFE有清除作用,其他的提取物清除作用很弱。     

蛹虫草无性型菌丝体提取液体外抗氧化活性研究

分别测定了蛹虫草无性型菌丝体不同溶剂提取液在不同抗氧化模型中的抗氧化作用。结果表明,各种提取液对二苯基苦味酰基苯肼自由基(·DPPH)和羟自由基(·OH)均有显著的清除作用:在50mg/mL时,去离子水、70%乙醇和70%丙酮提取物对DPPH自由基的清除率分别为89.2%、83.6%和75.9%;70%乙醇提取物在30mg/mL时对·OH自由基的清除率达到100%;在50mg/mL时70%丙酮和去离子水提取物的·OH自由基清除率分别为95.6%和89.6%。在一定浓度下,各提取液对邻苯三酚自氧化也均有抑制作用;不同溶剂提取物的还原能力强弱为:70%乙醇>去离子水>70%丙酮。各种提取物的抗氧化组分不同,提取物浓度与抗氧化性成正相关。     

The role of fleshy pericarp in seed germination and dispersal under flooded conditions in three wetland forest species

In flooded habitats, inundations affect important forest regeneration processes, such as seed dispersal and germination. The main seed dispersal mechanism used by species in Austral South American temperate swamp and riparian forests is endozoochory, which releases seeds from the fleshy pericarp. Endozoochory could be favorable or unfavorable in wetland habitats, since this mechanism exposes seeds directly to water and can, in some cases, be detrimental to germination. In this study, we studied whether or not the fleshy pericarp favors germination after the flooding period's end. Furthermore, we quantified if the number of days which the fruit was found to be floating related to its germination success. We used the seeds of three common fleshy fruit species of flooded habitats from southern Chile, the trees Luma apiculata and Rhaphithamnus spinosus, and the vine Luzuriaga radicans. We simulated flooding periods of 7, 15, 30 and 45 days submerging seeds, with and without pericarps, in water. We found that the pericarp's presence significantly increased Luma's germination success and significantly decreased that of Luzuriaga. The germination of Rhaphithamnus was low after periods of flooding in both seed treatments, with no significant differences found between them. The fruits could float for an average of one to four weeks, depending on the species, which did not relate to their germination success. These results show that germination was affected by the presence of fleshy pericarps in flooded conditions and furthermore, that flotation allows for hydrochory from one week to one month. We suggest that in swamp forests multiple seed dispersal mechanisms are advantageous, especially for fleshy-fruited species.     

Persistence of poliovirus 1 in soil and on vegetables grown in soil previously flooded with inoculated sewage sludge or effluent.

Land disposal of sewage sludge and effluent is becoming a common practice in the United States. The fertilizer content and humus value of such wastes are useful for agricultural purposes, and the recycling of sewage onto the land eliminates many of our stream pollution problems. The potential exists for crops grown in such irrigated soil to be contaminated by viruses that may be present in the sewage. Studies were initiated to determine viral persistence in soil and on crops grown under natural conditions in field plots that had been flooded to a depth of 1 inch (2.54 cm) with poliovirus 1-inoculated sewage wastes. Lettuce and radishes were planted in sludge- or effluent-flooded soil. In one study, the vegetables were planted 1 day before flooding, and in another they were planted 3 days after the plots were flooded. Survival of poliovirus 1 in soil irrigated with inoculated sewage sludge and effluent was determined during two summer growing seasons and one winter period. The longest period of survival was during the winter, when virus was detected after 96 days. During the summer, the longest survival period was 11 days. Poliovirus 1 was recovered from the mature vegetables 23 days after flooding of the plots had ceased. Lettuce and radishes are usually harvested 3 to 4 weeks after planting.     

Persistence of poliovirus 1 in soil and on vegetables grown in soil previously flooded with inoculated sewage sludge or effluent.

Land disposal of sewage sludge and effluent is becoming a common practice in the United States. The fertilizer content and humus value of such wastes are useful for agricultural purposes, and the recycling of sewage onto the land eliminates many of our stream pollution problems. The potential exists for crops grown in such irrigated soil to be contaminated by viruses that may be present in the sewage. Studies were initiated to determine viral persistence in soil and on crops grown under natural conditions in field plots that had been flooded to a depth of 1 inch (2.54 cm) with poliovirus 1-inoculated sewage wastes. Lettuce and radishes were planted in sludge- or effluent-flooded soil. In one study, the vegetables were planted 1 day before flooding, and in another they were planted 3 days after the plots were flooded. Survival of poliovirus 1 in soil irrigated with inoculated sewage sludge and effluent was determined during two summer growing seasons and one winter period. The longest period of survival was during the winter, when virus was detected after 96 days. During the summer, the longest survival period was 11 days. Poliovirus 1 was recovered from the mature vegetables 23 days after flooding of the plots had ceased. Lettuce and radishes are usually harvested 3 to 4 weeks after planting.     

Spatial distribution of methane-oxidizing activity in a flooded rice soil

In a study on spatial distribution of methane oxidation in an unplanted flooded field, methane-oxidizing activity, analysed in soil samples under laboratory conditions, decreased with increasing depth (25 cm and beyond). In a flooded field planted to rice, rates of methane oxidation followed the order : rhizosphere (collected from roots at 10-20 cm depth) > surface soil at (0-1 cm) > subsurface soil at 10-20 cm depth, diagonally 10-15 cm away from the centre of hill. Application of ammonium sulfate and, to a lesser extent, urea to surface, rhizosphere and subsurface soil samples from flooded field planted to rice effected a distinct inhibition of methane oxidation. Nitrification inhibitors (thiourea, sodium thiosulfate and dicyandiamide) were also effective in inhibiting methane oxidation. Both surface and rhizosphere soil samples harbored higher populations of methane-oxidizing bacteria than the subsurface soil. Inhibition of methane oxidation in surface and rhizosphere soil samples concomitant with the suppression of autotrophic ammonium oxidizers by nitrification inhibitors implicates an active involvement of autotrophic ammonium oxidizers in methane oxidation.