Antioxidant flavonoids and chlorogenic acid from the leaves ofEriobotrya japonica

The antioxidant activity of Eriobotrya japonica was determined by measuring the radical scavenging effect on DPPH (1,1-diphenyl-2-picrylhydrazyl) radical and lipid peroxidation produced when mouse liver homogenate was exposed to the air at 37 degrees C, using 2-thiobarbituric acid (TBA). The methanol extract and its fractions of Eriobotrya japonica leaves showed strong antioxidant activity. The antioxidant activity of EtOAc and n-BuOH soluble fractions were stronger than the others, and were further purified by repeated silica gel, MCl gel CHP-20P, and Sephadex LH-20 column chromatography. Antioxidant chlorogenic acid, quercetin-3-sambubioside from n-BuOH fraction, and methyl chlorogenate, kaempferol- and quercetin-3-rhamnosides, together with the inactive ursolic acid and 2 alpha-hydroxyursolic acid from EtOAc fraction were isolated. Antioxidant flavonoids and chlorogenic acid also showed prominent inhibitory activity against free radical generation in dichlorofluorescein (DCF) method.     

Antioxidant activity from the stem bark of<Emphasis Type="Italic">Albizzia julibrissin</Emphasis>

The antioxidant activity of the stem bark from Albizzia julibrissin was evaluated for its potential to scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals, to inhibit the generation of the hydroxyl radical (*OH), total reactive oxygen species (ROS) and to scavenge authentic peroxynitrites (ONOO-). The methanol extract of A. julibrissin exhibited strong antioxidant activity in the tested model systems. Therefore, it was further fractionated using several solvents. The antioxidant activity of the individual fractions were in the order of ethyl acetate (EtOAc) > n-butanol (n-BuOH) > dichloromethane (CH2Cl2) > and water (H2O). The ethyl acetate soluble fraction, which exhibited strong antioxidant activity, was further purified by repeated silicagel, Sephadex LH-20 and RP-18 gel column chromatography. Sulfuretin (1) and 3',4',7-trihydroxyflavone (2) were isolated as the active principles. Compounds 1 and 2 exhibited good activity in all tested model systems. Compound 1 exhibited five times more inhibitory activity on the total ROS than Trolox. Compound 2 showed six times stronger DPPH radical scavenging activity than L-ascorbic acid. These results show the possible antioxidant activity of the A. julibrissin crude extract and its major constituents.     

Anti-lipid peroxidative principles from the stem bark ofKalopanax pictus Nakai

Hepatic lipid peroxide contents were examined in bromobenzene-treated rats firstly after the oral administration of MeOH extract of Kalopanax pictus stem barks, its n-BuOH fraction, EtOAc fraction and an alkaline hydrolysate of the n-BuOH fraction, and secondly after the intraperitoneal administration of hederagenin monodesmosides and bisdesmosides. Two hederagenin monodesmosides, kalopanaxsaponin A (KPS-A) and sapindoside C, exhibited significant anti-lipid peroxidation effects after intraperitoneal administration at doses of 10-30 micromole/kg, whereas their bisdesmosides did not exhibit any significant activity. These results suggest that it is the hederagenin monodesmosides that are responsible for anti-lipid peroxidation in vivo. The activity of KPS-A was established by the observation of decreased aminopyrine N-demethylase activity and increased epoxide hydrolase activity.     

菟丝子提取物清除自由基作用的研究

目的 研究菟丝子提取物的体外抗氧化活性.方法 采用热水提取、酶-Sevage法除蛋白、不同比例乙醇分级沉淀等方法获得菟丝子多糖提取物;经95％乙醇回流提取,2乙酸乙酯、正丁醇萃取,得到乙酸乙酯和正丁醇提取物.利用1,1-二苯基-2-苦苯肼自由基(DPPH·)和超氧阴离子自由基(O2-·)分别测定了各组分的抗氧化活性.结果 菟丝子提取物均具有一定的抗氧化活性,且呈显著的量效关系.菟丝子乙酸乙酯、正丁醇提取物清除自由基的能力大于氧化型谷胱甘肽,小于还原型谷胱甘肽;菟丝子多糖清除自由基的能力均小于氧化型谷胱甘肽,其中90％醇沉多糖清除自由基的能力较强.结论 菟丝子乙酸乙酯、正丁醇提取物以及90％醇沉多糖是天然抗氧化剂的良好来源,可以进一步分离纯化.     

4种海星的α-葡萄糖苷酶抑制活性研究

目的寻找具有降糖活性作用的海星并确定其活性部位。方法首先采用正常和糖尿病小鼠口服糖耐量试验,比较4种海星粗提物改善口服糖耐量的作用,然后利用体外α-葡萄糖苷酶抑制剂模型进一步确定具有改善口服糖耐量作用的海星中抑制α-葡萄糖苷酶的活性部位。结果罗氏海盘车粗提物对正常小鼠和糖尿病小鼠餐后0.5、1 h血糖均有显著降低作用,其中的正丁醇部位具有很强的α-葡萄糖苷酶抑制活性。结论罗氏海盘车的正丁醇部位具有α-葡萄糖苷酶抑制作用。     

Resveratrol/phloroglucinol glycosides from the roots of Lysidice rhodostegia

Two new phloroglucinol glycosides, lysidisides C (1) and D (2), together with two new resveratrol glycosides, lysidisides E (3) and F (4), were isolated from the n-BuOH extract of the roots of Lysidice rhodostegia. The structures were elucidated on the basis of spectroscopic and chemical evidence. The antioxidant activity of the isolates was also investigated     

Isorhamnetin glycosides with free radical and ONOO− scavenging activities from the stamens ofNelumbo nucifera

In this study, we isolated two new isorhamnetin glycosides, designated as nelumboroside A (3) and nelumboroside B (4), as well as the previously-characterized isorhamnetin glucoside (1) and isorhamnetin rutinoside (2), from the n-BuOH fraction of Nelumbo nucifera stamens. The structures of the two new compounds were then determined, using chemical and spectroscopic techniques. All isolated isorhamnetin glycosides 1-4 showed marked antioxidant activities in the DPPH, and ONOO- assays.     

Antioxidant principles of<Emphasis Type="Italic">Nelumbo nucifera</Emphasis> stamens

In our ongoing study to identity antioxidants from natural sources, the antioxidant activity of Nelumbo nucifera stamens was evaluated for their potential to scavenge stable 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radicals, inhibit total reactive oxygen species (ROS) generation, in kidney homogenatas using 2',7'-dichlorodihydrofluorescein diacetate (DCHF-DA), and scavenge authentic peroxynitrites (ONOO-). A methanol (MeOH) extract of the stamens of N. nucifera showed strong antioxidant activity in the ONOO- system, and marginal activity in the DPPH and total ROS systems, so were therefore fractionated with several organic solvents, such as dichloromethane (CH2Cl2), ethyl acetate (EtOAc) and n-butanol (n-BuOH). The EtOAc soluble fraction, which exhibited strong antioxidant activity in all the model systems tested, was further purified by repeated silica gel and Sephadex LH-20 column chromatographies. Seven known flavonoids [kaempferol (1), kaempferol 3-O-beta-D-glucuronopyranosyl methylester (2), kaempferol 3-O-beta-D-glucopyranoside (3), kaempferol 3-O-beta-D-galactopyranoside (4), myricetin 3',5'-dimethylether 3-O-beta-D-glucopyranoside (5), kaempferol 3-O-alpha-L-rhamnopyranosyl-(1-->6)-beta-D-glucopyranoside (6) and kaempferol 3-O-beta-D-glucuronopyranoside (7)], along with beta-sitosterol glucopyranoside (8), were isolated. Compound 1 possessed good activities in all the model systems tested. Compounds 2 and 7 showed scavenging activities in the DPPH and ONOO- tests, while compounds 3 and 4 were only active in the ONOO- test. Conversely, compound 8 showed no activities in any of the model systems tested.     

Antioxidant activity of extracts and flavonoids from Bidens tripartita

Extracts from herb and flowers of Bidens tripartita L. (Asteraceae), obtained using solvents of different polarity, were studied for their radical scavenging effects. Antioxidant activities of pure flavonoids: flavanomarein (isookanin 7-O-glucoside), cynaroside (luteolin 7-O-glucoside) and luteolin, which had been isolated from this plant, were also evaluated. Radical-scavenging activity was measured by electron paramagnetic resonance (EPR) spectroscopy using stable 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. The content of flavonoids in flower heads is half of that found in the herb; however, the extract from flowers showed that the antioxidant activity was almost two times higher there. Some extracts (n-BuOH fraction) showed long lasting radical scavenging activity and the EPR spectra were recorded in time to follow the reaction kinetics. Scavenging of DPPH showed second-order kinetics at the beginning of the assay period and later the first-order one. Different kinetics suggested the presence of polymerized and/or less active antioxidants with different scavenging mechanisms for particular polyphenolic compounds. Bur-marigold extracts are a potential source of natural antioxidants that may be used in pharmaceutical or food industry.     

黄连花薹HPLC指纹图谱的建立及其抗氧化和抑菌作用谱效关系研究

目的:建立黄连花薹的高效液相色谱(HPLC)指纹图谱,并研究其与抗氧化和抑菌作用的谱效关系。方法:以14批不同产地的黄连花薹为对象,采用HPLC法测定。色谱柱为Supersil C18,流动相为乙腈-0.1%磷酸溶液(梯度洗脱),流速为1.0 mL/min,柱温为25℃,检测波长为329 nm,进样量为10μL。采用《中药指纹图谱相似度评价系统》(2012A版)建立14批黄连花薹的指纹图谱并进行相似度评价和共有峰指认。以DPPH自由基清除率和羟自由基清除率为抗氧化作用指标,以相对抑菌活性(大肠埃希菌)为抑菌作用指标,利用SPSS 21.0软件对黄连花薹共有峰与上述两种药效指标进行Pearson相关性分析,建立谱效关系模型,并进行验证。结果:黄连花薹的HPLC指纹图谱中共得到7个共有峰,相似度均不低于0.916,并指认5号峰为盐酸小檗碱。7个共有峰均与DPPH自由基清除率呈正相关;1~3、4、6、7号峰与羟自由基清除率呈正相关,5号峰与羟自由基清除率呈负相关;5号峰与相对抑菌活性呈正相关。经验证,黄连花薹样品的DPPH自由基清除率、羟自由基清除率、相对抑菌活性的预测值与测量值的相对误差为0.92%~14.5%。结论:所建立的谱效关系模型可用于黄连花薹抗氧化、抑菌作用的评价;1、2、3、4、6、7号峰所代表化学成分是黄连花薹抗氧化作用的物质基础,盐酸小檗碱是其抑菌作用的物质基础。     

红丝线草保肝护肝活性部位的筛选

目的：研究红丝线草保肝护肝的活性部位。方法：对红丝线草的乙醇提取物进行萃取分离，分成4个极性部位，用大鼠D-氨基半乳糖（D-GlaN）急性肝损伤模型确定红丝线草保肝护肝的活性部位。结果：大鼠口服红丝线草正丁醇部位的高、低剂量组（I、J）均可明显抑制大鼠血清中ALT、AST的升高（P＜0.05），且其作用与阳性对照药相比差异无显著性。结论：正丁醇部位为红丝线草保肝护肝的活性部位。     

筒鞘蛇菰镇痛有效部位的筛选

目的筛选筒鞘蛇菰镇痛作用的有效部位。方法采用小鼠热板法和醋酸扭体法，筛选筒鞘蛇菰的镇痛有效部位。结果筒鞘蛇菰甲醇提取物的正丁醇部位能显著提高小鼠热刺激的痛阀；且对小鼠醋酸扭体反应具有显著的抑制作用。结论正丁醇部位为筒鞘蛇菰镇痛有效部位。     

猕猴桃根抗肿瘤作用研究

目的评价猕猴桃根提取物的体外、内抗肿瘤活性。方法猕猴桃根活性成分的分离、纯化采用传统的天然产物化学方法,猕猴桃根先用甲醇回流提取,然后用乙酸乙酯、氯仿、正丁醇萃取。不同组分对体外培养的肿瘤细胞增殖的作用采用磺酰罗丹明B方法;猕猴桃根的体内抗肿瘤作用采用小鼠肿瘤和人肿瘤裸小鼠移植瘤模型评价。结果氯仿提取物对肿瘤细胞增殖抑制作用最强,甲醇提取物次之。体内实验证实氯仿提取物有效地抑制小鼠肝癌模型和人肝癌裸小鼠移植瘤模型的生长,抑制率大概在38.0%。结论猕猴桃根提取物有一定的抗肿瘤作用;其活性成分主要存在于极性较小的组分。     

Anticonvulsant compounds from the wood ofCaesalpinia sappan L.

80% Aqueous MeOH extracts from the wood of Caesalpinia sappan, which showed remarkable anticonvulsant activity, were fractionated using EtOAc, n-BuOH, and H2O. Among them, the EtOAc fraction significantly inhibited the activities of two GABA degradative enzymes, succinic semialdehyde dehydrogenase (SSADH) and succinic semialdehyde reductase (SSAR). Repeated column chromatographies for the fraction guided by activity test led to the isolation of the two active principal components. Their chemical structures were determined to be sappanchalcone and brazilin based on spectral data. The pure compounds, sappanchalcone (1) and brazilin (2), inactivated the SSAR activities in a dose dependent manner, whereas SSADH was inhibited partially by sappanchalcone and not by brazilin.     

Antioxidant, antimalarial and antimicrobial activities of tannin-rich fractions, ellagitannins and phenolic acids from Punica granatum L

The Punica granatum L. (pomegranate) by-product POMx was partitioned between water, EtOAc and n-BuOH, and the EtOAc and n-BuOH extracts were purified by XAD-16 and Sephadex LH-20 column chromatography to afford ellagic acid (1), gallagic acid (2), punicalins (3), and punicalagins (4). Compounds 1 - 4 and the mixture of tannin fractions (XAD-16 eluates) were evaluated for antioxidant, antiplasmodial, and antimicrobial activities in cell-based assays. The mixture of tannins (TPT), XAD-EtOAc, XAD-H2O, XAD-PJ and XAD-BuOH, exhibited IC50 values against reactive oxygen species (ROS) generation at 0.8 - 19 microg/mL. Compounds 1 - 4 showed IC50 values of 1.1, 3.2, 2.3 and 1.4 microM, respectively, against ROS generation and no toxicity up to 31.25 microg/mL against HL-60 cells. Gallagic acid (2) and punicalagins (4) exhibited antiplasmodial activity against Plasmodium falciparum D6 and W2 clones with IC50 values of 10.9, 10.6, 7.5 and 8.8 microM, respectively. Fractions XAD-EtOAc, XAD-BuOH, XAD-H2O and XAD-PJ compounds 1 - 4 revealed antimicrobial activity when assayed against Escherichia coli, Pseudomonas aeruginosa, Candida albicans, Cryptococcus neoformans, methicillin-resistant Staphylococcus aureus (MRSA), Aspergillus fumigatus and Mycobacterium intracellulare. Compounds 2 and 4 showed activity against P. aeruginosa, C. neoformans, and MRSA. This is the first report on the antioxidant, antiplasmodial and antimicrobial activities of POMx isolates, including structure-activity relationships (SAR) of the free radical inhibition activity of compounds 1 - 4. Our results suggest a beneficial effect from the daily intake of POMx and pomegranate juice (PJ) as dietary supplements to augment the human immune system's antioxidant, antimalarial and antimicrobial capacities.     

Anti-inflammatory and antioxidant activities of constituents isolated from Pueraria lobata roots

In order to evaluate the anti-inflammatory and antioxidant activities of Pueraria lobata roots and its active components, in vitro inhibitory activities against lipopolysaccharide (LPS)-induced nitric oxide (NO) production, inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2) protein expression, and tert-butylhydroperoxide (t-BHP)-induced reactive oxygen species (ROS) generation in RAW 264.7 cells, as well as in vitro scavenging activities against 1,1-diphenyl-2-picrylhydrazyl (DPPH), peroxynitrite (ONOO(-)), nitric oxide (NO·), superoxide anion (·O(2)(-)) and total ROS, and inhibitory activities against ONOO(-)-mediated tyrosine nitration, were determined. Repeated column chromatography was performed to isolate four known compounds from the anti-inflammatory and antioxidant EtOAc fraction: daidzein; genistein; puerarin; (+)-puerarol B-2-O-glucopyranoside; four known compounds from the anti-inflammatory n-hexane fraction: lupenone; lupeol; puerarol; coumestrol; seven known compounds from the antioxidant n-BuOH fraction: allantoin; 3'-hydroxypuerarin; daidzein 8-C-apiosyl-(1→6)-glucoside; puerarin; genistin; 3'-methoxypuerarin; daidzin. Among these compounds, lupenone and lupeol reduced NO production, as well as iNOS and COX-2 protein levels in LPS-stimulated RAW 264.7 cells. Furthermore, lupeol showed significant inhibitory activity against intracellular ROS generation by t-BHP. Meanwhile, 3'-hydroxypuerarin showed marked ONOO(-), NO·, total ROS scavenging activities, and weak ·O(2)(-) scavenging activity, while 3'-methoxypuerarin showed ONOO(-) scavenging activity and weak NO· and O(2)(-) scavenging activities, suggesting that existence of the 3'-hydroxyl group in puerarin plays an important role in the scavenging of ONOO(-), NO·, and total ROS, as well as inhibiting the ONOO(-)-mediated tyrosine nitration mechanism. These results indicate that P. lobata roots and its constituents may be a useful therapeutic and preventive approach to various inflammatory diseases and oxidative stress-related disease.     

滇越金线兰活性部位降血糖、增敏胰岛素和抗氧化活性研究

采用高糖高脂饮食联合低剂量STZ诱导造成糖尿病大鼠模型,实验组大鼠分别灌胃给予滇越金线兰总膏和溶剂萃取法所得各极性部位,测定给药后大鼠血糖、胰岛素敏感性、抗氧化活性及NO水平等相关指标。胰腺切片,进行病理学检查。与模型组相比,乙酸乙酯部位给药组的随机血糖可见明显降低,从给药前402．66至226．26mg／dl（P〈0．05）,而且该组大鼠的体重值明显高于模型对照组,同时能提高胰岛素敏感性,改善高糖负荷以后的糖耐量;胰腺细胞形态较模型组有明显改善;同时SOD活性增加,NO含量均显著降低。表明滇越金线兰的乙酸乙酯部位是其降血糖的主要活性部位,其作用机制可能与改善胰岛素抵抗、增强机体抗氧化活性和降低血浆NO等机制有关。     

马尾松松针中化学成分的分离与结构鉴定马尾松松针中化学成分的分离与结构鉴定

目的研究松科植物马尾松(Pinus massoniana Lamb.)松针的化学成分。方法应用色谱技术分离纯化,IR,NMR,MS等波谱方法解析化学结构。结果从马尾松松针中分离出4个化合物,分别鉴定为:3-甲氧基-9′-O-α-L-鼠李糖基-4′:7,5′:8-二氧环新木脂素-4,9-二醇(命名为massonianoside E,I),4,4′,8,8′,9-五羟基-3,3′-二甲氧基-7,9′-单环氧木脂素(II),伞花内酯(III),4-(4′-羟基-3′-甲氧基苯基)-2-丁酮(IV)。结论化合物I为新化合物,II,III和IV为首次从松科植物中分离得到。     

一种中华稻蝗成虫抗菌蛋白质的初步分离

目的提取中华稻蝗成虫中的抗菌蛋白质并测定其抗菌活性。方法对中华稻蝗成虫经针刺损伤和菌液浸泡相接合的方法处理,粗提液经沸水浴热变性、凝胶过滤色谱、高效液相色谱分析,初步分离中华稻蝗成虫中的抗菌蛋白质,以金黄色葡萄球菌为指示菌,抑菌圈法检测其抗菌活性。结果经高效液相色谱分析表明中华稻蝗成虫中能产生抗菌蛋白质,其相对分子质量约为3 600。结论首次从直翅目昆虫中华稻蝗中分离到对革兰阳性菌有较强活性的抗菌蛋白质。     

白药子黄酮的抗氧化稳定性

目的 以白药子为原料,研究白药子黄酮各部位的抗氧化稳定性.方法 以大孔吸附树脂分离得到A、B、C部位,以清除DPPH的活性保持率为指标,研究溶液pH值、温度、金属离子、光照对各部位抗氧化稳定性的影响.结果 在pH6及金属离子K+、Na+、Ca2+存在的条件下,各部位均保持较高的清除活性;碱性条件下,清除活性迅速丧失;当加热至70 ℃时,C部位的活性保持较好,大于90％;光照条件下,抗氧化的稳定性依次为:C部位＞A部位＞B部位.结论 C部位具有较好的抗氧化稳定性.