黄芩多糖的提取及其抗氧化和抗肿瘤活性研究

以中药黄芩(Scutellaria baicalensis)为材料,通过比较分析水提醇沉法、微波提取法及超声波提取法的提取率,寻找最优的提取方法.对黄芩多糖(S.baicalensis polysaccharides,SBP)进行精制后,通过体外抗氧化实验,检测SBP的羟自由基和超氧阴离子的清除能力及总抗氧化能力.通过...     

毛咀地星的抗氧化、抗菌和抗肿瘤活性和化学成分研究

毛咀地星是一种药用蘑菇,为了进一步开发利用毛咀地星,该研究探讨了毛咀地星乙醇提取物的抗氧化、抗菌和抗肿瘤活性,并采用硅胶柱色谱、制备薄层色谱和重结晶等方法,对毛咀地星乙醇提取物进行分离纯化,研究了其化学成分。结果表明:毛咀地星乙醇提取物多酚含量为10.53μg·mg~(-1),DPPH和·OH自由基清除能力的IC50值分别为91.35和148.76μg·m L~(-1);乙醇提取物对金黄葡萄球菌、大肠杆菌和枯草芽抱杆菌均无抑制作用;乙醇提取物在浓度为1 mg·m L~(-1)时,对燕麦镰刀菌的抑制率为36.11%;乙醇提取物在浓度为200μg·m L~(-1)时,对BG-803、NCI-H502和MDA-MB-231肿瘤细胞的抑制率分别为18.87%、17.71%和41.23%。并从乙醇提取物中分离纯化到6个化合物,根据理化性质和波谱数据分析,化合物结构分别鉴定为5α,8α-过氧化麦角甾-6,9(11),22-三烯-3β-醇(1)、5α,8α-过氧化麦角甾-6,22-二烯-3β-醇(2)、D-阿拉伯糖醇(3)、L-谷氨酸(4)、麦芽糖(5)和蔗糖(6),以上化合物均为首次从该菌中分离得到。     

朱红栓菌提取物抗氧化、抗肿瘤活性评价及相关化学成分分析

采用石油醚、乙酸乙酯、乙醇浸提朱红栓菌 Trametes cinnabarina 子实体干粉,得到不同极性提取物;采用清除DPPH 自由基、羟自由基、超氧阴离子自由基能力,测定提取物的体外抗氧化活性;MTT法检测提取物对人肝癌细胞株HepG2细胞增殖的抑制作用。结果表明,朱红栓菌石油醚、乙酸乙酯、乙醇提取物均具有一定的抗氧化、抗肿瘤活性;各提取物在浓度为4-5mg/mL时,对DPPH自由基、羟自由基和超氧阴离子自由基清除能力大小依次为乙酸乙酯提取物>乙醇提取物>石油醚提取物;乙酸乙酯提取物对3种自由基的最高清除率分别为60.23%、74.49%、63.84%。各提取物对人肝癌细胞株HepG2细胞增殖抑制作用大小依次为乙酸乙酯提取物>乙醇提取物>石油醚提取物;乙酸乙酯提取物的抑制率最高达55.93%。采用硅胶和凝胶等柱色谱方法结合核磁、波谱和质谱等技术对乙酸乙酯提取物的化学组分进行分析,共分离纯化出11种化合物,分别鉴定为：麦角甾醇（1）,邻苯二甲酸二丁酯（2）,对羟基苯甲酸甲酯（3）,麦角甾-7,22,二烯-3-酮（4）,1-[(12E,16E)-12,16-二十碳二烯酰基]-2-[(E,E)-7,11-十八碳二烯酰基]-3-硬脂酰基甘油（5）,cinnabarin（6）,过氧麦角甾醇（7）,尿嘧啶（8）,甘露醇（9）,腺嘌呤核苷（10）,豆甾-7,22-二烯-3β,5α,6β-三醇（11）。除化合物6外均为首次从朱红栓菌子实体中分离得到。研究结果为开发利用朱红栓菌子实体提供了科学依据。     

南极地衣提取物抗氧化能力的初步研究

本文讨论4种南极地衣簇花石萝Usnea aurantiacoatra,南极石萝Usnea antarctica,粉球衣Sphaerophorus globosus及一种石蕊Cladonia sp.甲醇提取物的体外抗氧化能力;采用亚油酸氧化体系、二苯代苦味酰自由基体系、还原力实验对其抗氧化活性进行测定,并同维生素C、丁基甲氧基苯酚进行比较。结果显示供试南极地衣均具有较高的抗氧化活性,且呈剂量依赖关系;其中,簇花石萝的脂质过氧化抑制率最高,还原力最大;石蕊的二苯代苦味酰自由基清除能力最大。此外,从簇花石萝中提取的松萝酸具有一定的抗氧化活性,但明显低于簇花石萝粗提物。     

水麻果多酚的提取纯化及其抗氧化、抗肿瘤活性作用

为提取分离水麻果多酚,探索水麻果多酚的抗氧化及抗肿瘤能力。本研究通过单因素试验和正交试验优化水麻果多酚超声提取工艺,使用大孔树脂纯化水麻果多酚,通过测定水麻果多酚的总还原力以及清除·OH、DPPH·、ABTS·的能力来表征其抗氧化活性,以宫颈癌Hela细胞和肺癌A549细胞为抗肿瘤研究对象,测定水麻果多酚的抗肿瘤作用。在最优超声提取工艺条件下,即乙醇浓度为60%,料液比为1∶30,超声功率200 W,超声温度为70℃,提取时间为40 min,水麻果多酚得率为3. 29%,纯化产物总酚含量为40. 47 mg/100 mg,水麻果多酚的总还原力与维生素C相当,对·OH、DPPH·、ABTS·均具有显著清除作用,可抑制Hela细胞和A549细胞的生长增殖,并导致癌细胞产生大量活性氧,出现凋亡形态特征。该提取工艺简单、高效且多酚得率高,提取物经大孔树脂纯化后总多酚含量显著提高,且具有显著的抗氧化和抗肿瘤活性。     

银杏叶提取物抗肿瘤机制研究进展

银杏叶提取物已被广泛应用于治疗心血管和外周血管灌注不足、过敏性疾病和神经性疾病等,最近研究证明银杏叶提取物对多种肿瘤具有抑制作用,其机制主要包括诱导凋亡、抗氧化和免疫调节等,银杏叶提取物抗肿瘤作用的具体研究对指导临床预防和治疗肿瘤有重要意义,对目前银杏叶提取物的抗肿瘤机制做一综述。     

从红树植物中筛选具有抗菌、抗氧化和抗肿瘤活性的内生真菌

从红树植物无瓣海桑(Sonneratia apetala),海马齿(Sesuvium portulacastrum)和秋茄(Kandelia candel)中分离得到25株内生真菌,采用滤纸片琼脂扩散法、自由基清除法(DPPH、.OH和ABTS+)和MTT法对其发酵液上清乙酸乙酯抽提物的抗菌、抗氧化和抗肿瘤活性进行研究。结果显示,有12株菌株至少对一种指示菌有抑制作用,占总供测菌株的48%;对DPPH自由基、.OH自由基和ABTS+自由基具有较强清除作用(0 mg/mL﹤EC50≦1 mg/mL)的菌株分别有3株、12株和8株;对HepG2肿瘤细胞或HeLa肿瘤细胞具有抑制作用(抑制率>50%)的有8株菌株。研究结果表明,红树植物来源的内生真菌能够产生丰富的抗菌、抗氧化和抗肿瘤活性物质,是开发抗菌、抗氧化和抗肿瘤药物的重要资源。     

富硒灵芝菌丝多糖、蛋白的提取及其体外抗氧化和抗肿瘤活性研究

灵芝具有较强的硒富集能力,其中的硒元素多以硒多糖、硒蛋白等有机硒形式存在。本研究以灵芝菌丝为研究对象,采用不同方法提取菌丝多糖及菌丝蛋白,探究外源施硒对二者的含量及其抗氧化活性的影响,并初步探究了水提多糖和可溶性蛋白的抗肿瘤活性。结果表明,以硒含量为95μg/mL的培养基发酵得到的菌丝体,其可溶性蛋白及硒含量较高,分别为1.630 8 mg/g和36.905 7μg/g;采用超声辅助碱提法时,多糖含量较高,为32.070 9 mg/g,且该多糖的硒含量为33.864μg/g。与对照组相比,富硒组灵芝菌丝体其多糖和蛋白的抗氧化性较强,且均表现出浓度依赖性。此外,富硒灵芝菌丝体其硒多糖对肿瘤细胞的抑制增殖效果较好,对HCCLM、A549和HSC-3肿瘤细胞的IC₅₀值分别为3.765、3.23和2.267 mg/mL;但其硒蛋白对上述三种癌细胞的增殖抑制效果较差,其IC₅₀值分别为636.987、506.97、555.598μg/mL。     

加拿大一枝黄花提取物的抗氧化活性研究

为进一步开发和利用加拿大一枝黄花(Solidago canadensis),该研究采用氯化铝显色法和福林酚法测定加拿大一枝黄花乙醇提取物及其不同极性萃取物中的总黄酮和总酚的含量;以抗坏血酸(Vitamin C,Vc)和二丁基羟基甲苯(BHT)为阳性对照,应用2,2-联氮-二(3-乙基-苯并噻唑-6-磺酸)二铵盐(ABTS)、1,1-二苯基苦基苯肼(DPPH)自由基清除体系、铁离子还原能力(FRAP)法和抗氧化能力指数(ORAC)法研究其体外抗氧化活性。结果表明:乙酸乙酯萃取物中的总黄酮(202.45 mg·g~(-1))和总酚(485.94 mg·g~(-1))含量最高,且其抗氧化活性最强,并强于阳性对照Vc(P0.05)。因而,加拿大一枝黄花乙酸乙酯萃取物将有可能成为一种潜在的天然高效抗氧化剂,具有广泛的应用前景。     

四种子囊菌甲醇提取物的抗氧化活性研究

比较了冬虫夏草Cordyceps sinensis、古尼虫草Cordyceps gunnii、蛹虫草Cordyceps militaris、黑柄炭角菌Xylaria nigripes等四种子囊菌提取物的抗氧化活性,对它们的子实体(F)和菌丝体(M)甲醇提取物清除DPPH自由基能力、还原力、金属离子鳌合能力和总酚含量进行了测定,结果显示四种子囊菌子实体的自由基清除能力、还原力和总酚含量均高于其菌丝体(P0.05),但四种子囊菌子实体的DPPH清除能力不存在显著差异(P0.05);古尼虫草和蛹虫草子实体的还原力和总酚含量显著高于冬虫夏草和黑柄炭角菌子实体(P0.05),但前两者之间不存在显著差异(P0.05)。总酚含量和DPPH自由基清除能力、还原力呈正相关。     

Antioxidant Activities of Some Extracts of Thymus zygis

The antioxidant activities of methanol and ethyl ether extracts obtained from Thymus zygis, collected during the flowering or non-flowering period, were evaluated and compared. To investigate this potential, extracts were tested on their capacity to react with diphenyl-picrylhydrazyl (DPPH) in a homogeneous medium, and to inhibit Fe²⁺/ascorbate-induced membrane lipid peroxidation, as estimated by the formation of thiobar-bituric acid-reactive substances (TBARS). Although methanol extracts reduce DPPH radicals more efficiently than ethyl ether extracts, suggesting a potent radical scavenger activity, the ethyl ether extracts were found to be most active in inhibiting lipid peroxidation in sarcoplasmic reticulum (SR) membranes. In addition, both extracts present peroxyl and superoxide radical scavenging activities. Peroxyl radicals were generated by the water soluble 2, 2A-azobis(2-amidinopropane) dihydrochloride (AAPH) azoinitiator, and the scavenging activities of the extracts were measured by the inhibition of cis-parinaric acid (PnA) fluorescence decay in SR. Superoxide radicals were generated either by an enzymatic or a non-enzymatic system, and the scavenger ability was evaluated by the inhibition of nitrob-lue tetrazolium reduction. Methanolic extracts are more potent as scavengers of peroxyl and super oxide radicals than the ethyl ether extracts. Apparently, there is a relationship between antioxidant potency and the total phenolic groups content in each extract.     

Antioxidant Activities of Some Extracts of Thymus zygis

The antioxidant activities of methanol and ethyl ether extracts obtained from Thymus zygis, collected during the flowering or non-flowering period, were evaluated and compared. To investigate this potential, extracts were tested on their capacity to react with diphenyl-picrylhydrazyl (DPPH) in a homogeneous medium, and to inhibit Fe²⁺/ascorbate-induced membrane lipid peroxidation, as estimated by the formation of thiobar-bituric acid-reactive substances (TBARS). Although methanol extracts reduce DPPH radicals more efficiently than ethyl ether extracts, suggesting a potent radical scavenger activity, the ethyl ether extracts were found to be most active in inhibiting lipid peroxidation in sarcoplasmic reticulum (SR) membranes. In addition, both extracts present peroxyl and superoxide radical scavenging activities. Peroxyl radicals were generated by the water soluble 2, 2A-azobis(2-amidinopropane) dihydrochloride (AAPH) azoinitiator, and the scavenging activities of the extracts were measured by the inhibition of cis-parinaric acid (PnA) fluorescence decay in SR. Superoxide radicals were generated either by an enzymatic or a non-enzymatic system, and the scavenger ability was evaluated by the inhibition of nitrob-lue tetrazolium reduction. Methanolic extracts are more potent as scavengers of peroxyl and super oxide radicals than the ethyl ether extracts. Apparently, there is a relationship between antioxidant potency and the total phenolic groups content in each extract.     

Comparison of Phytochemical Composition and Biological Activities of Rubus ulmifolius Extracts Originating from Four Regions of Tunisia

In the current study, the phenolic composition, antioxidant and antimicrobial activities of extracts from Rubus ulmifolius Schott leaves harvested in four localities (Sejnen, Tabarka, Faija and Ain drahem) in Tunisia were investigated for the first time. Great differences were found for the chemical composition, total phenol contents and biological activities among the evaluated extracts. HPLC analysis of methanolic extracts showed that the dominant compounds were kaempferol 3‐O‐rutinoside and naringenine. In addition, significant correlations were observed between antioxidant activities and phenolic contents. In fact, leaves collected from Sejnen presented higher total phenol content (53.32 mg GAE/g DW) and antioxidant activities (IC₅₀ = 39.40 mg/l) than the others samples. All extracts showed significant antimicrobial activity against six used bacteria with the inhibition zones diameters and minimal inhibitory concentration values were in the range of 8 – 16 mm and 6.25 – 25 mg/ml, respectively. The highest antimicrobial activities were recorded in Sejnen extract against Gram‐positive bacteria.     

Four New Nanaomycins Produced by Streptomyces hebeiensis Derived from Lichen

Four new nanaomycins ( 1  –  4 ), together with two known compounds, nanaomycin αA ( 5 ) and nanaomycin βA ( 6 ) were isolated from a fermentation broth of Streptomyces hebeiensis derived from lichen. The structures of the new nanaomycins 1  –  4 were established using comprehensive NMR spectroscopic data analysis as well as UV, IR, and MS data. The antimicrobial activities of 1  –  6 were evaluated against Gram‐positive bacteria and fungus. Compounds 5 and 6 showed antimicrobial activities against the test microorganisms, while 1  –  4 were inactive at 100 μg/ml.     

Antioxidant Activities of Aqueous Extract from Agrimonia pilosa Ledeb and Its Fractions

Agrimonia pilosa Ledeb is used as the tonic for asthenia and fatigue in China. Considering that the energizing effect might be correlated with antioxidant properties, we investigated the antioxidant activities of aqueous extract (AE) from Agrimonia pilosa Ledeb by assessing radical‐scavenging and anti‐lipid‐peroxidation abilities. We found that AE shows a moderate antioxidant activity to scavenge DPPH^., O , and ^.OH and inhibit β‐carotene bleaching with IC₅₀ values of 13.0, 33.2, 351, and 11.9 μg/ml, respectively, while its AcOEt‐soluble fraction (ESF) and BuOH soluble fraction (BSF) exhibit remarkable efficiencies. The ESF's IC₅₀ values of scavenging DPPH^., O , and ^.OH, and inhibiting β‐carotene bleaching are 5.6, 5.8, 171, and 7.6 μg/ml, respectively, and those of BSF are 7.5, 8.4, 82.0, and 6.2 μg/ml, respectively. In addition, we found that there is a significant correlation between total phenol content and the antioxidant activity determined by O and ^.OH scavenging, and β‐carotene‐bleaching assays. Furthermore, HPLC analysis revealed the presence of quercetin, hyperoside, quercitrin, taxifoliol, luteolin‐7‐O‐β‐D ‐glucopyranoside, and rutin in Agrimonia pilosa Ledeb . Thus, we suggest that the extracts from Agrimonia pilosa Ledeb , could be considered as natural antioxidant sources and dietary nutritional supplements to prevent oxidation‐related diseases.     

Biomolecular Characterization of Wild Sicilian Oregano: Phytochemical Screening of Essential Oils and Extracts,and Evaluation of Their Antioxidant Activities

An extensive survey of wild Sicilian oregano was made. A total of 57 samples were collected from various sites, followed by taxonomic characterization from an agronomic perspective. Based on morphological and production characteristics obtained from the 57 samples, cluster analysis was used to divide the samples into homogeneous groups, to identify the best biotypes. All samples were analyzed for their phytochemical content, applying a cascade‐extraction protocol and hydrodistillation, to obtain the non volatile components and the essential oils, respectively. The extracts contained thirteen polyphenol derivatives, i.e., four flavanones, seven flavones, and two organic acids. Their qualitative and quantitative characterization was carried out by LC/MS analyses. The essential oils were characterized using a combination of GC‐FID and GC/MS analyses; a total of 81 components were identified. The major components of the oils were thymol, p‐cymene, and γ‐terpinene. Cluster analysis was carried out on both phytochemical profiles and resulted in the division of the oregano samples into different chemical groups. The antioxidant activity of the essential oils and extracts was investigated by the Folin? Ciocalteau (FC) colorimetric assay, by UV radiation‐induced peroxidation in liposomal membranes (UV‐IP test), and by determining the O ‐scavenging activity.     

Seqarching for Antibacterial Activities of Extracts and Fractions Derived from Natural Sources Targeting Enoylpyruvate Transferase

To discover inhibitors of enoylpyruvate transferase with antibacterial activity a batch of 2490 extract or fraction samples from plants and animals belonging to 169 families, 560 genera and 916 species were tested on enoylpyruvate transferase bioassay in 96-well microtiterplates. Finally 309 samples, which belong to 80 families, 169 genera and 218 species, showed inhibitory activity at 96.15ug/ml, in which 14 samples showed IC50 at=<10.00ug/ml, 40 samples showed IC50 at 10.01-30.00ug/ml, 83 samples showed IC50 at 30.01-50.00ug/ml and 172 samples showed IC50 at 50.01-96.15ug/ml. It is indicated that this in-vitro bioassay is convenient, stable, rapid, sensitive and effective in searching for antibacterial activity samples from natural sources.     

香桃木叶片粗多酚抗氧化活性的研究

以香桃木叶片为材料,60%乙醇提取获得粗多酚样品,并对样品的油脂抗氧化性和自由基清除能力进行研究。结果表明,未经纯化的香桃木粗多酚对油脂抗氧化效果优于BHT和V_C等人工合成抗氧化剂;在清除自由基的实验中,相同浓度的香桃木粗多酚对DPPH自由基的清除率为V_E的5倍,对羟自由基的清除效果也略优于V_C。由此可以预见香桃木粗多酚在精细加工、经纯化后抗氧化效果会更加显著。     

见血封喉乳汁脂溶性成分及其抗氧化活性研究

首次采用气相色谱.质谱联用技术(GC-MS)对见血封喉(Antiaris toxicaria(Pers.)Lesch.)乳汁的脂溶性成分进行了分析,共鉴定了27个化学成分,占其总量的91.7%.用清除DPPH自由基能力的方法测定了见血封喉乳汁脂溶性部位的抗氧化活性,结果显示出一定的抗氧化活性,SC50值为500μg ml-1.     

Antioxidant,hepatoprotective and cytotoxic effects of icetexanes isolated from stem-bark of Premna tomentosa

The study investigates the antioxidant, hepatoprotective and antiproliferative effects of novel icetexane diterpenoids (ice 1–4) isolated from hexane extract of stem bark of Premna tomentosa. A549, HT-29, MCF-7, MDA-MB-231, A431 cells were used to assess the antiproliferative activity by MTT assay. Cell death induced by apoptosis was determined by morphological assessment studies using acridine orange/ethidium bromide staining (dual staining), mitochondrial potential measurement by JC-1 staining, and cell cycle analysis by propidium iodide staining method by Muse cell analyser. Anti oxidant activity was investigated by in vitro assays such as DPPH, nitric oxide and superoxide scavenging activities. Hepatoprotective activity was determined in vitro with HepG2 cells and in vivo by tBHP induced hepatic damage mice model. Based on the in vitro cytotoxic assays and morphological assessment studies using fluorescence microscopic study (acridine orange and ethidium bromide double staining) and mitochondrial potential measurements, it was found that ice 2 and 3 possess good antiproliferative effect via mitochondrial mediated apoptosis in human lung and breast cancer cells. Results of in vitro antioxidant studies demonstrated that ice-4 has showed good antioxidant activity. The restoration of serum levels of SGOT, SGPT and ALKP, liver GSH status and reduction or inhibition of lipid peroxidation in liver of tBHP intoxicated mice after administration of ice-4 at dose of 250 mg/kg indicated its potential use for hepatoprotective activity.