三叶木通(Akebia trifoliata)果实乙醇提取物对酪氨酸酶体外活性的影响

以人工栽培条件下三叶木通(Akebia trifoliata)果实为试材,用80%乙醇分别提取果皮、果肉、种子中的有效成分,经离心过滤后,于旋转蒸发仪上减压蒸馏浓缩,再经真空干燥处理得到三叶木通乙醇提取物.以L-DOPA为底物,熊果苷作阳性对照,分析测定了该提取物对酪氨酸酶活性的抑制百分率.结果表明:不同部位的三叶木通果实乙醇提取物对酪氨酸酶活性均有一定的抑制作用,其中果肉对酪氨酸酶活性的抑制作用最佳,中等浓度的果肉乙醇提取物(200 μg/mL)与270 μg/mL的熊果苷对酪氨酸酶活性的抑制率相当.     

黄柏果实提取物对植物病原真菌的抑制作用

在室内测定了芸香科植物黄柏(Phellodendron chinese Schneid.)果实乙醇粗提物及其4个不同极性溶剂的萃取部分在浓度为1 mg/mL时对小麦纹枯病菌(Rhizoctonia cerealis)、稻纹枯病菌(Rhizoctonia solani)、番茄镰刀菌萎焉病菌(Fusarium oxysporum f. sp.lycopersici)、黄瓜枯萎病菌(Fusarium oxysporum f.sp.cucumerinum)、棉花枯萎病菌(Fusarium vasinfectum)、棉花黄萎病菌(Verticillium dahliae)、小麦赤霉病菌(Fusarium graminearum)、玉米小斑病菌(Bipolaris maydis)、西瓜枯萎病菌(Fusarium oxysporum f.sp.niverum)、梨黑星病菌(Venturia piri-na)、稻瘟病菌(Magnaporthe grisea)等11种植物病原真菌的抑制作用.乙酸乙酯部分和正丁醇部分对植物病原菌均表现出较强的抑制活性,其中乙酸乙酯部分对两种丝核菌小麦纹枯病菌和稻纹枯病菌的生长抑制作用最强,抑制率分别为100.00%和89.36%;正丁醇部分对两者的抑制率分别为97.32%和61.32%.实验结果表明,黄柏果实中的抗真菌活性成分主要存在于乙醇粗提物中的乙酸乙酯和正丁醇萃取部分中.     

一株罗布泊盐湖链霉菌的鉴定及其代谢产物对酪氨酸酶活性、黑色素生成的抑制效应CSCD

本研究采用多相分类法对一株分离自新疆罗布泊盐湖链霉菌89-2-2进行鉴定,通过CCK-8法、L-多巴氧化法和NaOH溶解法检测该菌株乙酸乙酯提取物对小鼠黑色素瘤B16细胞增殖、细胞内酪氨酸酶活性及黑色素含量的影响。以抑制酪氨酸酶活性为指标,应用LC-MS代谢组学方法检测链霉菌89-2-2发酵条件优化前后所产生的差异代谢物,分析可能具有抑制活性的代谢产物类型。结果初步鉴定该菌株为西唐氏链霉菌(Streptomyces setonii)89-2-2。S.setonii 89-2-2乙酸乙酯提取物在100~1000μg/mL浓度范围内几乎无细胞毒性,但能有效抑制B16细胞内酪氨酸酶活性和黑色素生成,与空白组相比均具有显著性差异(P<0.05)。代谢组学实验的结果显示S.setonii 89-2-2产生的差异代谢物主要为维生素类化合物、芳香类化合物和羧酸类化合物。本研究为从新疆罗布泊链霉菌中开发酪氨酸酶抑制剂和黑色素合成抑制剂提供重要的科学依据。     

羽叶千里光不同部位提取物的抗氧化活性研究

目的:比较研究羽叶千里光根、茎、叶和花四个部位甲醇提取物的抗氧化活性.方法:采用索式提取法分别对羽叶千里光根、茎、叶和花进行甲醇提取;采用分光光度法测定提取物对二苯代苦味酰自由基(DPPH)清除能力及其在β-胡萝卜素/亚油酸体系中的抗氧化活性.结果:羽叶千里光叶甲醇提取物对DPPH的清除能力最强,其次为茎、花、根.在β-胡萝卜素/亚油酸体系中,羽叶千里光抗氧化作用强弱依次为叶、茎、根、花.结论:羽叶千里光四个部位甲醇提取物均有抗氧化活性.其中,叶甲醇提取物的抗氧化能力最强.     

醇溶性丝胶肽的提纯及对酪氨酸酶抑制作用的研究

经过A8 1.398中性蛋白酶水解,75%乙醇低温提取得到的醇溶性丝胶肽是相对分子量小于500 Da的寡肽混合物,采用非极性的DA201-C大孔吸附树脂同时进行脱盐处理和初步分离,得到3个提纯的组分.它们均有抑制酪氨酸酶的活性,并且经过DA201-C大孔吸附树脂提纯后的组分随着分子疏水性的增加,抑制作用更加明显,说明丝胶肽抑制酪氨酸酶的活性与其疏水性有关.以多巴(L-DOPA)为底物,用Lineweaver-Burk双倒数曲线推断醇溶性丝胶肽对酪氨酸酶的抑制效应属于反竞争性抑制类型.     

石榴皮多酚提取物对醛糖还原酶的抑制作用

本文分别以丙酮、甲醇和水为溶剂对石榴皮中的多酚进行了提取,得到3种提取物,采用紫外分光光度法表征了其对AR的抑制作用及抑制类型.3种提取物对AR活性均表现出抑制作用,且其作用大小与浓度呈明显的剂量-效应关系.3种提取物中,丙酮提取物的抑酶活性最强,甲醇提取物次之,水提物最弱,其对AR的半数抑制浓度(IC50,μg/mL)分别为34.77、44.18和62.07.石榴皮的丙酮和甲醇提取物对AR均能产生反竞争性抑制;当浓度为0.033 mg/mL时,其对AR的抑制常数(Ki)分别为49和71 μg/mL.     

念珠藻葛仙米生理生化特性对不同低温胁迫的响应

研究了不同培养温度下对念珠藻葛仙米的生长和相关生理生化特性的变化.结果表明,低温抑制葛仙米的生长,在2℃～5℃低温下其生长甚至完全停止;在10℃低温胁迫下,其生长延滞期变长,其后仍能保持正常生长.低温胁迫下,葛仙米光合系统II(PSII)的光合效率(Fv/Fm)的变化趋势与生长曲线相似;细胞电解质渗透率在低温胁迫初期尚能保持比较低的水平,但随着时间延长而升高;可溶性糖和还原性糖含量的变化则随胁迫加剧有不同程度升高.可溶性蛋白含量则在低温下保持比较低的水平.这些结果表明,低温对葛仙米的生长和光合作用具有抑制作用,但葛仙米也表现出了一定的抵抗低温胁迫的能力,并通过调节细胞膜的渗透性、重新合成低温适应调节物质(如总糖和可溶性糖等)来减少低温伤害,从而适应低温胁迫.     

六种微藻的抗MRSA活性筛选

本文以琼脂扩散法为体外抗菌活性测定方法,研究了六种微藻(两种绿藻,三种硅藻和一种蓝藻)的不同溶剂提取物对耐甲氧西林金黄色葡萄球菌的抑制活性.结果表明,每种微藻的提取物对耐甲氧西林金黄色葡萄球菌具有不同程度的抑制活性.其中,蓝隐藻、牟氏角毛藻和青岛大扁藻的提取物具有良好的抗菌活性.结论:微藻是一种新的开发抗耐甲氧西林金黄色葡萄球菌物质的潜在资源.     

表没食子儿茶素没食子酸酯及其不同氧化级分的抑菌活性研究

本文研究了表没食子儿茶素没食子酸酯(EGCG)及其氧化产物中性萃取级分(EOFA)、酸性萃取级分(EOFB)的抑菌活性.结果表明,EGCG及其氧化级分EOFA、EOFB对细菌有较强的抑菌活性,而对供试的酵母和霉菌抑制作用不明显.抑菌活性大小为:EGCG>EOFA>EOFB,且EGCG及其氧化级分随温度升高抑菌活性下降;在弱酸性条件下,EGCG、EOFA及EOFB抑菌活性较强,强酸或强碱条件下,抑菌活性均大幅下降;一定浓度的氯化钠可增强EGCG、EOFA及EOFB的抑菌活性.     

夜香树提取物体外抗肿瘤作用的实验研究

为探讨夜香树(CN)不同提取物体对体外培养的肿瘤细胞的作用,采用系统溶剂法提取CN皂苷和多糖,采用MTT法、细胞集落形成法、生长曲线法观察CN皂苷和多糖对宫颈癌细胞株Hela、人胃癌细胞株SGC7901、人肝癌细胞株Bele7404的生长抑制情况,结果发现CN皂苷和多糖对人胃癌细胞株SGC7901、宫颈癌细胞株Hela、肝癌细胞株Bele7404、等3种肿瘤细胞均有明显的抑制作用:在终浓度为62.5 μg/mL范围,CN皂苷和多糖对上述3种肿瘤细胞的抑制率均大于80%,细胞抑制率均有明显的剂量依赖性,IC50均小于20 μg/mL.CN皂苷和多糖对宫顶癌细胞株Hela、人胃癌细胞株SGC7901、人肝癌细胞株Bele7404细胞有显著的抗增殖作用,其抗增殖作用呈明显的剂量依赖关系.     

Antifilarial and Antibiotic Activities of Methanolic Extracts of Melaleuca cajuputi Flowers

We evaluated the activity of methanolic extracts of Melaleuca cajuputi flowers against the filarial worm Brugia pahangi and its bacterial endosymbiont Wolbachia. Anti-Wolbachia activity was measured in worms and in Aedes albopictus Aa23 cells by PCR, electron microscopy, and other biological assays. In particular, microfilarial release, worm motility, and viability were determined. M. cajuputi flower extracts were found to significantly reduce Wolbachia endosymbionts in Aa23 cells, Wolbachia surface protein, and microfilarial release, as well as the viability and motility of adult worms. Anti-Wolbachia activity was further confirmed by observation of degraded and phagocytized Wolbachia in worms treated with the flower extracts. The data provided in vitro and in vivo evidence that M. cajuputi flower extracts inhibit Wolbachia, an activity that may be exploited as an alternative strategy to treat human lymphatic filariasis.     

桦褐孔菌提取物抗氧化与糖苷酶抑制活性研究

为探索桦褐孔菌(Inonotus obliquus (Fr.) Pila)生物活性与化学成分之间的相关性,本文用乙醇回流提取、梯度萃取得桦褐孔菌的石油醚、乙酸乙酯、正丁醇和水提取物,对其进行黄酮和多酚类化合物的含量测定,并从抗氧化和降血糖两个方面测定了总还原力、清除DPPH自由基、抑制肝脂质过氧化、抑制α-葡萄糖苷酶活性四种体外模型对不同提取物活性的影响.结果显示:乙酸乙酯和正丁醇提取物所含的黄酮和多酚类化合物较多(P<0.01)且抗氧化和降血糖活性较好.因此,桦褐孔菌抗氧化和降血糖活性的大小与其所含黄酮和多酚类化合物量密切相关,本研究结果为桦褐孔菌生物活性成分的深入研究奠定了良好的基础.     

Caffeoylquinic Acids,Cytotoxic, Antioxidant,Acetylcholinesterase and Tyrosinase Enzyme Inhibitory Activities of Six Inula Species from Bulgaria

Chlorogenic (5‐CQA), 1,5‐, 3,5‐, 4,5‐ and 3,4‐dicaffeoylquinic (DCQA) acids were identified and quantified in the methanol extracts of Inula oculus‐christi L., I. bifrons L., I. aschersoniana Janka var. aschersoniana, I. ensifolia L., I. conyza (Griess .) DC. and I. germanica L. by HPLC analysis. The amount of 5‐CQA varied from 5.48 to 28.44 mg/g DE and the highest content was detected in I. ensifolia. 1,5‐DCQA (4.05–55.25 mg/g DE) was the most abundant dicaffeoyl ester of quinic acid followed by 3,5‐DCQA, 4,5‐DCQA and 3,4‐DCQA. The extract of I. ensifolia showed the highest total phenolic content (119.92±0.95 mg GAE/g DE) and exhibited the strongest DPPH radical scavenging activity (69.41±0.55 %). I. bifrons extract was found to be the most active sample against ABTS^.+ (TEAC 0.257±0.012 mg/mL) and the best tyrosinase inhibitor. The studied extracts demonstrated a low inhibitory effect towards acetylcholinesterase and possessed low cytotoxicity in concentration range from 10 to 300 μg/mL toward non‐cancer (MDCK II) and cancer (A 549) cells.     

Tyrosinase Inhibitory Effects and Antioxidative Activities of Saponins from Xanthoceras Sorbifolia Nutshell

Certain saponins are bioactive compounds with anticancer, antivirus and antioxidant activities. This paper discussed inhibitory effects of saponins from Xanthoceras Sorbifolia on tyrosinase, through the research of the rate of tyrosinase catalyzed L-DOPA oxidation. The inhibition rate of tyrosinase activity presented non-linear changes with the saponins concentration. The rate reached 52.0% when the saponins concentration was 0.96 mg/ml. Antioxidant activities of saponins from Xanthoceras Sorbifolia were evaluated by using hydroxyl and superoxide radical scavenging assays. The hydroxyl radical scavenging effects of the saponins were 15.5–68.7%, respectively at the concentration of 0.18–2.52 mg/ml. The superoxide radical scavenging activity reduced from 96.6% to 7.05% with the time increasing at the concentration of 1.44 mg/ml. All the above antioxidant evaluation indicated that saponins from Xanthoceras Sorbifolia exhibited good antioxidant activity in a concentration- dependent manner.     

Antimutagenic Effect of Methanolic Extracts from Peanut Hulls

The antimutagenic effects of methanolic extracts of peanut hulls (MEPH) were evaluated by the Ames test. MEPH inhibited the mutagenicity of 4-nitroquinoline-N-oxide (NQNO), a direct-acting mutagen. MEPH also inhibited the mutagenicity of some indirect-acting mutagens and decreased in the order of 2-amino-3-methylimidazo(4,5-f)quinoline (IQ)>aflatoxin B₁ (AFB₁)>2-amino-6-methyldipyrido(1,2-a : 3′, 2′-d)imidazole (Glu-P-1) > 3-amino-1,4-dimethyl-5H-pyridol(4,3-b)indole (Trp-P-1) > benzo(a)pyrene (B(a)P) for 5. typhimurium TA98, and IQ > Trp-P-1 > Glu-P-1 > AFB₁ > B(a)P for S. typhimurium TA100.     

3种念珠藻多糖对自由基的清除作用

研究了地木耳（Nostoc commune）、葛仙米（N．sphaerohies）和发菜（N．flagelliforme）3种念珠藻多糖对自由基的清除作用。结果表明,3种念珠藻多糖对超氧阴离子自由基和羟自由基具有很强的清除作用,且呈量效关系,地木耳清除超氧自由基作用最强,最高清除率达72．3％,葛仙米和发菜分别为46．7％、35．5％;发菜清除羟自由基效果最强,最高清除率达74．3％,葛仙米和地木耳清除率分别为49．0％、46．7％;3种念珠藻多糖对DPPH自由基的清除作用不显著。     

Antifungal Activities of Different Extracts of Marine Macroalgae Against Dermatophytes and Candida Species

Algae are bioactive natural resources, and due to the medical importance of superficial mycoses, we focused the action of macroalgae extracts against dermatophytes and Candida species. Seaweed obtained from the Riacho Doce beach, Alagoas (Brazil), were screened for the antifungal activity, through crude extracts using dichloromethane, chloroform, methanol, ethanol, water and chloroform and hexane fractions of green, brown and red algae in assays with standard strains of the dermatophytes Trichophyton rubrum, T. tonsurans, T. mentagrophytes, Microsporum canis, M. gypseum and yeasts Candida albicans, C. krusei, C. guilliermondi and C. parapsilosis. The M44-A and M27-A2/M38A manuals by CLSI were followed, and the minimum inhibitory concentration (MIC) ranged from 0.03 to 16.00 μg ml(-1), and an inhibition halo of 10.00-25.00 mm was observed for dermatophytes, while for yeast, it was from 8.00 to 16.00 μg ml(-1) and 10.00-15.00 mm. M. canis showed MIC of 0.03 μg ml(-1) and the largest inhibition halo in T. rubrum (25.00 mm) through the use of the methanol extract. For C. albicans, dichloromethane, methanol and ethanol extracts formed the largest inhibition halo. The ethanol extract was shown to be the best inhibiting fungi growth, and chloroform and hexane fractions of H. musciformis inhibited the growth of all dermatophytes and C. albicans, yielding the conclusion that apolar extracts obtained from algae presented the best activity against important pathogenic fungi.     

Comparison of Phytochemical Profile and Bioproperties of Methanolic Extracts from Different Parts of Tunisian Rumex roseus

The genus Rumex (Polygonaceae) is distributed worldwide and the different species belonging to it are used in traditional medicine. The present study aimed at the evaluation of the phytochemical profile and the biochemical properties of methanolic extracts from different parts (roots, stems, and leaves) of Rumex roseus, a wild local Tunisian plant traditionally used as food. The phytochemical analysis on the extracts was performed using standard colorimetric procedures, HPLC-DAD, and HPLC-DAD-ESI-MS; then, several in vitro cell-free assays have been used to estimate their antioxidant/free radical scavenging capability (TAC-PM, DPPH, TEAC, FRAP, ORAC, SOD-like activity, and HOCl-induced albumin degradation). Additionally, anti-inflammatory effect of these extracts was evaluated in an in vitro model of acute intestinal inflammation in differentiated Caco-2 cells. The results showed that the methanolic extracts from stems and, especially, leaves contain substantial amounts of flavones (apigenin and luteolin, together with their derivatives), while the extract from roots is characterized by the presence of tannins and quinic acid derivatives. All the extracts appeared endowed with excellent antioxidant/free radical scavenging properties. In particular, the extract from roots was characterized by a remarkable activity, probably due to its different and peculiar polyphenolic composition. Furthermore, both Rumex roseus roots and stems extracts demonstrated an anti-inflammatory effect in intestinal epithelial cells, reducing TNF-α-induced gene expression of IL-6 and IL-8. In conclusion, R. roseus methanolic extracts have shown to be potential sources of bioactive compounds to be used in the prevention and treatment of pathologies related to oxidative stress and inflammation.     

葛根提取物对酪氨酸酶活性的影响

研究了葛根不同提取物对酪氨酸酶活性的影响,结果表明:葛根水提物及乙醇提取物在60 mg/mL时对酪氨酸酶的激活作用最强,激活率分别为101.4%和137.7%.两者对酪氨酸酶的激活作用与其葛根素含量无明显相关性.葛根水提物及醇提物能使酪氨酸酶对底物结合的亲和力明显增强(Km/Km′=5.89,Km/Km″=6.43),同时使最大酶促反应速度有了明显提高(Vm′/Vm=2.088,Vm″/Vm=2.354),两者的激活作用都表现为混合型.