Evaluation of Various Extraction Techniques for Efficient Lipid Recovery from Thermo-Resistant Microalgae, Hindakia, Scenedesmus and Micractinium Species—Comparison of Lipid Extraction Methods from Microalgae

In recent years, photosynthetic microalgae regained attention for biodiesel production. For efficient utilization of microalgae, a number of criteria including a strain with high biomass and lipid productivities and employment of effective and reliable methods for oil extraction from the obtained biomass should be met. Recently, we have isolated and identified three thermo-resistant green microalgae strains, namely;Scenedesmus sp. ME02, Hindakia tetrachotoma ME03 and Mic-ractinium sp. ME05. In this study, we compared percent lipid content of thermos-tolerant mic-roalgal strains using the following solvent extraction methods: Soxhlet, Bligh and Dyer and Folch methods with or without assisted cell disruption techniques including lyophilization, homogenization, ultrasonication, bead and microwave-assisted. The highest increase in lipid yield was obtained with a combination of lyophilization and ultrasonication techniques together with Soxhlet method: 27% of total dry weight for Micractinium sp. ME05. We conclude that lyophilization and ultrasonication are effective assistance methods for lipid extraction from thermo-resistant microalgae.

Characterization of wet microalgal cells pretreated with steam for lipid extraction

Steam pretreatment was employed to disrupt Microalgal cells for lipids extraction.Effects of steam pretreatment on microstructure of microalgal cells were investigated through scanning electron microscopy(SEM)and transmission electron microscopy(TEM).Effect of treatment on lipid extraction was also studied.Microalgal cell walls were distorted after steam pretreatment due to the hydrolysis of organic macromolecules contained in cell wall.Maximum curvature was increased from 1.88×10^(-6) m^(-1) to 1.43×10^(-7) m^(-1) after treatment with the steam at 130℃.The fractal dimension of microalgal cells increased from 1.25 to 1.30 after pretreatment for 15 min,and further increased to 1.47 when the pretreatment time was increased to 60 min.Increased steam pretreatment temperature and time enhanced the hydrolysis of organic macromolecules,and finally destroyed microalgal cell walls at pretreatment temperature of 130℃and pretreatment time of 60 min.Lipid extracted from wet microalgal was significantly increased(2.1-fold)after pretreatment.

Lipid extraction and CO_(2)capture with switchable polarity solvent

In this study,lipid extraction and CO_(2)capture are combined using N,N-dimethylcyclohexylamine(DMCHA)as switchable polarity solvent.The effects of operation parameters are discussed according to the CO_(2)absorption/desorption and lipid/DMCHA recovery results.A triphasic models considering lipid,water,and gas phases are established to analyze the kinetic behaviors.The results show that DMCHA is reversible through CO_(2)absorption/desorption,and the enhanced dispersion of droplets and bubbles in water phase improves the lipid/DMCHA recovery and CO_(2)absorption/desorption.The triphasic kinetic models fit well with experimental data,and gas-liquid mass transfer is regarded as the rate-determining step.The lower interfacial areas result in the poorer gas-liquid mass transfer for the DMCHA recovery than lipid recovery process.

Antibacterial and anti-biofilm activity of the lipid extract from Mantidis ootheca on Pseudomonas aeruginosa

The aim of this study is to assess the antibacterial and anti-biofilm properties of the lipid extract from Man- tidis ootheca against the gentamycin resistant Pseudomonas aeruginosa. The chemical composition of the lipid extract and its relative proportion were determined using the technique of gas chromatography coupled with mass spec- trometry （GC-MS）. Antibacterial susceptibility tests were performed using a disc diffusion assay and the minimum inhibition concentration （MIC） was determined by way of the agar dilution method. The anti-biofilm test was carried out with crystal violet staining and scanning electron microscopy （SEM）. There were 16 compounds detected, and the most abundant components were sesquiterpenoids, monoterpenes, and trace aromatic compounds. The MIC for P. aeruginosa was 4 mg/ml and the eradication effect on preformed biofilms was established and compared with a ciprofloxacin control. The results of our study indicated that a lipid extract from M. ootheca could be used as a topical and antibacterial agent with anti-biofilm activity in the future.

Comparison of lipid extraction methods for the microalgae Acutodesmus obliquus

Microalgae are widely used in the pharmaceutical and energy industries,therefore the conditions for their cultivation and extraction methods play an important role in the profiling and acquisition of lipids.The efficiency of lipid extraction from microalgae has attracted great interest from industry because of the wide variety of lipids and amounts that can be obtained.Acutodesmus obliquus(Scenedesmus obliquus UTEX 393)was used in this study.It was cultivated in Bold 3N medium modified with 75%nitrogen at 25℃,pH 6.8,125 r/min and a photoperiod of 18/6 h and illuminated with white light provided by a Light-Emitting Diode Surface Mount Device extensions(LED SMD)with an intensity of 1200μE/(m^(2)·s).The cells were stained with the Red Nile(RN)technique to indicate lipid production.Four extraction methods were compared,classical,microwave(MW),Soxhlet,and ultrasound(US),using the same solvent proportions(hexane:chloroform:methanol=1:2:3).All samples were analyzed with Fourier Transform Infrared Spectroscopy(FTIR)and Gas Chromatography coupled to Mass Spectrometry(GC-MS).The results showed:1)lipid production detected by RN was consistent with microalgal growth;2)the MW technique was the best extraction method,according to the statistical analysis through Randomized Complete Block(RCB)design and performance of 4.6%;and 3)the presence of saturated and unsaturated acids was indicated by FTIR spectra.GC-MS was able to identify palmitic and linoleic acids as the likely major constituents of the sample.

Modeling and Optimization of Lipid Extraction Process from Municipal Secondary Sludge for Biodiesel Production

In the current study,the potentiality and optimization of lipid extraction from secondary sludge for biodiesel production were investigated.Four lipid extraction parameters were examined and used for process optimization and model development using Design of Experiment(DoE)method(namely methanol to hexane ratio-%,solvent to sludge ratio-ml/g,temperature-oC and extraction time-h).During the optimization process,free fatty acid(FFA)and saponifiable lipids(SLs)content of the extracted lipid were analyzed.The results revealed that,the maximum lipid extraction yield(Ylipid)predicted through numerically optimized conditions by the model for highest desirability(0.99)was 16.5%at methanol to hexane ratio(%)of 84%,solvent to sludge ratio(v/wt)of 45 ml/g,temperature at 90℃ for 6 hours extraction time.The extracted lipid contained a maximum amount of 31%(wt/wt)FFA,where palmatic acid was predominant.The FAMEs yield produced from ex-situ acid-catalyzed esterification/transesterification of the methanol-hexane co-solvent extracted lipid ranged between 4.5-5%(wt/wt)based on sludge weight.Fatty acid profile of FAMEs was found to be dominated by methyl palmitate(C16:0)representing 36%of FAMEs composition,followed by palmitoleic acid methyl ester(C16:1),oleic acid methyl ester(C18:1)and stearic acid methyl ester(C18:1)representing 24%,18%and 10%of the FFA composition respectively.PCA analysis showed that solvent to sludge ratio(ml/g)has the highest significant positive effect on FAMEs yield(p-value<0.05)where methanol to hexane ratio(X1),temperature(X3)and extraction time(X4)were inversely correlated with FAMEs yield.The results indicated the feasibility of using secondary sludge as an alternative feedstock for biodiesel production.However,the optimized conditions for maximizing extracted lipid content should not be considered suitable for FAMEs yield as well.

Quantification of Lipid Content and Identification of the Main Lipid Classes Present in Microalgae Extracts Scenedesmus sp. for Obtaining Fatty Compounds for Biofuel Production

Microalgae biomass has been reported in the literature as one of the most promising sources for obtaining different products of industrial interest such as lipids, fatty acids, carotenoids, proteins and fibers. The lipid fraction of microalgae comprises neutral lipids, free fatty acids and polar lipids. It is of great importance to estimate the composition of the lipid fraction to define the potential for use, either as a raw material for the production of biofuels or for use for nutraceuticals and/or food purposes. The microalgae Scenedesmus sp. cultivated in a photobioreactor, the sky open raceway type, was evaluated for lipid content, identification and quantification of lipid components obtained from different extracts. In the quantification of the lipid content, extraction methods were proposed without chemical treatment (use of solvents only) such as chloroform:methanol (2:1 v/v)—Bligh & Dyer, Ethanol, Ethyl acetate:Hexane (1:1 v/v) and others with chemical treatment such as J-Schmid-Bondzynski-Ratzlaff (acid) and saponification (basic). For the identification of the main lipid components present in the extracts, the Thin layer chromatography (TLC) technique was used. This made it possible, using a simple and inexpensive method, to identify the compounds extracted by different extraction methods, that is, it was possible to verify the selectivity of the different extraction methods. In addition, it has been shown that using these methods, widely described in the literature as methods of extracting lipids in practice, extracts a wide diversity of compounds. The levels of lipids obtained via solvent extraction were up to 50% higher than those obtained with chemical treatment. In lipid extracts, obtained via solvent extraction, the presence of polar compounds, glycerides, carotenoids, pigments and sterols was identified, with up to 53% being composed of an unsaponifiable fraction, thus, presenting low selectivity for extracting fatty components. The acidic and basic treatments applied to the biomass of Scenedesmus sp. showed greater selectivity for obtaining fat components of 71.47% and 94.99%, respectively. The results showed that depending on the solvent/method used to quantify the lipids, the selectivity for obtaining the grease fraction, fundamental for conversion into biofuels, varies and the total lipid content may be overestimated.

Modulatory effect of pineapple peel extract on lipid peroxidation,catalase activity and hepatic biomarker levels in blood plasma of alcoholinduced oxidative stressed rats

Objective:To investigate the ability of the methanolic extract of pineapple peel to modulate alcohol-induced lipid peroxidation,changes in catalase activities and hepatic biochemical marker levels in blood plasma.Methods:Oxidative stress was induced by oral administration of ethanol(20%w/v) at a dosage of 5 niL/kg bw in rats.After 28 days of treatment,the rats were fasted overnight and sacrificed by cervical dislocation.Blood was collected with a 2 mL syringe by cardiac puncture and was centrifuged at 3000 rpm for 10 min.The plasma was analyzed to evaluate malondialdehyde(MDA),catalase activity,aspartate aminotransferase(AST),alkaline phosphatase(ALP) and alanine aminotransferase(ALT) concentrations.Results:Administration of alcohol caused a drastic increase(87.74%) in MDA level compared with the control.Pineapple peel extract significantly reduced the MDA level by 60.16%at 2.S mL/kg bw.Rats fed alcohol only had the highest catalase activity,treatment with pineapple peel extract at 2.5 mL/kg bw however, reduced the activity.Increased AST,ALP and ALT activities were observed in rats fed alcohol only respectively,treatment with pineapple peel extract drastically reduced their activities. Conclusions:The positive modulation of lipid peroxidation,catalase activities as well as hepatic biomarker levels of blood plasma by the methanolic extract of pineapple peels under alcoholinduced oxidative stress is an indication of its protective ability in the management of alcoholinduced toxicity.

<i>Trapa japonica</i>Flerov Extract Attenuates Lipid Accumulation through Downregulation of Adipogenic Transcription Factors in 3T3-L1 Cells

Obesity is a major human health problem associated with various diseases, including cardiac injury and type 2 diabetes. Trapa japonica Flerov (TJF) has been used in traditional oriental medicine to treat diabetes. In this study, we evaluated the inhibitory effect of and the mechanism underlying the effect of TJF extract on adipogenesis in 3T3-L1 cells. The effects of TJF extract on cell viability were analyzed using a 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay, and the anti-adipogenic effect was measured by oil red O staining. The expression of peroxisomal proliferator activated receptor (PPAR)γ, CCAAT/enhancer-binding protein-α (C/EBP)α, adenosine monophosphate-activated protein kinase (AMPK), acetyl-CoA carboxylase (ACC), adiponectin, and fatty acid binding protein (FABP)4 involved in adipogenesis was determined by western blot analysis. TJF extract effectively inhibited lipid accumulation and the expression of PPARγ and C/EBPα in 3T3-L1 cells. TJF also increased the phosphorylation of AMPK and ACC, and decreased the expression of adiponectin and FABP4. These results indicate that TJF extract exerts its anti-obesity effect through the downregulation of adipogenic transcription factors and adipogenic marker genes.

Influence of Modifiers, Extractants, and Trappers on Lipid Composition with Liquids in Standard State Extraction, Supercritical Fluid Extraction and Trapping by Supercritical Fluid Extraction, Part II

Modifiers have a broad array of influences on extraction with liquids in standard state, supercritical fluid extraction (SFE), trapping by SFE and supercritical fluid chromatography (SFC). They can significantly change the qualitative and quantitative results. Quantitative and qualitative results can be influenced by different extractants and modifiers in different ways as it was shown by Brondz et al. at 2007 in “The real nature of the indole alkaloids in Cortinarius infractus: Evaluation of artifact formation through solvent extraction method development”, J. Chromatography A, 1148, 1-7. The choice of correct extractant, modifier, and trapper to the bulk mobile phase for supercritical fluids (SFs) or for liquids in subcritical or in the liquids in standard state is a challenge in any extraction procedure. This is the second paper in a sequence that describes the influence of extractants and modifiers on the performance of SFs and results of extraction with liquids in standard state and SFE. Here, attention is given to possible mistakes in qualitative and quantitative results by poor understanding of the influence of extractants, modifiers, and trappers on extraction and trapping process by a careless choice of extractant, modifier, and trapper for extraction with liquids in standard state and SFE. The SF chosen for discussion in the paper is CO2. However, similar effects can be observed with use of other SFs and fluids in subcritical and standard states. In this paper, the discussion of lipids, fatty and carboxylic acids have been chosen as target analytes for extraction, trapping and analysis. Some examples from extraction with liquids in the standard state and trapping in the supercritical state (collection) have been furnished with the wrong extractant, modifier, or trapper which is presented for illustration of inappropriate choice of extractants, modifiers, and trappers.

Antidiabetic and Antihyperlipidemic Activities of Methanolic Leaf Extract of <i>Stephania japonica</i>in Alloxan Induced Diabetic Rats

This present study was aimed to investigate the antidiabetic and antihyperlipidemic activities of methanolic leaf extract (LE) of Stephania japonica alone and in combination with metformin in alloxan induced diabetic rats. Primarily acute toxicity study and oral glucose tolerance test were performed. Diabetes was confirmed after 12 days of single intraperitoneal injection of alloxan (120 mg/kg BW) in albino male rats. Rats were divided into six groups’;normal control (Group I) and diabetic induced groups as (Group II, III, IV, V and VI). Group III & IV were treated with leaf extract of S. japonica (200 mg/kg BW & 350 mg/kg BW). Group V (Met 850 mg/70 kg BW) and group VI: (combination of Met 425 mg/70 kg BW and LE 250 mg/kg BW) for four weeks. Body weight of each rat in the different groups was recorded at 0, 7th, 14th, 21st and 28th day of treatment. TC, TG, LDL-C and HDL-C were measured analytically after 28 days of treatment. Alloxan induction also caused left ventricular hypertrophy. LE of S. Japonica showed a good result in OGTT. Oral treatment of different doses of LE and combination therapy reduced elevated level of BG, TC, TG, LDL-C and increased HDL-C level significantly (p S. japonica (Thunb.) Miers showed antihyperlipidemic and antidiabetic effect and hence could be suggested as a potential therapeutic agent for diabetic treatment.

Captiva EMR-Lipid技术结合UPLC-Q-TOF/MS测定压片糖果中非法添加的美托拉宗

目的 建立一种超高效液相色谱-四极杆飞行时间质谱(UPLC-QTOF/MS)分析方法对压片糖果中的非法添加药物美托拉宗进行快速筛查与定量检测。方法 使用乙腈提取待测组分,Captiva EMR-Lipid净化柱进行净化,经Agilent RRHD Eclipse Plus C_(18)(100 mm×2.1 mm,1.8μm)色谱柱进行分离,运用UPLC-Q-TOF/MS的Targeted MS/MS模式进行检测分析。结果 美托拉宗在浓度范围50~1 000 ng·mL^(-1)内线性良好(r=0.999 0);检测限为1.0μg·g^(-1);定量限为2.5μg·g^(-1),平均回收率为98.15%,RSD为2.2%(n=18)。结论 该方法具有操作简易快速、定性定量准确等特点,能应用于日常样品的检验检测。

超声辅助水剂法提取硅藻土中玉米蜡脂的工艺优化

为了提高玉米油精炼的附加值,并实现硅藻土的可循环利用,以玉米油精炼副产物含蜡脂的硅藻土为原料,采用超声辅助水剂法提取玉米蜡脂,考察了不同提取条件对玉米蜡脂提取率的影响,并通过响应面法优化玉米蜡脂提取的工艺条件。结果表明:超声辅助水剂法提取玉米蜡脂的最佳工艺条件为超声功率480 W、超声时间4 h、提取温度95℃、料液比1∶3,在此条件下玉米蜡脂提取率为(59.46±0.91)%。综上,超声辅助水剂法可以有效提取硅藻土中的玉米蜡脂。

不同工艺制取油莎豆油的品质与风味分析

分别采用液压榨(HP)、螺旋压榨(SP)、亚临界丁烷萃取(SBE)和超临界CO_(2)萃取(SCE)法提取油莎豆油,研究4种工艺对出油率、油脂理化指标和脂质伴随物含量的影响,并通过顶空固相微萃取-气质联用法分析4种油莎豆油的挥发性成分。结果表明:制油工艺对油莎豆油出油率及基本理化指标的影响显著(P<0.05),SBE出油率最高(31.89%),在SCE、SP、SP油样中分别检测出最低的酸价(0.44 mg/g)、过氧化值(0.03×10^(-1)g/100 g)和水分(0.06 g/100 g)。SCE油和SBE油的色泽更加清亮透明。SCE油中不饱和脂肪酸含量为49.63 mg/g,比其它3种工艺增加了3.50%~5.54%(P<0.05)。4种油莎豆油样中脂质伴随物含量及其氧化稳定性有显著差异(P<0.05),SP油中生育酚(26.85 mg/100 g)、总酚(16.65 mg GAE/100 g)含量最高,SCE油中总甾醇(283.48 mg/100 g)含量最高,SBE油中磷脂含量(1.05 mg/g)最高。SP油表现出较强的氧化稳定性,其氧化诱导期为34.40 h,分别是SBE、HP和SCE油的1.24,8.27倍和6.70倍。从4种油莎豆油中共检出162种挥发性物质,主要为杂环类物质、酸类、醛类、醇类、酮类、酯类和烃类,SP油中杂环类相对含量最高为44.86%,HP油及SBE油中醛类物质相对含量最高分别为50.18%和26.03%,SCE油中苯类物质相对含量最多为60.00%。根据气味活力值(OAV)得出4种油样的关键风味物质,其中SP油有16种,HP油有23种,SCE油有8种,SBE油有22种,己醛为共有成分。主成分分析(PCA)发现4种油的特征风味存在差异。研究结果可为油莎豆油的产品开发提供数据参考。

栀子花多糖的提取工艺及其脂代谢调节作用

【目的】研究栀子花多糖的提取工艺及其脂代谢调节作用,开发栀子花多糖资源。【方法】采用单因素试验和响应面法进行多糖提取工艺优化,并采用油酸钠诱导建立HepG2细胞脂肪积累模型,评价各栀子花多糖提取物对HepG2脂肪积累细胞中脂代谢指标的影响。【结果】在液料比25 mL·g^(-1)、超声功率550 W、超声时间140 min、提取温度63℃的条件下,栀子花多糖的提取率高达17.48%,且栀子花多糖可下调高脂HepG2细胞的甘油三酯(TG)、总胆固醇(TC)和低密度脂蛋白(LDL-C)含量,上调细胞内高密度脂蛋白(HDL-C)含量,不影响HepG2细胞的存活率。【结论】栀子花多糖具有良好的降血脂作用。

腊梅花提取物对高脂膳食诱导小鼠肥胖的预防作用

目的:探究腊梅花提取物对高脂膳食诱导小鼠肥胖的预防作用。方法:将50只C57BL/6小黑鼠分为5组,即空白对照组(NC),模型对照组(HFD),腊梅花提取物(Chimonanthus praecox flower extract,CPFE)低(LDG)、中(MDG)、高(HDG)剂量组。空白对照组给予基础维持饲料,模型对照组和剂量组给予高脂饲料。低、中、高剂量组分别给予腊梅花提取物0.2、0.4、0.8 g/(kg mb·d)进行干预,即腊梅花多酚剂量分别为24.81、49.62、99.25 mg/(kg mb·d),对照组给予等量0.9%NaCl。连续灌胃4周,测定小鼠体重、肝脏系数、血清生化指标、脏器抗氧化能力,观察肝脏组织形态学变化。结果:模型对照组与空白对照组比较,体重、肝脏系数、血清总胆固醇(Total Cholesterol,TC)、低密度脂蛋白胆固醇(Low-Density Lipoprotein Cholesterol,LDLC)和脏器丙二醛(Malondialdehyde,MDA)水平升高(P<0.05);血清高密度脂蛋白胆固醇(High-Density Lipoprotein Cholesterol,HDL-C)和脏器谷胱甘肽过氧化物酶(Glutathione peroxidase,GSH-Px)、过氧化氢酶(Catalase,CAT),超氧化物歧化酶(Superoxide Dismutase,SOD)、谷胱甘肽(Glutathione,GSH)水平降低(P<0.05);肝脏病理结果显示,模型对照组与空白对照组相比,肝小叶结构不规则,细胞形态被破坏,出现空泡变性,且肝索不清晰,肝窦被挤压变形,表明高脂饮食诱导小鼠肥胖成功。剂量组与模型对照组相比,腊梅花提取物能够下调血清TC、LDL-C、甘油三酯(Triglyceride,TG)和脏器MDA水平,高剂量组效果更明显(P<0.05);腊梅花提取物还能使血清HDL-C水平和脏器GSH-Px、CAT、SOD、GSH水平升高,效果与腊梅花提取物浓度呈剂量效应。肝脏组织病理结果较模型对照组有所改善,可见肝脏组织形态和结构更加完整。腊梅花提取物还能降低肥胖小鼠的体质量和肝脏指数且高剂量组效果更显著。结论:腊梅花提取物具有降低血清胆固醇,增强小鼠抗氧化能力和保护肝组织细胞功能形态的作用。

苜蓿、山楂叶复配物对油酸诱导HepG2细胞脂肪堆积的影响及其抗氧化活性

研究旨在探究紫花苜蓿水提物与山楂叶水提物复配对HepG2细胞脂肪堆积的影响及其抗氧化活性。以油酸体外诱导HepG2细胞建立脂肪堆积模型,并分别以紫花苜蓿提取物、山楂叶提取物、紫花苜蓿提取物-山楂叶提取物复配进行干预,采用MTT法测定细胞活力;油红O染色法观察脂滴分布;生物试剂盒测定细胞内三酰甘油(TG)、总胆固醇(TC)、丙二醛(MDA)含量,超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)活性及总抗氧化能力(T-AOC)。结果显示,紫花苜蓿提取物-山楂叶提取物复配(6∶4)复配可减少油酸诱导HepG2细胞所导致的脂滴数量增加,降低细胞中TG、TC含量。并增强抗氧化能力,可提高细胞内SOD、GSH-Px酶活性和总抗氧化能力(P<0.01),减少MDA的产生(P<0.05)。综上可得出结论,紫花苜蓿提取物-山楂叶提取物复配可显著抑制油酸诱导HepG2脂肪堆积,其作用优于紫花苜蓿提取物或山楂叶提取物单体,并可提高细胞内源性抗氧化能力。

植物提取物在蛋鸡生产中的应用研究进展

植物提取物是源自植物的天然活性物质,具有抗氧化、抗炎和调控菌群的功能,在医药、食品等领域有着广泛应用。许多研究表明,植物提取物在畜牧领域有着良好的表现,是重要的绿色饲料添加剂。文章简述了植物提取物在蛋鸡养殖上的应用研究进展,着重介绍了植物多酚、植物多糖、植物黄酮和生物碱对蛋鸡生产性能、抗氧化、免疫功能、脂质代谢以及肠道菌群的调控作用,旨在为其在蛋鸡养殖上的应用提供参考。

葱白提取物通过PPARγ/HO-1途径对动脉粥样硬化大鼠血脂异常和炎症反应的调节作用

目的探讨葱白提取物(FOB)通过调控过氧化物酶体增殖物激活受体γ(PPARγ)/血红素氧合酶1(HO-1)途径对动脉粥样硬化(AS)大鼠血脂异常和炎症反应的影响。方法40只SD大鼠随机分为对照组、模型组(AS组)、FOB组和FOB+GW9662组,每组10只。对照组大鼠给予正常饲料喂养,其余3组大鼠均建立AS模型。各组大鼠连续给药4周。采用苏木精-伊红(HE)染色与油红O染色观察主动脉病变和脂质沉积情况;采用全自动分析仪检测总胆固醇(TC)、甘油三酯(TG)、低密度脂蛋白胆固醇(LDL-C)和高密度脂蛋白胆固醇(HDL-C)水平,并计算动脉粥样硬化指数(AI);采用酶联免疫吸附试验(ELISA)检测白细胞介素-6(IL-6)、白细胞介素-1β(IL-1β)和肿瘤坏死因子-α(TNF-α)水平;采用实时定量聚合酶链反应(qRT-PCR)法和Western blot法分别检测大鼠胸主动脉组织中PPARγ和HO-1的mRNA和蛋白表达水平。结果与对照组相比,AS组大鼠胸主动脉管壁明显增厚,内膜下可见炎症细胞浸润和泡沫细胞堆积,脂质斑块形成;FOB组大鼠胸主动脉组织病理变化及脂质斑块较AS组明显改善;FOB+GW9662组大鼠胸主动脉组织病理变化及脂质斑块较FOB组明显加重。与对照组相比,AS组大鼠血清TC、TG、LDL-C、IL-6、IL-1β、TNF-α水平及AI均显著升高(P<0.05),HDL-C水平及胸主动脉组织中PPARγ和HO-1的mRNA、蛋白表达水平均显著降低(P<0.05)。与AS组相比,FOB组大鼠血清TC、TG、LDL-C、IL-6、IL-1β、TNF-α水平及AI均显著降低(P<0.05),HDL-C水平及胸主动脉组织中PPARγ和HO-1的mRNA、蛋白表达水平均显著升高(P<0.05)。与FOB组相比,FOB+GW9662组大鼠血清TC、TG、LDL-C、IL-6、IL-1β、TNF-α水平及AI均显著升高(P<0.05),HDL-C水平及胸主动脉组织中PPARγ和HO-1的mRNA、蛋白表达水平均显著降低(P<0.05)。结论FOB可能通过激活PPARγ/HO-1信号通路调节血脂异常和炎症反应,缓解大鼠AS进展。

均相和非均相催化微藻脂质提取和酯交换制备生物燃料的研究进展

随着化石燃料燃烧导致的二氧化碳排放不断加剧气候变化,且化石燃料储量日益减少,寻求可再生能源已成为一项紧迫的任务.其中,藻类衍生可持续燃料因具有成本优势和可运输性,在解决全球能源危机方面展现出广阔前景,备受关注.利用化学转化技术从微藻中提取脂质,并通过酯交换反应可以将其转化为脂肪酸甲酯,是生产绿色生物燃料的有效途径.这一过程涉及游离脂肪酸、磷脂和甘油三酯的提取,并且生产过程能耗低,成为满足日益增长的能源需求的一种理想解决方案.本文综述了微藻脂质提取和酯交换制备生物燃料的相关研究进展.首先,介绍了微藻脂质的提取方法,包括溶剂提取法、索氏提取法、布利格和戴耶法、超临界二氧化碳提取以及离子液体溶剂法等,并分析了各方法的优缺点.随后,重点阐述了酯交换技术在微藻脂质转化中的应用,包括酸碱催化、酶催化以及原位酯交换反应等,并探讨了这些技术的反应机理、催化剂选择、反应器设计以及生物油生产工艺等方面的研究进展.通过综述上述研究进展,为微藻脂质的生产和应用提供了理论指导.研究表明,通过优化催化剂种类、反应条件以及提取方法,可以有效提高微藻脂质的转化效率和生物油品质.同时,本文也指出了当前微藻脂质生产中面临的挑战,如微藻栽培和生长条件优化、高效转化技术的开发等.随着可持续能源日益受到重视,微藻脂质作为一种可再生能源具有巨大的发展潜力.未来研究应进一步关注微藻的规模化栽培、生长条件优化以及高效转化技术的研发,以提高微藻脂质的产量和品质.同时,应进一步推动和实现微藻生物燃料的实际应用,从而为应对气候变化和能源危机提供有效的解决方案.