环烯醚萜类化合物在防治糖尿病方面研究进展

目前糖尿病的治疗以口服西药为主,疗效迅速,但临床中多有不良反应的报道,不适于长期使用,易产生耐药性.近年来,不少学者以药材中提取出的天然化合物为主要成分,以期开发出治疗、预防糖尿病的新型药物.因此,在这一领域出现了大量的研究报道.其中,环烯醚萜苷类化合物梓醇、山茱萸环烯醚萜总苷、桃叶珊瑚苷等具有显著的降糖效果,并对糖尿...     

玄参环烯醚萜苷的回流提取工艺研究

为研究玄参环烯醚萜苷的最佳回流提取工艺条件,从提取时间、乙醇浓度、液固比、提取次数四个方面进行对比实验,总结出提取方法操作简单、快速的参数。     

鸡矢藤中环烯醚萜苷类提取工艺研究现状

鸡矢藤是传统中药,现代研究表明其中的环烯醚萜苷类具有较强的镇痛作用,其独特的化学结构和药理作用已引起人们的关注。文章从鸡矢藤中有效成分提取方法和环烯醚萜苷类的纯化富集方法两方面对鸡矢藤中环烯醚萜苷类的研究现状进行总结,为鸡矢藤中环烯醚萜苷类的开发利用提供参考依据,也为其进一步研究提供基础。     

杜仲中环烯醚萜类化合物的快速制备色谱制备及反相高效液相色谱/核磁共振鉴定

建立了杜仲中环烯醚萜类化合物京尼平甙酸(GPA)和京尼平甙(GPS)的快速制备色谱制备及反相高效液相色谱/核磁共振(RP-HPLC/NMR)鉴定方法。杜仲皮醇提物用硅胶柱层析法纯化后,进行快速制备液相色谱分离,根据制备色谱图收集流出液,采用HPLC-PDA和核磁共振(NMR)法定性定量分析。制备色谱条件为:流动相,V(甲醇)∶V(水)∶V(乙酸)=40∶60∶0.5;流速,2.5 mL/m in;检测波长,254 nm;进样体积,2.5 mL;进样量,100 mg;柱温,室温。结果表明,RP-HPLC分析制得产品的质量分数分别为w(GPA)=94.69%和w(GPS)=93.27%,核磁共振法测定结果与文献报道一致,确定实验所得两种单体为京尼平甙酸和京尼平甙。     

杜仲中环烯醚萜类物质对性激素转化的调控作用

杜仲是中国传统名贵滋补药材,有补益肝肾、强筋壮骨、固经安胎的功效,而这些功效与性激素水平息息相关,故本文研究了杜仲中3种主要的环烯醚萜类物质（京尼平、京尼平苷和京尼平苷酸）对性激素的转化作用。以卵巢颗粒细胞的肿瘤细胞系KGN作为激素的转化系统,孕烯醇酮为转化底物,分别测量环烯醚萜类物质干预24h后培养基中的孕酮、睾酮以及雌二醇的浓度,并提取细胞的RNA,以反转录实时荧光定量法来研究其催化酶3β-HSD、CYP17A1以及17β-HSD表达水平的影响。研究结果表明,50 μmol/L的京尼平能显著提升3β-HSD、CYP17A1以及17β-HSD的表达水平,从而显著促进睾酮和雌二醇的合成。     

油橄榄中橄榄苦苷的提取及纯化工艺研究

采用ODS C18色谱柱,流动相为甲醇:水(0.2%醋酸)体积比45:55,检测波长为230 nm,建立油橄榄叶中橄榄苦苷的HPLC分析方法。采用单因素和正交试验筛选优化油橄榄叶橄榄苦苷浸提的最佳工艺,并进一步研究大孔树脂静态和动态吸附和解吸附性能。结果表明:1)热回流浸提的最佳工艺为乙醇体积分数80%,温度70℃,提取时间3.5 h,料液比1:15(g:mL),提取次数2次。2)通过对比不同树脂对橄榄苦苷的吸附,筛选出选择性吸附好的AB-8树脂,吸附量为每克湿树脂32.1 mg。AB-8树脂纯化的最佳条件为:上样质量浓度为2 g/L,70%乙醇-水洗脱,流速为3 mL/min,洗脱液用量为3 BV。3)橄榄苦苷的粗提物经过AB-8树脂纯化后,橄榄苦苷的纯度达到47.90%,黄酮含量为16.4%,收率为6.43%。     

在α-蒎烯生物环氧化反应过程中酯对反应的影响及机理探讨

在以过氧化脲(UHP)为氧源、Nov435为催化剂的体系中进行α-蒎烯生物环氧化反应的研究,重点考察不同酯作为酰基供体对反应的影响。从反应速率和酶批次稳定性综合考虑,以丙酸乙酯为最佳溶剂,30℃下α-蒎烯3h的环氧转化率可达到87%左右,经6批次反应后仍可达到47.6%,发现过酸和H₂O₂的协同作用对酶稳定性的影响要高于单一因素。酶催化乙酸乙酯、丙酸乙酯、乙酸戊酯、己酸乙酯等不同酰基供体过水解反应均可在60min达到平衡,但过酸平衡浓度和α-蒎烯化学环氧化反应速率受酯影响较大,进而对总反应化学-酶法联合催化环氧化产生影响。最后探讨了丙酸乙酯为唯一酰基供体时的反应机制,认为酶利用丙酸产过酸的反应速率和过酸平衡浓度远低于酯;丙酸乙酯的水解和过水解反应为一对竞争性反应,因此有机体系更有利于环氧化反应。     

油橄榄果渣中山楂酸和齐墩果酸的提取工艺

以油橄榄果渣为原料,对其主要有效成分山楂酸(MA)和齐墩果酸(OA)的提取工艺进行研究。以MA、OA的提取率和浸膏得率为评价指标,采用正交实验优选油橄榄果渣中MA、OA的最佳提取工艺,得到的最佳条件为:以φ(CH3CH2OH)=90%的乙醇为提取剂,料液比〔即油橄榄果渣质量与溶剂体积的比(g/mL),下同〕1∶10,回流提取3 h,提取1次,在该条件下MA、OA提取率分别为91.27%、94.73%,浸膏得率为23.38%。     

Antioxidant and aldose reductase inhibition activity of Ligustrum japonicum and Olea europaea L. leaf extracts

Ligustrum japonicum and Olea europaea leaf extracts prepared via domestic techniques were studied for antioxidant and aldose reductase inhibitory activity (ARI) in relation to individual phenol/flavonoid composition (HPLC‐various detection means) and content. On the same extract weight basis L. japonicum leaf extracts, poorer in total polar phenol (TPP) content and in most cases in flavonoids, were less efficient than olive leaf extracts in radical scavenging and in retarding lipid oxidation. On the same TPP content basis, the former were of comparable efficiency in radical scavenging but exhibited lower activity than the latter in bulk oils or liposomes. L. japonicum extracts were characterized by the presence of verbascoside and apigenin derivatives, whereas O. europaea extracts by that of oleuropein. Superiority of L. japonicum infusion versus O. europaea infusion was evidenced using the ARI activity assay either on the same extract weight or on TPP content basis. The former was also superior in comparison to oleuropein, tyrosol, and hydroxytyrosol activity. These findings suggest the presence of other active compounds besides the so far identified phenolics and enhance our view on the importance of Oleaceae plants as sources of bioactive compounds beyond O. europaea. Practical applications : Oleaceae plants are a unique source for the secoiridoid oleuropein or verbascoside that confer well documented biological properties. On continuation of our effort to valorize plants of this family as sources for functional constituents we examined, in parallel, leaf extracts of the less investigated species Ligustrum japonicum versus those of Olea europaea L. The data presented for the extracts obtained via domestic preparations techniques (infusions, decoctions, tinctures) are expected to attract the interest of those involved in herbal teas and dietary supplements sector.     

Comparative analysis of triacylglycerols from Olea europaea L. fruits using HPLC and MALDI‐TOFMS

MALDI‐TOFMS and HPLC are two analytical methods that were used to characterize triacylglycerols (TAG) of the Meski, Sayali, and Picholine Tunisian olive varieties. The HPLC chromatograms of the oils showed the presence of 15 TAG species, among which triolein (OOO) was the most abundant (21–48%). In the Sayali cultivar, OOO was the predominant TAG species followed by POO and LOO. However, the minor TAG molecules were represented by LnLO and LnLP. MALDI mass spectra produced sodiated ([M + Na]⁺) and potassiated ([M + K]⁺) TAG molecules; only the major TAG were potassiated [OOO + K] ([OOO + K]⁺, [POO + K]⁺, and [LOO + K]⁺). In contrast to the HPLC chromatograms, the MALDI mass spectra showed 13 peaks of TAG. The major peak was detected at m/z 907, which corresponds to OOO with an Na⁺ adduct. The results from both HPLC and MALDI techniques predict the fatty acid composition and their percentages for each olive variety. Practical applications: TAG are the main components in vegetable oils. These biomolecules determine the physical, chemical, and nutritional properties of the oils. The nutritional benefits of TAG are related to DAG (moderate plasma lipid level) and esterified FA, which are intermediate biosynthetic molecules of TAG. TAG analysis is necessary to discriminate between oils of different origin, since some oils have similar FA profiles. Olive products, oils, and table olives, are the main diet sources of TAG in the Mediterranean countries. In this work, chromatographic and spectrometric methods were used for TAG analysis and characterization of Tunisian olive varieties.     

油橄榄酒体外抗氧化作用研究

利用Fenton反应、连苯三酚自氧化产生羟自由基（·OH）和超氧阴离子自由基（·Of）,采用分光光度法研究了油橄榄酒活性物对自由基的清除作用,实验结果表明,橄榄酒能较好清除·OH、·02-自由基,清除效果接近于Vc。     

Phenolic composition of virgin olive oils from cross breeding segregating populations

The evaluation and characterization of segregating populations is a critical step in olive breeding programs. In this work, phenolic profiles of virgin olive oils (VOOs) from segregating populations obtained by cross breeding in Cordoba (Spain) have been evaluated. Genotypes obtained from open pollination of the cultivar Manzanilla de Sevilla, and from crosses between the cultivars Arbequina × Arbosana, Picual × Koroneiki and Sikitita × Arbosana were tested. The phenolic composition was determined after liquid–liquid extraction with 60:40 v/v methanol–water and subsequent chromatographic analysis with ultraviolet (UV) detection of both absorption and fluorescence in a sequential configuration. Results for all studied compounds showed high degree of variability between genotypes, with a higher range of variation than the observed for the genitors. Most of the observed variability was attributable to differences in genotypes within crosses rather than among crosses. Some issues related to breeding strategies are discussed. Practical applications: Phenolic compounds are considered to be of paramount importance for the assessment of virgin olive oil quality due to their contribution to the nutraceutical and sensory profile of this natural food. This study focuses on the evaluation of the content of phenolic compounds in olive oils originated from cross breeding in an olive breeding program (Cordoba, Spain). This step is crucial to determine the range of variation of phenolic compounds and the selection of interesting genotypes with higher composition in total phenols or in an individual phenol targeted at a breeding program.     

Solid/liquid extraction and isolation by molecular distillation of hydroxytyrosol from Olea europaea L. leaves

Molecular distillation, or short‐path distillation (SPD), is particularly appropriate for processing of low‐volatility compounds, which are easily altered at high temperature. Olea europaea L. leaves constitute an olive tree by‐product very interesting for their natural antioxidants content. In this research, molecular distillation technology has been applied to obtain high‐value‐added compounds by the SPD fractionation of an olive tree leaf extract. The process consists of two stages: (a) ethanolic extraction of the olive leaves, followed by incorporation of the extract into glycerine and (b) molecular distillation of the glycerine enriched in olive leaf extract compounds (terpenic and phenolic compounds). Four molecular distillation tests under different conditions were carried out. Results showed that 80.9% 3,4‐dihydroxy‐phenylethanol (hydroxytyrosol) was recovered from the glycerine admixture under a pressure of 1.50–2.00 mbar, a temperature of 190 °C and a feed rate of 15 mL/min.     

微波辅助提取山竹夹层中黄酮化合物的研究

研究微波辅助提取山竹夹层中黄酮类化合物的提取工艺与条件。采用正交试验法确定提取优化条件为:90%甲醇为提取溶剂,原料与提取剂的固液比1∶100,微波功率800 W,微波提取时间15 s,提取次数两次。对比传统溶剂提取法,微波辅助提取的一次提取量是传统溶剂提取法的1.65倍,提取时间则是后者的1/80。     

Regional and cultivar comparison of Italian single cultivar olive oils according to flavor profiling

Geographical origin, cultivar, and olive ripening stage are important factors which affect the typical flavor profile of extra virgin olive oils. Aromatic compounds and sensorial profiles of “Casaliva”, “Frantoio”, and “Leccino” olive oils from three different Italian production regions Abruzzo (eastern‐central Italy), Lombardy (northern Italy), and Tuscany (western‐central Italy) were assessed in two cropping years and at three olive ripening stages (green, veraison, and ripe). The chemical aromatic compounds were more effective in discriminating the oils than their sensorial attributes. Oils showed peculiar aromatic and sensorial profiles according to their region of origin. Genetically similar “Casaliva” and “Frantoio” showed also analogous profiles, but distinct from “Leccino”. The interaction between regions of cultivation and cultivars significantly affected the flavor profiling. Practical applications: This research provides a sound proof that geographical origin, cultivar, and fruit ripening stage, could play an important interactive role in shaping the flavor profiling of extra virgin olive oils. This represents a scientific basis of the “typicality” concept, which should address the marketing strategies for exploiting of the PDO products.     

Study on Oleuropein Extraction from Olive Tree (Olea europaea) Leaves by means of SFE: Comparison of Water and Ethanol as Co-Solvent

The present study focuses on developing methods for olive leaf extraction and deals with obtaining extract, rich in oleuropein, which is the most abundant phenolic compound in olive leaves. Supercritical fluid extraction (SFE) was applied to the dried and ground olive leaves by using CO₂ as supercritical (SC) fluid in the presence of water and ethanol as co-solvent. The influences of operating parameters by means of co-solvent content (0-1 mL/min), temperature (50 and 100°C) and pressure (100-300 bar) on both extract and oleuropein yields were investigated. Quantitative analysis was performed by using a liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) technique. The experimental results obtained by using SC-CO₂ alone were not satisfactory, and it was seen that addition of a polar modifier is necessary in order to improve yield and selectivity of the process. It was observed that CO₂ modified by water and ethanol showed nearly the same extract performance, where CO₂ modified by water is better for high oleuropein yield.