高效液相色谱-高分辨质谱法鉴定拉萨大黄化学成分

建立了高效液相色谱-高分辨质谱法分析鉴定拉萨大黄化学成分。选用Agilent Zorbax SB-C18柱（150 mm×4.6 mm×5 μm）,以乙腈和水为流动相进行梯度洗脱,流速0.5 mL/min;采用电喷雾离子源,在正、负离子模式下对拉萨大黄提取物进行一级和多级全扫描质谱分析。综合分析化合物的色谱和质谱行为,并结合对照品、文献和数据库等相关数据鉴定化合物。在负离子模式下,鉴定出63种化合物;正离子模式下,鉴定出54种化合物。所检测到的化合物包括22种鞣质类、28种茋类、6种黄酮类、3种苯丙酸类、2种苯丁酮类和2种有机酸类,其中有53种化合物为在该药材中首次发现,且未发现蒽醌类成分。该方法快速、灵敏,不仅提高了拉萨大黄复杂基质中微量化合物的鉴定效率,同时实现了对拉萨大黄提取物中不同类型化合物的分析鉴别,为进一步阐明拉萨大黄的药效物质基础及质控标准提供了科学依据。     

二苯乙烯基双苯并(口恶)唑类化合物的合成及光谱性能的研究

以对氰基氯苄为原料与取代的邻氨基苯酚反应,合成了标题化合物。测定了此类化合物的紫外光谱和荧光光谱,并以硫酸喹宁为参比标准测定了化合物的荧光量子产率。研究了分子结构与紫外光谱、荧光光谱的关系。     

UPLC-MS/MS法同时测定何首乌中二苯乙烯、蒽醌、黄酮及酚酸类成分

建立了超高效液相色谱-串联质谱（UPLC-MS/MS）同时测定何首乌中二苯乙烯（二苯乙烯苷、虎杖苷、白藜芦醇）、蒽醌（大黄素、大黄素甲醚、大黄素-8-β-D -吡喃葡萄糖苷、芦荟大黄素、大黄酸）、黄酮（表儿茶素、芦丁、金丝桃苷、紫云英苷、槲皮素）和酚酸（没食子酸）等4类共14种目标成分的方法。何首乌样品用70%甲醇在室温下以料液比1∶25超声提取45 min,提取液以12 000 r/min离心10 min,取上清液,经0.22 μm微孔滤膜过滤。采用Waters BEH C18色谱柱（100 mm×2.1 mm×1.7 μm）,以水（含0.1%甲酸）-乙腈为流动相,梯度洗脱,柱温35 ℃,体积流量0.25 mL/min,电喷雾离子源（ESI）,多反应离子监测（MRM）扫描方式进行检测。结果表明：14种目标化合物在一定浓度范围内均呈现良好的线性关系,线性相关系数大于0.991 5;精密度、重复性和稳定性良好;加样回收率在95.85%~102.13%之间,RSD均小于5%。该方法操作简便、灵敏度高、重现性好,可用于何首乌中多元功效物质或指标成分的同时测定,为何首乌药材内在质量的综合评价和全面控制提供新的方法参考。     

Sodium Sulfinate‐Mediated trans‐Stilbene Formation from Benzylic Halides

A convenient and efficient method for the synthesis of various symmetrical and non‐symmetrical trans‐stilbene derivatives from benzylic halides in the absence of any transition metals is described. Sodium sulfinates played an important role in this transformation. Various functional groups were well tolerated under the optimized reaction conditions.     

Polyphenols: food sources,properties and applications – a review

There is currently much interest in phytochemicals as bioactive compounds of food. The roles of fruit, vegetables and red wine in disease prevention have been attributed, in part, to the antioxidant properties of their constituent polyphenols (vitamins E and C, and the carotenoids). Recent studies have shown that many dietary polyphenolic constituents derived from plants are more effective antioxidants in vitro than vitamins E or C, and thus might contribute significantly to the protective effects in vivo. Polyphenols are abundant micronutrients in our diet, and evidence for their role in the prevention of degenerative diseases is emerging. Dietary polyphenols show a great diversity of structures, ranging from rather simple molecules (monomers and oligomers) to polymers. Higher‐molecular‐weight structures (with molecular weights of ～500) are usually designated as tannins, which refers to their ability to interact with proteins. Among them, condensed tannins (proanthocyanidins) are particularly important because of their wide distribution in plants and their contributions to major food qualities. This paper focuses on polyphenols; we illustrate their sources from food, properties and their beneficial uses.     

An improved analytical method for determination of trans-resveratrol and related stilbenes in grape skin by QuEChERS coupled with HPLC-PDA-MS

Grape is a popular fruit crop that generates about one-fourth of total weight as pomace during winemaking and commercial juice production. However, a significant amount of resveratrol and related stilbenes is present in grape skin, and their effective isolation enables the production of functional foods. Herein, an improved analytical method for the determination of trans-resveratrol and related stilbenes in grape skin waste by QuEChERS method coupled with a high-performance liquid chromatograph-photodiode array detector-mass spectrometer was developed. By employing a Gemini C18 column and a mobile phase of acetic acid in water (pH 3.6) and acetonitrile, a total of five resveratrol and related stilbenes could be separated within 15 min with a flow rate of 0.8 mL min⁻¹ and detection wavelength at 306 nm. The optimised QuEChERS conditions were 10 mL of acetonitrile, 1 mL of grape skin extract and 900 mg of magnesium sulphate plus 25 mg of primary secondary amine. Principal component analysis by two principal components (74.18%, 25.82%) could well describe the trans-resveratrol recovery at different QuEChERS conditions. A mean recovery, as well as coefficient of variation (CV, %) of repeatability and intermediate precision, ranged from 96.6% to 104.4%, 1.96% to 3.10% and 1.68% to 4.27%, respectively, conforming to the regulation set by Taiwan Food and Drug Administration. Quantitation revealed cis-piceid to be present in largest amount (2.616 μg mL⁻¹), followed by trans-piceid (1.027 μg mL⁻¹), trans-resveratrol (0.967 μg mL⁻¹), ε-viniferin (0.660 μg mL⁻¹) and cis-resveratrol (0.183 μg mL⁻¹) in grape skin extract, with their corresponding contents in dried grape skin being 4.185, 1.643, 1.539, 1.056 and 0.293 μg g⁻¹, respectively.     

Functional components in peanuts

Peanut is one of the most widely used legumes due to its nutrition and taste. The fact that is has been recognized recently as a functional food, its evaluation for its role in a heart-healthy diet has received tremendous attention. Functional compounds have been isolated, identified, quantified, and even enhanced to maximize the amount for adequate health benefits. The peanut industry's byproducts such as peanut hulls and shells, skins, and even leaves and roots have also been identified as possible sources of bioactive compounds. New uses for these underutilized renewable sources can create new market opportunities and increase the value of agricultural residues.