蒲公英黄酮类物质提取条件的优化与含量测定

蒲公英是一种常见的药用植物,内含多种化学物质,研究蒲公英内含的化学成分对其药用价值的开发利用具有重要意义。以蒲公英全草为研究对象,采用超声辅助溶剂提取法提取其黄酮类物质,对提取时间和提取温度进行优化,确定最佳提取条件;采用分光光度法,以芦丁标准溶液为标样,测定蒲公英内黄酮类物质的含量。结果表明,提取温度为70℃、提取时间为30min时,蒲公英黄酮类物质的提取效果最佳;蒲公英中黄酮类物质含量为4.33%。     

响应面法优化干花豆总黄酮提取工艺研究

干花豆( Fordia cauliflora)的主要有效成分为黄酮类、生物碱、有机酸等,具有益智、抗衰老、抗炎等作用。目前的研究主要集中在化学成分及药理活性等方面,对总黄酮成分提取工艺优化报道较少。该研究以新鲜干花豆为材料,以总黄酮提取量为评价指标,在提取温度、料液比、乙醇浓度和提取时间单因素实验基础上,采用响应面法优化了干花豆总黄酮提取工艺,同时测定了总黄酮对1,1-二苯基苦基苯肼自由基( DPPH.)和羟基自由基(.OH)清除能力。结果表明：干花豆总黄酮提取最佳工艺条件为提取温度78℃、料液比为1∶30(g.mL-1)、乙醇浓度71％和提取时间为187 min。在此条件下,总黄酮得率预测值为10.61 mg.g-1,实际为10.53 mg.g-1,理论值与预测值的相对误差为0.76％;干花豆总黄酮对DPPH和OH自由基清除能力IC50值分别为14.09和78.43μg.mL-1,弱于Vc(8.11和67.95μg.mL-1)。该提取工艺稳定合理,准确可靠,是提取干花豆总黄酮的可行方法。该研究结果为干花豆中总黄酮成分的进一步开发利用奠定了基础。     

Metabolomics driven analysis of artichoke leaf and its commercial products via UHPLC–q-TOF-MS and chemometrics

The demand to develop efficient and reliable analytical methods for the quality control of herbal medicines and nutraceuticals is on the rise, together with an increase in the legal requirements for safe and consistent levels of active principles. Here, we describe an ultra-high performance liquid chromatography method (UHPLC) coupled with quadrupole high resolution time of flight mass spectrometry (qTOF-MS) analysis for the comprehensive measurement of metabolites from three Cynara scolymus (artichoke) cultivars: American Green Globe, French Hyrious, and Egyptian Baladi. Under optimized conditions, 50 metabolites were simultaneously quantified and identified including: eight caffeic acid derivatives, six saponins, 12 flavonoids and 10 fatty acids. Principal component analysis (PCA) was used to define both similarities and differences among the three artichoke leaf cultivars. In addition, batches from seven commercially available artichoke market products were analysed and showed variable quality, particularly in caffeic acid derivatives, flavonoid and fatty acid contents. PCA analysis was able to discriminate between various preparations, including differentiation between various batches from the same supplier. To the best of our knowledge, this study provides the first approach utilizing UHPLC–MS based metabolite fingerprinting to reveal secondary metabolite compositional differences in artichoke leaf extracts.     

响应面法优化余甘叶中黄酮提取工艺

以余甘叶为试材,利用超声波辅助提取余甘叶黄酮,研究料液比、乙醇浓度、超声时间、超声功率对黄酮提取率的影响,并在单因素试验的基础上,通过响应面分析法优化提取工艺。结果表明,余甘叶中黄酮最佳超声提取条件为：料液比1∶73、乙醇浓度50%、超声时间30 min、超声功率210 W,在此条件下黄酮实际提取率为19.51%。     

拐枣中总黄酮提取工艺优化及其抗黄嘌呤氧化酶活性研究

为了研究拐枣总黄酮(TF)最佳提取工艺及其体外抗黄嘌呤氧化酶(xanthine oxidase,XO)活性。在单因素试验基础上,实验选择料液比、提取时间和乙醇浓度为自变量,应用Box-Benhnken中心组合法进行3因素3水平试验设计,以拐枣总黄酮得率为响应值,进行响应面分析,并采用D101大孔树脂对总黄酮进行进一步富集纯化,在此基础上研究拐枣总黄酮体外抗XO活性。结果表明,拐枣总黄酮的最佳提取条件为料液比15.0 mL/g、提取时间1.85 h、乙醇浓度53.0%,在此条件下,拐枣总黄酮的平均提取率可达到2.56%。体外活性结果表明,我们首次发现拐枣总黄酮具有显著的抗XO活性,其IC_(50 )为18.63±1.67μg/mL。本研究可为从拐枣中寻找和发现天然抗XO活性分子提供参考,同时可为拐枣的开发利用提供思路。     

超声提取枸杞叶总黄酮的工艺研究

目的：优选超声辅助提取枸杞叶总黄酮的提取工艺并探讨枸杞叶的合理采收时期。方法：分别研究乙醇浓度、乙醇用量、超声提取时间、超声时温度四个单因素对提取效果的影响,设计正交试验,所得结果采用方差分析。利用优选出的最佳超声提取工艺测定比较不同采收时期枸杞叶中的总黄酮含量。结果：确定了最佳单因素水平,通过正交试验法优选出超声辅助提取枸杞叶总黄酮的最佳工艺条件为乙醇浓度75％、乙醇用量1：40、超声提取时间30min、超声时温度50℃。结论：通过比较不同采收时期枸杞叶总黄酮的含量,发现总黄酮的含量随枸杞叶生长而下降,结合枸杞果园生产探讨得出枸杞叶合理采摘时期为4月上旬和11月中旬。     

Elaboration and validation of methods for quantitative analysis of phenolic compounds and flavonoids in the extracts of higher fungi

Simple express methods for the quantitative evaluation of phenolic compounds and flavonoids in the extracts of basidiomycetes and plants were developed using ethanol extracts of the Fomes fomentarius xylotrophic fungus as a model system. The analysis of phenolic compounds was based on the photocolorimetric Folin–Ciocalteu method. The spectrophotometric method based on the reaction of complex formation with aluminum chloride was chosen for the analysis of flavonoids. The composition of the reactants and their concentrations in the reaction mixtures were optimized for both techniques. The advantages of the developed techniques were the following: the simplicity, speed, the use of commonly used laboratory equipment, and the small volumes of the test samples and reagents. The proposed methods allow for serial analyses of up to four dozen samples. It was found that the decrease of the volume of the studied sample by factors of 5–10 did not reduce the sensitivity of the techniques in comparison with the classic versions of the methods. The proposed methods were examined for linearity, accuracy, repeatability, and convergence. The validation showed that the methods meet the eligibility criteria. The proposed methods for the quantitative analysis of phenolic compounds and flavonoids can be recommended for the characterization of fungi and plant extracts of both natural and biotechnological origin.     

Selection to attract pollinators and to confuse antagonists specializes fig–pollinator chemical communications

Chemical communication is critical in establishing angiosperm–pollinator mutualisms. However, our understanding of how chemical communication shapes coevolution remains limited. Here, we integrated information theory to model three coevolutionary scenarios (I‒III), where the pollinator fitness is always optimized by the highest certainty of chemical information provided by plants, but plant fitness is determined by (I) the certainty of chemical information attracting pollinators, (II) the uncertainty of chemical information confusing antagonists, or (III) both aspects. We found that the statistical properties of empirical plant volatiles from 45 pairs of fig–pollinator mutualisms were best explained by the selection from both pollinators and antagonists (scenario III). Under this scenario, plant–pollinator mutualisms evolve to be specialized and as few as two volatile chemicals could supply sufficient information for pollinators’ host identification. Our study provides new insights into plant–pollinator coevolution and will facilitate further studies on the evolution and diversification in specialized plant–pollinator–herbivore systems.     

Comparison between the univariate and multivariate analysis on the partial characterization of the endoglucanase produced in the solid state fermentation by Aspergillus oryzae ATCC 10124

Endoglucanase production by Aspergillus oryzae ATCC 10124 cultivated in rice husks or peanut shells was optimized by experimental design as a function of humidity, time, and temperature. The optimum temperature for the endoglucanase activity was estimated by a univariate analysis (one factor at the time) as 50°C (rice husks) and 60°C (peanut shells), however, by a multivariate analysis (synergism of factors), it was determined a different temperature (56°C) for endoglucanase from peanut shells. For the optimum pH, values determined by univariate and multivariate analysis were 5 and 5.2 (rice husk) and 5 and 7.6 (peanut shells). In addition, the best half-lives were observed at 50°C as 22.8?hr (rice husks) and 7.3?hr (peanut shells), also, 80% of residual activities was obtained between 30 and 50°C for both substrates, and the pH stability was improved at 5–7 (rice hulls) and 6–9 (peanut shells). Both endoglucanases obtained presented different characteristics as a result of the versatility of fungi in different substrates.     

Application of arsenic field test kit to stream sediment: effect of fine particles and chemical extraction

Abstract

The field test kit for the on-site analysis of arsenic has been previously evaluated for aqueous solutions such as surface water and groundwater. In this study, the field test kit was optimized for arsenic determination in a sandy sediment The field test kit was found to be applicable to on site screening of arsenic contamination at levels around 6 mgkg^?1, the soil regulatory standard for arsenic concentration in Korean soils. However, the method requires a simple chemical pre-extraction. This arsenic extraction has been optimized and the effects of soil–solution ratio, extraction time and fine particles are discussed in detail. The fine particles in the sediment sample strongly bind to arsenic resulting in variability of its extraction, both in extractability and extraction time. Under the optimized conditions, the arsenic content using the field test kit had a high regression coefficient with respect to that found by chemical analysis of the sediment sample.     

Optimization of ultrasound-assisted aqueous two-phase system extraction of polyphenolic compounds from Aronia melanocarpa pomace by response surface methodology

Aronia melanocarpa berries are abundant in polyphenolic compounds. After juice production, the pomace of pressed berries still contains a substantial amount of polyphenolic compounds. For efficient utilization of A. melanocarpa berries and the enhancement of polyphenolic compound yields in Aronia melanocarpa pomace (AMP), total phenolics (TP) and total flavonoids (TF) from AMP were extracted, using ultrasound-assisted aqueous two-phase system (UAE-ATPS) extraction method. First, the influences of ammonium sulfate concentration, ethanol–water ratio, ultrasonic time, and ultrasonic power on TP and TF yields were investigated. On this basis, process variables such as ammonium sulfate concentration (0.30–0.35?g?mL^?1), ethanol–water ratio (0.6–0.8), ultrasonic time (40–60?min), and ultrasonic power (175–225?W) were further optimized by implementing Box–Benhnken design with response surface methodology. The experimental results showed that optimal extraction conditions of TP from AMP were as follows: ammonium sulfate concentration of 0.324?g?mL^?1, ethanol–water ratio of 0.69, ultrasonic time of 52?min, and ultrasonic power of 200?W. Meanwhile, ammonium sulfate concentration of 0.320?g?mL^?1, ethanol–water ratio of 0.71, ultrasonic time of 50?min, and ultrasonic power of 200?W were determined as optimum extraction conditions of TF in AMP. Experimental validation was performed, where TP and TF yields reached 68.15?±?1.04 and 11.67?±?0.63?mg?g^?1, respectively. Close agreement was found between experimental and predicted values. Overall, the present results demonstrated that ultrasound-assisted aqueous two-phase system extraction method was successfully used to extract total phenolics and flavonoids in A. melanocarpa pomace.     

Light controls stamen elongation via cryptochromes,phytochromes and COP1 through HY5 and HYH

In Arabidopsis, stamen elongation, which ensures male fertility, is controlled by the auxin response factor ARF8, which regulates the expression of the auxin repressor IAA19. Here, we uncover a role for light in controlling stamen elongation. By an extensive genetic and molecular analysis we show that the repressor of light signaling COP1, through its targets HY5 and HYH, controls stamen elongation, and that HY5 – oppositely to ARF8 – directly represses the expression of IAA19 in stamens. In addition, we show that in closed flower buds, when light is shielded by sepals and petals, the blue light receptors CRY1/CRY2 repress stamen elongation. Coherently, at flower disclosure and in subsequent stages, stamen elongation is repressed by the red and far‐red light receptors PHYA/PHYB. In conclusion, different light qualities – sequentially perceived by specific photoreceptors – and the downstream COP1–HY5/HYH module finely tune auxin‐induced stamen elongation and thus male fertility.     

红花玉兰MwAG基因在花发育不同时期的表达

MwAG基因是调控红花玉兰(Magnolia wufengensis)雌雄蕊发育的关键转录因子。采用半定量RT-PCR、Northern blot杂交和实时荧光定量PCR技术检测了MwAG基因在红花玉兰花芽形态分化几个关键时期表达的组织特异性和表达水平的变化。研究结果表明, MwAG基因仅在红花玉兰雌雄蕊中表达, 而在幼叶、外轮花被和内轮花被中不表达。在花器官形态分化过程中, MwAG基因在雌雄蕊原基分化期和雌雄蕊成熟期均维持在一个较高的水平, 且在雄蕊中的表达波峰早于雌蕊, 这与雌雄蕊形态分化的时间基本吻合; 在花芽分化早期, 相同大小的花芽, 瓣数越多, MwAG基因在雌雄蕊中的表达量越低, 其结果与不同瓣数雌雄蕊分化的时间一致, 即瓣数越多, 雌雄蕊分化越晚。     

大孔树脂分离纯化辣椒叶总黄酮的工艺研究

目的:筛选适合分离纯化辣椒叶总黄酮的一种大孔树脂,同时用响应面法进行优化得到最佳纯化工艺。方法:采用热回流法提取辣椒叶总黄酮,以吸附率和解吸率为考察指标,考察6种不同型号的大孔树脂(HPD100、HPD450、HPD600、HPD826、D101、AB-8)对辣椒叶总黄酮的吸附能力与解吸能力,确定最佳树脂。通过动态吸附解吸实验考察此树脂对辣椒叶总黄酮的最佳分离纯化工艺。结果:通过对辣椒叶总黄酮吸附分离性能的分析显示HPD600为最佳树脂,最优工艺为:上样浓度为10 mg/mL,上样量为10 mL,洗脱体积为4 BV,洗脱液流速为4 mL/min,洗脱液pH为7,依次用水、10%、30%乙醇冲洗树脂柱,50%乙醇为洗脱液。纯化后的黄酮纯度435.4 mg/g。结论:该方法简便,操作简单,对辣椒叶总黄酮的纯化效果较好。     

Structure-activity relationships and molecular docking of thirteen synthesized flavonoids as horseradish peroxidase inhibitors

For the first time, the structure–activity relationships of thirteen synthesized flavonoids have been investigated by evaluating their ability to modulate horseradish peroxidase (HRP) catalytic activity. Indeed, a modified spectrophotometrically method was carried out and optimized using 4-methylcatechol (4-MC) as peroxidase co-substrate.The results show that these flavonoids exhibit a great capacity to inhibit peroxidase with Ki values ranged from 0.14 ± 0.01 to 65 ± 0.04 mM. Molecular docking has been achieved using Auto Dock Vina program to discuss the nature of interactions and the mechanism of inhibition. According to the docking results, all the flavonoids have shown great binding affinity to peroxidase. These molecular modeling studies suggested that pyran-4-one cycle acts as an inhibition key for peroxidase. Therefore, potent peroxidase inhibitors are flavonoids with these structural requirements: the presence of the hydroxyl (OH) group in 7, 5 and 4′ positions and the absence of the methoxy (O–CH₃) group. Apigenin contributed better in HRP inhibitory activity.The present study has shown that the studied flavonoids could be promising HRP inhibitors, which can help in developing new molecules to control thyroid diseases.     

An acetylcholinesterase biosensor based on graphene–gold nanocomposite and calcined layered double hydroxide

In this study, a novel acetylcholinesterase-based biosensor was fabricated. Acetylcholinesterase (AChE) was immobilized onto a glassy carbon electrode (GCE) with the aid of Cu–Mg–Al calcined layered double hydroxide (CLDH). CLDH can provide a bigger effective surface area for AChE loading, which could improve the precision and stability of AChE biosensor. However, the poor electroconductibility of CLDHs could lead to the low sensitivity of AChE biosensor. In order to effectively compensate the disadvantages of CLDHs, graphene–gold nanocomposites were used for improving the electron transfer rate. Thus, the graphene–gold nanocomposite (GN-AuNPs) was firstly modified onto the GCE, and then the prepared CLDH-AChE composite was immobilized onto the modified GCE to construct a sensitive AChE biosensor for pesticides detection. Relevant parameters were studied in detail and optimized, including the pH of the acetylthiocholine chloride (ATCl) solution, the amount of AChE immobilized on the biosensor and the inhibition time governing the analytical performance of the biosensor. The biosensor detected chlorpyrifos at concentrations ranging from 0.05 to 150 μg/L. The detection limit for chlorpyrifos was 0.05 μg/L.     

Discrimination of Different Parts of Saffron by Metabolomic‐Based Ultra‐Performance Liquid Chromatography Coupled with High‐Definition Mass Spectrometry

In this study, the metabolite profiling of three different parts of Crocus sativus L. was measured by using ultra‐performance liquid chromatography‐quadrupole time‐of‐flight mass spectrometry (UPLC‐QTof‐MS/MS). Multivariate statistical analysis was used to distinguish among the samples from different parts. A total of 54 compounds were identified in tepals, stigmas and stamens by UPLC‐QTof‐MS/MS. The results stated that chemical characteristics of saffron were obviously diverse in terms of the parts of flower. Through analysis, coniferin and crocin‐2 were special components in stigmas when compared to tepals and stamens. The content of flavonoids was high in tepals when compared with the stigmas. The tepal of saffron may processed as a source of flavonoids in the future. The research provided the basis for the theory that only the stigma can be used as medicine.     

Quality control and producing areas differentiation of Gardeniae Fructus for eight bioactive constituents by HPLC–DAD–ESI/MS

Gardeniae Fructus (G.Fructus), the fruit of Gardenia jasminoides Ellis (Rubiaceae), is a commonly used traditional Chinese medicine (TCM) that has been used for the treatment of hepatitis, jaundice, hypersonic, diabetes and hematuria. Numerous researches have demonstrated that the major active constituents in G.Fructus were responsible for the majority of medical effects of this fruit and their quantification were important for the quality control of G.Fructus. However, in the current quality control standard, only geniposide was used as characteristic marker of G.Fructus, which could not reflect the overall quality of this fruit. In order to identify more chemical makers for improving the quality control standard and evaluate producing areas differentiation of G.Fructus, in the present study, a novel and sensitive high-performance liquid chromatography–diode array detector coupled to an electrospray tandem mass spectrometer (HPLC–DAD–ESI/MS) was developed for the simultaneous determination of 8 major constituents, including geniposidic acid (1), chlorogenic acid (2), genipin-1-β-gentiobioside (3), geniposide (4), genipin (5), rutin (6), crocin-1 (7), crocin-2 (8) in G.Fructus. Moreover, chemometric analysis techniques with principal component constituent analysis (PCA) and cluster analysis (CA) involved were introduced in statistical analysis of 8 investigated constituents in the 34 batches samples to discriminate the samples from different producing areas.The results indicated that the contents of the 8 major bioactive constituents in G.Fructus varied significantly among different producing areas. From results of the loading plot from PCA analysis, genipin-1-β-gentiobioside may have more influence in discriminating the sample from different producing areas, and which was found to be the most abundant bioactive component besides geniposide in all the 34 batches samples, suggesting that it should be added as chemical marker for further investigation on the pharmacological actions and the quality control of G.Fructus.     

A review on structure–affinity relationship of dietary flavonoids with serum albumins

Flavonoids are a class of plant secondary metabolites and among thousands of flavonoids few are considered as dietary flavonoids. Serum albumin (SA), the most abundant protein in plasma, functions as the most important carrier of vital drugs, including dietary flavonoids. The binding affinity of dietary flavonoids to SA is demonstrated to be governed by structure–affinity relationship (SAR) and its bioavailability. The present review summarizes the interactions of flavonoids categorized as flavanol, flavonol, flavone, isoflavone, flavanones, and anthocyanidins with SAs (bovine serum albumin and human serum albumin) in light of SAR. The key findings are: (1) the position and degree of hydroxylation highly influence the affinity of flavonoids to SAs, (2) glycosylation decreases and substitution of methoxy group increases the affinity of flavonoids for SAs, (3) catechin gallates have higher binding affinity to SAs than catechins and gallocatechins, (4) inorganic metal ions modulate the binding affinity of flavonoids to SAs, and (5) hydrophobic interaction plays a major role in the interactions of all flavonoids with SAs.