Analysis of kavalactones from Piper methysticum (kava-kava)

The chemical analysis and quality control of both Piper methysticum G. Forster (kava-kava) and extracts obtained by aqueous acetone or aqueous methanol as well as supercritical fluid extraction are reviewed. In the last two decades various procedures concerning the separation and detection of kavalactones have been routinely carried out by gas chromatography (without previous derivatization of kavalactones) and high performance liquid chromatography but most of them are not validated or only partially validated. Recently, analyses by supercritical fluid chromatography and micellar electrokinetic chromatography have also been reported. Both gas chromatography and high performance liquid chromatography can be used for the analysis of kavalactones with some advantages and disadvantages for each method. Using gas chromatography analysis, methysticin and yangonin, which are two of the major components, are generally not separated. In addition, the high temperature of the injection port caused the decomposition of methysticin. Concerning high performance liquid chromatography analyses, the reversed-phase is generally better because highly reproducible with a very low detection limit for all compounds even if the quantitative analysis of the kavalactones by liquid chromatography needs to be carried out in the absence of light to prevent the cis/trans isomerisation of yangonin.     

Evaluation of extraction methods for analysis of domoic acid in naturally contaminated shellfish from Portugal

Domoic acid (DA) is a marine neurotoxin that is somewhat unstable, particularly in acidic media. Several protocols were used to extract DA from naturally contaminated tissues of shellfish harvested in Portugal. A modified version of AOAC method no. 991.26, with a simplified 10 g extraction, was used and compared with an aqueous 50% methanol extraction. Mean recoveries were between 81 and 85% when extracts were analysed by LC on the same day of extraction. When acid extracts were frozen for 1 or 2 days recoveries lowered to 72%, and if injection was repeated on the following 3rd or 4th days only 57–65% was recovered. Relative standard deviation of recovery for these miscellaneous samples, which was between 10 and 13% on the day of extraction, increased approximately 10% each day the extract was reanalysed. On our regulatory monitoring work, we employ an aqueous 80% methanol extraction that is common with the lipid-soluble DSP toxins. We report here a mean recovery of 90±6% for this methodology. Our long-term stability studies of domoic acid in shellfish extracts showed that slow decomposition of this compound occur in filtered aqueous methanol extracts. Additionally, we also found that in frozen tissues slow decomposition is clearly observable over a time span of 1 month.     

Solvent based optimization for extraction and stability of thymoquinone from <Emphasis Type="Italic">Nigella sativa</Emphasis> Linn. and its quantification using RP-HPLC

The Nigella sativa pharmacological properties are mainly ascribed to its volatile oil, of which thymoquinone is an important bioactive component. Surprisingly, till date, no standard formulation or thymoquinone rich N. sativa extract is under clinical use probably due to its poor extraction and lesser stability in the already used solvents. In the present investigation solubility, extraction, percent composition and total antioxidant activity from the seeds of N. sativa was explored using five solvents. An HPLC method was standardized in an isocratic system (C-18 column, flow rate of 1.0 ml/min, mobile phase—water:methanol: 30:70, detection wavelength—254 nm, retention time—8.77 min) for quantification of thymoquinone. To further confirm the presence of thymoquinone in the respective extracts absorbance spectra analysis has been carried out and compared with pure thymoquinone. Additionally total antioxidant activity of Nigella sativa extracts has been evaluated using ascorbic acid as standard. Our results showed maximum percentage yield in aqueous extract while methanol having the least yield and the ethanol, benzene and hexane extracts exhibited moderate yields. A linear standard calibration curve of thymoquinone showed R² as 0.999 and % RSD as 7.166. The HPLC analysis revealed maximum percentage composition of thymoquinone in the benzene extract, whereas in the hexane and methanol extracts the content was less. Aqueous and ethanol extracts displayed insignificant thymoquinone content. Absorbance spectra analysis confirms the presence of thymoquinone peak in the benzene, hexane and methanol extracts while aqueous and ethanol extracts showed minimal absorbance. Maximum total antioxidant activity was observed in the aqueous extract while minimum was observed in the methanolic extract. Weak positive (+?0.3676) correlation was established between percent composition of thymoquinone and antioxidant activity among different extracts indicating that thymoquinone may not be the only factor for antioxidant activity, but other phytochemicals might also contribute. However, we for the first time demonstrated that the benzene extract of N. sativa has better solubility and percent composition of thymoquinone as compared to other solvents. It can be concluded that the solubility, differential composition of bioactive components among these extracts may have diverse effects on the total antiradical activity. Thus, our study provides insights on optimization and standardization of bioactive rich formulation of N. sativa.     

Chemiluminescence analysis of oil oxidizing bacteria Actinetobacter calcoaceticus extracts: effects of the extracts on pSoxS-lux biosensor

A comparative H2O2-luminol- and Fe(II)-induced chemiluminescence analysis of extracts of two strains of marine oil oxidizing bacteria Actinetobacter calcoaceticus cultivated either in the presence or absence of oil was carried out. Effects of these extracts on E. coli MG1655 biosensor (pSoxS-lux) were studied. Activation of H2O2-induced chemiluminescence in the presence of oil was observed. This suggests activation of free radical lipid peroxidation. Aqueous extracts of microorganisms cultivated in the presence of oil were shown to activate reactive oxygen species production (ROS) in Fe(II)-induced chemiluminescence reaction mixture. Acetone-ethanol extracts induced antioxidative systems of both strains. Chemiluminescence analysis in a biological system carried utilizing E. coli MG1655 (pSoxS-lux) revealed that aqueous extracts of the strains cultivated in the absence of oil contained potential antioxidants.     

苜蓿化感作用的初步研究

利用生物测定法和气相色谱 /质谱 (GC/MS)联用技术对中国北方广为种植的紫花苜蓿的化感作用进行了初步研究。结果表明 ,紫花苜蓿全草的水和 95 %乙醇浸提液对玉米和小麦种子萌发均有显著的抑制作用 ,进一步用柱层析对苜蓿浸提液进行了初步分离 ,分离组份对玉米和小麦种子萌发的影响有所变化。抑制玉米萌发的活性物质主要在弱极性的二氯甲烷组份中 ,而抑制小麦萌发的活性物质不仅存在于二氯甲烷组份中 ,也存在于水中。采用GC/MS技术 ,初步推测苜蓿的化感物质是酚和皂甙两类化合物     

Economic comparison of multiple techniques for recovering leaf protein in biomass processing

Leaf protein concentrates (LPC) can be used as a valuable co-product to cellulosic biofuel production and can also mitigate the food versus fuel controversy. Two major approaches have been considered for LPC production: a well-characterized mechanical pressing method and a less studied method involving aqueous extraction with recovery using ultrafiltration. Experimental results with switchgrass extracts show low protein recovery after filtration, particularly if protein is recovered after cellulose hydrolysis. Economic modeling suggests that aqueous extraction costs less than mechanical pressing, but due to lower protein yields and lower quality, overall profit is higher for mechanical pressing versus aqueous extraction ($26/Mg feedstock vs. $14/Mg). If modest improvements can be made in extraction yields, filtration recovery, and protein quality, then the profitability of the aqueous extraction approach can be increased to $37/Mg feedstock. This study suggests that aqueous extraction is a viable alternative for LPC co-production in a biorefinery if key improvements can be made in the process.     

Phytochemical profile of fresh and senescent leaves due to storage for Ficus deltoidea

This study was carried out to investigate the phytochemical profiles of plant leaves, namely fresh and senescent leaves from Ficus deltoidea upon storage at room temperature. The phytochemical profile is of great importance, since this herb is widely used as traditional herbal medicine. Both chromatographic and mass spectrometric profiles of the plant extracts were fingerprinted using a high sensitivity hyphenated system consisting of liquid chromatography integrated with tandem mass spectrometer. Identical extraction protocol was used to extract phytochemicals from both leaf samples using 50% v/v methanolic aqueous solvent system. The plant extracts were determined for their total phenolic and flavonoid contents, as well as their antioxidant capacities based on radical scavenging, ferrous chelation, and ferric reducing power assays. The results showed that senescent leaf extracts exhibited higher antioxidant capacity than fresh leaf samples. This observation could be due to the higher number of phenolic compounds in the senescent leaf samples. The senescence of postharvest leaves was likely to consume organic acids including phenolic acids in the defense mechanism against the drought stress. However, flavonoids, particularly flavones and isoflavones, were abundant in the senescent leaf extracts. The findings may explain the significant pharmacological properties reported by previous investigators.     

Multistage aqueous two‐phase extraction of a monoclonal antibody from cell supernatant

This article presents results of continuous multistage aqueous two‐phase extraction of an immunoglobulin G1 from cell supernatant in a mixer‐settler unit. An aqueous two‐phase system consisting of polyethylene glycol 2000, phosphate salt, and water was applied without and with sodium chloride (NaCl). Influences of different parameters such as throughput, phase ratio, and stage number on the extraction performance were analyzed. For systems without NaCl, the extraction was carried out as a washing step. An increase of stage number from one to five stages enabled to increase the immunoglobulin G1 purity from 11.8 to 32.6% at a yield of nearly 90%. Furthermore, a reduction of product phase volume due to a higher phase ratio led to an increase of purity from 20.8 to 29.6% in a three‐stage countercurrent extraction. For experiments with NaCl moderate partitioning conditions were adjusted by adding 8 wt% NaCl. In that case, the extraction was carried out as a stripping step. © 2015 American Institute of Chemical Engineers Biotechnol. Prog., 31:925–936, 2015     

High anti-inflammatory activity of harpagoside-enriched extracts obtained from solvent-modified super- and subcritical carbon dioxide extractions of the roots of Harpagophytum procumbens

Solvent-modified carbon dioxide extractions of the roots of Harpagophytum procumbens have been investigated with respect to extraction efficiency and content of harpagoside, and compared with a conventional extract. The effects of pressure, temperature, type and concentration of the modifier have been examined. Two extraction steps were necessary in order to achievehigh anti-inflammatory harpagoside-enriched extracts. The first extraction step was carried out in the supercritical state using carbon dioxide modified with n-propanol to remove undesired lipophilic substances. The main extraction was performed either in the supercritical or in the subcritical state with carbon dioxide modified with ethanol. The supercritical fluid extraction resulted in extracts containing up to 30% harpagoside. The subcritical extracts showed a harpagoside content of ca. 20%, but the extraction yield was nearly three times greater compared with supercritical conditions. The total harpagoside recovery resulting from the sum of the extract and the crude drug residue was greater than 99% in all experiments. The conventional extract and two carbon dioxide extracts were tested for in-vitro inhibition of 5-lipoxygenase or cyclooxygenase-2 biosynthesis. Both carbon dioxide extracts showed total inhibition on 5-lipoxygenase biosynthesis at a concentration of 51.8 mg/L. In contrast, the conventional extract failed to show any inhibition of 5-lipoxygenase biosynthesis.     

Extraction of succinic acid with 1-octanol/n-heptane solutions of mixed tertiary amine

The reactive extraction of succinic acid was carried out by mixed tertiary amine which consisted of tripropylamine (TPA) and trioctylamine (TOA) as the extraction agent in 1-octanol/n-heptane diluent. Maximum distribution coefficient was obtained at 8:2 weight ratio of TPA/TOA. At this ratio, its extraction efficiency is above 90% at the 3.9 wt.% of succinic acid in aqueous solution. Furthermore, the prevention of the third phase formation made the phase separation between organic phase and aqueous phase easy.     

Investigation of the pharmaceutical and pharmacological equivalence of different Hawthorn extracts

Seven Hawthorn extracts were tested in isolated guinea pig aorta rings. The effect on noradrenaline- (10 microM) induced contraction was investigated. The extracts were prepared using ethanol (40 to 70% v/v), methanol (40 to 70% v/v), and water as the extraction solvents. The aqueous-alcoholic extracts displayed similar spectra of constituents. They were characterised by similar procyanidin, flavonoid, total vitexin and total phenols content and by similar TLC fingerprint chromatograms. The aqueous extract, however, showed a different fingerprint and a noticeably lower concentration of procyanidins, flavonoids and total phenols but a similar total vitexin content. All 7 extracts had a relaxant effect on the aorta precontracted by noradrenaline and led to relaxations to 44 until 29% of the initial values. The EC50 values of the aqueous-alcoholic extracts varied between 4.16 and 9.8 mg/l. The aqueous extract produced a similarly strong maximal relaxation as the other extracts, but the EC50, at 22.39 mg/l, was markedly higher. The results show that Hawthorn extracts with comparable quality profiles were obtained by using aqueous-alcoholic extraction solvents (40 to 70% ethanol or methanol). The extracts exerted comparable pharmacological effects. When using water as the extraction solvent, both, the spectrum of constituents and the pharmacological effect, deviated remarkably. It is thus possible to obtain bioequivalent extracts with comparable effect profiles by using 40 to 70% ethanol or methanol as the extraction solvent.     

Potential application of aromatic plant extracts to prevent cheese blowing

This study aimed to inhibit the growth of Escherichia coli and Clostridium tyrobutyricum, common bacteria responsible for early and late cheese blowing defects respectively, by using novel aqueous extracts obtained by dynamic solid–liquid extraction and essential oils obtained by solvent free microwave extraction from 12 aromatic plants. In terms of antibacterial activity, a total of 13 extracts inhibited one of the two bacteria, and only two essential oils, Lavandula angustifolia Mill. and Lavandula hybrida, inhibited both. Four aqueous extracts were capable of inhibiting C. tyrobutyricum, but none were effective against E. coli. After extracts’ chemical composition identification, relationship between the identified compounds and their antibacterial activity were performed by partial least square regression models revealing that compounds such as 1,8 cineole, linalool, linalyl acetate, β-phellandrene or verbene (present in essential oils), pinocarvone, pinocamphone or coumaric acid derivate (in aqueous extracts) were compounds highly correlated to the antibacterial activity.     

太子参粗提物抗氧化性及护肤功效分析

比较三种不同萃取方式对太子参Pseudostellaria heterophylla粗提物抗氧化、美白、保湿等方面的影响。结果显示,在ABTS和DPPH自由基及细胞内活性氧(ROS)抑制率分析中,以水萃方式所得粗提物的抑制效果最佳,优于醇萃取及超临界流体萃取。在美白功效方面,B16细胞黑色素含量抑制率以醇萃物最佳,酪氨酸酶活性抑制率则以水萃物最佳。进一步萃取太子参粗多糖体分析其保湿及吸湿效果,结果显示太子参粗多糖体具有良好的保湿及吸湿功效,其效果与透明质酸相近,应用于皮肤水分散失率评估,也具有显著的预防功效。     

Supercritical carbon dioxide extraction of lipids from Eucalyptus globulus wood

Various typical lipid components of wood extractives have been isolated from Eucalyptus globulus wood by supercritical carbon dioxide modified with methanol. The influence of various extraction parameters on the yield and qualitative composition of the extracts have been studied. The extracts were analyzed by gas chromatography-mass spectrometry and compared with those obtained by Soxhlet extraction with acetone, the standard method for the determination of wood extractives. The qualitative and quantitative results obtained by both methods were in good agreement. The experimental planning to asses the influence of pressure, temperature and percentage of methanol and their interactions on the extraction efficiency was carried out with a factorial design, followed by multiple linear regression algorithm.     

Preliminary studies on antihyperglycemic effect of aqueous extract of Brassica nigra (L.) Koch in streptozotocin induced diabetic rats

In the streptozotocin induced diabetic rats treated separately with aqueous, ethanol, acetone and chloroform extracts of the seeds of B. nigra, the increase in serum glucose value between 0 and 1 hr of glucose tolerance test (GTT) was the least (29 mg/dl) in aqueous extract treated animals while it was 54, 44 and 44 mg/dl with chloroform, acetone and ethanol extracts respectively. In further studies carried out with aqueous extract, the effective dose was found to be 200 mg/kg body weight in GTT. Administration of 200 mg/kg body weight of aqueous extract to diabetic animals daily once for one month brought down fasting serum glucose (FSG) levels while in the untreated group FSG remained at a higher value. In the treated animals the increase in glycosylated hemoglobin (HbA1c) and serum lipids was much less when compared with the levels in untreated diabetic controls. These findings suggest that further studies with the aqueous extract of B. nigra seeds on its antidiabetic activity would be useful.     

Linear solvation energy relationship modeling and kinetic studies on reactive extraction of succinic acid by tridodecylamine dissolved in MIBK

Equilibrium and kinetic studies for the extraction of succinic acid from aqueous solution with tridodecylamine diluted in MIBK are reported. All measurements were carried out at 298.15 K. The extent to which the organic phase may be loaded with succinic acid is expressed as a loading ratio, Z. The equilibrium data were also interpreted by a proposed mechanism of three reactions of complexation by which (1:1) and (2:1) acid-amine complexes are formed. Kinetics of extraction of succinic acid by tridodecylamine in MIBK has also been determined. Kinetic studies for the extraction of succinic acid from aqueous solution with tridodecylamine diluted in MIBK were carried out using a stirred cell for kinetic studies. The results of the liquid-liquid equilibrium measurements were correlated by a linear solvation energy relationship (LSER) model, which takes into account physical interactions. From the regression coefficients, information on the solvent-solute interaction is obtained and solvation models are proposed.     

Aqueous extraction of recombinant human proinsulin from transgenic maize endosperm

Different plant species have been used as systems to produce recombinant proteins. Maize is a crop considered to have a large potential to produce high levels of recombinant proteins and is the host for the recombinant proteins from plants currently available on the market. In the development of a plant system to produce a recombinant proteins it is important to consider the costs related to downstream processing. Also, the steps necessary to achieve the protein purity required will be highly influenced by the quality of the extract obtained. In this study, we analyzed aqueous extracts from the endosperm of transgenic maize expressing recombinant human proinsulin (rhProinsulin). A study of the effects of the variables pH and ionic strength on the extraction efficiency was carried out using experimental design and response surface methodology. Besides the concentration of the recombinant protein, the characteristics of the extracts were evaluated in terms of concentration of native components (proteins, carbohydrates, and phenolic compounds) and extract filterability. The highest rhProinsulin concentration (97.33 ng/mL) was found with a 200 mM NaCl pH 10.0 extraction solution. Under this experimental condition the concentrations of total soluble proteins, carbohydrates, and phenolics were 2.01 mg/mL, 2.21 mg/mL, and 0.11 mmol/L, respectively.     

几种常用中草药抗氧化活性研究(英文)

当归、黄芪、银杏叶、益母草、野甘草是中国传统中药材,几千年来一直为中国人民所认可,在中国和世界都具有重要的科研和药用价值。本研究采用HO&#183;清除及对肝微粒体和亚油酸脂质过氧化抑制的方法,测定五种草药精油和水煮提取物的抗氧化活性;采用Folin—Ciocalteu试剂法测定它们的总酚含量;用肝细胞体外培养法测定它们的细胞毒性并对它们的作用机制进行分析。结果发现五种草药提取物都具有一定的抗氧化活性,尤其是益母草、野甘草、银杏叶的水煮提取物活性较强,其抗氧化活性与总酚含量存在较好的线形关系。此外,本论文还为研究这些草药的一些抗病机制提供参考依据。     

Influence of plant matrix on microwave-assisted extraction process. The case of diosgenin extracted from fenugreek (Trigonella foenum-graecum L.)

A focused microwave-assisted extraction method was developed for the extraction of diosgenin from fenugreek (Trigonella foenum-graecum) seeds, air-dried and fresh leaves and air-dried roots. Several experimental parameters were studied, including extraction time, microwave power applied and percentage of 2-propanol in the extraction mixture as well as their interactions, in order to optimize the extraction efficiency. The two latter parameters were found to be the most important. Response surface modelling was used to predict the extraction yield of diosgenin in selected matrices. The analysis of diosgenin in crude extracts was carried out by capillary gas chromatography-mass spectrometry (GC-MS).     

葛花不同工艺提取物的异黄酮成分含量比较研究

目的:以不同浓度乙醇和大孔吸附树脂法提取和纯化葛花的提取物,并用HPLC和UV进行异黄酮成分含量比较分析。方法:以不同浓度的乙醇回流提取葛花药材制备提取物,并采用大孔吸附树脂对其进行纯化;然后以HPLC法对提取物中的3种主要黄酮类成分进行定量分析,并以UV法测定其总黄酮含量。结果:葛花不同提取物的黄酮类成分含量差别较大;所建立的HPLC方法可以同时测定葛花提取物中鸢尾苷、6"-O-木糖鸢尾苷和染料木素的含量;UV法与HPLC法联合应用,可对不同葛花提取物中的异黄酮类成分进行评价。结论:不同工艺提取的葛花提取物中异黄酮类成分有较大区别,大孔吸附树脂纯化后可显著提高总黄酮的纯度;HPLC联合UV法可共同用于葛花的质量评价及提取工艺的研究。