In vitro avarol does affect the growth of Candida sp.

This work extends in vitro screening of antimicrobial activity of avarol, the marine natural product firstly isolated from the Mediterranean sponge Dysidea avara. Its anticandidial activity was evaluated by microdilution method against eight Candida strains, two ATCC and six clinical ones. At a different extent this compound was proven to be active against all the strains tested (MIC 0.8–6.0 μg/mL and MFC 1.6–12.0 μg/mL, respectively). According to the best of our knowledge, this is the first report on avarol activity towards any yeast strain which may be of relevance for Alzheimer’s disease. Indeed, avarol derivatives showing moderate AChE activity should be screened for anticandidial activity both in vitro and in vivo.     

Excretion of Hydroxy Derivatives of Polycyclic Aromatic Hydrocarbons of the Masses 178, 202, 228 and 252 in the Urine of Coke and Road Workers

Abstract

Urinary PAH-metabolite excretion by non-exposed volunteers, temporarily living on a PAH-poor and PAH-rich diet, respectively, as well as by occupationally PAH-exposed coke plant workers and road workers has been studied. Significant differences in the amount of the metabolites excreted in the urine were detected; the ratio of various metabolites was also found to be different. The mass excretion per liter of the metabolites from phenanthrene was found to be for the unexposed volunteers about 3.5μg/1, for coke plant workers about 70μg/l and for road workers about 35 μg/l. For the metabolites of chrysene the values were 0.03 μg/1 2.5 μg/l and 0.09μg/l, respectively, and for the total metabolites of benzo(a)pyrene: 0.006μg/l for unexposed persons, 0.37 μg/l for coke plant workers and 0.019 μg/l for road workers.     

Bioactive DOPA melanin isolated and characterised from a marine actinobacterium Streptomyces sp. MVCS6 from Versova coast

The melanin pigment produced from Streptomyces sp., MVCS6 was isolated and dihydroxyphenyalanine (DOPA) melanin compound was biochemically identified and spectroscopically characterised (ultraviolet and FT-IR). DOPA melanin showed a promising activity as an antibacterial natural product against 12 pathogenic bacteria from hospital isolations, particularly, against Pseudomonas aeruginosa RMMH7 (inhibition zone of 18 ± 0.02 at 30 μg/disc, and MIC of 10 ± 0.02 μg/mL) and Vibrio parahaemolytics RMMH12 (inhibition zone of 15 mm ± 0.03 at 30 μg/disc, and MIC of 14 ± 0.02 μg/mL). Moreover, in vitro evaluation of reducing power (Ascorbic Acid Equivalent (160 μg/mL)), DPPH radical-scavenging (89%), NO-scavenging (72%) and lipid peroxidation activities (89.6%) were determined. Cytotoxicity of DOPA melanin against cervical cancer cell line showed a dose–response activity, and IC₅₀ value was found to be 300 μg/mL. These results would open the way to propose Streptomyces sp. MVCS6 as a promising source of bioactive eumelanin with therapeutic potential in medicine.     

Development and validation of RP-HPLC method for the determination of stigmasterol in the botanical extract of Ficus deltoidea

A simple, rapid, accurate and precise RP-HPLC method was developed for the determination of stigmasterol in botanical extract of Ficus deltoidea. Separation was achieved with acetonitrile and acetic acid in water (75:25% v/v) in isocratic mode at 210?nm. Single sharp peak of standard stigmasterol was detected at retention time 3.17?min which overlay with the peak of plant extract at 3.14?min. The calibration curve was found to be linear in a concentration range of 2–10?μg/ml with correlation coefficient of 0.998. The LOD and LOQ were found to be 1.50?μg/ml and 4.55?μg/ml respectively. Accuracy and precision was determined with overall recovery of 99.6–100.1% for stigmasterol and RSD values in both intra-day and inter-day repeatability assay lesser than 0.340%, respectively. The robustness study also indicated that there is no influence of minor changes in detecting wavelength and flow rate of mobile phase on the response.     

Essential oil from the leaves of Xylopia langsdorfiana (Annonaceae) as a possible spasmolytic agent

Xylopia langsdorfiana A. St.-Hil. &Tul. (Annonaceae) is popularly known in the northeast of Brazil as ‘pimenteira da terra’, and an essential oil (XL-OE) was extracted from its leaves. Since Xylopia species are cited in folk medicine and diterpenes from X. langsdorfiana have spasmolytic activity, this study aimed to investigate a possible spasmolytic action of XL-OE on smooth muscle models. XL-OE (243 and 729 μg/mL) showed low pharmacologic efficacy on guinea pig trachea and rat aorta and uterus. However, in guinea pig ileum, XL-OE (27–729 μg/mL) inhibited carbachol or histamine-induced phasic contractions (1 μM) in a significant and concentration-dependent manner. In addition, XL-OE (81 μg/mL) reduced fluorescence intensity in ileal myocytes stimulated by histamine, indicating a decrease in cytosolic calcium concentration, which could explain the spasmolytic activity. Thus, XL-OE proved to be a promising natural product to be used in gastrointestinal diseases acting by modulating the cytosolic calcium concentration.     

超支化聚合物作为放大信号的纳米磁性微球电化学免疫分析法

提出了一种基于超支化聚合物(HBP)固化酶标二抗作为放大信号和纳米磁球相结合的超灵敏的免疫分析新方法。首先羧基纳米磁性微球共价键合乙肝抗体(HBsAb)形成免疫磁性微球,然后与待测乙肝表面抗原(HBsAg)发生特异性结合,加入HBP标记的酶标二抗(HBPS)与结合的抗原结合发生夹心反应。在外加磁场的作用下,抗体抗原免疫复合物易从样品溶液中分离,在含有邻氨基苯酚和H2O2的底液中,快速生成具有电活性的化合物3-氨基吩呃嗪,用示差脉冲伏安法(DPV)测定响应电流,电流强度(I)与乙肝表面抗原浓度(c)在0.05～10.0μg/L范围内呈线性关系,线性回归方程为I(μA)=0.140+16.80 c(μg/L),相关系数r=0.9995,检出限达0.008μg/L,并用于实际样品的测定。     

酶联免疫吸附分析法测定水产品及水中孔雀石绿和无色孔雀石绿

本文报道一种同时测定水产品及水样中孔雀石绿(MG)和无色孔雀石绿(LMG)的间接竞争酶联免疫吸附分析法。对无色孔雀石绿分子进行修饰,使其与载体蛋白交联,得到免疫原和包被抗原,经过多次免疫动物制得抗无色孔雀石绿的多克隆抗体。在优化的实验条件下,IC50值(标准曲线中吸光度抑制至最大吸光度值的50%时所对应的待测物浓度)为0.9~2.6μg/L,检出限为0.02~0.10μg/L,无色孔雀石绿在水样及水产品中的回收率为76.2~95.0%,与孔雀石绿的交叉反应率为95.25%。真实样品测定中,两种食用鱼养殖水样及一个鱼样中未检出孔雀石绿和无色孔雀石绿,但在观赏鱼养殖水样及另一鱼样中检出孔雀石绿和无色孔雀石,浓度分别为1.84μg/L和1.38μg/L。     

Green micellar stability-indicating high-performance liquid chromatography method for determination of rupatadine fumarate in the presence of its main impurity desloratadine: Oxidative degradation kinetics study

A green micellar stability-indicating high-performance liquid chromatography method was developed for rupatadine fumarate determination in existence with its main impurity desloratadine. Separation was attained using Hypersil ODS column (150 × 4.6 mm, 5 μm), the micellar mobile phase consisted of 0.13 M sodium dodecyl sulfate, 0.1 M disodium hydrogen phosphate adjusted by phosphoric acid to pH 2.8 and 10% n-butanol. The column was maintained at 45^◦C and detection was carried out at 267 nm. A linear response was achieved over the range of 2–160 μg/ml for rupatadine and 0.4–8 μg/ml for desloratadine. The method was applied for rupatadine determination in alergoliber tablets and alergoliber syrup without the interference of methyl paraben and propyl paraben present as main excipients. Rupatadine fumarate revealed pronounced susceptibility to oxidation; further study of oxidative degradation kinetics was carried out. Rupatadine was found to follow pseudo-first-order kinetics when exposed to 10% H₂O₂ at 60 and 80°C and the activation energy was found to be 15.69 Kcal/mol. At a lower temperature (40°C), degradation kinetics regression was best fitted as a polynomial quadratic relationship, thus rupatadine oxidation at a lower temperature tends to adopt a second-order kinetics rate. Oxidative degradation product structure was revealed using infrared and found to be rupatadine N-oxide at all temperature values.     

A New Fluorimetric Method for the Determination of Ascorbic Acid

Abstract

The fluorescent reaction between ascorbic acid(AA) and 2-cyanoacetamide was studied. The experimental results showed that AA can react with 2-cyanoacetamide at pH 12.9–13.3, and form a fluorescent product, which emitted strong fluorescence. The fluorescence intensity was measured at excitation and emission wavelengths of 329 and 380nm, respectively. A linear relationship was obtained between the fluorescence intensity and AA concentration in the range of 0.1–50μg/ml, the regression coefficient is 0.9994, and the detection limit of AA is 0.03μg/ml. (signal-to-noise=3).     

Stability-indicating HPLC method development and validation for simultaneous estimation of metformin,dapagliflozin, and saxagliptin in bulk drug and pharmaceutical dosage form

A simple, precise, and rapid stability-indicating reversed-phase-HPLC method was developed and validated for the estimation of metformin (MET), dapagliflozin (DAP), and saxagliptin (SAX) combination in bulk and tablet dosage forms. The proposed method uses a Kromasil C18 column (150 × 4.6 mm, 5 μm) with column oven temperature of 30°C and mobile phase containing a mixture of 60% phosphate buffer (pH = 3) and 40% acetonitrile. The flow rate was set at 1.0 mL/min, and the injection volume was 10 μL. The detection was carried out at 230 nm using a photodiode array detector, and the total run time was 4 min. The proposed method was validated according to International Council for Harmonisation (ICH) guidelines for specificity, linearity, precision, accuracy, robustness, and solution stability. The method is linear over the range of 125–750 μg/mL for MET, 1.25–7.5 μg/mL for DAP, and 0.625–3.75 μg/mL for SAX. The observed correlation coefficients (R²) for MET, DAP, and SAX are >0.999. The proposed method is precise, and the percentage relative standard deviation was found to be between 0.4 and 0.8. The observed percentage recoveries were between 98.51 and 100.80 for all three compounds. The product was subjected to stress conditions of acid, base, oxidative, thermal, and photolytic degradation. The product was found to degrade significantly in oxidative, acid, and base hydrolysis degradation conditions, and the degradation products were well determined from the active peaks, thus proving the stability-indicating power of the method. The developed and validated stability-indicating reversed-phase-HPLC method was appropriate for quantitative determination of these drugs in pharmaceutical preparations and also for quality control in bulk manufacturing.     

Determination of resveratrol and piceid in beer matrices by solid-phase extraction and liquid chromatography-tandem mass spectrometry

Beer is one of the most commonly consumed undistilled alcoholic beverages in many countries. In recent studies, the stilbenes resveratrol and piceid have been found in some hop varieties which are used in the production of beer. Therefore, they could be transferred to beer. The aim of the present work was to validate a method to study the potential content of trans- and cis-resveratrol and piceid in 110 commercial beers from around the world. The resveratrol and piceid contents of 110 beers were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) after a solid-phase extraction (SPE) using optimized and validated procedures for the beer matrix. The beer matrix effect was also studied. Stilbenes were found in quantifiable amounts in 92 beers, while concentrations below the limit of quantification (LOQ) were found in 18 beers. Resveratrol was found in the range of 1.34-77.0μg/L in 79% of the beers analyzed, and piceid was found in the range of 1.80-27.3μg/L in only 33% of them. The mean of total resveratrol in all the beers was 14.7±20.5μg/L. The content of resveratrol has been compared with other resveratrol containing foods. A serving of beer contains similar amounts of stilbenes as berries, less than chocolate and grape products but more than pistachios, peanuts or tomatoes. Overall, beer is one of the products with the lowest levels of total resveratrol (μg/L), and despite its high consumption it should not be considered as a representative source of resveratrol.     

A stereo,regioselective synthesis and discovery of antimycobaterium tuberculosis activity of novel β-lactam grafted spirooxindolopyrrolidine hybrid heterocycles

A stereo- and regioselective synthesis of hitherto unexplored novel class of β-lactam embedded spirooxindolopyrrolidine hybrid heterocycles have been accomplished via ionic liquid accelerated [3 + 2]-cycloaddition reaction process. The expected unusual lactonization/lactamization product could not be observed even in traces. The in vitro antimycobacterium tubercular activity of the synthesized spiroheterocyclic hybrids were assessed against Mycobacterium tuberculosis H37Rv. Among them, the compounds with no substitution and chlorosubstitution on the oxindole ring showed the most potent activity with a MIC 0.78 μg/mL and 1.56 μg/mL, respectively which were two-fold and equal activity than the standard drug, ethambutol (MIC = 1.56 μg/mL).     

Headspace solid-phase microextraction applied to the simultaneous determination of sorbic and benzoic acids in beverages

A new analytical procedure was developed using headspace solid-phase microextraction (HS-SPME) for the simultaneous determination of sorbic and benzoic acids in beverages. The sample were processed depending on their nature, either only diluted with water, or treated with a NaOH solution and filtered through a 0.45-μm membrane filter. The samples were heated in a vial in the presence of sulfuric acid and anhydrous sodium sulfate and the analytes were collected from the headspace by using a 65-μm polydimethylsiloxane-divinylbenzene (PDMS-DVB) coated fiber and determined by gas chromatography with flame ionization detector (GC-FID). To enhance the sensitivity of HS-SPME, the temperature and time of the extraction and desorption, the acidity and salt concentration of the extraction solution were optimized. Linear range of the analytes was found to be between 0.1 and 20 mg/L with regression coefficients (R²) of 0.9998 for sorbic acid and 0.9980 for benzoic acid. Limits of detection (LOD) were 5.83 μg/L and 11.4 μg/L for sorbic and benzoic acids, respectively. Relative standard deviation (R.S.D.) for six replicate analyses within 3 days (two times/day) was found to be lower than 8.62% at three concentration levels (2, 6, 10 mg/L). Recoveries ranged from 81.20% to 108.1% for real samples. The results demonstrate the suitability of the HS-SPME technique to analyze sorbic and benzoic acids in a variety of beverages.     

Fluctuation in the ergosterol and deoxynivalenol content in barley and malt during malting process

This paper describes determination of the deoxynivalenol and ergosterol in samples from different varieties of barley and, consequently, malt produced from this barley. In total, 20 samples of barley and 20 samples of barley malt were analyzed. The alkaline hydrolysis with consequent extraction into hexane was applied to obtain the ergosterol from cereals. Extraction to acetonitrile/water and subsequent solid-phase extraction (SPE) were used for deoxynivalenol. The determination of the samples was performed on high-performance liquid chromatography using UV detection (ergosterol) and mass spectrometric detection (deoxynivalenol). The influence of the malting process on the production of two compounds of interest was assessed from obtained results. Ergosterol concentration ranged 0.88–15.87 mg/kg in barley and 2.63–34.96 mg/kg in malt, where its content increased to 95% compared to samples before malting. The malting process was observed as having a significant effect on ergosterol concentration (P = 0.07). The maximum concentration of deoxynivalenol was found to be 641 μg/kg in barley and 499 μg/kg in malt. Its concentration was lower than the legislative limit for unprocessed cereals (1,250 μg/kg). The statistic effect of the malting process on deoxynivalenol production was not found. Linear correlation between ergosterol and deoxynivalenol content was found to be very low (barley R = 0.02, malt R = 0.01). The results revealed that it is not possible to consider the ergosterol content as the indicator of deoxynivalenol contamination of naturally molded samples.     

气相色谱-串联质谱法测定蔬菜和水果中三氯生及甲基三氯生的含量

提出了应用气相色谱-串联质谱法测定蔬菜(西红柿、黄瓜等)和水果(橙子、苹果等)中潜在的污染物三氯生(TCS)和甲基三氯生(MTCS)的含量的方法,以期有助于对此污染物在蔬菜、水果等食品中的污染问题的研究,并应用于农产品质量的安全监测之中。将样品分别去皮后切块,匀浆后于-22℃保存。称取样品5.00g,先后2次用乙酸乙酯(每次10mL)超声提取10min后离心10min,合并2次的提取液。将提取液吹氮蒸发至近干。加入衍生试剂体积比为99∶1的N,O-双(三甲基硅烷基)三氟乙酰胺-三甲基氯硅烷混合溶液100μL,在60℃下进行衍生化反应40min。反应结束后,将溶液吹氮至近干,用乙酸乙酯1.0mL溶解残渣。所得溶液供气相色谱-串联质谱法分析。用DB-17MS毛细管色谱柱(30m×0.25mm,0.25μm)在150~290℃区间按程序升温条件进行分离,在电子轰击离子源及多反应监测模式下进行质谱测定。经试验确定,用两种扫描程序分别扫描,TCS衍生物的母离子和子离子依次为m/z 362,347和m/z 360,345,MTCS的母离子和子离子则均为m/z 304,254。测得TCS衍生物和MTCS的标准曲线的线性范围均为0.4~20.0μg·L^-1,其检出限(3S/N)为4~6ng·kg^-1。按标准加入法进行回收试验,测得TCS衍生物和MTCS在4种蔬菜、水果中的回收率为91.5%~107%和94.7%~111%。     

Modulation of antibiotic activity by the hydroalcoholic extract from leaves of Caryocar coriaceum WITTM

The aim of this study was to identify the presence of tannins, phenols and flavonoids on the hydroalcoholic extract of Caryocar coriaceum leaves (HECCL) and to determine the antioxidant and antibacterial activity of this extract. The extract was tested alone (1024–1 μg/mL) or associated (MIC/8) with several antibiotics in order to identify any antibacterial activity against multiresistant bacterial strains (Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa). The existence of tannins, total phenols (901.31 mg/g) and flavonoids (89.68 mg/g) was confirmed in the HECCL. The presence of rutin and quercetin were confirmed by Thin-layer chromatography (TLC). Using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method, the antioxidant activity of the extract (9 μg/mL) was determined. Moreover, the Minimum Inhibitory Concentration (MIC) value found for HECCL was 1024 μg/mL and the association between HECCL (MIC/8) with benzylpenicillin significantly changed its minimum inhibitory concentration from 2500 to 625 μg/mL against E. coli.     

Insecticidal activity of the root bark essential oil of Periploca sepium Bunge and its main component

During our screening programme for agrochemicals from Chinese medicinal herbs, the root bark essential oil of Periploca sepium was found to possess strong contact toxicity against the fruit flies, Drosophila melanogaster with a LD(50) value of 1.22?μg/adult. The main component of the essential oil was identified to be 2-hydroxy-4-methoxy-benzaldehyde (78.8%), followed by linalool (2.8%) and (-)-α-terpineol (2.7%). The 2-hydroxy-4-methoxy-benzaldehyde was further isolated and identified by bioassay-directed fractionation. The compound showed strong contact toxicity against D. melanogaster and the maize weevil (Sitophilus zeamais) with LD(50) values of 1.47 and 6.99?μg/adult, respectively.     

Appraisal of Conjugated Linoleic Acid Production by Probiotic Potential of Pediococcus spp. GS4

Probiotics with ability to produce conjugated linoleic acid (CLA) is considered as an additive health benefit property for its known role in colon cancer mitigation. The conversion involves the biohydrogenation of the unsaturated fatty acid into conjugated form. Probiotic strain Pediococcus spp. GS4 was efficiently able to biohydrogenate linoleic acid (LA) into its conjugated form within 48 h of incubation. Quantum of CLA produced with a concentration of 121 μg/ml and sustained cell viability of 8.94 log cfu/ml maximally. Moreover, antibacterial effect of LA on the strain ability for biohydrogenation was examined at different concentrations and concluded to have a direct relationship between LA and amount of CLA produced. The efficiency of the strain for CLA production at different pH was also estimated and found maximum at pH?6.0 with 149 μg/ml while this ability was reduced at pH?9.0 to 63 μg/ml. Sesame oil, which is rich in the triacylglycerol form of LA, was also found to act as a substrate for CLA production by Pediococcus spp. GS4 with the aid of lipase-catalyzed triacylglycerol hydrolysis and amount of CLA produced was 31 μg/ml at 0.2 % while 150 μg/ml at 1.0 % of lipolysed oil in skim milk medium. Conjugated form was analyzed using UV scanning, RP-HPLC, and GC-MS. This study also focused on the alternative use of lipolysed sesame oil instead of costly LA for biohydrogenation and could be a potential source for the industrial production of CLA.     

唾液中大麻毒品液相小体积提取HPLC检测

建立了小体积液相提取HPLC测定唾液中大麻类毒品含量的方法。在pH=4缓冲溶液中,加入1mL含大麻标准品的家兔唾液试样,用0.5mL氯仿超声振荡提取5min,4000r/min离心10min,取下层液体挥干,用1mL乙腈溶解后进行HPLC分析。唾液中四氢大麻酚(THC)、大麻二酚(CBD)、大麻酚(CBN)、四氢大麻酚酸的检出限(3S/N)分别为16ng、10ng、11ng、10 ng,标准曲线线性范围分别为0.32μg/μL～3.20μg/μL、0.10μg/μL～1.00μg/μL、0.11μg～1.10μg/μL、0.20μg/μL～2.00μg/μL。平均回收率均在95%～105%之间。相对标准偏差(n=6)均在3%以内。     

Antifungal activity study of the monoterpene thymol against Cryptococcus neoformans

Abstract

Cryptococcus neoformans is a yeast fungus, which causes cryptococcosis, triggered by basidiospore inhalation and consequent dissemination to the central nervous system. In this study, we analyzed the antifungal action of thymol against 10 clinical strains of C. neoformans and analyzed the interaction of this monoterpene with sterols. The MICs of thymol ranged from 20 to 51?μg/ml, while the MFC values varied between 40 and 101?μg/ml. For the strains ICB-2601 and LM-39, in the presence of ergosterol, the MIC of thymol was 64?μg/ml, and in the presence of cholesterol, its MIC was 32?μg/ml. Based on the results, thymol presents antifungal action and seems to interact with ergosterol, but not with cholesterol. Complementary studies are needed to analyze its full effects.