Free and Glycosidically Bound Volatiles of Mentha longifolia Growing in Croatia

The glycosides of volatile compounds and the essential oil were isolated from wild Mentha longifolia. After the enzymatic hydrolysis of glycosides, fourteen volatile aglycones were identified by GC/MS. The main aglycones were eugenol, 2-phenylethanol, benzyl alcohol, lavandulol, trans- and cis-carveol, 3-octanol, and 3-hexen-1-ol. The content of aglycones was 40.85 mg kg^-1 of dried plant material. The main components of the essential oil (yield 0.93 w/w) were carvone, piperitenone oxide, limonene, and -caryophyllene. Eugenol, carveol, 3-octanol, and -terpineol were identified in the aglycones and in the essential oil.     

Mentha longifolia subsp. typhoides and subsp. schimperi: Antimicrobial and Antiquorum-Sensing Bioactivities

Chemistry of Natural Compounds -     

In vitro antifungal activity of flavonoid diglycosides of Mentha piperita and their oxime derivatives against two cereals fungi

Flavonoids due to their various interesting biological properties such as antifungal activity were investigated in Mentha piperita leaves. The butanolic fraction obtained from the hydro-alcoholic crude extract of M. piperita is rich in flavonoids; it reduced in vitro the mycelium growth of Phoma sorghina and Fusarium moniliforme around 72% and 55%, respectively, when used at a concentration of 5 mg/ml. In addition, the chemical conversion of the flavonoids in the butanolic fraction into their oxime derivatives increased the antifungal activity since the percentage of inhibition increased to 84% and 65% against P. sorghina and F. moniliforme, respectively, at 5 mg/ml. Butanolic fraction and oxime inhibition effects on spore germination of the two fungi were also observed. These results suggest that, M. piperita flavonoids could be used as botanical fungicides to protect cereals against infection from P. sorghina and F. moniliforme.     

Determination of chlorogenic acid in plant samples by using near-infrared spectrum with wavelet transform preprocessing.

By theoretical analysis, it is found that wavelet transform (WT) with a wavelet function can be regarded as a smoothing and a differentiation process, and that the order of differentiation is determined by the vanishing moment, which is an important property of a wavelet function. Therefore, a method based on the continuous wavelet transform (CWT) for removing the background in the near-infrared (NIR) spectrum is proposed, and it is used in the determination of the chlorogenic acid in plant samples as a preprocessing tool for partial least square (PLS) modeling. It is shown that the benefit of the proposed method lies not only in its performance to improve the quality of PLS model and the prediction precision, but also in its simplicity and practicability. It may become a convenient and efficient tool for preprocessing NIR spectral data sets in multivariate calibration.     

Determination of platinum and rhodium in dust and plant samples using microwave-assisted sample digestion and ICP-MS

The platinum group elements (PGEs), particularly platinum, palladium and rhodium, are nowadays increasingly emitted into the environment from automotive catalytic converters. Thus, a method for the determination of PGEs (especially platinum and rhodium) in dust and plant samples was developed. The developed method was based on microwave-assisted sample digestion and inductively coupled plasma mass spectrometric (ICP-MS) determination. Spectral interferences in ICP-MS determination were corrected using mathematical correction equations based on signal ratio measurement. In addition, platinum and rhodium concentrations in the digested dust samples were also determined after Te coprecipitation without correction of the interferences. The results for platinum and rhodium in reference materials (NIST SRM 2557, recycled monolith autocatalyst and BCR-723, road dust) were in good agreement with the certified values. Preliminary results for the anthropogenic platinum and rhodium emissions in Oulu, northern Finland, based on dust and plant samples, indicated a common traffic-related source of these metals.     

离子色谱-电感耦合等离子体质谱法测定植物性样品中的碘及其形态

建立了离子色谱-电感耦合等离子体质谱联用(IC-ICP/MS)测定植物性样品中碘及其形态的方法。采用碱提取法处理样品后,应用IC-ICP/MS检测植物样品中的碘离子和碘酸根;采用高温裂解法处理样品,使样品中各种形态的碘最终均转化为碘离子,然后应用IC-ICP/MS检测碘离子,从而实现总碘的测定。碘的方法检出限为0.010 mg/kg。碱提取法和高温裂解法处理样品的碘的加标回收率分别为89.6%～97.5%和95.2%～111.2%,结果令人满意。按照所建立的方法分别考察了紫菜、海带、圆白菜、茶叶、菠菜等常见植物性样品中碘的存在形式,结果表明,紫菜中的碘以有机碘为主,而海带、圆白菜、茶叶、菠菜中的碘则以无机碘为主。     

Enhanced resolution of Mentha piperita volatile fraction using a novel medium‐polarity ionic liquid gas chromatography stationary phase

The evaluation of a novel medium‐polarity ionic‐liquid‐based gas chromatography column, SLB‐IL60, towards the analysis of a complex essential oil, namely, a peppermint essential oil sample, is reported. The SLB‐IL60 30 m column was subjected to bleeding measurements, by means of conventional gas chromatography with mass spectrometry. The SLB‐IL60 column was then evaluated in the analysis of pure standard compounds, chosen as typical constituents of peppermint essential oil. Resolution and peak symmetry (expressed as tailing factors at 10% of peak height) were measured and the results were compared to those obtained on the most widely used columns in such an application, namely a medium‐polarity [100% poly(ethyleneglycol)] stationary phase, and an apolar 5% diphenyl/95% dimethyl siloxane. The final part of the evaluation was dedicated to the gas chromatography with mass spectrometry analysis of a peppermint essential oil sample and again the data were compared to those obtained on the 100% poly(ethyleneglycol) and the 5% diphenyl/95% dimethyl siloxane phase. Linear retention indices were determined for all the identified components on the ionic liquid capillary.     

Determination of chlorophyll in plant samples by liquid chromatography using zinc-phthalocyanine as an internal standard

Chlorophyll analysis at high precision and accuracy is limited by the lack of suitable, commercially available internal standards for HPLC analysis. Here, the commercially available dye zinc-phthalocyanine is presented as a new internal standard to quantify chlorophylls in vegetable foods and to detect chlorophyll degradation products. The technique was applied to chlorophyll analysis of a selection of vegetable foods. Pigments were extracted with N,N-dimethylformamide from the vegetables and purified by solid phase extraction. Chlorophyll a, a', b, b', corresponding pheophytins, and zinc-phthalocyanine were separated by HPLC using a C18 reverse-phase column and fluorescence detection.     

薄荷中微量元素的测定

用电感耦合等离子体原子发射光谱法(ICP-AES)同时测定了薄荷的叶、茎和整株三部分中微量元素的含量，样品处理分别采用干法和微波消解法。并对于法和微波消解法的测定结果进行了比较。结果表明，薄荷中含有Al、Fe、Na、Zn等多种微量元素，其中Cu、Fe、Mn、Ni、Zn、Sr等是人体必需微量元素。于法中某些元素可能因挥发而全部或部分损失；某些元素在氯化物大量存在时具有挥发性；有些不挥发的元素会因进入坩埚壁而造成损失，当灰分体积很小时，更突出；用酸处理样品时，分析元素会因灼烧而难以溶解。微波消解法损耗的元素较少，测得的结果较准确。用ICP—AES法测定薄荷中的微量元素具有简单、快速、准确度高的优点。     

Determination of triazines and organophosphorus pesticides in water samples using solid-phase extraction.

Octadecyl (C18)-bonded porous silica was evaluated for the extraction of triazine and organophosphorus pesticides from natural water. The extraction results showed an effective performance when 11 of water was passed through small glass columns containing 500 mg of 50-100-microns C18 bonded porous silica. The adsorbed compounds were removed with ethyl acetate, evaporated to 200 microliters and determined by gas chromatography. The overall average recoveries were greater than 85% except for dimethoate and trichlorfon. Application of this procedure to the analysis of natural water samples gave results that agree well with those obtained by solvent extraction methods.     

Chemical and Antimicrobial Characterization of Mentha piperita L. and Rosmarinus officinalis L. Essential Oils and In Vitro Potential Cytotoxic Effect in Human Colorectal Carcinoma Cells

Colorectal cancer is one of the most frequently diagnosed forms of cancer, and the therapeutic solutions are frequently aggressive requiring improvements. Essential oils (EOs) are secondary metabolites of aromatic plants with important pharmacological properties that proved to be beneficial in multiple pathologies including cancer. Mentha piperita L. (M_EO) and Rosmarinus officinalis L. (R_EO) essential oils are well-known for their biological effects (antimicrobial, antioxidant, anti-inflammatory and cytotoxic in different cancer cells), but their potential as complementary treatment in colorectal cancer is underexplored. The aim of the present study was to investigate the M_EO and R_EO in terms of chemical composition, antioxidant, antimicrobial, and cytotoxic effects in a colorectal cancer cell line—HCT 116. The gas-chromatographic analysis revealed menthone and menthol, and eucalyptol, α-pinene and L-camphor as major compounds in M_EO and R_EO respectively. M_EO exhibited potent antimicrobial activity, moderate antioxidant activity and a low cytotoxic effect in HCT 116 cells. R_EO presented a significant cytotoxicity in colorectal cancer cells and a low antimicrobial effect. The cytotoxic effect on non-cancerous cell line HaCaT was not significant for both essential oils. These results may provide an experimental basis for further research concerning the potential use of M_EO and R_EO for anticancer treatment.     

HPLC-ICP-MS测定植物样品中6种砷形态化合物

通过优化色谱分离、样品前处理条件,同时对比了电感耦合等离子体质谱的标准模式(STD)、碰撞模式(KED)、氧气反应模式(Oxygen-DRC)、甲烷反应模式(Methane-DRC)的检测结果,建立了一种有效分离植物样品中砷甜菜碱(AsB)、二甲基砷酸(DMA)、亚砷酸(As(Ⅲ))、砷胆碱(AsC)、一甲基砷酸(MM...     

Determination of gold in water samples using electromembrane extraction

In this work, an electromembrane extraction (EME) technique was used for the extraction and determination of gold from water samples prior to UV-Vis spectrophotometry. An artificial neural network (ANN) combined with imperialist competitive algorithm (ICA) has been applied to optimize the EME. The effective parameters including pH of acceptor phase, extraction time (t), volume of sample solution (V), stirring rate (S), and voltage (E) were chosen as input variables and the extraction recovery of gold was considered as output variable. The mean of squared error (i.e., 0.0009) and determination coefficient (i.e., 0.9821) were applied to estimate the performance of the ANN model. The limit of detection was 4.5?µg L^?1 (S/N?=?3) on the optimized variables. The intra- and interday precisions (%) were found to be 6.7% and 2.6%, respectively. This technique was then applied for analysis of gold from environment water samples.     

Composition and antimicrobial activities of Lippia multiflora Moldenke, Mentha x piperita L. and Ocimum basilicum L. essential oils and their major monoterpene alcohols alone and in combination

Essential oils from leaves of Lippia multiflora, Mentha x piperita and Ocimum basilicum from Burkina Faso were analysed by GC-FID and GC-MS. Major components were p-cymene, thymol, b-caryophyllene, carvacrol and carvone for L. multiflora, menthol and iso-menthone for M. x piperita and, linalool and eugenol for O. basilicum. The essential oils and their major monoterpene alcohols were tested against nine bacterial strains using the disc diffusion and broth microdilution methods. The essential oils with high phenolic contents were the most effective antimicrobials. The checkerboard method was used to quantify the efficacy of paired combinations of essential oils and their major components. The best synergetic effects among essential oils and major components were obtained with combinations involving O. basilicum essential oil and eugenol, respectively. As phenolic components are characterized by a strong spicy aroma, this study suggests that the selection of certain combinations of EOs could help to reduce the amount of essential oils and consequently reduce any adverse sensory impact in food.     

液相色谱-串联质谱法测定污水处理厂水样中双酚A、四溴双酚A及烷基酚类化合物

近年来,双酚A、四溴双酚A及烷基酚类化合物由于其对水生生物的内分泌干扰作用受到越来越广泛的关注。污水处理厂是处理这类化合物的重要途径,研究目标物在其中的浓度分布对于探明此类物质在环境中的暴露水平具有重要意义,而建立相应的分析测定方法则是开展上述研究的基础。本研究建立了同时测定污水处理厂水样中双酚A、四溴双酚A及6种烷基酚类化合物的反相液相色谱-电喷雾串联质谱分析方法。结果发现,以ZORBAX Eclipse Plus C18色谱柱（150 mm×2.1 mm,3.5 μm）为分离柱,乙腈和0.02%（v/v）氨水溶液为梯度洗脱的流动相,电喷雾质谱负离子模式下目标化合物在11 min内分离;在1~100 μg/L范围内,双酚A、四溴双酚A及6种烷基酚类化合物的峰面积与质量浓度的线性关系良好（R²≥0.998）,方法定量限为2.0~20 ng/L;添加水平分别为0.2、2、20 μg/L时,目标化合物的平均回收率分别为64.3%~118.0%、65.9%~100.5%、70.3%~102.7%,相对标准偏差均小于7.1%。基于上述方法,对江苏省某工业园区污水处理厂水样中相关物质进行检测,出水中检出5种目标化合物,质量浓度范围为11.9~3015.3 ng/L。结果表明,该方法准确可靠、灵敏度高,适用于污水处理厂水样中相关烷基酚类化合物的检测。     

Determination of fluorine in geological samples using accelerator derived neutrons

A fast, neutron activation analysis technique is described for the determination of fluorine in geological samples. The method utilises the reaction¹⁹F(n,α)¹⁶N for the determination. However, it avoids the interference reaction from oxygen which produces the same radionuclide since the neutrons are derived from the bombardment of beryllium with 3 MeV deuterons. The maximum energy of the neutrons so produced is well below the threshold for the competing oxygen reaction. The results indicate that the method gives acceptable accuracy over the range of a few tens ppm to several percent fluorine content using suitable standards. Sample analysis time is only a few minutes allowing the analyses of large numbers of samples per day.