Optimized ultrasonic assisted extraction-dispersive liquid-liquid microextraction coupled with gas chromatography for determination of essential oil of Oliveria decumbens Vent

Cardamom seed bioactives: A review of agronomic factors, preparation, extraction and formulation methods based on emerging technologies to maximize spice aroma economic value and applications

Cardamom seed (Elettaria cardamomum (L.)) is a well-appreciated spice in food and pharmaceutical industries owing to its unique rich flavor dominated by oxygenated monoterpenoids, α-terpinyl acetate and 1,8-cineole, to which most of the quality of cardamom essential oil (CEO) is attributed. CEO output is greatly influenced by different agronomic factors, processing, and EO extraction methods. In that context, the goal of this study is to provide an overarching review regarding emerged technologies along with their optimization parameters to achieve optimal oil yield with the best flavor quality. Furthermore, the recent approaches employed in CEO stabilization were highlighted alongside their pharmaceutical and food applications. Moreover, the different aspects of superlative CEO production including agricultural aspects, climatic requirements, and processing methods were also explained.

Solvent-Focused Gas Chromatographic Determination of Thymol and Carvacrol Using Ultrasound-Assisted Dispersive Liquid-Liquid Microextraction through Solidifying Floating Organic Droplets (USA-DLLME-SFO)

An ultrasound-assisted dispersive liquid-liquid microextraction by solidifying floating organic droplets, coupled to a form of temperature-programmed gas chromatography flame ionization detection, has been developed for the extraction and determination of thymol and carvacrol. This method utilizes undecanol as the extraction solvent, offering advantages such as facilitating phase transfer through solidification and enhancing solvent-focusing efficiency. The optimal gas chromatography conditions include a sample injection volume of 0.2 µL, a split ratio of 1:10, and a flow rate of 0.7 mL min-1. The extraction conditions entail an extraction solvent volume of 20 µL, a disperser solvent (acetone) volume of 500 µL, pH 7.0, 7.0% NaCl (3.5 M), a sample volume of 5.0 mL, an ultrasound duration of 10 min, and a centrifuge time of 7.5 min (800 rpm). These conditions enable the achievement of a high and reasonable linear range of 3.5 to 70. 0 μg mL-1 for both thymol and carvacrol. The detection limits are found to be 0.95 and 0.89 μg mL-1, respectively, for thymol and carvacrol. The obtained relative standard deviations, 2.7% for thymol and 2.6% for carvacrol, demonstrate acceptable precision for the purpose of quantitative analysis.

Oliveria decumbens, a Long-Neglected Plant with Promising Phytochemical and Biological Properties

Oliveria decumbens is a folkloric medicinal plant belonging to the Apiaceae family, traditionally utilized to treat various diseases like gastrointestinal disorders, fever, and wounds. This review aims to provide a comprehensive overview of the plant's phytochemical composition and biological properties, with potential implications for various industries and avenues of further research. The data presented here has been compiled through searches utilizing the keyword "Oliveria" across scientific databases such as PubMed, Web of Science, Scopus, ScienceDirect, and SciFinder. Carvacrol and thymol have been identified as the primary volatile constituents, though the complete profile of the plant extract remains to be fully elucidated. Notably, Oliveria decumbens essential oil exhibits significant antibacterial, antifungal, antioxidant, and anticancer properties. Additionally, the plant extract demonstrates promising antiprotozoal, antiviral, hepatoprotective, and immunostimulant effects, although these findings are primarily derived from preliminary studies. While in vitro and in vivo investigations have validated some traditional uses of O. decumbens, further pre-clinical testing is warranted to ascertain both efficacy and safety profiles. Moreover, the identification of specific components within the plant extract is crucial for a more comprehensive understanding of the mechanisms of action underlying its therapeutic properties within the realm of phytomedicine.

Phytochemistry of Oliveria decumbens Vent. (Apiaceae) and its therapeutic potential: A systematic review

Oliveria decumbens Vent., an annual herb resistant to harsh environmental conditions, is an aromatic medicinal plant of the Apiaceae family. O. decumbens has numerous pharmacological, food and feed, and cosmetic applications. This species is endemic to Iran, Iraq, and Turkey. Published literature, available until 30 November 2022 on the morphology, phytochemistry, and bioactivity of O. decumbens, has been reviewed, and appraised for the potential therapeutic potential of this species, utilizing the databases, Web of Science, Google Scholar, PubMed, and Dictionary of Natural Products. The search term used was O. decumbens. Some manuscripts were issued on the chemical components of O. decumbens essential oil (EO) and various extracts. The EO of O. decumbens was evaluated for its chemical composition and medicinal potential against various diseases. Thymol and carvacrol constituted the primary oxygenated monoterpenes detected in substantial amounts within the EO. Additionally, diverse metabolites of O. decumbens were examined for their bactericidal, antioxidant, larvicidal, and immunomodulatory effects. This review article discusses morphology, phenology, and geographical distribution of O. decumbens and presents a critical appraisal of its phytochemistry and therapeutic potential as documented in the published literature.

Updating the status quo on the extraction of bioactive compounds in agro-products using a two-pot multivariate design. A comprehensive review

Extraction is regarded as the most crucial stage in analyzing bioactive compounds. Nonetheless, due to the intricacy of the matrix, numerous aspects must be optimized during the extraction of bioactive components. Although one variable at a time (OVAT) is mainly used, this is time-consuming and laborious. As a result, using an experimental design in the optimization process is beneficial with few experiments and low costs. This article critically reviewed two-pot multivariate techniques employed in extracting bioactive compounds in food in the last decade. First, a comparison of the parametric screening methods (factorial design, Taguchi, and Plackett-Burman design) was delved into, and its advantages and limitations in helping to select the critical extraction parameters were discussed. This was followed by a discussion of the response surface methodologies (central composite (CCD), Doehlert (DD), orthogonal array (OAD), mixture, D-optimal, and Box-Behnken designs (BBD), etc.), which are used to optimize the most critical variables in the extraction of bioactive compounds in food, providing a sequential comprehension of the linear and complex interactions and multiple responses and robustness tests. Next, the benefits, drawbacks, and possibilities of various response surface methodologies (RSM) and some of their usages were discussed, with food chemistry, analysis, and processing from the literature. Finally, extraction of food bioactive compounds using RSM was compared to artificial neural network modeling with their drawbacks discussed. We recommended that future experiments could compare these designs (BBD vs. CCD vs. DD, etc.) in the extraction of food-bioactive compounds. Besides, more research should be done comparing response surface methodologies and artificial neural networks regarding their practicality and limitations in extracting food-bioactive compounds.

Optimization of Essential Oil Extraction from Bitter Leaf (Vernonia Amygdalina) by Using an Ultrasonic Method and Response Surface Methodology

Bitter leaf (Vernonia amygdalina) is a common bush or small tree that grows in tropical Africa. In the Ethiopian highland, the bitter leaf has been classified by the farmer as a versatile tree with high biomass yield and easy propagation. It is also well known in traditional medicine and nutritional use. The objective of this study was extraction and optimization of essential oil (EO) from the bitter leaf by using the ultrasonic extraction method and response surface methodology. The experiment was designed by Box–Behnken Design (BBD) with three factors to investigate the effect of sonication time (10 min to 30 min), ultrasonic power (100 to 200 W), and liquid-solid ratio (4 to 8 ml/g (ml of solvent per g of bitter leaf powder)). The significance of the process variables was analyzed using analysis of variance (ANOVA), and the quadratic model was fitted to the experimental results. Thus, the independent variables, sonication time, sonication power, liquid-solid ratio, and their interactions contributed a significant effect on the yield of extraction. As the result of RSM optimization, the best yield of EO was found at sonication time (17.263 min), sonication power (150.677 W), and liquid-solid ratio (6.811 ml/g). Experiments conducted under these conditions resulted in an EO yield of (4.185% g/g). The results exhibited that the RSM and BBD were effective for optimization of studied ultrasonic process variables for the maximum yield of EO from the bitter leaf (V. amygdalina).

Second-order electrochemical data generation to quantify carvacrol in oregano essential oils

A novel analytical method using voltammetric second-order modeling based on multivariate curve resolution-alternating least-square (MCR-ALS) is presented for the first time for the quantitation of carvacrol (CAR) in oregano essential oils (OEO). The second-order cyclic voltammetry data were generated on the basis that CAR shows a diffusional system. Thus, the scan rate (v) was used as a second instrumental mode and cyclic voltammograms at different v were acquired for a single sample, generating the second-order data. CAR determination was performed in presence of thymol, included as a potential interferent. Results demonstrated that MCR-ALS successfully exploited the second-order advantage and the recoveries were not statistically different than 100%. The limits of detection and quantitation were estimated using the MCR-ALS which were 6.27 × 10^-5°mol°L^-1°and 1.90 × 10^-4°mol L^-1, respectively. Finally, the developed methodology was implemented to quantify of CAR in OEO samples.

In-vitro, in-vivo, and in-silico assessment of radical scavenging and cytotoxic activities of Oliveria decumbens essential oil and its main components

We aimed to explore and compare new insights on the pharmacological potential of Oliveria decumbence essential oil (OEO) and its main components highlighting their antioxidant activity in-vitro, in-vivo, and in-silico and also cytotoxic effects of OEO against A549 lung cancer cells. At first, based on GC-MS analysis, thymol, carvacrol, p-cymene, and γ-terpinene were introduced as basic ingredients of OEO and their in-vitro antioxidant capacity was considered by standard methods. Collectively, OEO exhibited strong antioxidant properties even more than its components. In LPS-stimulated macrophages treated with OEO, the reduction of ROS (Reactive-oxygen-species) and NO (nitric-oxide) and down-regulation of iNOS (inducible nitric-oxide-synthase) and NOX (NADPH-oxidase) mRNA expression was observed and compared with that of OEO components. According to the results, OEO, thymol, and carvacrol exhibited the highest radical scavenging potency compared to p-cymene, and γ-terpinene. In-silico Molecular-Docking and Molecular-Dynamics simulation indicated that thymol and carvacrol but no p-cymene and γ-terpinene may establish coordinative bonds in iNOS active site and thereby inhibit iNOS. However, they did not show any evidence for NOX inhibition. In the following, MTT assay showed that OEO induces cytotoxicity in A549 cancer cells despite having a limited effect on L929 normal cells. Apoptotic death and its dependence on caspase-3 activity and Bax/Bcl2 ratio in OEO-treated cells were established by fluorescence microscopy, flow cytometry, colorimetric assay, and western blot analysis. Additionally, flow cytometry studies demonstrated increased levels of ROS in OEO-treated cells. Therefore, OEO, despite showing antioxidant properties, induces apoptosis in cancer cells by increasing ROS levels. Collectively, our results provided new insight into the usage of OEO and main components, thymol, and carvacrol, into the development of novel antioxidant and anti-cancer agents.

Application of liquid-phase microextraction to the analysis of plant and herbal samples

INTRODUCTION

The analysis of plant and herbal samples is a challenging task for analytical chemists due to the complexity of the matrix combined with the low concentration of analytes. In recent years different liquid-phase microextraction (LPME) techniques coupled with a variety of analytical equipment have been developed for the determination of both organic and inorganic analytes.

OBJECTIVE

Over the past few years, the number of research papers in this field has shown a markedly growing tendency. Therefore, the purpose of this review paper is to summarise and critically evaluate research articles focused on the application of LPME techniques for the analysis of plant and herbal samples.

RESULTS

Due to the complex nature of the samples, the direct application of LPME techniques to the analysis of plants has not often been done. LPME techniques as well as their modalities have been commonly applied in combination with other pretreatment techniques, including a solid-liquid extraction technique supported by mechanical agitation or auxiliary energies for plant analysis. Applications and the most important parameters are summarised in the tables.

CONCLUSION

This review summarises the application of the LPME procedure and shows the major benefits of LPME, such as the low volume of solvents used, high enrichment factor, simplicity of operation and wide selection of applicable detection techniques. We can expect further development of microextraction analytical methods that focus on direct sample analysis with the application of green extraction solvents while fully automating procedures for the analysis of plant materials.

The Variability of Thymol and Carvacrol Contents Reveals the Level of Antibacterial Activity of the Essential Oils from Different Accessions of Oliveria decumbens

Oliveria decumbens (Apiaceae) is an aromatic herb traditionally employed in the Persian medicine for the treatment of infectious and gastrointestinal disorders. In the present study, we analyzed the chemical composition of essential oils obtained from different Iranian populations and evaluated their efficacy on a panel of human pathogens (Staphylococcus aureus and Escherichia coli), probiotic (Bacillus subtilis), and phytopathogens (Clavibacter michiganensis, Curtobacterium flaccumfaciens, Xanthomonas citri, and Agrobacterium tumefaciens). The gas chromatographic-mass spectrometry analysis put in evidence four main volatile constituents such as thymol (20.3–36.4%), carvacrol (18.8–33.1%), γ-terpinene (10.6–25.9%), and p-cymene (9.5–17.3%), though with significant variability from an essential oil to another. Notably, the oils from the populations sited in Nourabad Mamasani and Dehdasht showed the highest amount of the phenolic monoterpenes thymol (36.4 and 35.2%, respectively) and carvacrol (33.1 and 30.6%, respectively). The antibacterial activity of O. decumbens essential oils was assessed by the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) methods, showing high activity for the samples from Nourabad Mamasani and Dehdasht populations exhibiting high level of the above phenolics. The obtained MIC and MBC values (mg/ml) were in the ranges 0.0625–2 mg/ml and 1–16 mg/ml, respectively. Noteworthy, in some cases, the antibacterial activity of O. decumbens essential oils was higher than that of chloramphenicol used as positive control. The average MBCs displayed by the O. decumbens samples showed that C. flaccumfaciens had the highest sensitivity to the essential oils. Based on these results, our work shed light on selected O. decumbens populations deserving proper breeding and cultivation strategies in order to warrantee production of bioactive essential oils to be used at pharmaceutical and agricultural level to combat several pathogens.

Ultrasound Assisted Dispersive Solid Phase Microextraction of Thymol and Carvacrol in Pharmaceutical Products Using Graphene Oxide as an Adsorbent Prior to Analysis by High Performance Liquid Chromatography

Background:

Thymol and carvacrol are the most important dietary constituents in thyme species. These two active compounds are used for the standardization of pharmaceutical compounds.

Objective:

In this work, a simple and reliable ultrasonic assisted dispersive solid phase microextraction method (USA-DSPME) coupled with high performance liquid chromatography-ultra violet detection system was developed to determine thymol and carvacrol in pharmaceutical syrups. The efficiency of SPME sorbent was examined through several sorbents and finally Graphene Oxide (GO) was applied for extraction of the analytes. Method: The efficiency of GO was compared with three reduced forms of GO adsorbents as well. Several effective factors on the extraction performance were investigated.

Results:

Under the optimized conditions for the GO sorbent, inter and intra-day relative standard deviations (RSDs, n = 3) and the Limits of Detections (LODs) were lower than 5.0% and 0.02 μg/ml, respectively. Moreover, good linear ranges were observed in wide concentration ranges with R-squared larger than 0.9961 for both thymol and carvacrol.

Conclusion:

The present method is reliable and simple for determination of carvacrol and thymol in pharmaceutical products.

Essential Oil Chemical Variability in Oliveria decumbens (Apiaceae) from Different Regions of Iran and Its Relationship with Environmental Factors

Oliveria decumbens Vent. (Apiaceae) is an annual herb resistant to harsh environmental conditions, which has got numerous pharmacological, food and feed, and cosmetic applications. In the present study, the variation in the essential oil (EO) content and composition of twelve O. decumbens populations growing wild in several habitats of Iran was studied. The EO contents varied from 2.71% (Darab) to 8.52% (Behbahan) on a dry matter basis, where the latter population revealed to be the highest source of essential oil reported so far in this species. Gas chromatography (GC-FID) and gas chromatography-mass spectrometry (GC-MS) analysis revealed that carvacrol (18.8-51.8%), thymol (20.3-38.7%), γ-terpinene (0.9-28.8%), p-cymene (1.6-21.3%) and myristicin (0.8-9.9%) were the major volatile compounds in all the investigated populations. The EO content had a strong and significant positive correlation with temperature (r = 0.62) and sand content (r = 0.73), but a strong and significant negative correlation with altitude (r = -0.61). On the other hand, the rising altitude led to an increase in thymol content. Cluster and principal component analyses placed the samples from different regions into two main groups based on the main EO components, including thymol/carvacrol type and γ-terpinene/thymol/carvacrol/p-cymene type. This study provides valuable information for identifying chemotypes in O. decumbens as well as insight into planning a domestication and cultivation program.

Dispersive liquid-liquid microextraction for rapid and inexpensive determination of tetramethylpyrazine in vinegar

The concentration of tetramethylpyrazine (TMP) in vinegar is an active indicator of vinegar quality. Dispersive liquid-liquid microextraction (DLLME) was first applied to vinegar as a clean-up pre-treatment for the rapid (5 min) determination of TMP by high-pressure liquid chromatography with ultraviolet detection (HPLC-UV), and may serve as an alternative to solid-phase extraction (SPE) or solid-phase microextraction (SPME). High sensitivity of HPLC for TMP determination was obtained using the DLLME pretreatment, with a limit of detection (LOD) of 0.001 mg L^-1 and limit of quantification (LOQ) of 0.005 mg L^-1. The developed method exhibited excellent linearity in the concentration range of 0.050-80.000 mg L^-1, with a correlation coefficient R² > 0.999. Furthermore, the percentage recovery of TMP in vinegar using the developed method was within the range 97.97-105.24%. Therefore, DLLME coupled with HPLC-UV is a sensitive and promising method for vinegar clean-up and TMP assay.

A novel naphthalene carboxylic acid-based ionic liquid mixed disperser combined with ultrasonic-enhanced in-situ metathesis reaction for preconcentration of triclosan and methyltriclosan in milk and eggs

A microextraction method was developed based on utilization of a novel ionic liquid (IL) [C₄MIM][NCA] as disperser and conventional ILs as extractor (IL-IL-DLLME). This method was integrated with an in-situ metathesis reaction to achieve high extraction efficiency by eliminating the loss of analytes in the discarded disperser after microextraction. Ultrasonic energy was compared to traditional mechanical shaking to accelerate the in-situ metathesis reaction. A 3-min ultrasonic treatment provided similar extraction efficiency as a 120-min mechanical shaking. Due to their strong acidity and lower solubility than traditional hydrophilic ILs, utilization of [C₄MIM][NCA] in the IL-IL-DLLME procedure increased extraction recoveries (ERs) for triclosan (TCS) and methyltriclosan (MTCS) by 10-12% and also avoided an extra pH adjustment step. A series of operational parameters were optimized using single-factor screening and central composite design as follows: 65 µL extraction solvent, 150 µL [C₄MIM][BF₄] and [C₄MIM][NCA] (132/18, v/v, μL) as dispersive solvent, 0.16 g NH₄PF₆ and 3.3 min ultrasonic time. Under optimized conditions with a fortification of 100 µg kg^-1, ERs were 92.6-93.4% for TCS and 92.7-94.2% for MTCS in bovine milk and chicken egg samples. LODs for TCS and MTCS were 0.16-0.24 µg kg^-1 and the enrichment factors were 21.8-23.1. Inter- and intra-day precisions had relative standard deviations of 3.3-5.4% for the optimized method. Overall, this newly developed IL-IL-DLLME method was effective for detecting trace levels of TCS and MTCS in real-world, animal-based foods. Prominent advantages of the new method include high precision and accuracy, high extraction efficiency, simple analytical operations, and no use of organic solvents making the procedure environmentally benign.

Extraction of triclosan and methyltriclosan in human fluids by in situ ionic liquid morphologic transformation

Herein, we established an ionic liquid (IL)-based liquid-solid transformation microextraction (IL-LTME) combined with HPLC-UV detection for the simultaneous determination of triclosan (TCS) and its methylated product, methyltriclosan (MTCS), in human fluids. The IL-LTME method was based on an in situ metathesis between hydrophilic IL and ion-exchange salt to form a solid hydrophobic IL. According to the above principle, a hydrophilic IL, [C₁₂MIM]Br, was selected as the extractant, and NH₄PF₆ as ion-exchange salt. The prominent advantages of the newly developed method are: (1) the in-situ reaction between the extractant [C₁₂MIM]Br and ion-exchange salt NH₄PF₆ changed the IL from hydrophilic to hydrophobic that avoiding the stick of ionic liquid on the tube wall; (2) bubbling with NH₃ greatly increased the contact area between IL-extractant and analytes resulting in improved extraction recovery; and (3) solidification of the [C₁₂MIM] PF₆ provided a good separation and avoided the use of specialized equipment. A series of main parameters were optimized by single-factor screening and central composite design as follows: 0.9 mL of NaOH, 2.0 min of second ultrasonically time, 10 min of centrifugation time, 21 mg of extractant [C₁₂MIM]PF₆, 2.4 min of ultrasonic time, 65 mg of NH₄PF₆ and 13.8 min of cooling time. Under the optimized conditions, the limits of detection for TCS and MTCS were 0.126-0.161 μg L^-1 in plasma samples, and 0.211-0.254 μg L^-1 in urine samples, respectively. The extraction recoveries for TCS and MTCS were in the range of 94.1-103.8%. The intra-day and inter-day precisions were 1.00-4.74% and 1.02-5.21%, respectively. In general, the IL-LTME method is environment-friendly, time-saving, economical, high efficient and robust with low detection limits and high recoveries. Thus, the newly developed method has excellent prospects for sample pretreatment and analysis of trace TCS and MTCS in blood and urine samples.

Differentiation of essential oils in Atractylodes lancea and Atractylodes koreana by gas chromatography with mass spectrometry

Atractylodes rhizome is a valuable traditional Chinese medicinal herb that comprises complex several species whose essential oils are the primary pharmacologically active component. Essential oils of Atractylodes lancea and Atractylodes koreana were extracted by hydrodistillation, and the yield was determined. The average yield of essential oil obtained from A. lancea (2.91%) was higher than that from A. koreana (2.42%). The volatile components of the essential oils were then identified by a gas chromatography with mass spectrometry method that demonstrated good precision. The method showed clear differences in the numbers and contents of volatile components between the two species. 41 and 45 volatile components were identified in A. lancea and A. koreana, respectively. Atractylon (48.68%) was the primary volatile component in A. lancea, while eudesma-4(14)-en-11-ol (11.81%) was major in A. koreana. However, the most significant difference between A. lancea and A. koreana was the major component of atractylon and atractydin. Principal component analysis was utilized to reveal the correlation between volatile components and species, and the analysis was used to successfully discriminate between A. lancea and A. koreana samples. These results suggest that different species of Atractylodes rhizome may yield essential oils that differ significantly in content and composition.

Optimization of ionic liquid based dispersive liquid–liquid microextraction combined with dispersive micro-solid phase extraction for the spectrofluorimetric determination of sulfasalazine in aqueous samples by response surface methodology

A new method based on fluorescent IL-DLLME and μ-SPE was applied for the pretreatment of sulfasalazine (SSZ) prior to determination by fluorimetry.

Optimization of an accelerated solvent extraction dispersive liquid-liquid microextraction method for the separation and determination of essential oil from Ligusticum chuanxiong Hort by gas chromatography with mass spectrometry

In this study, an accelerated solvent extraction dispersive liquid-liquid microextraction coupled with gas chromatography and mass spectrometry was established and employed for the extraction, concentration and analysis of essential oil constituents from Ligusticum chuanxiong Hort. Response surface methodology was performed to optimize the key parameters in accelerated solvent extraction on the extraction efficiency, and key parameters in dispersive liquid-liquid microextraction were discussed as well. Two representative constituents in Ligusticum chuanxiong Hort, (Z)-ligustilide and n-butylphthalide, were quantitatively analyzed. It was shown that the qualitative result of the accelerated solvent extraction dispersive liquid-liquid microextraction approach was in good agreement with that of hydro-distillation, whereas the proposed approach took far less extraction time (30 min), consumed less plant material (usually <1 g, 0.01 g for this study) and solvent (<20 mL) than the conventional system. To sum up, the proposed method could be recommended as a new approach in the extraction and analysis of essential oil.

Application of multivariate optimization procedures for preconcentration and determination of Au(III) and Pt(IV) in aqueous samples with graphene oxide by X-ray fluorescence spectrometry

A simple method was developed for the determination of Au(III) and Pt(IV) contents in aqueous samples after preconcentration. The method was based on the sorption of analytes as 2-amino-5-mercapto-1,3,4-thiadiazol complexes onto graphene oxide and subsequent direct determination by wavelength dispersive X-ray fluorescence (WDXRF). The optimization step was carried out using two-level full-factorial and Box-Behnken designs. The effects of four variables (pH, ligand mass, sonication time, and temperature) were studied by a full-factorial design to find significant variables and their interactions. Results of two-level full-factorial design for Au extraction showed that the factors: pH, ligand mass, temperature of sonication beside the interaction of pH-ligand mass, and interaction sonication temperature-ligand mass were significant. For Pt, the results revealed pH, ligand mass, sonication time, and interaction of pH-ligand mass were statistically significant. Box-Behnken matrix design was applied to determine the optimum level of significant parameters for extraction of two analytes simultaneously. The optimum values of the factors were pH 2.5, 0.9 mL ligand solution, 56 min sonication time and 15 °C temperature. The limits of detection (LOD) were found to be 8 ng mL(-1) for Au and 6 ng mL(-1) for Pt. The adsorption capacity for Au and Pt were 115 and 169 μg mg(-1), respectively. The relative standard deviation (RSD) was lower than 1.4 % (n = 5), and the extraction percentage was more than 95 % for both elements. The method was validated by determination of Au and Pt in spiked water samples and certified reference standard materials.

Ultrasound assisted microextraction-nano material solid phase dispersion for extraction and determination of thymol and carvacrol in pharmaceutical samples: experimental design methodology

In the present study, for the first time, a new extraction method based on "ultrasound assisted microextraction-nanomaterial solid phase dispersion (UAME-NMSPD)" was developed to preconcentrate the low quantity of thymol and carvacrol in pharmaceutical samples prior to their HPLC-UV separation/determination. The analytes were accumulated on nickel sulfide nanomaterial loaded on activated carbon (NiS-NP-AC) that with more detail identified by XRD, FESEM and UV-vis technique. Central composite design (CCD) combined with desirability function (DF) was used to search for optimum operational conditions. Working under optimum conditions specified as: 10 min ultrasonic time, pH 3, 0.011 g of adsorbent and 600 μL extraction solvent) permit achievement of high and reasonable linear range over 0.005-2.0 μg mL(-1) (r(2)>0.9993) with LOD of thymol and carvacrol as 0.23 and 0.21 μg L(-1), respectively. The relative standard deviations (RSDs) were less than 4.93% (n=3).

Multivariate optimization of a headspace solid-phase microextraction method followed by gas chromatography with mass spectrometry for the determination of terpenes in Nicotiana langsdorffii

A simple and sensitive procedure based on headspace solid-phase microextraction and gas chromatography with mass spectrometry was developed for the determination of five terpenes (α-pinene, limonene, linalool, α-terpineol, and geraniol) in the leaves of Nicotiana langsdorffii. The microextraction conditions (extraction temperature, equilibration time, and extraction time) were optimized by means of a Doehlert design. The experimental design showed that, for α-pinene and limonene, a low temperature and a long extraction time were needed for optimal extraction, while linalool, α-terpineol, and geraniol required a high temperature and a long extraction time. The chosen compromise conditions were temperature 60°C, equilibration time 15 min and extraction time 50 min. The main analytical figures of the optimized method were evaluated; LODs ranged from 0.07 ng/g (α-pinene) to 8.0 ng/g (geraniol), while intraday and interday repeatability were in the range 10-17% and 9-13%, respectively. Finally, the procedure was applied to in vitro wild-type and transgenic specimens of N. langsdorffii subjected to abiotic stresses (chemical and heat stress). With the exception of geraniol (75-374 ng/g), low concentration levels of terpenes were measured (ng/g level or lower); some interesting variations in terpene concentration induced by abiotic stress were observed.

Cytotoxicity and enhancement activity of essential oil from Zanthoxylum bungeanum Maxim. as a natural transdermal penetration enhancer

The aim of this present study is to investigate the effect of Zanthoxylum bungeanum oil (essential oil from Z. bungeanum Maxim.) on cytotoxicity and the transdermal permeation of 5-fluorouracil and indomethacin. The cytotoxicity of Z. bungeanum oil on dermal fibroblasts and epidermal keratinocytes was studied using an MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. The rat skin was employed to determine the percutaneous penetration enhancement effect of Z. bungeanum oil on hydrophilic and lipophilic model drugs, i.e., 5-fluorouracil and indomethacin. The secondary structure changes of the rat stratum corneum (SC) were determined using attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), and saturated solubilities and SC/vehicle partition coefficients of two model drugs with and without Z. bungeanum oil were also measured to understand its related mechanisms of action. It was found that the half maximal inhibitory concentration (IC50) values of Z. bungeanum oil were significantly lower in HaCaT and CCC-ESF-1 cell lines compared to the well-established and standard penetration enhancer Azone. The Z. bungeanum oil at various concentrations effectively facilitated the percutaneous penetration of two model drugs across the rat skin. In addition, the mechanisms of permeation enhancement by Z. bungeanum oil could be explained with saturated solubility, SC/vehicle partition coefficient, and secondary structure changes of SC.

Recent advances in application of liquid-based micro-extraction: A review

Liquid-based micro-extraction is a novel “green” sample preparation technique using micro-litre levels of organic solvent to extract target analytes from various sample matrices for subsequent instrumental analysis. This technique developed rapidly from its introduction in the mid-1990s. Micro-extraction methods can be conveniently combined with a wide selection of instruments commonly used in a chemical laboratory; they significantly reduce analysis time and costs of solvents’ use and waste disposal. This review focuses on recent advances in several liquid-based micro-extraction methods, including single-drop micro-extraction, hollow fibre-liquid phase micro-extraction, and dispersive liquid-liquid micro-extraction. Examples of application of these methods to environmental, food, and biomedical analysis are listed.

Ionic-liquid-assisted microwave distillation coupled with headspace single-drop microextraction followed by GC-MS for the rapid analysis of essential oil in Dryopteris fragrans

A rapid, green and effective miniaturized sample preparation technique, ionic-liquid-assisted microwave distillation coupled with headspace single-drop microextraction was developed for the extraction of essential oil from dried Dryopteris fragrans. 1-Ethyl-3-methylimidazolium acetate was the optimal ionic liquid as the destruction agent of plant cell walls and microwave absorption was medium. n-Heptadecane (2.0 μL) was adopted as the suspended microdrop solvent in the headspace for the extraction and concentration of essential oil. The optimal parameters of the proposed method were an irradiation power of 300 W, sample mass of 0.9 g, mass ratio of ionic liquids to sample of 2.8, extraction temperature of 79°C, and extraction time of 3.6 min. In comparison to the previous reports, the proposed technique could equally monitor all the essential oil components with no significant differences in a simple way, which was more rapid and required a much lower amount of sample.