The use of hydrophobic and aromatic polymer nanofibers as novel sorbents for extracting polycyclic aromatic hydrocarbons (PAHs) from river water has been evaluated. Of the materials tested, the biodegradable aliphatic polymer polycaprolactone (PCL) exhibited strong retention of all analytes via hydrophobic interactions. In contrast, the aromatic polymer polyphenylene sulfide (PPS) demonstrated superior performance with higher-ring PAHs due to a combination of hydrophobic and π–π stacking interactions. The porous, permeable structure of the fibrous sorbents enabled rapid extraction. The spin-filter µSPE format required only 10 s for sorbent activation, extraction, and elution, resulting in a total processing time of 30 s per sample. Up to 48 samples could be processed simultaneously, reducing manual handling and simplifying the workflow. Analytical performance was evaluated using river water spiked at different concentration levels. The method showed good linearity (R² ≥ 0.98) across concentration ranges of 0.1–5 µg L⁻¹ for most analytes, with limits of detection of 0.009–0.14 µg L⁻¹ for PCL and 0.012–0.27 µg L⁻¹ for PPS. Recoveries ranged from 57 to 102 % for PCL and 88–139 % for PPS, with relative standard deviations below 15 %, and preconcentration factors of approximately twofold. These results demonstrate that meltblown PCL and PPS nanofibers combined with spin-filter µSPE provide a rapid and practical approach to extracting PAHs from environmental water samples.

Background Matrix effect (ME) evaluation is an indispensable part of the method development and validation when using ultra-high performance liquid chromatography coupled with mass spectrometry (UHPLC-MS). The rotational and translational matrix effects are often observed. The rotational matrix effect depends on the analyte concentration and affects the slope of the calibration function, while the translational matrix effect is independent of the analyte concentration and affects the intercept of the calibration function. Two matrix effect evaluation strategies, the post-extraction addition and the comparison of calibration curve slopes, are the most widely used for the quantitative ME evaluation. The post-extraction addition approach recommended by the European Medicines Agency (EMA) guideline is considered the reference approach. However, the extent to which these approaches provide comparable results has not been systematically assessed. Results We evaluated the suitability of the calibration curve slope approach for quantifying ME. Two ME evaluation strategies were systematically compared using ESI-UHPLC-MS/MS in both negative and positive ionization modes for the analysis of 26 compounds in serum. Various calibration models, including 1/X0, 1/X, and 1/X2 weighting or logarithmic transformation, were assessed. None of the tested models provided overestimated results compared to the post-extraction addition approach. However, several models exhibited underestimated results. Thus, we developed a new approach for calculation of ME taking into account also the translational ME expressed by the intercept of the calibration curve. The accuracy of the new approach was subsequently determined using three different matrices and two different instrumental platforms. Significance It is not advisable to rely solely on the calibration curve slope approach for accurate estimation of ME unless translational ME derived from calibration curve intercept are also involved in calculation. Therefore, a novel intercept-based equation was proposed for the calculation of translational matrix effects. The total matrix effect, obtained as the sum of the slope- and intercept-derived contributions, closely corresponds to matrix effects determined by the post-extraction addition approach.

For the first time, polymer microfibers filled in pipette tip format were used to extract polycyclic aromatic hydrocarbons from river water. Centrifugal force was used to push the sample through the sorbent, thereby increasing the speed and throughput of the extraction process. A broad range of almost 30 different microfibrous materials, including various polymers and their coated counterparts, were evaluated to identify the most efficient sorbent. Biodegradable polycaprolactone microfibers provided the best recovery rates (72–127%) with relative standard deviations (RSD) of 2.7–6.4%. The method exhibited linearity from 0.1 to 5 µg L⁻¹ for most analytes (R² > 0.9994), except for dibenzo(a,h)anthracene (R² = 0.9981). Preconcentration factors ranged from 2.9 to 5.1. Intra- and inter-day repeatability tests confirmed stability and reusability of the sorbent for over six consecutive extraction cycles conducted within three experimental days. The high permeability of polycaprolactone microfibers allows for short contact times while maintaining high recoveries. The centrifuge-assisted setup enables the processing of up to 36 samples per run. Our approach provides a practical alternative for extracting hydrophobic analytes from water. The novelty of this study lies in the development of a reusable, centrifugation-driven pipette-tip microextraction approach using biodegradable polycaprolactone microfibers for fast and efficient determination of polycyclic aromatic hydrocarbons in water.

Liquid chromatography (LC) is widely considered as one of the most commonly used instrumental analytical techniques, second only to the most fundamental techniques, such as weighing and pH measurement. The development, current challenges, and future of LC have already been discussed more extensively elsewhere, including in this journal. This article focuses on two protagonists, Mikhail Semyonovich Tsvet and Csaba Horv & aacute;th, whose groundbreaking works have substantially advanced the field of LC. This year, we are celebrating the significant anniversaries of their publications. Their pioneering research was a "giant leap for mankind" because it demonstrated the power of chromatography as an indispensable tool in analytical chemistry.

Garden nasturtium (Tropaeolum majus L.) is a rich source of bioactive compounds, particularly glucotropaeolin, and is increasingly used in functional foods. Maintaining glucosinolate stability during processing is critical for ensuring consistent bioactivity. This study systematically investigated the kinetics and mechanism of glucotropaeolin degradation in edible extracts obtained from seeds, leaves, and flower buds under typical processing and storage conditions. Glucotropaeolin hydrolysis was primarily driven by myrosinase, producing benzyl isothiocyanate, which then degraded to form benzyl thiocarbamate and 1,3-dibenzyl-2-thiourea. Untreated or lyophilised extracts showed rapid glucotropaeolin degradation, whereas boiling-induced myrosinase inactivation substantially improved glucotropaeolin stability. Additionally, an analysis of commercial garden nasturtium extracts revealed surprisingly low levels of glucotropaeolin and benzyl isothiocyanate, highlighting the impact of industrial processing. These findings provide insight into the mechanism of glucotropaeolin stability and highlight processing strategies for preserving bioactive glucosinolates, supporting the development of functional foods with predictable bioactive profiles.

Due to their significant surface area and tunable surface chemistry, polymer nanofibers are promising advanced sorbents for miniaturized solid phase extraction of a broad range of model analytes that differ in chemical structures and physical properties. In this study, in-situ modified and coated polyamide 6 nanofibers were evaluated as sorbents for spin-filter solid phase extraction. The modified nanofibers were produced by electrospinning from polymer solutions containing either 3-[dodecyl(dimethyl)ammonio]-1-propanesulfonate (sulfobetaine 12) or tetramethylammonium chloride. Alternatively, the nanofibers were coated with sulfonated azo dyes. This surface modification of nanofibers was identified as a key factor in governing sorbent performance, and led to significantly enhanced extraction efficiency compared to native and uncoated materials. Among the tested sorbents, tartrazine-coated nanofibers exhibited the highest extraction efficiency, particularly for phenolic acids and non-steroidal anti-inflammatory drugs. Recoveries exceeded 90% for most analytes. The developed spin-filter solid phase extraction method coupled with ultra-high performance liquid chromatography with spectrophotometric detection showed good accuracy (85.8–106.6%) and precision (RSD ≤ 4.7%). Applying the method to analyze river water confirmed the suitability of the sorbent for extracting polar xenobiotics prior to chromatographic analysis.

A novel, simplified microextraction technique, the centrifugation-assisted extraction method that uses C18-functionalized glass beads as the sorbent has been developed. This procedure is demonstrated with extracting retinol from a small volume of human serum. First, the beads containing C18-functionalities are added to the liquid serum sample to extract retinol. Upon addition of a high-density perfluorinated liquid, a three-phase system is created. Centrifugation enables density-driven separation, in which the perfluorinated inert liquid forms a physical barrier that cleanly separates the matrix components on the top from the analyte-loaded beads collected at the bottom of the tube. Subsequent desorption of the adsorbed compound of interest using a minimal volume of methanol provides a sample suitable for rapid analysis by high-performance liquid chromatography with a diode-array detector. This method has been validated according to the International Council for Harmonization M10 guideline by the European Medicines Agency. Our procedure demonstrated excellent linearity over the concentration range of 0.26–5 μmol/L (r = 0.9999) achieving a lower limit of quantification of 0.26 μmol/L, which is sufficient for clinical monitoring. The method showed a high accuracy (bias < 12%, calculated against nominal concentrations established by the reference liquid-liquid procedure) and precision (relative standard deviation <7% for within-run and <5% for between-run). The developed method is a rapid, cost-effective, and robust alternative to other techniques for determining retinol in human serum. Combining a functionalized, freely moving sorbent with density-driven separation provides a simple, pump-free microextraction approach that is suitable for routine clinical and analytical laboratories because it significantly reduces solvent usage and simplifies the workflow to a single tube.

Selection of the optimal makeup solvent composition is critical for achieving sensitive and reproducible ionization in supercritical fluid chromatography-mass spectrometry (SFC-MS). This study investigated the ionization processes in a spray-based ionization source called UniSpray (US), by an artificial neural network driven approach, emphasizing the effect of makeup solvent composition. A set of compounds with different physicochemical properties was analyzed using a generic SFC method and 24 makeup solvents. Artificial neural networks were used to correlate molecular descriptors with MS responses and to identify key analyte properties affecting ionization. Statistical analysis of this extensive dataset revealed significant differences in ionization efficiency compared to electrospray ionization (ESI), depending on makeup solvent composition and analyte properties. While US outperformed ESI for 82 % of compounds, certain analytes, including basic beta-blockers, fluorine-substituted compounds, and small lipophilic molecules, benefited from ESI. Optimized makeup solvent compositions differed notably between ESI and US. For example, ethanol and isopropanol were recommended for US+ but not for ESI+. The use of water and ammonia also affected MS responses differently between sources and ionization modes, with optimal concentrations varying depending on the analyte and organic modifier of the SFC mobile phase. This study highlights key differences between SFC-ESI-MS and SFC-US-MS ionization efficiency and demonstrates the utility of data-driven methodologies for faster and more efficient method development.

Advanced polyacrylonitrile, polypropylene, polyhydroxybutyrate, polycaprolactone, and poly(vinylidene difluoride) nanofibers, including composite materials containing carbon nanoparticle additives, combined micro/nanofibers, and modified nanofibers with polyhydroxy coatings were filled into a cartridge and tested for the online solid phase extraction (SPE) of highly lipophilic and fluorinated organic contaminants. The reusable nanofiber-packed cartridge was coupled to an HPLC column to separate the analytes after direct elution. Electrospun poly(vinylidene difluoride) nanofibers embedded in a meltblown microfibrous polycaprolactone scaffold were sufficiently robust in a high-pressure SPE-HPLC system and the most efficient adsorbent for the selective extraction of fluorinated pesticides. The optimized and validated online solid-phase extraction method coupled with chromatographic separation demonstrated an excellent trueness of 93-108 % and precision of better than 3.2 % RSD with six replicates. The entire analysis run took only 7 min, including the preconcentration step with the direct application of a 200 μL sample volume. Since the method is fully automated, it significantly reduces time, solvent consumption, and the occurrence of human error. Our study highlights the potential of polymer nanofiber sorbents for the efficient environmental monitoring of emerging fluorinated contaminants and demonstrates a reliable, fully automated method for their determination.

Archive Tokaj wines from the vineyards in the Slovak part of the Tokaj region have been characterized in terms of the content of phenolic compounds specific to that type of botrytized wine. More than 60 archive samples (1959-2017) were evaluated in terms of phenolic profile. Eighteen individual phenolic compounds were quantified by UHPLC-DAD method. The total concentration of phenolic compounds in the wines ranged from 58.28 to 302.57 mg/L. The most abundant compound in the phenolic profile was caftaric acid with average values of around 60 mg/L followed by catechin ranging from 2.24 to 49.35 mg/L, gallic acid with a mean concentration of 14.65 mg/L, and vanillic acid. Statistical evaluation using PCA and SIMCA model showed significant correlations between the phenolic profile, botrytized/non-botrytized wines, and their origin. Total antioxidant capacity determination using a CoulArray detector proved the correlation between the "putňa" number of Tokaj selections and antioxidant activity of wines.

A rapid ultra-high performance liquid chromatography with diode array detection (UHPLC-DAD) method for determination of bioactive compounds in Berberis aristata extracts containing berberine, aromoline, magnoflorine, berbamine, tetrahydropalmatine, tetrahydroberberine, jatrorrhizine, palmatine, and oxyberberine was developed. The stationary phase was Ascentis Express AQ C-18 (150 x 4.6 mm, 2.7 mu m core-shell particles with embedded polar modification). The method run time with gradient elution comprising 0.1 % aqueous phosphoric acid and acetonitrile (1.0 mL/min) was 9.2 min. Ultrasound-assisted solid-liquid extraction with methanol was used for extraction. The validated method yielded recovery from 94.60 % to 104.10 % and limits of quantification from 0.125 to 0.250 mg/L. The results of berberine content ranged from 82.99 % to 107.47 % of the declared amount. An alarmingly low content 0.46 % of declared amount of extract was also found. The biological activity and cytotoxic properties of Berberis aristata extract and berberine powder on the Hep-2 cell lines was also evaluated and corelated with the content of berberine and protoberberine alkaloids in individual extracts. The majority of food extracts showed the negligible cytotoxicity for Hep-2 cell lines while one containing the highest level of jathrorrhizine showed significant cytotoxicity. However, the inhibitory effect on the Hep-2 cell lines has not been clearly demonstrated.

Understanding and predicting mass spectrometry responses in supercritical fluid chromatography-mass spectrometry (SFC-MS) is critical for optimizing detection across diverse analytes and solvent compositions. We present a novel approach using artificial neural networks (ANN) to explore the complex relationships between molecular descriptors of analytes and MS responses in different makeup solvent compositions enabling SFC-MS coupling. 226 molecular descriptors were evaluated for compounds under standardized SFC conditions, with 24 makeup solvent compositions. These makeup solvents included pure alcohols and methanol with varying concentrations of volatile additives. Our results highlight distinct ionization processes for the two most commonly used soft ionization techniques: (i) electrospray ionization (ESI), primarily involving proton or cation transfer, and (ii) atmospheric pressure chemical ionization (APCI), associated with charged ion transfer. Principal component analysis of weights assigned to molecular descriptors reveals that, in positive detection mode, these descriptors effectively differentiate ionization efficiency between ESI and APCI. In contrast, this differentiation is less pronounced in negative mode, where the variance explained is more homogeneously distributed, with stronger discrimination observed when NH3 is used as an additive to the organic modifier. These findings provide critical insights into the influence of molecular descriptors and solvent composition on ionization efficiency, serving as a foundation for future investigations into SFC-MS optimization. This proof-of-concept underscores the feasibility of using predictive models to advance understanding of ionization efficiency and offers a valuable framework for refining SFC-MS workflows in analytical chemistry.

Dried blood spot (DBS) technique has gained significant attention due to the growth of decentralized diagnostics. This technique reduces the number of hospital visits for patients and the workload for personnel in specialized hospitals. This microsampling method provides an environmentally friendly (green) and patient-friendly alternative to conventional phlebotomy. Challenges related to sample heterogeneity in traditional DBS cards have been overcome by the volumetric DBS sampling using new types of commercially available devices. Due to the unstable nature of the analytes, commercial volumetric DBS devices allow blood sampling at primary care units in remote settings and facilitate transport it via temperature-controlled systems. Blood sample stability has improved from 24 h at 4-8 °C to 30 days at -80°C. DBS also requires over 1000 times less shipping and storage space than liquid blood. We optimized the DBS method to require only 10 µL of blood and achieve extraction efficiencies of over 90 % for retinol when the result from validated method is the reference value. However, α-tocopherol recovery varied from 53 to 75 % depending on the filter paper type used. Furthermore, we successfully developed a liquid-liquid extraction method for both analytes from whole blood, with over 90 % recovery. Our approaches eliminate the need for separate serum and erythrocyte extractions, simplify sample preparation, and reduce reagent use and energy consumption. Both devices enable reliable volumetric collection. Our approach makes micronutrient monitoring more accessible and enables sample collection in decentralized settings. This aligns with the objectives of green analytical chemistry and universal health coverage.

A simple and rapid method for determining diclofenac in a sequential injection system was developed for the selective and sensitive on-line determination of the analyte in sample from a metabolic study. The fluorescence properties of complexes of 13 types of cyclodextrins and their derivatives, including salts, were studied off-line, while two of the complexes were then used in the flow conditions. Optimisation was carried out with (2-hydroxypropyl)-γ-cyclodextrin, which is fluorescent and the intensity of its complex with diclofenac was found to be lower. In the flow system, we tested different types of mixing of zones and stop-flow periods. Simple mixing using flow reversal and a 1-min stop-flow in the holding coil were sufficient to rapidly determine diclofenac, even at low concentrations with a limit of quantitation of 1 × 10-6 mol/L. The relationship between fluorescence intensity and diclofenac concentration showed a different pattern in the two intervals: decreasing in the range of 1-5x10-7 mol/l and linearly increasing in the range of 1-5x10-6 mol/l, which was used for analysis. Real samples from a metabolic activity study based on the activation of xenobiotics recognition receptors were analysed, and the results were compared with off-line liquid chromatography/mass spectrometry measurements. The differences corresponded to the complexity of the matrix and were not significant. The trend of diclofenac metabolism was obvious. The developed method is prepared for the fully automated, real-time monitoring of the metabolic study with more frequent sampling than just once daily and the prediction of sample collection for the mass spectrometric determination of diclofenac metabolites.

The retention mechanisms of small molecules on a wide range of stationary phases using different mobile phase compositions are one of the most discussed topics in current state-of-the-art supercritical fluid chromatography (SFC). Although various theories have been published on retention behavior, prediction, and stability over time, an in-depth insight into the mechanisms is still lacking. Our study focused on the description of the retention mechanisms on columns with amine moieties, i.e., 2-ethylpyridine, 2-picolylamine, 1-aminoanthracene, and diethylamine, dedicated to SFC, using three different compositions of organic modifier, i.e., methanol, methanol + 10 mmol/L NH3, and methanol + 2 % H2O, in CO2. An extensive set of analytes characterized by more than 200 molecular descriptors was used. The importance of the effect of each molecular descriptor on the retention behavior was determined by artificial neural networks. Thus, the descriptors increasing and/or decreasing retention on individual columns using different mobile phase compositions were defined. The data collected over one year of column use were statistically evaluated to describe the retention behavior of small molecules on the tested stationary phases using three organic modifiers and to describe the changes in retention behavior over time. As the development of the SFC method can be laborious and time-consuming, this publication offers a detailed description of the interactions taking place between the analyte and the SFC stationary phase. Understanding these fundamental processes will enable faster development of SFC methods using quality-by-design principles.

New polyamide (PA) homopolymers and copolymers nanofibers with different alkyl chain lengths as novel materials have been investigated for the automation of on-line sample preparation step and extraction of polycyclic aromatic hydrocarbons (PAHs) from the environment. PA 4/6 nanofiber copolymer showed the highest extraction yield of tested analytes and comparable performance with commercial reversed phase C18 sorbent. Our study presents an automation of on-line solid phase extraction method coupled with ultra-high performance liquid chromatography with fluorescence detection for the analysis of nine PAHs in river water. The optimal conditions included 50 μL injection volume, washing with 10 % acetonitrile at a flow rate of 1.0 mL min-1 for 1 min, followed by backflush elution of analytes using a gradient of acetonitrile (from 60 % to 74 %) in water at 1.5 mL min-1 over 12.25 min on a YMC-Triart PFP column (150 × 4.6 mm, 3 μm particle size). The total analysis time, including extraction, separation, and column equilibration, was 14 min. This method provides excellent analytical performance, with linearity ranging from 0.01 to 0.5 μg L-1 for acenaphthene, anthracene, pyrene, chrysene, and 0.05-0.3 μg L-1 for benzo(k)fluoranthene, benzo(a)pyrene, dibenzo(a,h)anthracene, indeno(c,d)pyrene and benzo(g,h,i)perylene, with coefficients of determination (R2) ranging 0.9989-0.9999. The limits of detection and quantification were 0.003-0.01 and 0.01-0.05 μg L-1, respectively. The recoveries were between 92 and 105 %, with RSD 1.53-6.66 %. The polyamide-based sorbent requires no modification and can be inexpensively prepared as homogeneous mats by electrospinning. It can be cut and manually packed into a column or filtration device, allowing for easy replacement, when needed, with inter-columns repeatability of RSD <13 %. In addition, a single extraction column can be reused repeatedly.

The retention behavior in supercritical fluid chromatography (SFC) remains a complex and poorly understood phenomenon despite the development of various models to explain retention mechanisms. This study aims to deepen the understanding of retention by investigating three distinct stationary phases: high-strength silica octadecyl (HSS C18 SB), charged surface hybrid pentafluorophenyl (CSH PFP), and porous graphitic carbon (PGC) as a nonsilica-based phase. Three mobile phase compositions, i.e., CO2/methanol, CO2/methanol +10 mmol/L NH3, and CO2/methanol +2% H2O, were investigated using an extensive set of analytes characterized by over 200 molecular descriptors. Artificial neural networks were employed to analyze the influence of these descriptors on retention behavior, revealing the most significant molecular features that increase or decrease retention on each column with the three different mobile phases. This complex evaluation of the large set of experimental data enabled to link specific analyte properties to retention interactions in SFC, including the interaction of analytes with partial positive charge with silanol groups on the HSS C18 SB column when using methanol + H2O as the organic modifier. The flexibility of the alkyl chain in the HSS C18 SB column is also affected by the composition of the organic modifier, which alters retention mechanisms, especially when NH3 is used as an additive. This highlights the critical role of the mobile phase composition in modulating the behavior of nonpolar stationary phases. Completely different interaction mechanisms were observed for the PGC column when comparing methanol with and without additives, suggesting possible modifications to the planar structure and surface polarizability of the PGC phase. Statistical evaluation of data collected over a year of column usage demonstrated distinct long-term retention stability trends. The HSS C18 SB column exhibited the greatest stability with methanol + H2O, whereas significant retention decreases were observed with methanol + NH3 modifier, particularly for CSH PFP and, unexpectedly, also for PGC. These findings provide crucial insights into the long-term retention behavior and aging of SFC columns, with practical implications for optimizing SFC conditions and improving column lifetime.

We evaluated the application of nanofibers made from different biodegradable and synthetic polymers as sorbents in a new technique of spin filter fiber-microextraction. Biodegradable polycaprolactone fibers, produced via the meltblowing process exhibited robust hydrophobic interactions with lipophilic analytes and were the most effective. The highly porous and permeable structure of the fibrous material ensured exhaustive extraction of xenobiotics from river water. Recovery rates ranged from 81.8 to 105.2 %, except for 4-nitrophenol, a more polar analyte, for which the recovery was 60 %. Only 10 s were needed for activation, extraction, and elution, significantly reducing the time required to complete the procedure in only 30 s per sample. Our method exhibited excellent analytical performance, achieving linearity in the range of 50-2000 mu g L-1 for most analytes (100-2000 mu g L-1 for PNP and 2-CP; and 100-1000 mu g L-1 for PER) with a coefficient of determination (R2) greater than 0.9952. The limits of detection were recalculated based on the slope of the calibration curves and the standard deviation of six replicate measurements at the lowest calibration point for each analyte, yielding values in the range of 7.0-36.6 mu gL-1. Repeatability between extractions (i.e. inter-extraction precision) was evaluated by performing six parallel runs using different cartridges (n = 6). The obtained RSD precision values ranged from 2.2 to 3.3 % demonstrating the excellent uniformity of the nanofibrous materials filled in the devices . We also assessed the reusability of the individual cartridges by performing six consecutive extractions on the same spin filter (i.e. intra-cartridge precision, n = 6), yielding RSD values between 1.1 and 3.6 %. These results confirm that the spin filters cartridges filled with polycaprolactone nanofibers can be effectively reused for multiple extractions in absence of sample carry-over effect.

This study deals with the determination of bioactive compounds in Curcuma longa extract with addition of piperine to enhance the bioavailability of curcuminoids. The supplements containing bioactive phytochemicals including curcumin, demethoxycurcumin, bisdemethoxycurcumin, tetrahydrocurcumin, and piperine were quantified by ultra-high performance liquid chromatography method with diode array detection using an Ascentis Express RP-Amide column with 2.7 mu m core-shell particles. The chromatographic analysis was performed at 30 degrees C with a run time of 12.5 min. Ultrasound-assisted solid-liquid extraction was applied to herbal extracts prior to analysis. The validated method yielded recoveries ranging from 91.52 +/- 0.54-97.23 +/- 0.54 %, and the limit of detection from 0.02 to 0.06 mu g/mL. The content of curcuminoids and piperine in food supplements was alarmingly low, ranging from 1.04 % to 81.22 % of the declared content. The biological activity and cytotoxic properties of Curcuma longa extracts on the Hep-2 cell lines from a laryngeal carcinoma using Neutral Red assay and WST-1 proliferation test were also evaluated and positively correlated with the content of curcuminoids in individual preparations after 48 h. The supplement containing the lowest level of curcuminoids showed negligible cytotoxicity for Hep-2 cell lines while those containing the highest level of curcuminoids showed significant cytotoxicity.