A Validated HPTLC Method for the Determination of Illegal Dyes in Spices and Spice Mixtures

Marine halophyte derived polyphenols inhibit glioma cell growth through mitogen-activated protein kinase signaling pathway

Plants that are pharmacologically significant require intensive phytochemical characterization for bioactive profiling of the compounds, which has enabled their safe use in ayurvedic medicine. The present study is focused on the phytochemical analyses, quantitative estimation and profiling of secondary metabolites of leaf extract, as well as the antioxidant and cytotoxic activity of the potent halophytes such as Avicennia marina, Ceriops tagal, Ipomoea pes-caprae, and Sonneratia apetala. The in vitro antioxidant property was investigated using DPPH, ferric reducing antioxidant capacity (FRAP) assay. Bioactive compounds such as phenols, flavonoids, saponin and alkaloids were quantitatively estimated from the extracts of A.marina, C.tagal, I.pes-capra and S.apetala, which possessed higher phenol content than the other studied halophytes. The extracts at 200 µg/ml revealed higher antioxidant activity than the standard ascorbic acid and it functions as a powerful oxygen free radical scavenger with 77.37%, 75.35% and 72.84% for S.apetala, I.pes-caprae and C.tagal respectively and with least IC₅₀ for I.pes-caprae (11.95 µg/ml) followed by C.tagal (49.94 µg/ml). Cell viability and anti-proliferative activity of different polyphenolic fractions of C.tagal (CT1 and CT2) and I.pes-caprae fraction (IP) against LN229, SNB19 revealed Ipomoea as the promising anti-cytotoxic fraction. IP-derived polyphenols was further subjected to apoptosis, migration assay, ROS and caspase - 3 and - 7 to elucidate its potentiality as a therapeutic drug. IP-polyphenols was found to have higher percentage of inhibition than the CT1 and CT2 polyphenols of C.tagal on comparison with TMZ. All the above-mentioned in-vitro analysis further validated the ability of IP-polyphenols inducing cell death via ROS-mediated caspase dependent pathway. Further, proteomic and phospho-proteomic analysis revealed the potential role of IP-polyphenols in the regulation of cell proliferation through MMK3, p53, p70 S6 kinase and RSK1 proteins involved in mitogen-activated protein kinase signaling pathway. Our analysis confirmed the promising role of I.pes-caprae derived polyphenols as an anti-metastatic compound against GBM cells.

Rapid UV/Vis Spectroscopic Dye Authentication Assay for the Determination and Classification of Reactive Dyes, Monascus Pigments, and Natural Dyes in Coloring Foodstuff

Food authenticity in the field of food dyes can be interpreted as the correctness of the coloring ingredients indicated. The Rapid UV/vis Spectroscopic Dye Authentication Assay (RaSDAY) presented in this work was used to verify the authenticity of water-soluble reddish colorings for food use. RaSDAY includes the processing of samples under different experimental conditions with pH variations and heat exposure. The absorbances measured are analyzed by principal component analysis and a k-nearest neighbors algorithm. As a result, classification of anthocyanins, betalains, and carmine and the detection of Monascus pigments, undeclared artificial food dyes, and reactive textile azo dyes can be performed by utilizing a rapid screening method. In 17 out of 20 samples of coloring food additives that were included in this work, reactive dyes, unpermitted Monascus pigments, and artificial food dyes were detected using the developed method. "Reactive Red 120", "Reactive Red 195", and "Reactive Red 198" were identified by subsequent ¹H NMR spectroscopy in eight of those samples.

A new high-throughput screening method to determine multiple dyes in herbs and spices

The unauthorised addition of colours to herbs and spices is a recurrent issue affecting food business operators. Such a practice aims at improving food visual attractiveness, masking poor product quality, and/or compensating for natural colour variation with the ultimate goal to increase profits. To detect this fraud, a new LC-MS/MS method was developed for screening 58 dyes in both herbs and spices. This extended list of targets was established based on requirements from international spices organisations, past issues identified by web scouting and by notifications from the European Rapid Alert System for Food and Feed (RASFF). The method is intended to quickly detect fraudulent addition of dyes with Screening Target Concentrations ranging from 0.1 to 2.5 mg/kg. Validation was performed according to the European Community Reference Laboratories Residues Guidelines 20/1/2010. False positive and false negative rates were below 5% for all analytes and applicability of the method was further demonstrated by analysing 117 samples collected worldwide. None of the surveyed dyes was found in herbs (n = 28, 16 varieties) whereas 6% of spice samples (n = 89, 21 varieties) was found contaminated with one or two dyes at levels ranging from 0.12 to 255 mg/kg. Four out of the nine detected compounds have never been reported in the RASFF, thus demonstrating the usefulness of this analytical approach.

Analysis of unauthorized Sudan dyes in food by high-performance thin-layer chromatography

Food authenticity and food safety are of high importance to organizations as well as to the food industry to ensure an accurate labeling of food products. Respective analytical methods should provide a fast screening and a reliable cost-efficient quantitation. HPTLC was pointed out as key analytical technique in this field. A new HPTLC method applying caffeine-impregnated silica gel plates was developed for eight most frequently found fat-soluble azo dyes unauthorizedly added to spices, spice mixtures, pastes, sauces, and palm oils. A simple post-chromatographic UV irradiation provided an effective sample cleanup, which took 4 min for up to 46 samples in parallel. The method was trimmed to enable 23 simultaneous separations within 20 min for quantitation or 46 separations within 5 min for screening. Linear (4-40 ng/band) or polynomial (10-200 ng/band) calibrations of the eight azo dyes revealed high correlation coefficients and low standard deviations. Limits of detection and quantification were determined to be 2-3 and 6-9 ng/zone, respectively. After an easy sample extraction, recoveries of 70-120% were obtained from chili, paprika, and curcuma powder as well as from chili sauce, curry paste, and palm oil spiked at low (mainly 25-50 mg/kg) and high levels (150-300 mg/kg). For unequivocal identification, the compound in a suspect zone was eluted via a column into the mass spectrometer. This resulted in the hyphenation HPTLC-vis-HPLC-DAD-ESI-MS. Graphical abstract Simplified clean-up by UV irradiation for Sudan dye analysis in food by HPTLC-vis-HPLC-DAD-ESI-MS.

Qualitative and quantitative analysis of hyaluronan oligosaccharides with high performance thin layer chromatography using reagent-free derivatization on amino-modified silica and electrospray ionization-quadrupole time-of-flight mass spectrometry coupling on normal phase

Purified oligomers of hyalobiuronic acid are indispensable tools to elucidate the physiological and pathophysiological role of hyaluronan degradation by various hyaluronidase isoenzymes. Therefore, we established and validated a novel sensitive, convenient, rapid, and cost-effective high performance thin layer chromatography (HPTLC) method for the qualitative and quantitative analysis of small saturated hyaluronan oligosaccharides consisting of 2-4 hyalobiuronic acid moieties. The use of amino-modified silica as stationary phase allows a simple reagent-free in situ derivatization by heating, resulting in a very low limit of detection (7-19 pmol per band, depending on the analyzed saturated oligosaccharide). By this derivatization procedure for the first time densitometric quantification of the analytes could be performed by HPTLC. The validated method showed a quantification limit of 37-71 pmol per band and was proven to be superior in comparison to conventional detection of hyaluronan oligosaccharides. The analytes were identified by hyphenation of normal phase planar chromatography to mass spectrometry (TLC-MS) using electrospray ionization. As an alternative to sequential techniques such as high performance liquid chromatography (HPLC) and capillary electrophoresis (CE), the validated HPTLC quantification method can easily be automated and is applicable to the analysis of multiple samples in parallel.