Jpc-journal of Planar Chromatography-modern Tlc最新文献

In the last 20 years, isatin and its derivatives stand out as promising precursors in the synthesis of new pharmacologically active compounds. Since it can act as both an electrophile and nucleophile, the possibilities of its structural modification are numerous, which is what makes it an interesting moiety in structure–activity relationship (SAR) studies. The early stages of the study of potentially pharmacologically active compounds involve a detailed analysis of their physicochemical, pharmacokinetic, and toxicological properties. This research deals with studying the chromatographic behavior, lipophilicity, of the series of isatin derivatives by using reversed-phase thin-layer chromatography (RPTLC) as well as with evaluating their important in silico absorption, distribution, metabolism, excretion, and toxicity (ADMET) and ecotoxic properties. A comprehensive interpretation of the relationship between the obtained parameters was performed by using the method of multivariate analysis—hierarchical cluster analysis (HCA) and principal component analysis (PCA). Established meaningful mathematical models indicate that the chromatographic parameters obtained by RPTLC (R_M⁰ and m) can be interpreted as reliable descriptors of bioactivity properties of examined isatin derivatives.

Predicting the biological properties of newly synthesized compounds plays a key role in the process of synthesis of new compounds and their evaluation as potential drug candidates. The large number of methods and models available often makes it confusing to choose a suitable one in the context of given investigated compounds. In this paper, a comparison of data obtained using 46 in silico models predicting various properties and retention parameters of compounds on the basis of data obtained in 8 commonly available thin-layer chromatographic (TLC) systems for 14 commercially available drugs was carried out using the principal component analysis (PCA) method. The results obtained show similarities between the R_M0, S, and φ₀ values calculated for the investigated TLC systems and the sets of descriptors obtained from the in silico calculations, enabling an evaluation of the interchangeability of the investigated methods.

Equol, an exclusive gut bacteria metabolite, is associated with the incidence of low blood pressure, strokes, and hormone-related cancers due to its estrogen-mimicking structure and antioxidant properties. However, all humans cannot produce S-equol upon consumption of soybean and are thus deprived of the health benefits. Existing methods of equol estimation involve complex instrumentation, which is time-consuming and expensive. Therefore, in this study, we develop a simple, cost-effective, accurate, and rapid high-performance thin-layer chromatography (HPTLC) method for equol estimation. Chromatography was performed on precoated silica gel aluminum 60 F₂₅₄ HPTLC plates, and it produced a compact spot of equol [retardation factor (R_F) value of 0.77 ± 0.04] with a mobile phase ethyl acetate–toluene–formic acid in the ratio 5:4:1 (V/V). Ultraviolet detection was performed densitometrically at λ_max 200 nm. The method was validated for precision, recovery, robustness, specificity, limit of detection, and limit of quantification, following the International Council for Harmonisation (ICH) guidelines. It was found that S-equol concentration was higher in rats fed with fermented soybean, and the concentration was higher in feces as compared with urine samples. The highest S-equol content in feces and urine was 16.74 µg g⁻¹ and 6.34 µg mL⁻¹, respectively. Quantification of S-equol by HPTLC enables us to segregate the human population into two groups: equol producers/healthy individuals and nonequol producers/nonhealthy individuals. In this era of personalized medicine, such an insight will prove to be of great value and also reduce the drug load on our body.

Graphical abstract

A new high-performance thin-layer chromatography (HPTLC) method for the determination of adapalene and phenoxyethanol was developed and validated. An excellent resolution with R_F values 0.43 ± 0.03 and 0.75 ± 0.02 for adapalene and phenoxyethanol was achieved by using optimized chromatographic conditions. A mixture of toluene‒acetone (8:2, V/V) was chosen as the mobile phase and detected at 228 nm. When the marketed formulation was analysed by the developed method, the percentage of drug contents were found to be 100 ± 1.3839% w/w for adapalene and 101 ± 1.1809% w/w for phenoxyethanol. The developed method was validated for linearity range, limits of detection and quantification, accuracy, precision, robustness, solution stability, specificity and forced degradation studies. The method was found to be linear, accurate, precise, robust and sensitive. The method was found to be linear in the range of 40‒240 ng per band for adapalene with R² value of 0.99 and 100‒600 ng per band for phenoxyethanol with R² value of 0.994. The limits of detection and quantification were found to be 4.79 and 14.52 ng per band for adapalene and 6.91 and 20.93 ng per band for phenoxyethanol, respectively. The percentage of drug recovery was found to be near 100% w/w confirming the accuracy of the method. In the case of precision studies, relative standard deviation (%RSD) values were found to be less than 2, indicating that the method was precise. The %RSD values of deliberate variations like amount of mobile phase and saturation time were found to be less than 2 showing that the method was robust. Forced degradation study concluded that adapalene and phenoxyethanol were highly labile for acid and alkali hydrolysis. Both were found to be stable during photo and thermal degradation.

High-performance thin-layer chromatographic (HPTLC) silica gel and amino plates in combination with developing solvents containing formic and acetic acid were examined for HPTLC‒multi-stage mass spectrometry (MSⁿ) analyses of chestnut bee pollen samples from Slovenia and Türkiye. Ethyl acetate‒formic acid‒acetic acid‒water (10:1.1:1.1:2.6, V/V) and ethyl acetate‒dichloromethane‒formic acid‒acetic acid (10:2.5:1:1.1, V/V) were used for development of silica gel and amino plates, respectively. Twofold pre-development was required for the developed HPTLC‒MSⁿ methods. The first pre-development was performed with methanol‒formic acid (10:3, V/V) for silica gel plates and methanol‒formic acid (10:5, V/V) for amino plates. The second pre-development with methanol was equal for both types of the plates. Using the developed HPTLC‒MSⁿ methods, five phenylamides (spermidines), six isorhamnetin glycosides and gluconic acid were identified in both chestnut bee pollen samples. Glycosylated phenolic acid (caffeic acid-hexoside) was detected only in the Turkish bee pollen sample. To the best of our knowledge, this is the first report on isorhamnetin-(hexosyl)hexoside, isorhamnetin-acetylhexoside, isorhamnetin-(pentosyl-deoxyhexosyl)hexoside and caffeic acid-hexoside in chestnut bee pollen. This is also the first report on isorhamnetin-(pentosyl-deoxyhexosyl)hexoside and caffeic acid-hexoside in any bee products.

High-performance thin-layer chromatography (HPTLC) is a cost-effective method for the separation of small molecules, such as active pharmaceutically ingredients. The method can be used without sophisticated equipment. For example, the detection and quantification of colored compounds on an HPTLC plate can be performed with a CCD camera. For noncolored compounds, a new dipping solution for the generation of chemiluminescence on an HPTLC plates is presented. In combination with a charge-coupled diode (CCD) camera, this can be used as a universal detection system. The efficiency of this new staining reagent is demonstrated by the detection of trimethoprim and sulfamethoxazole from a fixed-dose combination in a ratio of 1:5.

The combination of trimethoprim and sulfamethoxazole as a fixed-dose combination in the ratio 1:5 is known as cotrimoxazole. It is used as antibiotic to treat a variety of bacterial infections. Cotrimoxazole is part of the World Health Organization’s list of essential medicines. Cotrimoxazole is an example of a drug that was partially unavailable in Germany during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic and the Ukraine war. The dependency on foreign sources of medicines is well known in Europe and resulted in the Pharmaceutical Strategy for Europe 2020, a strategy concept “will support the competitiveness and innovative capacity of the EU’s pharmaceutical industry”. High-performance thin-layer chromatography (HPTLC) is a cost-effective method for quantifying pharmaceutically active compounds. Diode-array detection (DAD) in conjunction with HPTLC can simultaneously detect ultraviolet‒visible (UV‒VIS) and fluorescence spectra directly from the plate. Visualization as a contour plot helps to identify the optimal wavelengths for compound quantification and reduce uncertainty in the determination. The quantification of trimethoprim and sulfamethoxazole is presented in a case study that highlights the key aspects for HPTLC quantification of pharmaceutical fixed-dose combinations with minimal uncertainty. HPTLC‒DAD allows quantification of trimethoprim and sulfamethoxazole with a required relative standard deviation of less than 2.5%.

Abstract

Thin-layer chromatography (TLC) coupled with bioassays has proven effective for detecting bioactive compounds in complex samples. In this study, a TLC enzyme-inhibition assay was developed for the detection of α-glucosidase inhibitors. The basic principle of the method involves the enzymatic hydrolysis of the substrate (2-naphthyl-α-d-glucopyranoside), resulting in the formation of β-naphthol that is subsequently reacted with Fast Blue B salt to produce a diazonium dye, resulting in a purple background. Assay development involved the utilization of enzyme gel entrapment, with either agar (over normal-phase plates) or poloxamer (over reversed-phase plates), and the optimization of key parameters including the substrate and enzyme concentrations, derivatization reagent concentrations, buffer type and pH, and plate type. The results showed good linearity within a range of 0.250–2.0 μg for the positive control, acarbose, with a coefficient of determination (r²) of 0.99. Detection and quantification limits were 0.060 μg and 0.199 μg, respectively. To address potential false positive results arising from secondary reactions with the reagents used, a nonenzymatic assay was conducted. In this control assay, the enzyme was replaced by the reaction product (β-naphthol). The developed TLC gel-overlay autographic method was able to detect the α-glucosidase inhibitor chlorogenic acid in a yerba mate extract.

Two accurate and efficient reversed-phase methods, one by high-performance thin-layer chromatography with ultraviolet‒visible detection (RP-HPTLC‒UV/VIS) and the other by high-performance liquid chromatography with diode array detection (RP-HPLC‒DAD), for the simultaneous determination of eight synthetic food dyes (Tartrazine, Ponceau 4R, Sunset yellow FCF, Allura red AC, Brilliant blue FCF, Carmoisine, Quinoline yellow, and Patent blue V) in drinks with simple pretreatment were developed and applied to analyze some alcoholic and soft drinks. Detection was performed in the visible range in both cases at wavelengths (nm) of maximum absorbance (420 yellow, 500 red, or 630 blue), depending on the color of each dye. Both developed methods were validated for selectivity, linearity, limit of detection (LOD), limit of quantification (LOQ), intra- and interday precision, and recovery, with good results. The RP-HPTLC‒UV/VIS method showed linearity (R² > 0.998) in the 7–125 µg/mL calibration range, LOD of 0.27–0.92 µg/mL, LOQ of 0.82–1.49 µg/mL, intraday precision (%RSD) of 2.57–7.57, interday precision (%RSD) of 4.21–9.31, and recovery for alcoholic and soft drinks of 86.87–99.87% and 82.70–96.67%, respectively. The RP-HPLC–DAD method showed linearity (R² > 0.999) in the 1.56–50.0 µg/mL calibration range, LOD of 0.11–0.29 µg/mL, LOQ of 0.32–0.90 µg/mL, intraday precision (%RSD) of 0.13–2.15, interday precision (%RSD) of 0.30–2.47, and recovery of 98.17–101.30% and 88.13–101.9% for alcoholic and soft drinks, respectively. These methods were successfully applied to analyze the 8 synthetic food dyes in 11 (3 alcoholic and 8 soft) drinks from the Romanian market to verify compliance with the label and the maximum permitted level of food dyes in drinks to ensure food safety.

Abstract

A simple, reliable high-performance thin-layer chromatography (HPTLC)‒densitometry method was developed and validated for the quantification of β-sitosterol, a significant bioactive phytosterol, in Manilkara zapota L. P. Royen leaves. This method is combined with mass spectroscopy (MS) for relevant structural identification, responsible for their antioxidant and antiinflammatory therapeutic potential. The pet ether (PE), chloroform (CH), ethyl acetate (EA), and hydro-ethanolic (HE) leaf extracts were prepared using the cold maceration technique. These extracts were screened for preliminary qualitative tests, and based on the screening results, secondary metabolites such as flavonoids, phenols, steroids, terpenoids, and tannins were further quantified. Antioxidant potential was assessed using 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2-azino-bis-(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS), ferric reducing antioxidant power (FRAP), and nitric oxide (NO) free radical scavenging assays. antiinflammatory activity was evaluated through protein denaturation and human red blood cell (HRBC) membrane stability methods. Additionally, an HPTLC method was developed and validated for β-sitosterol quantification. Among all the extracts, the ethyl acetate leaf extract exhibited the highest steroidal content [50% inhibitory concentration (IC₅₀) 2.92 ± 0.21 mg β-sitosterol equivalent (BSE)/g dry extract (DE)], flavonoid content [IC₅₀ 22.9 ± 0.25 mg quercetin equivalent (QE)/g DE], and phenolic content [IC₅₀ 103.8 ± 0.23 mg gallic acid equivalent (GAE)/g DE]. The ethyl acetate extract also demonstrated the highest efficacy against DPPH (IC₅₀ 16.35 ± 1.49), ABTS (IC₅₀ 17.52 ± 2.36), FRAP [41.32 ± 0.02 mg ascorbic acid (AA)/g crude extract], NO (IC₅₀ 17.13 ± 2.06), protein denaturation (IC₅₀ 31.75 ± 2.1), and HRBC membrane stability (IC₅₀ 24.8 ± 2.44). Correlation analysis further supported these findings. Furthermore, following the International Council for Harmonisation guidelines, an HPTLC method was developed, and 434.4 ng of β-sitosterol was quantified, with the highest content found in the ethyl acetate extract. Therefore, M. zapota leaf extract exhibits beneficial antioxidant and antiinflammatory effects due to its richness in phytosterols. This extract has the potential to be further explored as a therapeutic agent against inflammatory diseases.