Two-Dimensional High-Performance Thin-Layer Chromatography with Bioautography for Distinguishing Angelicae Dahuricae Radix Varieties: Chemical Fingerprinting and Antioxidant Profiling.

Angelicae Dahuricae Radix (ADR) holds a prominent place in traditional medicine for its remarkable antioxidative, anti-allergic, and antiproliferative capabilities. Recognized within the Korean Pharmacopoeia (KP 12th), Angelica dahurica (Hoffm.) Benth. and Hook.f. ex Franch. and Sav. (AD) and Angelica dahurica var. formosana (H. Boissieu) Yen (ADF) serve as the botanical origins for ADR. Differentiating these two varieties is crucial for the formulation and quality control of botanical drugs, as they are categorized under the same medicinal label. This research utilized two-dimensional high-performance thin-layer chromatography (2D-HPTLC) to effectively distinguish AD from ADF. Additionally, a quantitative analysis reveals significant differences in the concentrations of key active constituents such as oxypeucedanin, imperatorin, and isoimperatorin, with AD showing higher total coumarin levels. We further enhanced our investigative depth by incorporating a DPPH bioautography, which confirmed known antioxidant coumarins and unearthed previously undetected antioxidant profiles, including byakangelicin, byakangelicol, falcarindiol in both AD and ADF, and notably, 2-linoleoyl glycerol detected only in AD as an antioxidant spot. This comprehensive approach affords a valuable tool set for botanical drug development, emphasizing the critical need for accurate source plant identification and differentiation in ensuring the efficacy and safety of herbal medicine products.

Coding recognition of the dose-effect interdependence of small biomolecules encrypted on paired chromatographic-based microassay arrays.

The discovery of small biomolecules has suffered from the lack of a comprehensive framework to express the intrinsic correlation between bioactivity and the contribution from small molecules in complex samples with molecular and bioactivity diversity. Here, by mapping a sample's 2D-HPTLC fingerprint to microplates, paired chromatographic-based microassay arrays are created, which can be used as quasi-chips to characterize multiple attributes of chromatographic components; as the array differential expression of the bioactivity and molecular attributes of irregular chromatographic spots for dose-effect interdependent encoding; and also as the automatic-collimated array mosaics of the multi-attributes of each component itself encrypted by its chromatographic fingerprint. Based on this homologous framework, we propose a correlating recognition strategy for small biomolecules through their self-consistent chromatographic behavior characteristics. In the approach, the small biomolecule recognition in diverse compounds is transformed into a constraint satisfaction problem, which is addressed through examining the dose-effect interdependence of the homologous 2D code pairs by an array matching algorithm, instead of preparing diverse compound monomers of complex test samples for identification item-by-item. Furthermore, considering the dose-effect interdependent 2D code pairs as links and the digital-specific quasimolecular ions as nodes, an extendable self-consistent framework that correlates mammalian cell phenotypic and target-based bioassays with small biomolecules is established. Therefore, the small molecule contributions and the correlations of bioactivities, as well as their pathways, can be comprehensively revealed, so as to improve the reliability and efficiency of screening. This strategy was successfully applied to galangal, and demonstrated the high-throughput digital preliminary screening of small biomolecules in a natural product.

Separation and detection of apricot leaf triterpenes by high-performance thin-layer chromatography combined with direct bioautography and mass spectrometry.

Prunus armeniaca leaf extract was screened for antibacterial compounds by high-performance thin-layer chromatography (HPTLC)-direct bioautography using a Gram-positive Bacillus subtilis bacterium. Six chromatographic zones exhibited characteristic bioactivity. Five of them also appeared after derivatization with vanillin-sulfuric acid reagent and could be characterized with HPTLC-electrospray ionization (ESI)-mass spectrometry (MS), suggesting the presence of triterpenoids and the fatty acids linolenic and palmitic acid. To confirm the identification of triterpenoids an HPTLC method using in situ pre-chromatographic derivatization with iodine was developed to separate the closely related triterpenoids. After development, the iodine could be eliminated from the chromatogram (verified by HPTLC-MS), making it suitable for the B. subtilis assay. Ursolic acid, oleanolic acid, betulinic acid, corosolic acid, and maslinic acid were discovered for the first time as antibacterial components of P. armeniaca leaves. Their presence was proved also by 2D-HPTLC combined with intermediate in situ derivatization by iodine.

Benzyl isothiocyanate-modified α-lactalbumin - Two-dimensional high-performance thin-layer chromatography for analyzing modified peptides.

In complex food matrices, non-directed reactions between food proteins and secondary plant metabolites (SPM) are conceivable. In this study, the interaction between the bioactive metabolite from garden cress (Lepidium sativum) and selected Brassicaceae - benzyl isothiocyanate (BITC) - and the dairy protein α-lactalbumin (α-LA) was investigated. It was focused on monitoring the proteolytic degradation behaviour of unmodified and BITC-modified α-LA with two-dimensional high-performance thin-layer chromatography (2D-HPTLC). The two-dimensional approach of HPTLC offers high resolution in the separation of complex peptide mixtures and might enable differentiation of protein modifications. Based on the specific peptide patterns of native and modified peptides, conclusions can be drawn about differences in protein/peptide polarity, location of a modification, and digestibility. The aim was to characterize tryptically hydrolyzed unmodified and BITC-modified peptides using the 2D method and to investigate the influence of BITC modification of α-LA on polarity and digestibility. To determine the repeatability of peptide separation by 2D-HPTLC, the unmodified and BITC-modified protein hydrolyzates were separated six times. The absolute standard deviations between the retardation factors of the individual peptide spots varied between 0.52 and 4.79 mm for the x-coordinates and between 0.41 and 6.47 mm for the y-coordinates for all three samples. Here, the mean relative standard deviations ranged from 5.80 to 10.4% for the x-coordinates and from 5.91 to 18.3% for the y-coordinates. The results of the tryptic hydrolysis indicated that, depending on the concentration of BITC used, the modification sterically hinders the cleavage sites for the enzyme, resulting in a reduced digestibility. Covalent binding of the hydrophobic BITC altered the digestibility and polarity of the protein, leading to a difference in peptide patterns between the unmodified and modified α-LA. It was concluded that the reaction was undirected, resulting in a mixture of unmodified and modified peptides, and that elongated modified peptides were formed by BITC blocking of trypsin cleavage sites.

Two-dimensional high-performance thin-layer chromatography for the characterization of milk peptide properties and a prediction of the retention behavior - a proof-of-principle study.

High-performance thin-layer chromatography (HPTLC) is a suitable method for the analysis of peptides and proteins due to a wide selection of stationary and mobile phases and various detection options. Especially, two-dimensional HPTLC (2D-HPTLC) enables a higher resolution compared to one-dimensional HPTLC in the separation of complex peptide mixtures. Similar to 2D electrophoresis, characteristic peptide patterns can be obtained, allowing a differentiation of ingredients based on varying protein origins. The aim of this study was to evaluate 2D-HPTLC with regard to its suitability for the characterization of proteins/peptides and to verify whether it is possible to predict the retention behavior of peptides based on their properties. As models, the five most abundant milk proteins α-lactalbumin, ß-lactoglobulin, α-, ß-, and κ-Casein were used. In order to determine the repeatability of the peptide separation by 2D-HPTLC, each tryptic protein hydrolyzate was separated eight times. The standard deviations of the retardation factors for the separated peptides varied between 1.0 and 11.1 mm for the x-coordinate and 0.5-7.3 mm for the y-coordinate. It was also shown that after the chromatographic separation, peptides of the individual protein hydrolyzates were located in specific areas on the HPTLC plate, so that a clustering could be obtained for the whey proteins' as well as the caseins' hydrolyzates. For establishing correlations between the properties of the peptides and their retardation factors, 51 of 85 selected peptides were identified by matrix-assisted laser desorption/ionization time-of-flight tandem mass spectrometry (MALDI-TOF-MS/MS). On this basis, statistically significant correlations (α = 0.05) between the retardation factors of the peptides and their isoelectric points, as well as the percentage of anionic and non-polar amino acids in the peptides were established. Finally, it was investigated, whether the retardation factors for peptides can be predicted on the basis of a linear regression of the percentage of non-polar amino acids in a peptide. For this purpose, a mixture of artifical (synthetic) peptides (n = 14) was separated by 2D-HPTLC and the measured retardation factors were compared with the corresponding retardation factors calculated. Absolute deviations of 0.3-17.9 mm were obtained. In addition, the universal applicability of the method to other protein sources other than milk proteins (animal protein) was tested using a mixture of pea peptides (plant protein, n = 3) resulting in absolute deviations of 0.7-8.6 mm.

TLC profiling, nutritional and pharmacological properties of Siberian ginseng (Eleutherococcus senticosus) cultivated in Poland.

The chemical composition and pharmacological activity of E. senticosus cultivated in Poland were investigated. Studies included the assay of TPC and TFC, 2D-TLC identification of phenolic acids, HPTLC-detection of antioxidants, and antioxidative, antileukemic, anti-MMPs properties of E. senticosus. The ethanolic extracts from the roots, spring leaves, fruits, and the chloroform extract from the roots were tested. The richest in polyphenols are the fresh fruits (57.5 mg/g), while in flavonoids the spring leaves (27.4 mg/g). The antioxidant ability both in extracts and single phenolic constituents were checked out by the measurement of the DPPH radical scavenging activity, iron (II) chelating and lipid peroxidation inhibitory activity. Using HPTLC-DB test eleutherosides B and E1 have been found as the phenolic antioxidants. Thirty six percent of apoptotic cells have been observed in Jurkatt 45 line by the treatment with the chloroform extract from the roots. Only the chloroform extract from the roots and the ethanolic one from the dried fruits have shown the inhibitory activities against MMPs. It is noteworthy, that our studies have been done for the first time, and the plant material has come from another geographical zone (Poland) than native (Asia).