Non-target estrogenic screening of 60 pesticides, six plant protection products, and tomato, grape, and wine samples by planar chromatography combined with the planar yeast estrogen screen bioassay.

For non-target residue analysis of xenoestrogens in food, sophisticated chromatographic-mass spectrometric techniques lack in biological effect detection. Various in vitro assays providing sum values encounter problems when opposing signals are present in a complex sample. Due to physicochemical signal reduction, cytotoxic or antagonistic effect responses, the resulting sum value is falsified. Instead, the demonstrated non-target estrogenic screening with an integrated planar chromatographic separation differentiated opposing signals, detected and prioritized important estrogenic compounds, and directly assigned tentatively the responsible compounds. Sixty pesticides were investigated, ten of which showed estrogenic effects. Exemplarily, half-maximal effective concentrations and 17ß-estradiol equivalents were determined. Estrogenic pesticide responses were confirmed in six tested plant protection products. In food, such as tomato, grape, and wine, several compounds with an estrogenic effect were detected. It showed that rinsing with water was not sufficient to remove selected residues and illustrated that, though not usually performed for tomatoes, peeling would be more appropriate. Though not in the focus, reaction or breakdown products that are estrogenic were detected, underlining the great potential of non-target planar chromatographic bioassay screening for food safety and food control.

TLC-bioautography-guided identification and assessment of the antibacterial compounds from Feijoa sellowiana.

INTRODUCTION: A rapid procedure was developed for the targeted isolation and assessment of antibacterial compounds from plant-based materials. The effectiveness of this method was demonstrated using Feijoa sellowiana fruit peels. OBJECTIVE: The objectives of this study are as follows: develop an efficient procedure utilizing direct thin-layer chromatography (TLC)-bioautography to facilitate the targeting, identification, and purification of antibacterial compounds from plant extracts and delineate a method based on TLC-bioautography to determine the minimum effective dose (MED), alongside a colorimetric broth microdilution aided by high-performance liquid chromatography (HPLC) for evaluating the isolated active compounds. METHODOLOGY: Active compounds were targeted using TLC-bioautography against Staphylococcus aureus, and the identification was achieved through liquid chromatography-mass spectrometry (LC-MS) combined with Compound Discoverer. Purification was carried out using a customized separation method. The structure was confirmed using nuclear magnetic resonance (NMR) spectroscopy. The MED, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) were determined by two enhanced antibacterial assays. RESULTS: The main antibacterial compound identified was flavone. A TLC-bioautography-based antibacterial assay and a colorimetric broth microdilution assisted by HPLC were described as the enhanced antibacterial assay protocols. The MED, MIC, and MBC of flavone against S. aureus were found to be 4.2-5.2 µg/cm2, 225-275 µg/mL, and 550-650 µg/mL, respectively. Similarly, the MED, MIC, and MBC against Escherichia coli were determined to be 5.2-6.1 µg/cm2, 325-375 µg/mL, and 375-425 µg/mL, respectively. CONCLUSION: This study proposed an enhanced bioassay-guided separation technique for the isolation of antibacterial compounds from plants, along with two improved methods for assessing the antibacterial efficacy of insoluble or colored compounds.

Characterization of Secondary Metabolites of Leaf Buds from Some Species and Hybrids of Populus by Gas Chromatography Coupled with Mass Detection and Two-Dimensional High-Performance Thin-Layer Chromatography Methods with Assessment of Their Antioxidant Activity.

Poplars provide medicinal raw plant materials used in pharmacy. Leaf buds are one of the herbal medicinal products collected from poplars, having anti-inflammatory and antiseptic properties, but there are no quality standards for their production and there is a need to determine their botanical sources. Therefore, the chemical compositions of the leaf buds from four species and varieties of poplars, Populus balsamifera, P. × berolinensis, P. × canadensis 'Marilandica', and P. wilsonii were investigated and compared using gas chromatography coupled with mass detection (GC-MS) and two-dimensional high-performance thin-layer chromatography (2D-HPTLC) in order to search for taxa characterized by a high content of biologically active compounds and with a diverse chemical composition that determines their therapeutic effects. The presence of 163 compounds belonging to the groups of flavonoids, phenolic acids derivatives, glycerides, and sesquiterpenes was revealed. Moreover, the conditions for the separation and identification of biologically active compounds occurring in analyzed leaf buds using 2D-HPTLC were optimized and used for metabolomic profiling of the studied poplars, enabling their fast and simple botanical identification. The total phenolic (TPC) and flavonoid (TFC) contents of examined extracts were determined and their antioxidant capacities were estimated by spectrophotometric DPPH, ABTS, and FRAP assays. Based on the analysis of phytochemicals and antioxidant activity, P. × berolinensis buds were selected as the raw plant material for medicinal purposes with the highest content of active compounds and the strongest antioxidant activity.

TLC-Bioautography-Guided Isolation and Assessment of Antibacterial Compounds from Manuka (Leptospermum scoparium) Leaf and Branch Extracts.

A rapid procedure for the targeted isolation of antibacterial compounds from Manuka (Leptospermum scoparium) leaf and branch extracts was described in this paper. Antibacterial compounds from three different Manuka samples collected from New Zealand and China were compared. The active compounds were targeted by TLC-bioautography against S. aureus and were identified by HR-ESI-MS, and -MS/MS analysis in conjunction with Compound Discoverer 3.3. The major antibacterial component, grandiflorone, was identified, along with 20 ß-triketones, flavonoids, and phloroglucinol derivatives. To verify the software identification, grandiflorone underwent purification via column chromatography, and its structure was elucidated through NMR analysis, ultimately confirming its identity as grandiflorone. This study successfully demonstrated that the leaves and branches remaining after Manuka essential oil distillation serve as excellent source for extracting grandiflorone. Additionally, we proposed an improved TLC-bioautography protocol for evaluating the antibacterial efficacy on solid surfaces, which is suitable for both S. aureus and E. coli. The minimum effective dose (MED) of grandiflorone was observed to be 0.29-0.59 µg/cm2 against S. aureus and 2.34-4.68 µg/cm2 against E. coli, respectively. Furthermore, the synthetic plant growth retardant, paclobutrazol, was isolated from the samples obtained in China. It is hypothesized that this compound may disrupt the synthesis pathway of triketones, consequently diminishing the antibacterial efficacy of Chinese Manuka extract in comparison to that of New Zealand.

A simple thin-layer chromatography autography for the detection of peroxidase inhibitors.

Thin layer chromatography bioautographic assays facilitate the acquisition of activity-profile chromatograms and assist in pinpointing active constituents within complex mixtures by observing the inhibition halos they produce. Peroxidase is an enzyme implicated in the browning of different fresh cut vegetables and in several diseases. A peroxidase bioautographic assay was developed, based on enzyme agarose immobilization and the 2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt/radical cation (ABTS/ABTS·+) reporter system. Peroxidase was purified from potatoes with the aim to detect specific inhibitors. To reduce false positives, a non-enzymatic assay was also employed. The best results are obtained when a solution containing agarose, ABTS, hydrogen peroxide, and peroxidase in phosphate buffer is poured over the TLC plate (final concentrations: 0.031 mmoles/cm2, 0.239 µmoles/cm2, and 84.04 U/cm2) and incubated for 70 min. Limit of detection and quantification for quercetin is 0.16 µg and 0.54 µg, respectively. The developed system is able to detect quercetin in a Solidago chilensis Meyen extract and a peroxidase inhibitor in a Cichorium intybus L. extract. Therefore, the assay can detect inhibitory constituents in complex mixtures and differentiate between peroxidase inhibitors and ABTS·+ radical scavengers before any preparative fractionation, helping to take early operational decisions that can save time and resources. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-024-05946-w.

Antibacterial metabolites from an unexplored strain of marine fungi Emericellopsis minima and determination of the probable mode of action against Staphylococcus aureus and methicillin-resistant S. aureus.

Increasing prevalence of drug resistance has led researchers to focus on discovering new antibacterial agents derived from the marine biome. Although ample studies have investigated marine fungi for their bioactive metabolites with hopeful prospects in drug discovery. The present study was aimed to isolate/ identify potential antimethicillin-resistant Staphylococcus aureus compounds producing marine fungal strain from the Indian marine environment. The effective anti-MRSA compound was produced by a marine fungal strain designated as D6. The D6 strain exhibited 99% similarity to Emericellopsis minima based on 18S rRNA gene analysis. The culture conditions of E. minima D6 were optimized using nutritional and environmental parameters for enhanced anti-MRSA compound production. The agar well diffusion assay was used to determine the inhibition zone diameter of the crude extract against S. aureus and methicillin-resistant S. aureus, whereas the broth microdilution method was used to determine their minimum inhibitory concentration (MIC) active fraction. MIC values of the ethyl acetate fraction ranged from 0.8 to 1 mg/mL. SEM analysis revealed that the ethyl acetate fraction induces deep craters in methicillin-resistant S. aureus. Further, GC-MS analysis confirmed the occurrence of a total of 15 major compounds in active ethyl acetate fraction. Some of the major antibacterial compounds included cyclopentanol, isothiazole, benzoic acid, pyrrolo[1,2-a] pyrazine-1,4-dione, and hexahydro. These findings suggest that the marine fungi of E. minima can be a valuable candidate for prospecting antibiotics and an alternative complementary strategy for drug-resistant bacterial infections.

Antioxidant and Antimicrobial Evaluations of Moringa oleifera Lam Leaves Extract and Isolated Compounds.

Moringa oleifera, native to India, grows in tropical and subtropical regions around the world and has valuable pharmacological properties such as anti-asthmatic, anti-diabetic, anti-inflammatory, anti-infertility, anti-cancer, anti-microbial, antioxidant, and many more. The purpose of this study was to assess the free radical scavenging ability of two extracts and two pure compounds of M. oleifera Lam (hexane, ethanol, compound E3, and compound Ra) against reactive oxygen species, as well as their reducing power and antimicrobial activities. Bioautography antioxidant assay, 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydrogen peroxide (H2O2) free radical scavenging, and iron (iii) (Fe3+ to Fe2+) chloride reducing power assays were used to assess the extracts' qualitative and quantitative free radical scavenging activities. Furthermore, the extract and the compounds were tested against both Gram-positive and Gram-negative bacterial strains suspended in Mueller-Hinton Broth. The extracts and pure compounds showed noteworthy antioxidant potential, with positive compound bands in the Rf range of 0.05-0.89. DPPH), H2O2, and Fe3+ to Fe2+ reduction assays revealed that ethanol extract has a high antioxidant potential, followed by compound E3, compound Ra, and finally hexane extract. Using regression analysis, the half maximal inhibitory concentration (IC50) values for test and control samples were calculated. Compound Ra and ethanol exhibited high antioxidant activity at concentrations as low as ≈0.28 mg/mL in comparison with n-hexane extract, compound E3, ascorbic acid, and butylated hydroxytoluene standards. The radical scavenging activity of almost all M. oleifera plant extracts against DPPH was observed at 0.28 mg/mL; however, the highest activity was observed at the same concentration for ascorbic acid and butylated hydroxytoluene (BHT) with a low IC50 value of 0.08 mg/mL and compound Ra and ethanol with a low IC50 of 0.4 mg/mL, respectively. The extracts and pure compounds of M. oleifera have little to no antibacterial potential. M. oleifera extracts contain antioxidant agents efficient to alleviate degenerative conditions such as cancer and cardiovascular disease but have little activity against infectious diseases.

Chemical Composition, Antimicrobial and Antioxidant Bioautography Activity of Essential Oil from Leaves of Amazon Plant Clinopodium brownei (Sw.).

The Amazonian region of Ecuador has an extremely rich vegetal biodiversity, and its inhabitants have proven to have a millennial ancestral knowledge of the therapeutic and medicinal use of these resources. This work aimed to evaluate the chemical composition and biological activity of the essential oil obtained from the medicinal plant Clinopodium brownei (Sw.) Kuntze, which is widely spread in tropical and subtropical America. This species is traditionally used for treating respiratory and digestive diseases and is also known for its analgesic properties. Most of the molecules detected on a non-polar column were ethyl cinnamate 21.4%, pulegone 20.76%, methyl cinnamate 16.68%, caryophyllene 8.17%, ß-selinene 7.92% and menthone 7.51%, while those detected on a polar column were: pulegone 29.90%, ethyl cinnamate 18.75%, methyl cinnamate 13.82%, caryophyllene 10.0% and menthone 8.04%. The antioxidant activity by the assays, DPPH (2.2-diphenyl-1-picrylhydrazyl) and ABTS (2.2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)), shows the following values of 50% inhibition of oxidation, IC50 DPPH 1.77 mg/mL, IC50 ABTS 0.06 mg/mL, which, compared to the essential oil of Thymus vulgaris (natural positive control), turn out to be less active. Bioautography indicates that the molecules responsible for the antioxidant activity are derived from cinnamic acid: ethyl cinnamate and methyl cinnamate, and caryophyllene. The antimicrobial activity on the nine microorganisms evaluated shows bacterial growth inhibitory concentrations ranging from 13.6 mg/mL for Staphylococcus epidermidis ATCC 14990 to 3.1 mg/mL for Candida albicans ATCC 10231; the results are lower than those of the positive control. Bioautography assigns antimicrobial activity to caryophyllene. The results indicate a very interesting activity of the essential oil and several of its molecules, validating the traditional use and the importance of this medicinal plant from Ecuador.

Chemical Composition, Antioxidant Properties, and Antibacterial Activity of Essential Oils of Satureja macrostema (Moc. and Sessé ex Benth.) Briq.

Satureja macrostema is a plant that is located in various regions of Mexico and is used in a traditional way against illness. Essential oils (EOs) were obtained from leaves Satureja macrostema and the chemical composition was evaluated by gas chromatography-mass spectrometry (GC-MS). The antioxidant effect of the oil was assayed by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and by Trolox Equivalent Antioxidant Capacity (TEAC). In vitro antibacterial activity against Escherichia coli and Staphylococcus aureus was determined using a broth microdilution assay and thin layer chromatography-direct bioautography (TLC-DB) to identify active antibacterial compounds. The EOs analysis showed 21 compounds, 99% terpenes, and 96% oxygenated monoterpenes, with trans-piperitone epoxide (46%), cis-piperitone epoxide (22%), and piperitenone oxide (11%) as more abundant compounds. Likewise, S. macrostema EOs showed an antioxidant activity of DPPH = 82%, with 50% free radical scavenging (IC50) = 7 mg/mL and TEAC = 0.005, an antibacterial effect against E. coli of 73% inhibition, and 81% over S. aureus at dose of 100 µL of undiluted crude oil. The TLC-DB assay showed that the most active compounds were derived from piperitone. The comparison with other studies on S. macrostema shows variability in the compounds and their abundances, which can be attributed to climatic factors and the maturity of plants with similar antioxidant and antibacterial activities.

Bioassay-Guided Assessment of Antioxidative, Anti-Inflammatory and Antimicrobial Activities of Extracts from Medicinal Plants via High-Performance Thin-Layer Chromatography.

Natural products and their analogues have contributed significantly to treatment options, especially for anti-inflammatory and infectious diseases. Thus, the primary objective of this work was to compare the bioactivity profiles of selected medicinal plants that are historically used in folk medicine to treat inflammation and infections in the body. Chemical HPTLC fingerprinting was used to assess antioxidant, phenolic and flavonoid content, while bioassay-guided HPTLC was used to detect compounds with the highest antibacterial and anti-inflammatory activities. The results of this study showed that green tea leaf, walnut leaf, St. John's wort herb, wild thyme herb, European goldenrod herb, chamomile flower, and immortelle flower extracts were strong radical scavengers. Green tea and nettle extracts were the most active extracts against E. coli, while calendula flower extract showed significant potency against S. aureus. Furthermore, green tea, greater celandine, and fumitory extracts exhibited pronounced potential in suppressing COX-1 activity. The bioactive compounds from the green tea extract, as the most bioactive, were isolated by preparative thin-layer chromatography and characterized with their FTIR spectra. Although earlier studies have related green tea's anti-inflammatory properties to the presence of catechins, particularly epigallocatechin-3-gallate, the FTIR spectrum of the compound from the most intense bioactive zone showed the strongest anti-inflammatory activity can be attributed to amino acids and heterocyclic compounds. As expected, antibacterial activity in extracts was related to fatty acids and monoglycerides.

Phenolic and flavonoid contents and antioxidant activity of an endophytic fungus Nigrospora sphaerica (EHL2), inhabiting the medicinal plant Euphorbia hirta (dudhi) L.

Since endophytic fungi are pivotal sources of various bioactive natural compounds, the present study is aimed to investigate the antioxidant compounds of the endophytic fungus Nigrospora sphaerica isolated from a pantropical weed, Euphorbia hirta L. The fungus was fermented in four different media and each filtered broth was sequentially extracted in various solvents. Crude extracts collected from different solvents were subjected to phytochemical analysis and antioxidant activity. The total phenolic content (TPC) and total flavonoid content (TFC) were maximal in ethyl acetate crude extract (EtOAcE) of endophyte fermented in potato dextrose broth (PDB) medium (77.74 ± 0.046mgGAE/g and 230.59 ± 2.0 mgRE/g) with the highest 96.80% antioxidant activity. However, TPC and TFC were absent in hexane extract of Czapek Dox broth (CDB) medium exhibiting the lowest 4.63 ± 2.75% activity. The EtOAcE (PDB) showed a positive correlation between TFC and antiradical activity (R2 = 0.762; P < 0.05), whereas a high positive correlation was noticed between TPC and antioxidant activity (R2 = 0.989; P < 0.05). Furthermore, to determine the antioxidant activity, EtOAcE (PDB) was subjected to TLC bioautography-based partial purification, while GC/MS analysis of the partial purified extract was done to confirm the presence of phenolics along with antioxidant compounds that resulted in the detection of 2,4-Di-tert-butylphenol (13.83%), a phenolic compound accountable for the antioxidant potential. Conclusively, N. sphaerica is a potential candidate for natural antioxidant.

Explicating genetic diversity based on ITS characterization and determination of antioxidant potential in sea buckthorn (Hippophae spp.).

BACKGROUND: Sea buckthorn (Hippophae) is in the focus of interest mainly for its positive effects on health of both human and animal organisms. Due to the similarities in vegetative morphology, Hippophae species are often misidentified. Therefore, current study was focused on ITS based sequence characterization of sea buckthorn species and comparative biochemical evaluation for its antioxidant properties. METHODS AND RESULTS: DNA was extracted from leaf samples. Primer pairs K-Lab-SeaBukRhm-ITS1F1- K-Lab-SeaBukRhm-ITS1R1 and K-LabSeaBukTib- ITSF1- K-LabSeaBukTib-ITSR1 were used for PCR amplification. The purified PCR products were outsourced for sequencing. Phylogenetic tree was constructed based on neighbor-joining (NJ) method. Moreover, comparison of antioxidant potential of leaves of two sea buckthorn species (Hippophae rhamnoides and Hippophae tibetana) collected from different regions of Ladakh viz., Stakna, Nubra, DRDO Leh and Zanskar was determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azino-bis (3- ethylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS), and Total antioxidant capacity (TAC) by phosphomolybdenum assays. The present investigation led to the differentiation of two sea buckthorn species viz., H. rhamnoides and H. tibetana based on Internal Transcribed Spacer (ITS) region. Moreover, significant variation was observed in antioxidant potential of leaf extracts collected from different regions. CONCLUSIONS: Primary ITS sequence analysis was found to be powerful tool for identification and genetic diversity studies in sea buckthorn. Leaves of sea buckthorn have pronounced antioxidant properties and can be used in food, neutraceuticals and pharmaceutical industries etc. The current study will pave the way to discover small bioactive molecules responsible for antioxidant and anticancer properties in sea buckthorn.

Bioautography-guided HPTLC-MS as a rapid hyphenated technique for the identification of antimicrobial compounds from selected South African Combretaceae species.

INTRODUCTION: Many species within Combretaceae are traditionally used for the treatment of bacterial infections. The similarity in chemistry and antimicrobial activities within the family pose a challenge in selecting suitable species for herbal drug development. OBJECTIVE: This study aimed at rapidly identifying antimicrobial compounds using bioautography-guided high-performance thin-layer chromatography coupled with mass spectrometry (HPTLC-MS). METHODS: Hierarchical cluster analysis of ultra-performance liquid chromatography-mass spectrometry data from the methanol extracts of 77 samples, representing four genera within Combretaceae, was carried out. Based on groupings on the dendrogram, 15 samples were selected for bioautography analysis against four pathogens (Staphylococcus aureus, Bacillus cereus, Escherichia coli and Salmonella typhimurium). Active compounds were identified using HPTLC-MS analysis of bands corresponding to the inhibition zones. RESULTS: Bioautography revealed 15 inhibition zones against the four pathogens, with the most prominent present for Combretum imberbe. Analysis of the active bands, using HPTLC-MS indicated that flavonoids, triterpenoids and combretastatin B5 contributed to the antibacterial activity. The compounds corresponding to molecular ions m/z 471 (Combretum imberbe) and 499 (Combretum elaeagnoides) inhibited all four pathogens, and were identified as imberbic acid and jessic acid, respectively. Chemotaxonomic analysis indicated that arjunic acid, ursolic acid and an unidentified triterpenoid (m/z 471) were ubiquitous in the Combretaceae species and could be responsible for their antibacterial activities. CONCLUSION: Application of HPTLC-MS enabled the rapid screening of extracts to identify active compounds within taxonomically related species. This approach allows for greater efficiency in the natural product research workflow to identify bioactive compounds in crude extracts.

Development of a validated HPTLC-bioautographic method for evaluation of aromatase inhibitory activity of plant extracts and their constituents.

INTRODUCTION: Aromatase is a CYP450 enzyme that catalyses the conversion of androgens into oestrogens, where the decrease in the production of oestrogens aided by aromatase inhibitors is considered a target in post-menopausal breast cancer therapy. TLC-bioautography is a technique employed for combining chromatographic separations on TLC plates with bioassays. This is the first report to evaluate aromatase inhibitory activity using this technique. OBJECTIVES: The aim of this study is to develop and validate a new TLC-bioautographic method for determination of aromatase inhibitory activity in 14 plant extracts. Two quantitation methods, the peak area method and reciprocal iso-inhibition volume (RIV) method, were compared and investigated to attain reliable results. Factors affecting the enzymatic reaction (temperature, pH, enzyme and substrate concentrations … etc.) were also investigated to attain the optimum parameters. METHODOLOGY: TLC assisted by digital image processing was implemented for quantitative estimation of the aromatase inhibition of 14 plant extracts using chrysin as positive control. The fluorometric substrate dibenzyl fluorescein (DBF) was utilised for the assay, where inhibitory compounds were visualised as dark spots against a blue fluorescent background. Two software programs, Sorbfil® videodensitometer (in the peak area method) and ImageJ® (in the RIV method), were thoroughly validated using the International Council on Harmonisation (ICH) guideline and used for quantitation. RESULTS: The RIV method showed superiority over the peak area method in the quantitation results of the tracks with non-homogenous background with %RSD values of 0.98 and 1.49 compared with 2.86 and 3.58, respectively. Further, the methods allow the comparison of the activity of different unknown inhibitory compounds without the need for a reference or a positive control. CONCLUSION: Using the TLC-bioautographic method by image processing combined with the RIV quantitation method, simultaneous separation and quantitation of aromatase inhibitory components could be applied to estimate the relative activity of various plant extracts.

Antibacterial Effect of Lemongrass (Cymbopogoncitratus) against the Aetiological Agents of Pitted Keratolyis.

Pitted keratolysis (PK) is a bacterial skin infection mostly affecting the pressure-bearing areas of the soles, causing unpleasant symptoms. Antibiotics are used for therapy, but the emergence of antiobiotic resistance, makes the application of novel topical therapeutic agents necessary. The antibacterial effects of 12 EOs were compared in the first part of this study against the three known aetiological agents of PK (Kytococcus sedentarius, Dermatophilus congolensis and Bacillus thuringiensis). The results of the minimal inhibitory concentration, minimal bactericidal concentration and spore-formation inhibition tests revealed that lemongrass was the most effective EO against all three bacterium species and was therefore chosen for further analysis. Seventeen compounds were identified with solid-phase microextraction followed by gas chromatography-mass spectrometry (HS-SPME/GC-MS) analysis while thin-layer chromatography combined with direct bioautography (TLC-BD) was used to detect the presence of antibacterially active compounds. Citral showed a characteristic spot at the Rf value of 0.47, while the HS-SPME/GC-MS analysis of an unknown spot with strong antibacterial activity revealed the presence of α-terpineol, γ-cadinene and calamenene. Of these, α-terpineol was confirmed to possess an antimicrobial effect on all three bacterium species associated with PK. Our study supports the hypothesis that, based on their spectrum, EO-based formulations have potent antibacterial effects against PK and warrant further investigation as topical therapeutics.

Effect-Directed Profiling of Monofloral Honeys from Ethiopia by High-Performance Thin-Layer Chromatography and High-Resolution Mass Spectrometry.

Ethiopian honey is used not only as food but also for treatment in traditional medicine. For its valorization, bioactive compounds were analyzed in nine types of monofloral Ethiopian honey. Therefore, a non-target effect-directed profiling was developed via high-performance thin-layer chromatography combined with multi-imaging and planar effect-directed assays. Characteristic bioactivity profiles of the different honeys were determined in terms of antibacterial, free-radical scavenging, and various enzyme inhibitory activities. Honeys from Hypoestes spp. and Leucas abyssinica showed low activity in all assays. In contrast, others from Acacia spp., Becium grandiflorum, Croton macrostachyus, Eucalyptus globulus, Schefflera abyssinica, Vernonia amygdalina, and Coffea arabica showed more intense activity profiles, but these differed depending on the assay. In particular, the radical scavenging activity of Croton macrostachyus and Coffea arabica honeys, the acetylcholinesterase-inhibiting activity of Eucalyptus globulus and Coffea arabica honeys, and the antibacterial activity of Schefflera abyssinica honey are highlighted. Bioactive compounds of interest were further characterized by high-resolution mass spectrometry. Identifying differences in bioactivity between mono-floral honey types affects quality designation and branding. Effect-directed profiling provides new insights that are valuable for food science and nutrition as well as for the market, and contributes to honey differentiation, categorization, and authentication.

Rapid Screening of Lipase Inhibitors from Ophiopogonis Radix Using High-Performance Thin Layer Chromatography by Two Step Gradient Elution Combined with Bioautographic Method.

In this study, a high-performance thin layer chromatography (HPTLC) method by two step gradient elution with two mobile phases was developed for the simultaneous analysis of seven constituents in Ophiopogonis Radix. The chromatography was performed on silica gel 60 F254 plate with dichloromethane-methanol-ethyl acetate-water (70:25:12:3, v/v/v/v) and dichloromethane-methanol (300:1, v/v) as the mobile phase for two step gradient elution. Then, the HPTLC profiles were observed after derivatization with 10% sulfuric acid in ethanol solution. The obtained HPTLC images were further analyzed by chemometric approaches and the samples could be clustered based on regions and/or growth years, which were two important factors affecting the constituents in Ophiopogonis Radix. Furthermore, five compounds including ophiopogonin D, ophiopojaponin C, ophiopogonin D', ophiopogonin C' and methylophiopogonanone B were screened as potential lipase inhibitors from Ophiopogonis Radix by the HPTLC-bioautographic method. The binding modes and interactions between the five compounds and lipase were further explored by molecular docking analysis. The developed HPTLC method could be used for quality control of Ophiopogonis Radix and screening of the potential lipase inhibitors.

Thin-Layer Chromatography (TLC) in the Screening of Botanicals-Its Versatile Potential and Selected Applications.

The aim of this paper is to present a comprehensive overview of the main aims and scopes in screening of botanicals, a task of which thin-layer chromatography (TLC) is, on an everyday basis, confronted with and engaged in. Stunning omnipresence of this modest analytical technique (both in its standard format (TLC) and the high-performance one (HPTLC), either hyphenated or not) for many analysts might at a first glance appear chaotic and random, with an auxiliary rather than leading role in research, and not capable of issuing meaningful final statements. Based on these reflections, our purpose is not to present a general review paper on TLC in screening of botanicals, but a blueprint rather (illustrated with a selection of practical examples), which highlights a sovereign and important role of TLC in accomplishing the following analytical tasks: (i) solving puzzles related to chemotaxonomy of plants, (ii) screening a wide spectrum of biological properties of plants, (iii) providing quality control of herbal medicines and alimentary and cosmetic products of biological origin, and (iv) tracing psychoactive plants under forensic surveillance.

Studies on the Polyphenolic Composition and the Antioxidant Properties of the Leaves of Poplar (Populus spp.) Various Species and Hybrids.

The chemical composition in terms of flavonoid and salicylic compounds of leaves from 6 species and 3 hybrids of poplars (Populus) was identified with the use of TLC and HPLC-DAD/ESI-MS methods. Chromatographic analyses were carried out with 21 standard compounds including salicylic compounds (2), phenolic acids (3) and flavonoids (16). Moreover, on the basis of the obtained chromatographic data from the HPLC-DAD/ESI-MS and TLC separations, the presence of salicortin, tremulacin and chlorogenic acid was confirmed, depending on the analyzed poplar species or hybrid. The content of salicylic compounds was determined by HPLC-UV method and expressed on salicin as free and total fraction. Total flavonoid content was determined by spectroscopic method as quercetin equivalent. Significant qualitative and quantitative differences in the chemical composition of the analyzed leaves were demonstrated. The highest concentration of flavonoids (8.02 mg/g) was found in the leaves of Populus nigra, while the highest content of salicylic compounds (47.14 mg/g) was found in the leaves of P.×berolinensis. The antioxidant and xanthine oxidase inhibition properties of extracts from poplar leaves were investigated by TLC bioautography. It has been shown that the richest set of compounds with antioxidant properties are present in the leaves of P. alba, P.×candicans and P. nigra.

An Evolving Technology That Integrates Classical Methods with Continuous Technological Developments: Thin-Layer Chromatography Bioautography.

Thin-layer chromatography (TLC) bioautography is an evolving technology that integrates the separation and analysis technology of TLC with biological activity detection technology, which has shown a steep rise in popularity over the past few decades. It connects TLC with convenient, economic and intuitive features and bioautography with high levels of sensitivity and specificity. In this study, we discuss the research progress of TLC bioautography and then establish a definite timeline to introduce it. This review summarizes known TLC bioautography types and practical applications for determining antibacterial, antifungal, antitumor and antioxidant compounds and for inhibiting glucosidase, pancreatic lipase, tyrosinase and cholinesterase activity constitutes. Nowadays, especially during the COVID-19 pandemic, it is important to identify original, natural products with anti-COVID potential compounds from Chinese traditional medicine and natural medicinal plants. We also give an account of detection techniques, including in situ and ex situ techniques; even in situ ion sources represent a major reform. Considering the current technical innovations, we propose that the technology will make more progress in TLC plates with higher separation and detection technology with a more portable and extensive scope of application. We believe this technology will be diffusely applied in medicine, biology, agriculture, animal husbandry, garden forestry, environmental management and other fields in the future.