PLoS Neglected Tropical Diseases 17(09), e0011646 (2023). Samples were extracts rich in sphingolipids obtained from Trypanosoma cruzi epimastigotes, or from Leishmania major promastigotes (Trypanosomatidae), or from Chlorocebus sp. kidney Vero cells (Cercopithecidae), all cell lines incubated 2h before the extractions with ceramide N-hexanoyl-D-erythro-sphingosine coupled to fluorescent NBD-amine group (NBD = nitrobenzoxadiazolyle). Dried extracts were resuspended in chloroform – methanol (1:1) before application on TLC silica gel layers. Development with chloroform – methanol – potassium chloride 0.25 % aqueous solution 11:9:2. Visualization under automated laser scanner. Three sphingolipids were detected due to the NBD fluorescent group: sphingomyelin (hRF 42) was present in Vero cells only (negative control), whereas the targeted inositol-phosphorylceramide (IPC, hRF 70), was present in both L. major (positive control) and T. cruzi wild-type. It was absent in T. cruzi cell lines knock-out (KO) for the IPC-synthase (IPCS) gene, but present again in the add-back cell-lines (obtained with plasmide transfection of the IPCS gene into KO cells). An unknown lipid (hRF 78) was detected in all T. cruzi samples.

PLoS ONE 18(10), e0292514 (2023). Samples were 8 glycolipids, either sialylated or not; the two main examples were monosialotetrahexosylganglioside (GM1) and gangliotetraosylceramide (= asialo-GM1 = ASGM1). TLC on silica gel with chloroform – methanol – water – acetic acid 300:200:30:1, followed by air-drying. Visualization of glycolipids by spraying 5-methylresorcinol solution (0.2 % in 2 M sulfuric acid), followed by 5 min heating at 110°C. For immunostaining, underivatized chromatograms were immersed into a blocking gel (1% gelatin, 1% polyvinylpyrrolidone and 1mM EDTA in phosphate-buffered saline solution (PBS)), followed by immersion into a solution of monoclonal (50 ng/mL) or polyclonal (1:1,000) anti-ASGM1 antibodies purposedly produced in rabbits. After 1h reaction at room temperature, the layers were washed thrice with T-PBS (0.05 % Tween 20 in PBS) and horseradish-peroxidase-conjugated anti-rabbit IgG (1:40,000) was added. After washing thrice with T-PBS, the TLC sheets were incubated in substrate solution (tetramethylbenzidine). Blue spots indicated the glycolipids bound by the antibody. In this TLC assay, each of the five monoclonal antibodies (as well as the polyclonal serum) was specific to ASGM1 (unsialylated), whereas in ELISA (enzyme-linked immunosorbent assay) at the same concentrations three of them displayed partial cross-reactivity towards GM1, GM3 or GD1b, which are sialylated glycolipids. 

PLoS ONE 18(11), e0294775 (2023). Sample was an Azadirachta indica seed extract (Meliaceae). TLC on silica gel with different mobile phases: (1) diethyl ether – methanol 49:1; (2) diethyl ether – acetone 2:1; (3) isopropanol – n-hexane 11:9; (4) dichloromethane – methanol – acetic acid 95:5:1. After 30 min hot air drying,detection under UV light. The hRF values of azadirachtin A (a limonoid) were 75, 42, 44, 55, respectively. Mobile phase (1) was therefore chosen as solvent for purification of azadirachtin A and for its quantification by Fourier transform infrared spectroscopy (FTIR).

PLoS ONE 18(11), e0295012 (2023). TLC on silica gel to monitor the synthesis of 15 new camphene-based thiosemicarbazones produced by the reaction of camphene thiosemicarbazide either with benzaldehydes, or with acetophenones, or with one of the following molecules: benzophenone, cinnamic aldehyde, ethyl pyruvate, furaldehyde, menthone, pyrrole carboxaldehyde or thiophene-carboxaldehyde. Development with n-hexane – ethyl acetate 3:7 in the case of benzaldehydes, except vanillin; or 7:3 for the vanillin derivative and all others, followed by visualization of products with resublimated iodine. The aldehyde used for compound 15 is in fact vanillin.

3 Biotech 13, 32 (2023). Samples were the products of transgalactosylation operated by β-galactosidase immobilized on modified carrageenan beads in a solution of lactose. Raffinose, a trisaccharide, was used as standard. TLC on silica gel with n-propanol – water 17:3. Detection of galacto-oligosaccharides by spraying naphthol reagent (50 mg α-naphtol in 95 mL ethanol and 5 mL sulfuric acid), followed by heating. The target zones from unsprayed layers were further extracted with methanol using a TLC-MS interface into a quadrupole MS (flow rate 0.2ml/min, positive and negative electrospray ionization (ESI), m/z range 10–1200). Galactose oligomers were found, from trimers to hexamers (heptamers were observed when the reaction time was beyond 3 hours).

J. AOAC Int. 106, 129-139 (2023). HPTLC fingerprint of Tinospora species on silica gel with chloroform - toluene - methanol - formic acid 35:20:10:1. Detection by spraying with vanillin sulfuric acid, followed by heating at 100 °C for 3 min. Further analysis by LC–ESI (electrospray ionization)-MS/MS.

J. AOAC Int. 106, 1598-1607 (2023). HPTLC bioautography of Rubia cordifolia on silica gel impregnated with kojic acid with toluene - ethyl acetate - formic acid 5:4:1. Antityrosinase activity by spraying with 2 mM L-tyrosine and incubated at room temperature for 10 min. The plate was the sprayed with tyrosinase solution (1 mL of mushroom tyrosinase enzyme (3333 units) in 10 mL PBS - sodium phosphate buffer solution, pH 6.8), followed by incubation at room temperature for 45 min. Clear white zones of tyrosinase enzyme inhibition allowed the detection of presence of active compounds. Further analysis by MS allowed the identification of purpurin with antityrosinase potential.

J. Liq. Chromatogr. Relat. Technol. doi:10.1080/10826076.2023.2284707 (2023). HPTLC of iridoids, coumarins, pharmaceutical drugs, flavonoids, triterpenes, sesquiterpenes, steroids, phospholipids and cannabinoids on silica gel with three complementary developing solvents (CDS) of different strength and selectivity. Detection by spraying with Fast Blue Salt B, followed by heating at 100 °C for 3 min. Other detection by spraying with the mixture NP/PEG 1:1, followed by drying for 2 min. Machine learning was applied by evaluating three regressor algorithms for their ability to predict the RF values of 178 chemicals in the low polarity developing solvent. RF values were correlated with polarity related properties such as the octanol/water partition coefficient (SlogP) or the topological polar surface area (TPSA).