Food Chem. 374, 131714 (2022). HPTLC of authentic samples (7 apricot and 5 pumpkin samples) and simulated adulterated products on silica gel with methanol - ethyl acetate - n-hexane 170:40:3. Fluorescence detection (FLD) at 366 nm. Carotenoids (hRF=18) were identified as chemical markers, being responsible for their differentiation in apricot and most pumpkins extracts. Partial least squares discriminant analysis (PLS-DA) proved to be a promising tool for predicting the amount of added pumpkin down to 2.5 %, with prediction errors as low as 20 %.

Journal Chromatogr A, 1641, 461727 (2021). HPTLc of an ethanolic maceration of Solidago gigantea roots (Asteraceae) on silica gel with n-hexane – isopropyl acetate – acetone 16:3:1, or n-hexane – isopropyl acetate – acetic acid 40:9:1. With the second mobile phase, acid residues had to be eliminated by 20 min automated drying or by 2 h incubation with potassium hydroxide in the opposite twin trough (followed by 15 min cold air streaming); this latter mobile phase allowed to obtain higher hRF values, but some butyrylcholinesterase (BChE) inhibiting activities were lost. The chromatograms were documented at UV 254 nm and 365 nm and white light before and after A) derivatization with vanillin – sulfuric acid reagent; B) enzymatic reaction by immersion into acetylcholinesterase, BChE, glucosidase and amylase solutions; C) Aliivibrio fischeri and Xanthomonas euvesicatoria bioassays, to detect activity against Gram-negative bacteria; D) Bacillus subtilis bioassay to detect activity against Gram-positive bacteria; E) a new antifungal assay with Fusarium avenaceum. For this assay, the chromatograms were immersed 6 s into the isolated mycelium suspension (diluted to OD600 0.4-0.8) and incubated in a vapor chamber at 21 °C for 48-72 h. Inhibition zones were indicated by the lack of visible white fungal hyphae. An aqueous solution of iodonitrotetrazolium (INT, 1 mg/ml) was sprayed on the plate to enhance the contrast (bright zones on a purple background). Benomyl (a benzimidazole fungicide) was used as positive control. Eight clerodane diterpenes (including kingidiol, hautriwaic lactone, and solidagoic acids A and B) were identified from six multipotent zones by bioassay-guided purification through preparative flash chromatography and HPLC, followed by HRMS and NMR, as well as by HPTLC hyphenated to quadrupole-orbitrap HRMS: A) by eluting with methanol (flow 100 µL/min) the compounds from the plate through the oval elution head of an interface of heated electro-spray ionization (spray voltage 3.5 kV, capillary temperature 270 °C, nitrogen as sheath and auxiliary gas, full scan in negative and positive ionization modes in m/z range 50-750); B) without eluent with a DART interface (Direct Analysis in Real-Time, needle voltage 4 kV, grid voltage 50 V, helium as gas, temperature 500 °C, full scan in positive ionization mode in m/z range 100-750).

J. Planar Chromatogr. 35, 43-50 (2022). HPTLC of curcumin (1) and cineole (2) on silica gel with n-hexane - ethyl acetate 12:7. Quantitative determination by absorbance measurement at 242 nm. The hRF values for (1) and (2) were 31 and 71, respectively. Linearity was between 1 and 6 µg/zone for (1) and 10 and 60 µg/zone for (2). Interday and intra-day precisions were below 2 % (n=3). The LOD and LOQ were 45 and 135 ng/zone for (1) and 34 and 102 ng/zone for (2), respectively. Recovery was between 93.3 and 98.8 % for (1) and 94.6 and 99.4 % for (2).

Journal of Chromatography B, 1184, 122956 (2021). Test for acetyl- and butyrylcholinesterase (AChE and BChE) inhibition without development of piperin (standard inhibitor of AChE and BChE) and ethanol – water (3:2) extracts of Iranian plants, on HPTLC silica gel prewashed twice with methanol – water 3:2 and dried 60 min at 120°C. After sample application the plate was immersed (speed 3.5 cm/s, time 2 s) into enzyme solution (6.6 units/mL AChE or 3.3 units/mL BChE in TRIS buffer 0.05 M, with bovine serum albumin 0.1 %, pH 7.8), incubation 25 min at 37°C and immersion (speed 3.5 cm/s, time 1 s) into chromogenic substrate solution (α-naphthyl acetate 0.1 % and Fast Blue salt B 0.2 % in ethanol – water, 1:2). Seven mobile phases were tested for the active samples. Best separation was obtained with toluene – ethyl acetate – formic acid – water 4:16:3:2 and with toluene – ethyl acetate – methanol 6:3:1. Before enzymatic assay, plates developed with acidic mobile phases were neutralized by spraying 3 mL citrate phosphate buffer (Na2HPO4 8 %, citric acid q.s. ad pH 7.5) followed by 10 min of automatic drying. Enzymatic assay was performed using a piezoelectric spraying device: a) pre-wetting by spraying 1 mL TRIS buffer (0.05 M, pH 7.8); b) spraying 3 mL of the enzyme solution; c) incubation 25 min in a humid box at 37°C; d) spraying 0.5 mL substrate solution; e) 5 min drying at room temperature, and then 10 min of automatic drying. By spraying, zone shift and zone diffusion, which occurred with plate immersion, were avoided. For development control, derivatization was done by piezoelectrically spraying 4 mL of sulfuric anisaldehyde reagent (anisaldehyde – sulfuric acid – acetic acid – methanol, 1:10:20:170), followed by heating 3 min at 110°C. For identification of zones of interest, direct elution with methanol from underivatized HPTLC plates through a TLC-MS interface directly to a MS. Identified zones were 3-O-acetyl-β-boswellic acid (triterpenoid) from Boswellia carteri gum-resin (Burseraceae), pimpinellin and psoralen (furocoumarins) from Heracleum persicum flowers (Apiaceae), oleuropein (seco-iridoid) from Olea europaea leaves (Oleaceae), harmine, harmaline, vasicine, deoxyvasine (alkaloids) from Peganum harmala seeds (Zygophyllaceae), costic acid (sesquiterpene) from Nardostachys jatamansi hypocotyl (Valerianaceae), elaidic, linoleic, palmitic, palmitoleic acids (fatty acids) from Pistacia atlantica fruits (Anacardiaceae).

J. Planar Chromatogr. 34, 377-401 (2021). HPTLC of flavonoid glycosides, phloroglucinol glycosides, monoterpene glycosides and monoterpene sugar esters, triterpenoids, phloroglucinols, monomeric phloroglucinols, dimeric phloroglucinols and phloroglucinol-terpene adducts in 15 eucalypts (13 Eucalyptus and 2 Corymbia) on silica gel with multiple mobile phases. Detection by spraying with anisaldehyde-sulfuric acid reagent. Zones were scanned from 200 to 700 nm.

J. Planar Chromatogr. 34, 345-351 (2021). HPTLC of Croton tiglium extracts on silica gel with toluene - ethyl acetate 9:1, toluene - ethyl acetate - methanol 6:4:1, toluene - ethyl acetate 3:2, toluene - ethyl acetate - methanol 4:6:1. Detection by spraying with anisaldehyde - sulfuric acid reagent. Identification of steroids and terpenoids on silica gel with toluene - ethyl acetate 9:1 and detection by spraying with the Liebermann‒Burchard reagent, followed by heating at 100 °C. Acidic compounds were analyzed on silica gel with toluene - ethyl acetate 9:1, followed by spraying with bromocresol green reagent. Coumarins were analyzed on silica gel with toluene - ethyl acetate - methanol 4:6:1, followed by spraying with alcoholic potassium hydroxide reagent and visualization under UV light at 366 nm.

Bioorg. Chem. 88, 102947 (2019). HPTLC of pentylcurcumene in the aerial part of Geophila repens on silica gel with benzene - methanol 3:1. Quantitative determination by absorbance measurement at 254 nm. The hRF value of pentylcurcumene was 50. Linearity was between 100 and 500 ng/zone. The intermediate precision was below 2 % (n=3). The LOD and LOQ were 16 and 49 ng/zone. Recovery was between 97.2 and 98.7 %.

Planta Med. 85(3), 195-202 (2019). The dichloromethane fraction of an ethanolic extract from Gloeophyllum odoratum sporocarp (Gloeophyllaceae, Basidiomycetes) was submitted to a multistep purification process (conventional, flash and supercritical fluid column chromatography). At each step, fractions were monitored on TLC silica gel with dichloromethane – methanol – water 40:4:1. Detection under white and UV light after derivatization with vanillin sulfuric acid 5 % in methanol and heating. Eight triterpenes were isolated for further identification: eburicodiol, gloeophyllins B and K, hydroxylanosterol, trametenolic acid B (all five from the lanostane type), gloeophyllins A and L (C‑nor-D-homoergosteroid type), and ergosterol peroxide (ergostane type).