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 Chromatogr. A, 1652, 462377 (2021). Samples were vanilla tinctures, water − ethanol − ethyl acetate 1:1:1 extracts of vanilla-flavored food products and of natural Vanilla sp. (Orchidaceae) pods, oleoresin, paste and powders, as well as calibration standards of vanillin (1) and ethylvanillin (2). HPTLC on silica gel with n-hexane – ethyl acetate 1:1 for profiling, 3:2 for quantification. Other mobile phases were also tested and given in the supplement. Compounds (1) and (2) (hRF 68 and 82, respectively) were quantified by absorbance densitometry (at maximal wavelength 310 nm, deuterium lamp, scanning speed 10mm/s). Contents were found to be between 1 μg/g and 36 mg/g for (1) and null for (2) except in one tincture (62 µg/mL). Derivatizations performed for five assays: A) to detect radical scavengers, immersion (speed 3 cm/s, time 5 s) into DPPH• (0.5 mM in methanol), followed by drying for 90 s at room temperature and 30 s at 60 °C; B) to detect activity against Gram-negative bacteria, immersion (speed 2 cm/s, time 3 s) into Aliivibrio fischeri suspension, followed by recording the bioluminescence; C) to detect activity against Gram-positive bacteria, immersion (speed 3.5 cm/s, time 6 s) into Bacillus subtilis, followed by incubation 2 h at 37 °C, immersion in MTT solution, incubation for 30 min at 37 °C and heating for 5 min at 50 °C; D) to detect acetylcholinesterase (AChE) inhibitors, immersion (speed 2.5 cm/s, time 2 s) into AChE solution (666 units in TRIS buffer 0.05M, with bovine serum albumin 0.1 %, pH 7.8), incubation for 25 min at 37 °C and immersion into substrate solution (α-naphthyl acetate 0.1 % and Fast Blue salt B 0.18 % in ethanol – water, 1:2; E) to detect tyrosinase inhibitors, spraying with enzyme solution (400 unit/mL, in phosphate buffer 0.02 M, pH 6.8), followed by 2 min drying, immersion into substrate levodopa (18 mM in phosphate buffer, pH 6.8), 10 min incubation at room temperature and drying. For identification, zones of interest were transferred with methanol from underivatized HPTLC layer through a TLC-MS interface and a filter frit directly to a Quadrupole-Orbitrap MS (heated electrospray ionization, probe heater at 270°C, spray voltage 3.5kV, lock masses acetic acid for negative, dibutyl phthalate for positive ionization, mode full HR-MS scan in m/z range 50–750). Afterwards, the following substances assigned by MS were confirmed by using HPTLC comparison with standards: (1) and (2), vanillyl alcohol, vanillic acid, ethyl vanillyl ether, coumarin, 4-hydroxybenzoic acid, 4-methoxybenzoic acid, 4-hydroxybenzaldehyde, 4-allyl benzoic acid, oleamide, triacetin.

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, 419-426 (2021). HPTLC of brazilin on silica gel with chloroform - acetone - formic acid 8:4:1. Detection by exposure to ammonia vapor, followed by spraying with aluminum chloride. Quantitative determination by absorbance measurement at 508 nm. Linearity was between 0 to 6 μg. Intermediate precisions were below 3 %. Recovery was between 100 and 105 %.

J. Planar Chromatogr. 34, 315-322 (2021). HPTLC of quercetin (1) and isorhamnetin (2) in the fruits of Hippophae rhamnoides on 3 % sodium acetate silica gel with dichloromethane - ethyl acetate - formic acid 7:3:1. Detection by spraying with 1 % ethanol solution of aluminum trichloride. Quantitative determination by absorbance measurement at 390 nm. The hRF values for (1) and (2) were 48 and 64, respectively. Linearity was between 60 and 420 ng/µL for (1) and 40 and 440 ng/µL for (2). The intermediate precision was below 5 % (n=6). LOD and LOQ were 50 and 165 ng for (1) and 50 and 167 ng for (2). Recovery was between 97.1 and 103.4 % for (1) and 98.1 and 103.9 % for (2).

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.

J. Planar Chromatogr. 34, 337-343 (2021). HPTLC of quercetin in the leaves of Coriandrum sativum on silica gel with formic acid - ethyl acetate - toluene 1:4:5. Quantitative determination by absorbance measurement at 254 nm. The hRF value for quercetin was 50. Linearity was between 20 and 1000 ng/zone. LOD and LOQ were 15 and 44 ng/zone, respectively. Intermediate precisions were below 2 % (n=3). Recovery was between 97.0 and 98.0 %.

J. Planar Chromatogr. 34, 307-313 (2021). HPTLC of gallic acid (1), orientin (2) and orientin-2″-O-β-l-galactoside (3) in Chinese medicine antibacterial gels on silica gel with dichloromethane - butanone - methanol - formic acid 60:5:20:6. Quantitative determination by absorbance measurement at 280 nm. The hRF values for (1) to (3) were 37, 51 and 65, respectively. Linearity was between 89 and 785 ng/zone for (1), 82 and 575 ng/zone for (2) and 26 and 209 ng/zone for (3). Intermediate precisions were below 3 % (n=6). Recovery ranged 95.6-103.3 % for (1), 95.4-104.6 % for (2) and 95.1-104.1 % for (3).