J. AOAC Int. 102, 726-733 (2019). HPTLC of different parts of Alpinia offcinarum on silica gel with n-hexane - ethyl acetate - acetic acid 6:1:1. Antioxidant activity analysis by spraying with methanolic 0.04 % 2,2-diphenyl-1-picrylhydrazyl (DPPH*) radical reagent, followed by densitometric detection at 535 nm. Zones were scraped from HPTLC plates and further analyzed by electrospray ionization quadrupole time-of-flight tandem mass spectrometry (ESI-Q-TOF-MS/MS). The method allowed the identification of three antioxidant compounds: (5R-hydroxy-7-(4-hydroxy-3-methoxyphenyl)-1-phenyl-3-heptanone, kaempferide, and galangal with hRF values of 21, 33 and 40, respectively.

J. Liq. Chromatogr. Relat. Technol. 32, 41-46 (2019). HPTLC of flavonoids apigenin, luteolin, chrysin, myricetin, prunin (or naringenin 7-O-glucoside), nicotiflorin (or kaempferol 3-O-rutinoside), rutin (or quercetin 3-O-rutinoside), quercetin 3-O-glucopyranoside, luteolin 7-O-glucoside, isovitexin (or apigenin-6-C-glucoside), apigenin-7-O-glucoside, naringenin, hesperetin, flavone, kaempferide, kaempferol, naringin, hesperidin, quercetin dihydrate and quercetin in Caigua (Cyclanthera pedata Scrabs) on silica gel (1) or RP-18 (2) with ethyl acetate - water - formic acid 17:3:2 for (1) or 5 % formic acid in methanol - water 7:3 for (2). Detection by heating at 110 ºC, followed by dipping into Natural product reagent for 2 min. Qualitative identification under UV light at 254 nm and 366 nm. Flavonoids were further analyzed by HPTLC–MS/(MSⁿ). 

Planta Med. 83(14/15), 1233-1241 (2017). HPTLC of standards and methanolic extracts of L. cardiaca, L. japonicus and L. sibiricus (Lamiaceae) acidified with formic acid on silica gel with ethyl acetate – acetic acid – formic acid – water 100:11:11:26, in an automatic development chamber with 48 % humidity (20 min presaturation). Detection under white and UV light, before and after immersion in 1) anisaldehyde – sulphuric acid (followed by heating) for the detection of iridoids; 2) natural product reagent A for phenylpropanoids; 3) modified Dragendorff reagent (bismuth oxynitrate 0.17 %, sulfuric acid 3.5 %, glacial acetic acid 2 %, potassium iodide 4 %) for alkaloids. Ajugoside (hR_F 29) and verbascoside (hR_F 53) were found in L. cardiaca and L. sibiricus, but absent in L. japonicus. The opposite was true for leonurine (hR_F 52), whereas stachydrine (hR_F 14) was found in the three species. This method allows to distinguish L. japonicus from the other species, which have to be distinguished from each other through morphology.

J. Planar Chromatogr. 32, 103-108 (2019). HPTLC of ursolic acid (1), β-sitosterol (2), lupeol (3) and quercetin (4) in the aerial parts of Ichnocarpus frutescens on silica gel with toluene - ethyl acetate - formic acid 80:20:1. Quantitative determination by absorbance measurement at 500 nm for (1), 550 nm for (2), 650 nm for (3) and 310 nm for (4). The hRF values for (1) to (4) were 66, 70, 75 and 42, respectively. Linearity was between 100 and 600 ng/zone for (1) to (4). The intermediate precision was below 2 % (n=3). The LOD and LOQ were 60 and 182 ng for (1), 80 and 242 ng for (2), 50 and 151 ng for (3) and 45 and 137 ng for (4), respectivley. Recovery rate was between 96.9 and 100.1 % for (1) to (4).

J. Planar Chromatogr. 32, 121-126 (2019). HPTLC of quercetin (1), rutin (2), and
gallic acid (3) in the aerial parts of Amaranthus tricolor on silica gel with toluene - ethyl acetate - formic acid 7:5:1. Quantitative determination by absorbance measurement at 254 nm. The hRF values for (1) to (3) were 49, 14 and 28, respectively. Linearity was between 200-800 ng for (1), 200-500 ng for (2) and 200-600 ng for (3). The intermediate precision was below 1 % (n=6). The LOD and LOQ  were 22 and 68 ng/zone for (1), 14 and 55 ng/zone for (2) and 16 and 52 ng/zone for (3), respectively. Recovery was between 99.0 and 99.9 % for (1), 98.4 and 99.3 % for (2) and 99.1 and 99.8 % for (3).

J. Planar Chromatogr. 32, 31-39 (2019). HPTLC of quercetin in the roots of Phoenix sylvestris on silica gel with toluene - ethyl acetate - formic acid 5:4:1. Quantitative determination by absorbance measurement at 254 nm. The hRF value of quercetin was 39. Linearity was between 50 and 250 ng/zone. The intermediate precision was below 2 % (n=5). The LOD and LOQ were 21 and 44 ng/zone, respectively. Recovery rate was 99.4 %.

J. Planar Chromatogr. 32, 41-46 (2019). HPTLC of ayapanin in the leaves of Ayapana triplinervis on silica gel with ether - ethyl acetate 3:2. Quantitative determination by absorbance measurement at 254 nm. The hRF value of ayapanin was 56. Linearity was between 200 and 1000 ng/zone. The intermediate precision was below 0.8 % (n=6). The LOD and LOQ for ayapanin were 54 and 169 ng/zone, respectively. Recovery rate was 99.7 % for ayapanin.

Planta Med. 83, 1011-1019 (2017). The subfractionation on silica gel column of a diethyl ether fraction of a hydromethanolic extract of Lamium album aerial parts was controlled by TLC on silica gel with ethyl acetate – formic acid – water 20:2:3. Detection was performed at UV light after derivatization with 1 % Natural Product Reagent A. From the last subfraction, caffeic acid and tiliroside were isolated. The same TLC monitoring was applied for the fractionation of the butanol fraction of the extract. Some fractions and their subfractions were purified on dextran gel (Sephadex LH-20), and monitored by TLC on silica gel with ethyl acetate – formic acid – acetic acid – water 100:11:11:26, with the same detection. These subfractions contained caryoptoside and other iridoids, glucomartynoside, lamiusides and other phenylpropanoid derivatives.