J. Liq. Chromatogr. Relat. Technol. https://doi.org/10.1080/10826076.2021.1939046 (2021). HPTLC of picroside-I (1), andrographolide (2) and silybin (3) in Picrorhiza kurroa (roots), Andrographis paniculata (aerial parts) and Silybum marianum (seeds), respectively, on silica gel with n-butanol - glacial acetic acid - water 6:1:3. Quantitative determination by absorbance measurement at 254 nm. The hRF values for (1) to (3) were 49, 68 and 89, respectively. Linearity was between 60 and 600 ng/zone for (1) to (3). The intermediate precision was below 2 %. The LOD and LOQ were 15 and 45 ng/zone for (1), 22 and 67 ng/zone for (2) and 26 and 78 ng/zone for (3), respectively. Recovery was between 99.7 and 103.7 % for (1), 99.7 and 101.1 % for (2) and 99.0 and 101.7 % for (3).

J. Food. Sci. 81, 2218-2223 (2016). HPTLC of Coreopsis tinctoria samples on silica gel with toluene - ethyl acetate - formic acid - water 9:20:6:3. DPPH bioautography assay by spraying with 0.04 % 2,2-diphenyl-1-picrylhydrazyl in methanol under dark conditions. Detection under UV light at 535 nm. The hRF values for the antioxidant compounds were 30 for flavanomarein, 37 for marein and chlorogenic acid, 45 for 5,7,3',5'-tetrahydroxyflavanone-7-O-glucoside, 62 for 3,5-dicaffeoylquinic acid and 76 for isookanin and okanin. 

Anal. Bioanal. Chem. 412, 6789-3809 (2020). HPTLC of Ginkgo biloba extracts on silica gel with ethyl acetate - acetic acid - formic acid - water 100:11:11:26 (1) or toluene - ethyl acetate - formic acid 7:3:1 (2). Detection under UV light at 366 nm or by spraying with  natural product reagent (NPR) and polyethylene glycol (PEG). The method allowed to distinguish between characteristic and uncharacteristic unfinished product samples based on the presence or absence of bands corresponding to caffeic acid, rutin, hyperoside, chlorogenic acid, and genistein standards.

J. Planar Chromatogr. 34, 173-181 (2021). HPTLC of caffeic acid (1), chlorogenic acid (2), quercetin (3), oleanolic acid (4), lupeol (5), betulinic acid (6), β-Sitosterol (7), campesterol (8) and ergosterol (9) in samples of Echinops echinatus on silica gel with toluene - ethyl acetate - formic acid - methanol 30:30:8:3 for (1) and (2), toluene - ethyl acetate - formic acid 5:4:1 for (3), toluene - methanol 9:1 for (4), petroleum ether - ethyl acetate - toluene 7:2:1 for (5) and (6), toluene - ethyl acetate 9:1 for (7) and toluene - methanol - formic acid for (8) and (9). Quantitative determination by absorbance measurement at 254 nm for (1) to (3), 540 nm for (4) to (6) and 530 nm for (7) to (9). The hRF values for (1) to (9) were 69, 80, 60, 30, 68, 55, 26, 67 and 75, respectively. Linearity was between 2 and 12 µg/mL for (1) to (9). Intermediate precision was below 2 % (n=6). The LOD and LOQ were 38 and 119 ng/zone for (1), 18 and 57 ng/zone for (2), 364 and 1100 ng/zone for (3), 11 and 32 ng/zone for (4), 40 and 123 ng/zone for (5), 15 and 46 ng/zone for (6), 8 and 23 ng/zone for (7), 52 and 159 ng/zone for (8) and 527 and 1598 ng/zone for (9), respectively. Recovery was between 95.7 and 99.6 % for (1) to (9). 

J. Planar Chromatogr. 34, 131-138 (2021). HPTLC of echioidin in Andrographis echioides on silica gel with chloroform - methanol 17:3. Quantitative determination by absorbance measurement at 266 nm. The hRF value for echioidin was 61. Linearity was between 200 and 1000 ng/zone. Intermediate precision was below 2 % (n=3). The LOD and LOQ were 11 and 34 ng/zone. Average recovery was 99.0 %.

J. Planar Chromatogr. 34, 61-69 (2021). HPTLC of quercetin (1), gallic acid (2), eugenol (3) and β-sitosterol (4) in Psidium guajava on silica gel with toluene - ethyl acetate - formic acid 7:3:1 for (1) and (2) and toluene - ethyl acetate - formic acid 18:2:1 for (3) and (4). Detection by spraying with vanillin reagent. Quantitative determination of (1) - (4) by absorbance measurement at 254 nm, 370 nm, 570 nm and 600 nm. The hRF values for (1) to (4) were 52, 28, 87 and 59, respectively. Linearity was between 1 and 5 µg/zone for (1) and 2 and 10 µg/zone for (2) to (4). Intermediate precision was below 5 % (n=3). The LOD and LOQ were 535 and 1621 ng/zone for (1), 1059 and 3210 ng/zone for (2), 1034 and 3134 ng/zone for (3) and 1059 and 3210 ng/zone for (3), respectively. Average recovery was 100.0 % for (1) to (4).

J. Planar Chromatogr. 34, 34-45 (2021). HPTLC of labiatenic acid (synonym: rosmarinic acid) (1), apigenin (2) and buddleoside (3) in Hyssopus officinalis on silica gel with dichloromethane - ethyl acetate - formic acid 6:5:1. Detection by spraying with 2 % aluminum trichloride ethanol solution, followed by heating until the zones were clear. Quantitative determination by absorbance measurement at 330 nm. The hRF values for (1) to (3) were 20, 36 and 59, respectively. Linearity was between 90 and 454 ng/zone for (1), 33 and 197 ng/zone for (2) and 20 and 120 ng/zone for (3). Intermediate precision was below 4 % (n=6). Average recovery was 101.3 % for (1), 99.8 % for (2) and 100.5 % for (3).

J. Planar Chromatogr. 34, 39-44 (2021). HPTLC of gallic acid (2) and quercetin (1) in Eclipta alba and Guiera senegalensis on silica gel with toluene - ethyl acetate - glacial acetic acid 6:3:1. Quantitative determination by absorbance measurement at 254 nm. The hRF values for (1) and (2) were 58 and 76. Linearity was between 200 and 2000 ng/zone for both (1) and (2). Intermediate precision was below 2 % (n=3). The LOD and LOQ were 3 and 10 ng/zone for (1) and 13 and 39 ng/zone for (2). Recovery was between 98.9 and 113.2 % for (1) and 100.8 and 113.7 % for (2).