J. Planar Chromatogr. 35, 439-451 (2022). HPTLC of withanoside IV (1), withanoside V (2), withaferin A (3), and kaempferol-based glucoside (4) in the roots and aerial parts of Withania somnifera on silica gel with ethyl acetate - chloroform - methanol - water 40:15:22:9. Detection of (1) to (3) by spraying with anisaldehyde sulfuric acid reagent, followed by heating at 100 °C for 3 min. Quantitative determination by absorbance measurement at 540 nm for (1) to (3) and 254 nm for (4). The hRF values for (1) to (4) were 33, 42, 62 and 21, respectively. Linearity was between 200 and 1000 ng/zone for (3) and (4) and 400 and 2000 ng/zone for (1) and (2). Interday and intra-day precisions were below 4 % (n=6). The LOD and LOQ were 180 and 544 ng/zone for (1), 215 and 652 ng/zone for (2), 170 and 516 ng/zone for (3) and 48 and 144 ng/zone for (4). Recovery was between 95.9 and 99.6 % for (1) and (4).

J. Planar Chromatogr. 35, 411-420 (2022). HPTLC of oleanolic acid (1), β‑sitosterol (2) and lupeol (3) in Urginea indica with toluene - ethyl acetate - methanol - acetone 35:10:1:1. Detection by dipping into aninsaldehyde sulfuric acid. Quantitative determination by absorbance measurement at 530 nm. The hRF values for (1) to (3) were 44, 55 and 68, respectively. Linearity was between 200 and 1000 ng/zone for (1) and (2) and 100 and 500 ng/zone for (3). Interday and intra-day precisions were below 4 % (n=3). Average recovery was 101.8 % for (1), 98.7 % for (2) and 100.2 % for (3).

J Chromatogr A, 1609, 460438 (2020). HPTLC of defatted hydro-methanolic extract of Anarrhinum pubescens (= A. duriminium) aerial parts (Plantaginaceae) on silica gel with chloroform – methanol 9:2. When intended for MS experiments, layers were previously washed twice with methanol – water 4:1 and heated 20 min at 110 °C. Derivatization by automatic piezoelectric spraying of anisaldehyde sulfuric acid reagent, followed by heating 4 min at 105 °C. Effect-directed analysis for acetyl-cholinesterase (AChE) inhibitors was performed by successive piezoelectric sprayings with TRIS buffer, with AChE solution and (after 30 min incubation at 37 °C) with naphthyl acetate and Fast Blue salt B solution. White inhibiting zones on purple background were documented under white light, and densitometry was measured by scanning in fluorescence mode at 500 nm. One of the active bands was eluted from untreated layer with methanol through the oval elution head of a TLC-MS interface pump, into a quadrupole-Orbitrap mass spectrometer using heated electrospray ionization (HESI); a full scan mass spectrum (m/z 50−750) in the positive ionization mode was recorded, as well as HRMS/MS data across a range of collision energies (10–50 V). The compound was identified as foliamenthoyl-cinnamoyl-antirrhinoside. It was applied with two other active antirrhinosides (iridoids), all isolated from the extract through column chromatography, on an HPTLC layer without migration and submitted to AChE assay; their activity was expressed as equivalency towards rivastigmine tartrate as positive control. 

J. Planar Chromatogr. 35, 169-179 (2022). HPTLC of arjungenin (1) and arjunetin (2) in the bark of Terminalia arjuna on silica gel with toluene - ethyl acetate - formic acid 5:4:1. Detection by spraying with 10 % solution of sulfuric acid dissolved in methanol. Quantitative determination by absorbance measurement at 420 and 475 nm for (1) and (2). The hRF values for (1) and (2) were 43 and 67, respectively. Linearity was between 100 and 1000 ng/zone for (1) and (2). The method facilitated the detection of traces amount of adulterants in herbal products.

J. Planar Chromatogr. 35, 139-151 (2022). HPTLC of diosgenin in Costus speciosus on silica gel with n-hexane - ethyl acetate 7:2. Detection by spraying with anisaldehyde  -sulfuric acid (0.5 mL anisaldehyde in 1 mL of 97 % sulfuric acid), followed by drying at 105 °C. Quantitative determination by absorbance measurement at 440 nm. The hRF value for diosgenin was 23. Linearity was between 0.1 and 0.7 µg/zone. The LOD and LOQ were 0.84 and 2.55 µg/zone. 

J. Planar Chromatogr. 35, 3-12 (2022). HPTLC of alisol B 23-acetate (1), alisol B (2), alisol A (3) and alisol C 23-acetate (4) in the rhizomes of Alisma orientale on silica gel with cyclohexane - ethyl acetate 1:1. The hRF values for (1), (4), (2) and (3) were 62, 42, 28 and 9, respectively Quantitative determination by absorbance measurement at 254 nm for (1) and 208 nm for (2), (3) and (4). Linearity was between 125 and 2000 μg/zone for (1) and 83 and 2000 μg/zone for (2), (3) and (4). Interday and intra-day precisions were below 1 % (n=3). Average recovery was 94.2 % for (1), 90.3 % for (2), 97.0 % for (3) and 90.2 % for (4).

J. Pharm. Biomed. Anal. 189, 113488 (2020). Various extracts from red alga Plocamium dilatatum (Plocamiaceae), green alga Codium fragile tasmanicum (Codiaceae) and brown algae Carpoglossum confluens (1), Cystophora platylobium (2) and C. retorta (3) (Sargassaceae), Ecklonia radiata (Lessoniaceae), Hormosira banksia (Hormosiraceae), Phyllospora comosa (4) (Seirococcaceae) were separated on HPTLC silica gel with n-hexane – ethyl acetate – acetic acid 70:27:3. Detection A) for antioxidant activity by spraying with methanolic DPPH solution, followed by waiting for 30 min at room temperature; B) for steroids and terpenes with anisaldehyde - sulfuric acid solution, followed by heating for 10 min at 110°C; C) for carbohydrates and polyols with thymol - sulfuric acid, followed by heating for 15-20 min at 120°C. Image-based evaluation in white light and UV 366 nm. The most active bands were also characterized by ATR-FTIR (= attenuated total reflectance – Fourier-transformed infrared) spectroscopy.

J. Food Sci. 85, 3183-3190 (2020). HPTLC of astragalosides standards (I-IV) in Pleurotus ostreatus on silica gel with trichloromethane - methanol - ethyl acetate - water 13:7:2:2. Detection by spraying with 10 % sulfuric acid in ethanol and visualization under IV light at 365 nm. The hRF values for (I) to (IV) were 71, 54, 34 and 31, respectively. Further analysis by mass spectrometry.