J. Chinese Trad. Patent Med. 44 (6), 1770-1772 (2022). Ganqingqinglan (Dracocephalum tanguticum Maxim.) is a traditional Tibetan medicinal plant, containing flavonoids, terpenes, polysaccharides. It has antihypoxic, antibacterial, antiviral, and hypoglycemic effects and is used as the main component in the traditional Tibetan medicine for the treatment of hepatitis and gastritis. For quality control, TLC of the plant extracts on silica gel (1) for oleanic acid, with toluene - ethyl acetate - glacial acetic acid 28:8:1, detection by spraying with 10 % sulfuric acid in ethanol and heating at 105 °C until the zones are clearly visualized, evaluation under UV 366 nm; (2) for chlorogenic acid, with toluene - methyl acetate - propanone - methanol - methyl acid 30:5:5:20:1, evaluation under UV 366 nm. The method was applied for the analysis of 18 batches of real life samples and proved to be simple, specific, reproducible, robust and well suitable for the purpose.

J. Ethnopharmacol. 317, 116831 (2023). Review of traditional uses, ethnopharmacology, chemical composition, pharmacological activities, and quality control of Glehnia littoralis. Methods and representative sample preparation procedures for analysis of markers in G. littoralis were described, including HPTLC for the analysis of markers such as falcarindiol, scopoletin, umbelliferone and isoimperatorin.

J. Ethnopharmacol. 318, 116900 (2024). HPTLC of gallic acid (1), quercetin (2), and ferulic acid (3) in the polyherbal formulation Sharbat-bazoori Motadil (SBM) on silica gel with toluene - ethyl acetate - formic acid 6:3:1. Quantitative determination by absorbance measurement at 254 nm. Linearity was in the range of 200-4000 ng/zone for (1) to (3). Intermediate precisions were below 3 % (n=3). LOD and LOQ were 18 and 54 ng/zone for (1), 17 and 52 ng/zone for (2) and 15 and 46 ng/zone for (3), respectively. Recovery was between 96.8 and 97.4 % for (1), 100.8 and 101.7 % for (2) and 101.6 and 102.6 % for (3).

J Pharmacogn Phytochem, 12(1), 159-167 (2023). TLC of methanolic Soxhlet extracts on silica gel with toluene – ethyl acetate – formic acid 16:4:1. Visualization under UV 254 nm and 366 nm. Two bands only (hRF values 10 and 45), observed with densitometric scanning at UV 366 nm, were present in Trianthema portulacastrum roots (Aizoaceae), whereas a different profile was observed with Boerhavia diffusa roots (Nyctaginaceae), which is sometimes substituted for T. portulacastrum.

J Pharm Bioallied Sci 15(Suppl.2), S948-S951 (2023). Sample was the ethyl acetate fraction of an ethanolic extract of Viola odorata aerial parts (Violaceae). Standards were coumarinic compounds: esculetin (1) and umbelliferone (2). TLC and HPTLC on silica gel with toluene – ethyl acetate – formic acid 5:4:1. Visualization under UV 254 nm and 366 nm; densitometric scanning at 366 nm. Both (1) and (2) were found in the extract (hRF values 30 and 53, respectively, in TLC). Alternative mobile phases were also tested (TLC only): toluene – ethyl acetate 1:1 (hRF values 47 and 68) and chloroform – methanol 97:3 (hRF values 20 and 41).

 J. Pharmacogn. Phytochem. 12(1), 6-14 (2023). TLC silica gel layers were used to monitor the purification through column chromatography (CC) of a chloroform fraction of the methanolic root bark extract of Rauvolfia vomitoria (Apocynaceae). Mobile phases were petroleum ether – ethyl acetate 4:1 (MP1), dichloromethane – methanol 20:1 (MP2), and dichloromethane – methanol 15:1 (MP3). Visualization under UV 254 nm. Preparative TLC on thicker silica gel was performed on two subfractions: (A) with dichloromethane – methanol 100:7 for the isolation of the methyl esters of eudesmic acid and of trimethoxycinnamic acid (hRF values 35 and 28, respectively, in MP1); (B) with MP2 for the isolation of an indole alkaloid: kumujan B (= 1-carbomethoxy-β-carboline, hRF value 40 in MP2). Other indole alkaloids were isolated through CC: ajmaline, mauensine and reserpine (hRF values 35, 13 and 47, respectively, in MP3).

J. Planar Chromatogr. 35, 603-608 (2022). HPTLC of berberine (1) and ursolic acid (2) in an Ayurvedic formulation on silica gel with chloroform - acetone - formic acid 12:7:1. Quantitative determination by absorbance measurement at 330 nm. The hRF values for (1) and (2) were 46 and 68, respectively. Linearity was between 200 and 1000 ng/zone for (1) and 500 and 2500 ng/zone for (2). Intermediate precisions were below 2 % (n=9). The LOD and LOQ were 91 and 175 ng/zone for (1) and 153 and 465 ng/zone for (2), respectively. Recovery was in the range of 98 and 102 % for (1) and (2).

Heliyon 7(2), e06116 (2021). Samples were a methanolic extract of a semi-solid ayurvedic conserve (ashwagandhadi lehyam) prepared with Withania somnifera roots (Solanaceae) and five other plants, as well as standards: withaferin A and withanolide A (= withaniol), two ergostane triterpene steroids with lactone cycle and epoxide. HPTLC on silica gel with toluene – ethyl acetate – formic acid 6:4:1. Visualization and densitometric scanning at UV 254 nm and 366 nm (deuterium lamps). Derivatization by immersion into vanillin – sulfuric acid reagent, followed by oven heating at 105 °C until optimal coloration. Documentation under white light and densitometry scanning at 540 nm (tungsten lamp). Both analytes (hRF 35 and 45 respectively) were shown at 254 nm and 540 nm (but not at 366 nm), in the standards and in the extract.