J. Planar Chromatogr. 33, 281-291 (2020). HPTLC of piperine in the fruit of Piper nigrum on silica gel with toluene - ethyl acetate - formic acid - methanol 15:15:4:1. Detection by dipping into anisaldehyde sulfuric acid reagent, followed by heating at 105 ºC for 5 min. Quantitative determination by absorbance measurement at 366 nm. The hRF value for piperine was 71. Linearity was between 100 and 500 ng. Intermediate precision was below 4 % (n=5). The LOD and LOQ were 72 and 218 ng, respectively. Average recovery was 98.8 %.

J. Planar Chromatogr. 33, 313-319 (2020). HPTLC of berberine (1) and rutin (2) on silica gel with n-hexane - ethyl acetate - glacial acetic acid - methanol 100:11:11:25. Quantitative determination by absorbance measurement at 241 nm. Antioxidant activity was determined by dipping into a 0.05 % DPPH solution followed by qualitative analysis at 366 nm. The hRF values for (1) and (2) were 67 and 47, respectively. Linearity was between 0.2 and 1.4 µg/zone for (1) and 2 and 14 µg/zone for (2). Intermediate precision was below 1 % (n=6). The LOD and LOQ were 0.2 and 2 µg for both (1) and (2), respectively. Average recovery was 94.9 % for (1) and 96.3 % for (2).

Phcog. Mag. 15, 440-448 (2019). HPTLC fingerprint of Psidium guajava on silica gel with toluene - ethyl acetate - formic acid 6:3:1. Qualitative determination under UV light at 254 and 450 nm. The hR_F values of common metabolites were 3, 18 and 42 in both aqueous and n‑butanol fractions.

Pharmacogn. Mag. 15, 256-260 (2019). HPTLC of piperine (1), asiaticoside (2), and withanolide A (3) in a polyherbal formulation of Piper longum, Centella asiatica, and Withania somnifera on silica gel with toluene - ethyl acetate 9:1 for (1), ethyl acetate - methanol - water 20:5:2 for (2) and toluene - ethyl acetate - formic acid 5:5:1 for (3). Detection by spraying with 5 % aqueous sulfuric acid, followed by heating at 110 °C. The developed plates were scanned at 254 nm, 366 nm and visible light. The hR_F values for (1) to (3) were 24, 71 and 77, respectively.

Pharmacogn. Mag. 16, 227-234 (2020). HPTLC fingerprint of Evolvulus alsinoides on silica gel with toluene - ethyl acetate - formic acid 14:6:1. Qualitative determination under UV light at 254 nm. Detection of antioxidant molecules using 2,2‑Diphenyl‑1‑picrylhydrazyl (DPPH) assay.

Pharmacogn. Mag. 15, 462-467 (2019). HPTLC of diosgenin in the rhizome of Costus speciosus on silica gel with n‑hexane - ethyl acetate 7:2. Detection by spraying with anisaldehyde‑sulfuric acid reagent. Quantitative determination by absorbance measurement at 440 nm. The hRF value for diosgenin was 23. Linearity was between 10 and 90 ng/zone. Intermediate precisions were below 5 % (n=2). The LOD and LOQ were 907 and 2751 ng/zone, respectively. Mean recovery was 100.3 %.

J. Sep. Sci. 43, 1431-1439 (2020). HPTLC fingerprint of flavan-3-ols and proanthocyanidins in five different Rosa species (R. canina, R. glutinosa, R. rubiginosa, R. multiflora, and R. spinosissima) on silica gel with n-propanol - water - acetic acid 4:2:1. Detection by dipping into 4-dimethylaminocinnamaldehyde solution (60 mg  in 13 mL of concentrated hydrochloric acid, which was made up to 200 mL with ethanol). Qualitative determination under UV light at 366 nm. The blue zones visible on the derivatized plate were used for further analysis using a TLC-MS interface. The flavanol and proanthocyanidin profiles of Rosa species depend on the geographical origin rather than on the cultivar and genotype.

J. Sep. Sci. 43, 1566-1575 (2020). HPTLC of phenyl myristate in the bark and leaves of Homalium nepalense on silica gel with chloroform - methanol 9:1. Quantitative determination by absorbance measurement at 254 nm. The hR_F value for phenyl myristate was 49. Linearity was in the range of 100-500 ng/5 µL. Intermediate precisions were below 1 % (n=5). The LOD and LOQ were 3 and 10 ng/5 µL, respectively. Average recovery was  between 90.1 and 95.6 %.