Biomed. Chromatogr. 21 (1), 94-100 (2006). Presentation of a post TLC developing technique to detect substances which can inhibit tyrosinase activity. The TLC plate is sprayed with tyrosinase and l-tyrosine solutions successively. A positive result is detected as white zone against a brownish-purple background. The method is suitable as a quick screening procedure for tyrosinase inhibitor detection, and as a guiding procedure for the isolation of tyrosinase inhibitors from mixtures or natural product extracts.

Science & Culture Jan.-Feb., 22-30 (2008). Isolation and identification of some unique chemical compounds is reported using chemical, chromatographic and spectroscopic methods such as GC-MS, HPTLC and HPLC. The presence of bio-organic molecules such as oxygenated dibenzo-a-pyrones (DBPs), their amino acyl conjugates (DCPs) and polyphenyl benzoquinones (PBQs) was observed in all the four samples of meteorites. HPTLC on silica gel with 1) n-butanol - acetone - acetic acid - water 7:7:2:4 for amino acids, detection with ninhydrine reagent and absorbance measurement at 610 nm; 2) n-butanol - acetic acid - water 3:1:2 for sugars, detection with p-anisidine reagent and absorbance measurement at 380 nm; 3) chloroform - methanol 9:1 for DBPs and absorbance measurement at 240 nm and 360 nm.

Abstract No. 9185, IHCB (2009). HPTLC of hydro alcoholic extracts of Berberis aristata on silica gel with benzene - ethyl acetate - diethyl amine 6:3:1. Detection by spraying with AlCl3 reagent (for estimation of flavonoids) or with Folin Ciocalteu reagent (for total phenolic content). The fingerprint profile was optimized using two different mobile phases: n-butanol - acetic acid - water 14:1:5 and n-propanol - formic acid - water 90:1:9. The extract showed 6 different spots and was found to contain 13.5 % w/w of berberin.

Rec. Nat. Prod. 3/4, 178-186 (2009). An HPTLC method has been reported for quantitative estimation of alpha-mangostin in fruit pericarp of Garcinia mangostana (Hypericaceae). HPTLC on silica gel with chloroform - methanol 9:1 in a saturated chamber (10 min). The plate was derivatized with anisaldehyde sulfuric acid reagent. Densitometric quantification at 382 nm. Alpha-mangostin was detected as a compact band with hRf value of 46. The method was linear in the range of 1-5 µg/band. The maximum yield of alpha-mangostin was obtained from the plant by hot extraction with methanol.

PHCOGJ 2(8), 211-215 (2011). TLC finger-print profiling of 4 cinnamomum species, C. malabatrum, C. sulphuratum, C. tamala and C. zeylanicum has been reported. The hexane extracts of the plants were separated on silica gel with toluene - ethyl acetate 8:1. Densitometric evaluation at 254 nm. Detection by dipping in vanillin-sulfuric acid reagent followed by heating at 105 °C and evaluation at 620 nm. The hRf value of eugenol was 69. The content of eugenol were higher in C. zeylanicum than in the other species. The fingerprint profile showed some other bands.

Acta Parasitologica 58(4), 615–618 (2013). HPTLC on silica gel (HLF plates with 19 scored channels of 9 mm width) for 1) neutral lipids with petroleum ether - diethyl ether - glacial acetic acid 80:20:1, detection by spraying with 5 % ethanolic phosphoric acid; and 2) polar lipids with chloroform - methanol - deionized water 65:25:4, detection by spraying with 10 % cupric sulfate in 8 % phosphoric acid. Quantitative determination by absorption measurement at 610 nm for neutral lipids and 370 nm for polar lipids. Polynomial regression via peak area.

Phytochem. Anal. 27, 5-12 (2015). TLC-bioautography (editors note: TLC-autography) of lipase inhibitors in the stems of Flammulina velutiper and Pleurotus eryngii and the roots of Panax quinquefolius on silica gel with chloroform - ethyl acetate - methanol - water 15:40:22:9. The plates were dipped in β-naphthyl myristate solution, followed by air-drying at room temperature and dipping into lipase solution (60 U/mL), followed by incubation at 37 °C for 20 min. After dipping in 1 mg/mL of Fast Blue B salt solution, the plates were incubated again. Detection at 606 nm. Relative lipase inhibitory activity was calculated as orlistat equivalents. LOD was 0.01 ng/zone for orlistat. The intermediate precision was below 4.9 % (n=3). Recovery was in the range of 92-105 %.

Marine Drugs 14(6), 108 (2016). A new, highly active alginate lyase (Cel32), isolated from the marine bacterium Cellulophaga sp. strain NJ-1, was incubated (10 mg/mL, 12-36 h, 30 °C, pH 7) with sodium alginate, related mannuronate and guluronate polymers and related oligosaccharides of different polymerisation degrees (PD 2-8), the reaction was stopped by boiling. TLC of the hydrolysates, purified by centrifuging and desalting, on unspecified layers with n-butanol – formic acid – water 4:6:1. Detection by spraying with ethanolic sulfuric acid 10 % and heating for 5 min at 130 °C. The enzyme was active on all substrates (except PD 2 and 3), cleaving them endolytically into oligomeric fragments (PD 2-4)._x000D_