J. Planar Chromatogr. 22, 293-296 (2009). TLC of verbascoside, forsythoside B, caffeoyl-malic acid and plant (Ballota nigra, B. hirsuta, and B. rupestris) extracts on silica gel with formic acid - acetic acid - water - ethyl acetate 15:15:36:134. Quantitative determination by fluorescence measurement at 395 nm. It was observed that amounts of phenylpropanoids in Ballota nigra leaves increase during the main and secondary flowering periods in June.

Abstract No. C-495, 61st IPC (2009). Screening of different phytoconstituents in a polyherbal tablet formulation. TLC of n-hexane, chloroform and methanol extracts of the tablets on silica gel with n-hexane - ethyl acetate 7:3; chloroform-methanol 9:1, and chloroform - glacial acetic acid - methanol - water 8:40:15:10. Evaluation under UV 254 nm as well as under UV 366 nm after spraying with different reagents: 20 % sulfuric acid, aniline-hydrogen phthalate reagent, anisaldehyde-sulfuric acid reagent, and vanillin-sulfuric acid reagent for the detection of piperine and andrographide, the active constituents present in formulations like Tefroliv Forte tablets. Other constituents (tannins etc) were analyzed by UV spectrophotometry.

Abstract No. C-97, 61st IPC (2009). Chromatographic methods are reported for identification (TLC) and quantification (HPTLC) of withaferin-A in methanolic and chloroform extract of dried fruits of Withania coagulans. Chromatographic separation on silica gel with toluene - ethyl acetate - formic acid 5:5:1. The identification of withaferin-A in both chloroform and methanolic extracts was performed by comparison of hRf values and UV absorbance maxima (209 nm). Quantification was performed by absorbance measurement at 540 nm after spraying the developed plate with Liebermann-Burchard reagent. Methanolic extracts and chloroform extracts contained 3.67 mg/g and 2.10 mg/g of withaferin-A, respectively. No withaferin-A was found in hydroalcoholic extracts.

Phytochem. Anal. 22, 59-65 (2011). TLC and free radical scavenging fingerprints of nineteen Salvia species on silica gel with toluene - ethyl acetate - formic acid 60:40:1 for the less polar constituents and ethyl acetate - water - formic acid - acetic acid 100:26:11:11 for the medium and highly polar substances. After drying at room temperature for 15 min derivatization with vanillin sulfuric acid reagent (1 g vanillin with 20 % sulfuric acid in methanol) followed by heating for 5 min at 105 °C. Quantitative determination by absorbance measurement at 254 nm. Free radical scavenging properties were investigated by spraying the plate with DPPH radical reagent (0.2 %) in methanol and left at ambient temperature for 30 min. The strongest free radical scavenging activity was observed for rosmarinic acid, with an hRf of 70.

Anal. Chim. Acta 690 (2), 148-161 (2011). Chromatographic fingerprinting has been generally accepted as analytical method for the quality control of herbal medicines. This review describes the evolution of the regulations and guidelines on the quality control of herbal medicines, and reviews the established analytical techniques in TLC, HPLC, UHPLC, hydrophilic interaction chromatography, and GC. Emphasis is put on the most recent developments, such as miniaturized techniques, new stationary phases, analysis at high temperatures and multi-dimensional chromatography. The new chemometric data handling techniques are discussed.

Acta Chromatographica 22 (2), 173-187 (2010), DOI:10.1556/AChrom.22.2010.2.2. HPTLC on silica gel with methanol – carbon tetrachloride – ethyl acetate – glacial acetic acid 80:636:280:4. The hRf values were 45 and 30 for atorvastatin calcium and losartan potassium, respectively. Quantification by densitometry at 238 nm. Linearity was in the range of 50–500 ng/band for each substance. The recoveries were 100.6 % and 100.5 % for atorvastatin calcium and losartan potassium, respectively. No interference from excipients was observed. The results were compared statistically using a paired t-test with results by an RP-HPLC method. Both methods provided comparable results.

Planta Med. 76, 523 (2010). HPTLC of diosgenin in callus and rhizome of Dioscorea deltoidea on silica gel with petroleum ether - isopropanol 12:1. The hRf value of diosgenin was 76. Quantitative determination by densitometry in absorption mode at 366 nm after spraying with methanolic sulfuric acid. The linear regression analysis data showed good linear relationship with r = 0.991 and 0.995 for diosgenin with respect to peak hight and peak area, respectively. LOD and LOQ were 17 and 50 ng/zone, respectively.

J. Planar Chromatogr. 24, 82-87 (2011). TLC of crude extracts and madecassoside, asiaticoside, madecassic acid, and asiatic acid on silica gel with concentration zone with chloroform - glacial acetic acid - methanol - water 15:8:3:2; the hRf value was 45, 55, 94, and 97, respectively. Detection by spraying with anisaldehyde-sulfuric acid reagent, followed by heating at 95 °C for 10 min or until the colored zones appeared. The correlation coefficients were between 0.9904 and 0.9982 and linearity was in the range of 1.25-10 nmol, corresponding to approximately 0.5-5 µg/zone for the acids and 1.2-10 µg/zone for the glycosides. The LOD and LOQ was 300 and 720 ng/zone for the sapogenin and saponin, respectively, and 500 and 1200 ng/zone. The average precision was less than 4 % for standards and between 4-6 % for samples.