Food Chemistry 132, 549-553 (2012).. New HPTLC-based method to examine quantitatively the free radical scavenging activity of plant extracts. After chromatographic separation of polar compounds, and immersion of HPTLC plates in methanolic DPPH radical reagent, bleaching was observed and recorded using a photo camera and data analysis was carried out using an image processing software. The method is simple, fast and efficient for free-radical scavenging activity analysis of phytochemicals and crude plant extracts.

J. Planar Chromatogr. 24, 344-347 (2011). HPTLC of ivermectin (IVM) and albendazole (ALB) on silica gel with toluene - ethyl acetate - glacial acetic acid 12:8:1 in a twin-trough chamber saturated for 30 min. Quantitative determination by densitometry in absorbance mode at 247 nm. Linearity was between 0.12 and 0.54 µg/band for IVM and 8 and 36 µg/band for ALB. The recovery was between 98-101 % for IVM and ALB. The hRf value was 39 for IVM and 62 for ALB. LOD and LOQ were 0.02 and 0.09 µg/band for IVM and 0.08 and 0.1 µg/band for ALB. The intra-day and inter-day precision (n = 6) was 0.6 % and 1.1 % for IVM and 0.6 % and 1.2 % for ALB, respectively. Recovery (by standard addition) ranged from 98-101 % for both compounds.

J. of Chromatogr. A 1245, 183-189 (2012). Anthocyanins are major flower pigments that can be affected by copigments, colorless compounds that can modify anthocyanin coloration. Application of TLC to separate and analyze anthocyanins and copigments. By slantingly cross loading samples compounds are symmetrically developed in various angles from the upper origin to individual Rf values and cross each other. Detection of copigments as color change on the developed line of anthocyanin. Demonstration by using pink sweet pea (Lathyrus odoratus L.) petals showing a more intense zone and a paler zone on the anthocyanin line. The zones were identified as kaempferol 3-rhamnoside and 2-cyanoethyl-isoxazolin-5-one. Kaempferol 3-rhamnoside is a flavonoid with general copigment effect of more intense and bluer coloration change, whereas the structure 2-cyanoethyl-isoxazolin-5-one is not a conventional copigment, it had a novel effect to change anthocyanin coloration paler while maintaining color tone.

J. Liq. Chromatogr. Relat. Technol. 35, 484-498 (2012). HPTLC of vitamin K homologues including phylloquinone (1), menaquinone-4 (2), and menaquinone-7 (3) on silica gel with methanol - ethanol - isopropanol - water 15:1:1:3. Quantitative determination by absorbance measurement at 254 nm. The hRf values of compounds (1) to (3) were 56, 43 and 23, respectively. Linearity was in the range of 1-200 ng/band. Limits of detection and quantification were in the range of 0.2-0.9 and 0.7-2.5 ng/band, respectively. The intermediate/inter-day/intra-day precisions for (1) to (3) were in the range of 0.5-1.3 % (n=5). Recoveries were ranged from 95.3 to 100.8 %.

J. Strait Pharm. 24 (2), 65-66 (2012). Yishen Antai ointment is a herbal TCM recipe specialized for tonifying the kidney and miscarriage prevention of pregnant woman with marked clinical curative effect. Description of a procedure for the analysis of Atractylodes macrocephala Koidz, one of the key components of the preparation. TLC on silica gel with petroleum ether (60-90 ºC) – ethyl acetate 50:1, detection by spraying with 5 % vanillin in a solution of ethanol – sulfuric acid 100:1 and heating at 105 °C until the zones were visualized.

Chinese J. Ethnomed. Ethnopharm. (2), 43-44 (2012). Cissus pteroclada Hayata is a TCM herb. Its crude drug dried rattan is effective in relieving rheumatic pains, invigorating the circulation of blood and vein relaxing, and is the main component of the compound preparations for curing rheumatism, lumbar muscle degeneration, limb paralysis, and traumatic injury. TLC of the extracts of the crude drug and its main active component bergeninum on silica gel with chloroform – ethyl acetate – methanol 5:4:2, detection by spraying with 2 % aqueous ferric chloride – 2 % aqueous potassium ferricyanide 1:1, followed by mild heating.

J. Planar Chromatogr. 25, 338-343 (2012). HPTLC of fluvoxamine in the presence of degradation products on silica gel with ethyl acetate - toluene - methanol - ammonia 14:4:2:1. Quantitative determination by absorbance measurement at 254 nm. The hRf of fluvoxamine was 63. Linearity was in the range of 100-1000 ng/zone. Limits of detection and quantification were 10 and 100 ng/zone. The intermediate/inter-day/intra-day precision was below 0.9 % (n=6). Recovery was between 96.9 and 100.1 %.

J. Chinese Med. 25 (151), 1134-1135 (2010). Yankening tablet, specially effective for diminishing inflammation, is a herbal TCM preparation with Rheum officinale as key component drug. However, some counterfeits are used to replace the certified products, thus abating seriously the curative effect of the medicine. To control the quality of the medicine a method has been presented for inspection of rhaponiticin in Yankening tablets. TLC of the extracts of the medicine on silica gel with ethyl acetate – butanone – formic acid – water 10:7:1:1, detection under UV 366 nm. Identification 1) by fingerprint comparison with the standard rhaponiticin; 2) by comparing the online scanning spectra over the wavelength range from 200 – 700 nm.