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.

obtained by use of different techniques. J. Planar Chromatogr. 22, 25-28 (2009). HPTLC of flavonoids (rosmarinic acid and luteoline) on silica gel with ethyl acetate - formic acid - water 136:5:6, ethyl acetate - methanol - water 77:13:10, ethyl acetate - diethyl ether 4:1, n-hexane - ethyl acetate - formic acid 60:40:3, chloroform - methanol - formic acid 882:60:47, and chloroform - acetone - formic acid 19:4:2. The mobile phase chosen for quantification was chloroform - ethyl acetate - formic acid 60:40:3. Detection by spraying with natural products reagent, followed by polyethylene glycol 400 reagent. Quantitative determination by densitometry at 328 nm (rosmarinic acid) and 349 nm (luteoline).

J. Planar Chromatogr. 21, 299-304 (2008). HPTLC of 21 amino acids on silica gel impregnated with 5 % Ag ion with borate phosphate buffer pH 2.3. After drying at 50 °C detection by spraying with ninhydrin. With this system separation of alanine, phenylalanine and tryptophane could be achieved, as well as separation of alanine, tyrosine and tryptophan. Separation of these amino acids was neither achieved on conventional silical gel (without Ag impregnation) nor by addtion of buffered 5 % silver nitrate solution (pH 2.3) to the mobile phase.

Ind. J. Pharm. Sci. 70(5), 644-647 (2008). HPTLC of meloxicam on silica gel with ethyl acetate - cyclohexane - glacial acetic acid 325:175:1 with chamber saturation for 45 min. Quantitative determination by absorbance measurement at 353 nm. The method was linear in the range of 100-500 ng/zone, recovery was 100.3 %. The method was evaluated for stability (acid, base, thermal, oxidative, photodegradation) and degradation products were well separated from the main drug.

Abstract No. 0983, IHCB (2009). HPTLC of mahanimbine (a carbazole alkaloid isolated from Murraya koenigi) on silica gel with petroleum ether - chloroform 13:7. The hRf value of mahanimbine was 60. Quantitative determination by absorbance measurement at 254 nm. The method was linear in the concentration range of 50-250 ng/spot. Enzyme inhibition activity of methanol, petroleum ether, and chloroform exctracts of the plant and of mahanimbine was evaluated using galantamine as standard inhibitor of the enzyme.

Ind. J. Pharm. Sci. 70(5), 689-693 (2008). HPTLC of andrographolide and wedelolactone (active components of Andrographis paniculata respectively Eclipta alba) on silica gel with toluene - acetone - formic acid 9:6:1. Quantitative determination by absorbance measurement at 254 nm. The hRf of andrographolide was 52 and of wedelolactone 58. The method was linear in the range of 200-400 ng/spot (andrographolide) and 100-200 ng/spot (wedelolactone). The herbal formulation contained 1.4 mg andrographolide and 1.7 mg wedelolactone per tablet. The proposed method could be applied for routine analysis of both compounds.

J. Chromatogr. A 1216 (11), 2150-2155 (2009). Chaihu roots (Bupleuri radix), roots of Bupleurum chinense and Bupleurum scorzonerifolium are monographed in the Chinese Pharmacopoeia. Evaluation of the quality of 33 lots of authenticated Chaihu samples versus 31 lots of commercial samples by HPLC-ELSD and HPTLC analysis of the principal bioactive components (saikosaponins). Data acquired from HPLC fingerprints and HPTLC fluorescent images was analyzed by chemometrics for similarity and pattern recognition, including artificial neural networks, k-nearest neighbor (k-NN) and an expert’s panel. The k-NN classifier showed good performance with sufficient flexibility for processing HPTLC fingerprint images. These images were otherwise not easily dealt with by other algorithms due to the shift of hRf values and varying hue/saturation of the band colors between different TLC plates. The two chromatographic fingerprint methods are complementary measures for quality control. Chaihu roots from different species of the genus Bupleurum could readily be distinguished from each other. Commercial samples of Chaihu can easily be classified by investigating the content of major saikosaponins.

Abstract No. 9923, IHCB (2009). HPTLC of several herbal formulations (tablets extracted with methanol) on silica gel with toluene - ethyl acetate 19:1. The fingerprint method was suitable for correct identification and for routine quality control of the herbal extracts.