Chemo-mapping and biochemical-modulatory and antioxidant/prooxidant effect of Galium verum extract during acute restraint and dark stress in female rats.

Galium verum is a well-known medicinal plant which is used in various pathologies. G. verum extracts are characterized here using chromatography, where among the rich pool of phenolic acids of flavonoids two known anti-stress modulators, chlorogenic acid and rutin are identified in high quantities. Additionally, the extracts are characterized using a series of in vitro assays (EPR, DPPH, TPC and TEAC). Considering the chemical findings, the potential beneficial effects of the G. verum extract are explored here in a living organism exposed to stress induced oxidative damages. Thus, the biochemical-modulatory and antioxidant roles of two doses of G. verum extract are examined in animals exposed to acute restraint and dark stress (S). The animals were divided in groups [control, S, SG1 (exposed to 25 mg G. verum extract), SG2 (50 mg extract)]. Increased levels of lipid peroxidation (TBARS from 4.43 to 8.06 nmol/mL), corticosterone from 0.43 to 1.96 µg/dL and epinephrine from 44.43 to 126.7 µg/mL, as well as decreased antioxidant enzymes activities (SOD/CAT) were observed in the S group. The G. verum extract afforded a near-normal equilibrium within the biochemical parameters of animals exposed to RS, by reducing oxidative damage (TBARS at a 3.73 nmol/mL; CS at 0.90 µg/dL; EP at 63.72 µg/mL) and by restoring the antioxidant balance.

Application of a newly developed and validated high-performance thin-layer chromatographic method to control honey adulteration.

Honey is a saturated solution of sugars, used for a long time as a natural source of sugars and is an important ingredient in traditional medicine due to its antimicrobial, anti-inflammatory and antioxidant effects. Therefore, methods for quality control of honey and detection of its adulteration are very important. For this reason, the aim of this study is to develop and validate a new, simple and economical analytical method for detecting the adulteration of some Romanian honeys based on high-performance thin-layer chromatography (HPTLC) combined with image analysis. The proposed method involved the chromatographic separations of glucose, fructose and sucrose on silica gel HPTLC plates, developed twice with ethyl acetate-pyridine-water-acetic acid, 6:3:1:0.5 (v/v/v/v), followed by dipping in an immersion solution. The documentation of plates was performed using TLC visualization device and the images of plates were processed using a digital processor. The developed HPTLC method was validated for selectivity, linearity and range, LOD and LOQ, precision, robustness and accuracy. The method was then applied for quantitative determination of glucose, fructose and sucrose from different types of Romanian honeys, commercially available.

Thin-layer chromatography with stationary phase gradient as a method for separation of water-soluble vitamins.

The group of hydrophilic vitamins play an important role in human health, and their lack or excess produces specific diseases. Therefore, the analysis of these compounds is indispensable for monitoring their content in pharmaceuticals and food in order to prevent some human diseases. TLC was successfully applied in the analysis of hydrophilic vitamins, but the most difficult problem in the simultaneous analysis of all these compounds is to find an optimum stationary phase-mobile phase system due to different chemical characteristics of analytes. Unfortunately structural analogues are difficult to separate in one chromatographic run, and this is the case in hydrophilic vitamins investigations. TLC gives the possibility to perform two-dimensional separations by using stationary phase gradient achieving the highest resolution by combining two systems with different selectivity. The goal of this work was to develop a method of analysis enabling separation of hydrophilic vitamins using TLC with adsorbent gradient. The developed method was used for identifying the water-soluble vitamins in alcoholic extracts of Hippophae rhamnoides and of Ribes nigrum.

Simultaneous determination of methylxanthines in different types of tea by a newly developed and validated TLC method.

The aim of this paper is to develop a new simple, fast and economical method for simultaneous quantitative determination of methylxanthine compounds based on TLC combined with image analysis. To obtain certain results, both extraction and chromatographic separation were optimized. The optimum extraction conditions were maceration in ethanol-water 8:2, v/v. The chromatographic separations were done on the silica gel F(254) TLC plates developed with chloroform-dichloromethane-isopropanol, 4:2:1 v/v/v. Detection was performed under UV lamp at 254 nm and the evaluation of the chromatographic plate was based on digital processing of chromatographic images. The developed TLC method was validated for parameters such as specificity, linearity and range, LOD and LOQ, precision, robustness and accuracy. This method was then applied for determination of caffeine, theobromine and theophylline in different types of tea, commercially available. Moreover, the content of methylxanthines detected and determined in commercial tea samples can be used as chemical marker in quality control.