Flavonoids of Guiera senegalensis J. F. GMEL. − thin-layer chromatography and numerical methods

The efficiency of seven thin-layer chromatographic systems for separating nine flavonoids isolated from Guiera senegalensis J. F. GMEL. (Combretaceae) was investigated. For this purpose, three mathematical techniques were applied. The first technique was the calculation of the information content derived from Shannon’s equation for each chromatographic system. In the second technique, the discriminating power of the systems was measured individually and in various combinations. The third technique classifies chromatographic systems according to clusters. The classification was carried out by the numerical taxonomy methods. The most suitable chromatographic systems for the separation of the investigated flavonoids are: ethyl acetate : ethylmethylketon : formic acid : water, 60:15:3:2, and ethyl acetate : formic acid : acetic acid : water, 100:11:11:27

Flavonoids of Guiera senegalensis J. F. GMEL. − Thin-layer Chromatography and Numerical Methods

The efficiency of seven thin-layer chromatographic systems for separating nine flavonoids isolated from Guiera senegalensis J. F. GMEL. (Combretaceae) was investigated. For this purpose, three mathematical techniques were applied. The first technique was the calculation of the information content derived from Shannon’s equation for each chromatographic system. In the second technique, the discriminating power of the systems was measured individually and in various combinations. The third technique classifies chromatographic systems according to clusters. The classification was carried out by the numerical taxonomy methods. The most suitable chromatographic systems for the separation of the investigated flavonoids are: ethyl acetate : ethylmethylketon : formic acid : water, 60:15:3:2, and ethyl acetate : formic acid : acetic acid : water, 100:11:11:27

Evaluation and selection of optimal solvent and solvent combinations in thin-Iayer chromatography of flavonoids and of phenolic acids of Zizyphus jujuba MilI.

A series of simple mathematical techniques for the evaluation of solvents and solvent combinations in thin-layer chromatography have been investigated. The classification has been carried out using the numerical taxonomy techniques and information content derived from Shannon's equation. The methods have been applied to an RF data set of flavonoids and phenolic acids identified in the methanolic extract of Zizyphus jujuba MilI. The most suitable chromatographic systems for the separation and future isolation of flavonoids and phenolic acids from Zizyphus jujuba Mill. are : ethyl acetate : formic acid : acetic acid : water, 100 : 11 : 11 : 27, and ethyl acetate : formic acid : water, 8 : 1 : 1

Polyphenolic Profiling of Croatian Propolis and Wine

Polifenoli su široko rasprostranjeni prirodni spojevi, koji uz farmakološko djelovanje imaju i bakteriostatski/baktericidni, antifungalni, protuupalni, kemopreventivni, citostatski, imunomodulacijski i antioksidacijski učinak. Upotrebljavaju se kao funkcionalna hrana u svakodnevnoj prehrani, a u većoj su količini prisutni u propolisu, vinu i različitom ljekovitom bilju. U ovom su radu opisani postupci kemijske analize (spektrofotometrija, visokodjelotvorna tekućinska kromatografija, visokodjelotvorna tankoslojna kromatografija, vezani sustav plinske kromatografije i spektrometrije masa, itd.) polifenola, tj. udjela flavonoida i fenolnih kiselina za određivanje autentičnosti i porijekla propolisa i vina. Navedene su analize osnova za kontrolu kvalitete propolisa, vina i ostalih prehrambenih dodataka koji pozitivno utječu na zdravlje.Polyphenols are ubiquitous natural compounds that show chemopreventive, cytostatic, immunomodulatory, bacteriostatic/bactericidal, antifungal, anti-inflammatory, antioxidant and many other pharmacological activities. Propolis, wine and many medicinal plants used in everyday life as functional food present rich sources of polyphenols. In this paper we focus on their production, chemical analysis (spectrophotometry, HPLC, HPTLC, GC/MS, etc.) of flavonoids and phenolic acids, all of which enable authentication and geographical traceability of propolis and wine. This represents the basis for quality control and regulatory framework for any dietary supplement claiming to have beneficial health effectiveness

Optimization of Chromatographic Conditions in Thin Layer Chromatography of Flavonoids and Phenolic Acids

Flavonoids are one of the largest groups of natural compounds known. They are supposed to have numerous physiological activities. There are many foods that contain flavonoids, but one of the most important sources of flavonoids is propolis. Besides flavonoids, phenolic acids are the main active substances of propolis. The list of uses and preparations of propolis is almost endless and demands an accurate analytical method to define the substances in this natural product. It can be easily analyzed by chromatographic methods, but before testing a new type of propolis it is opportune to optimize chromatographic conditions. The aim of this study is to optimize the chromatographic conditions in TLC of flavonoids and phenolic acids, as standard compounds that may be present in Croatian propolis. We compared 9 different mobile phases, using information theory and numerical taxonomy methods and applying the computer search program KT1, to find the most appropriate mobile phase, the optimal combination of two and three mobile phases for separation of standards

Experimental and Calculation Procedures for Molecular Lipophilicity: A Comparative Study for 3,3\u27-(2-Methoxybenzylidene)bis(4-hydroxycoumarin)

In our work, the log P value for 3,3\u27-(2-methoxybenzylidene)bis(4-hydroxycoumarin) (MBbisHC) was experimentally determined (»shake-flask« method) and calculated using six different computer programs: HyperChem 7.0 (based on atom contributions), XLOGP (based on atom contributions), KowWin (based on atom/fragment contributions), CLOGP (based on fragmental contributions), ALOGPS 2.1 (based on atom-type electrotopological-state indices and neural network modeling), and IA logP (based on atom-type electrotopological-state indices and neural network modeling). The experimental and calculated log P values were correlated. The best result was achieved using the HyperChem 7.0 program, which resulted in a nearly perfect agreement between the experimentally observed and calculated log P values

From functional food to medicinal product: Systematic approach in analysis of polyphenolics from propolis and wine

In the last decade we have been working on standardization of propolis extract and determination of active constituents of wine those are rich in polyphenolics and have nutritional as well as therapeutic value. Here we are summarizing our results and providing overview on systematic approach how to analyse natural products rich in flavonoids and phenolic acids

Najnovije spoznaje u istraživanju inhibitora aromataze

Most of the therapeutics used in chemotherapy are non selective drugs that act non specifically, effecting healthy tissue and causing serious side effects (depression of bone marrow, nausea, hair loss etc.). Every day new macromolecular targets are discovered. One of very important targets in therapy of breast cancer is aromatase - CYP enzyme unique for its function of converting male into female hormones. This paper is focused to the enzyme and its mechanism of action, as this was explained very recently. Physiology and patophysiology of aromatase is explained, as the basis for understanding action of aromatase inhibitors. Special attention is devoted to expression of aromatase and potential use of selective modulators of aromatase, as well as new indications of aromatase inhibitors