The interactions between lipase and pyridinium ligands investigated by electrochemical and spectrophotometric methods

The interaction between pyridinium ligands derived from 4,4’-bipyridine (N,N’-bis(p-bro-mophenacyl)-4,4’-bipyridinium dibromide – Lr) and (N,N’-bis(p-bromophenacyl)-1,2-bis (4-pyridyl) ethane dibromide – Lm) with lipase enzyme was evaluated. The stability of the pyridinium ligands, having an essential role in biological systems, in 0.1 M KNO3 as supporting electrolyte is influenced by the lipase concentration added. The pH and conductometry measurements in aqueous solution suggest a rapid ionic exchange process. The behavior of pyridinium ligands in the presence of lipase is investigated by cyclic voltammetry and UV/Vis spectroscopy, which indicated bindings and changes from the interaction between them. The voltammograms recorded on the glassy carbon elec-trode showed a more intense electronic transfer for the Lr interaction with lipase com-pared to Lm, which is due to the absence of mobile ethylene groups from Lr structure

Extraction and evaluation of bioactive compounds with antioxidant potential from green arabica coffee extract

During the last decade researches concerning the essential role of coffee in health and disease prevention showed an increased development. In the present study we obtained extracts from three green Arabica coffee varieties which demonstrated a significant antioxidant potential due to the presence in their composition of two bioactive compounds, caffeine and chlorogenic acids. The content and antioxidant activity of bioactive compounds were evaluated by qualitative and quantitative analyses using spectrophotometric and chromatography methods. The chlorogenic acid was found in high concentrations, being followed by gallic, p-coumaric and ferulic acids. The highest caffeine contents were found in the green coffee extracts of the Supremo–Columbia and Top Quality–Kenya products

Antioxidative activity and stability of the extracts of liquorice root (Glycyrrhiza glabra)

The active principles from the aqueous liquorice plant extracts were investigated and quantified by evaluation of bioactive compounds (saponins) through phytochemical reactions. The presence of saponins was evaluated by measuring the foam index, which was around 500. A major component was Glycyrrhizic acid, responsible for the antioxidant activity, found in concentration of 5.82 % at plant maturity. A time-dependent decrease in concentration of the bioactive compounds from aqueous liquorice extracts was observed. The antimicrobial activity of the extracts was tested by the agar diffusion method, showing a moderate inhibitory activity against Bacillus sp. and strong inhibitory activity against coliforms. A liquorice syrup was obtained and subsequently could be used as nutraceutical additive in bread with good results, showing characteristic, optical and antimicrobial properties and good stability in time. Adding liquorice syrup in food products could be an alternative to improve nutraceutical potential