DETERMINATION OF COMPOUNDS WITH POTENTIAL ANTIOXIDANT AND ANTIRADICAL CAPACITY IN DIFFERENT OREGANO EXTRACTS

Abstract

Oregano is an aromatic plant used both as a condiment and for medicinal purposes, with a great  number  of  antioxidant  compounds  (43).  The  study  analyzes  the  main  groups  of  antioxidant compounds – flavonoids, polyphenolcarboxilic acids and polyphenols and the antiradical capacity of this plant. The determinations are done spectrophotometrically, based on the reactions with AlCl₃ – for the flavonoids, with Arnow reagent – for the polyphenolcarboxilic acids and Folin – Ciocâlteau reagent for total polyphenols. Because it is very important to know the  way the observed antioxidant compounds can be extracted from  plants  eight  extractions  from  two  samples  of  dried oregano  –  condiment  and  medicinal  plant were performed: with water, with methanol solution 50% and ethanol, hot and cold, and two mixtures: of methanol – water – acetic acid and methanol – acetone – water – formic acid, cold. Water  and  methanolic  solution  had the  capacity  to  extract  the  compounds  both  from  the  condiment and  the  medicinal  plant,  the temperature  influencing  in  a  positive  way  the  extractability of  the antioxidant compounds. A valuable extract was obtained at low temperature, too, with the mixture of solvents methanol – acetone - water – formic acid (S 5 ). Its scavenger activity against the free radicals, determined by the  capacity of elimination of the radical 2,2-diphenyl-1-picrylhydrazyl (DPPH), was very good in the majority of the extracts. At the opposite end, there was the extract with ethanol, at low temperature.