engleski

Antioxidant capacity of the oregano and rosemary extracts obtained by high voltage discharge treatment

Due to their complex composition in bioactive compounds known to act as antioxidant and antimicrobial agents, oregano and rosemary are considered medicinal plants. Extraction of bioactive components from plant materials using high voltage discharge (HVED) leads to higher yields, less time, energy and solvent consumption compared to conventional extraction methods and is therefore considered as a "green" extraction method. In this work, the effect of high voltage discharge extraction technique on the antioxidant capacity of the oregano and rosemary extracts was investigated using the Oxygen Radical Absorbance Capacity (ORAC) assay. In extraction experiments, dry samples of oregano and rosemary were suspended in water or water:ethanol mixtures (25 % ethanol and 50 % ethanol) and treated with HVED in the presence of neon or argon for three or nine minutes. Untreated control samples were suspended in the same solvents and stirred for the same period of time as for the HVED treatment. From the studies performed, the following can be concluded: (i) longer treatment time in general leads to higher ORAC values, (ii) the highest ORAC values were determined for the extracts with the highest ethanol content (iii) the extracts obtained by HVED treatment have higher antioxidant activity than the control samples obtained by conventional extraction. This work has been fully supported by Croatian Science Foundation under the project IP- 2016-06-1913.

Antioxidant capacity ; High voltage discharge ; Oregano ; Oxygen radical absorbance capacity ; Rosemary

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