Natural antioxidants of horseradish and lovage extracted by accelerated solvent extraction.

Accelerated solvent extraction (ASE) is an alternative method for the extraction of organic compounds from natural material. Due to the elevated temperatures and pressures, the ASE is a time-saving procedure with low consumption of solvents. The aim of the current research was to determine natural antioxidants of horseradish and lovage extracted by accelerated solvent extraction. For isolation of biologically active compounds several methods can be applied, and in current research for extraction of phenolic compounds from horseradish (roots) and lovage (roots, stems and leaves) the accelerated solvent extraction (ASE) with ethanol was used. For comparison also traditional method Soxhlet extraction (SOXE) was used. The total phenol content (TPC) and total flavonoid content (TFC) of the extracts were determined according to the Folin-Ciocalteu spectrophotometric method and colorimetric method, respectively. Antioxidant activity of the plant extracts was measured on the basis of scavenging activities of the stable 1,1-diphenyl-2-picrylhydrazil (DPPH ) and 2,2'-Azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS +) radicals and reducing power. For statistical analysis Tukey’s test and Linear Correlation analysis were used. Differences were considered significant at p<0.05. Results of multivariate dispersion analyses showed that extraction method and plant material are significant factors affecting TPC, TFC, DPPH , ABTS + and reducing power (p<0.05). From studied 20 plant materials (different plant parts and genotypes) in 13 samples higher TPC was determined in ASE extracts, comparing to SOXE extracts. Whereas higher antioxidant activity was determined in SOXE extracts and reducing power in some SOXE extracts was 6.90 times higher than for corresponding ASE extract. The highest content of phenolic compounds was in lovage leaves extracts, whereas reducing power was higher in horseradish extracts. Selection of extraction method depends on target compounds. ASE is suitable for extraction of phenolic compounds, except flavonoid fraction, whereas using Soxlet extraction more compounds with secondary antioxidant activity could be isolated. ACKNOWLEDGEMENT: The research has been done within the State Research Programme AgroBioRes 20142017 and the framework of the “Osmose” between Latvia University of Agriculture and Institut Polytechnique de Toulouse entitled “Recherche et vise a valoriser les plantes et champignons aromatiques oublies de deux regions: une francaise ( Midi-Pyrenees) et une lettone (Zemgale)”. Authors acknowledge Pure Horticultural Research Centre for supply of horseradish roots.