Comparative Chemical Profiling of Underexploited Arctostaphylos uva-ursi L. Herbal Dust Extracts Obtained by Conventional, Ultrasound-Assisted and Subcritical Water Extractions

Purpose This study was designed to evaluate the influence of ultrasound-assisted extraction (UAE) parameters including temperature, time, and ultrasound power on the yield of phenolic compounds from A. uva-ursi herbal dust. Methods For comparative purposes of extraction efficiency, ultrasound-assisted (UAE), solid–liquid (SLE) and subcritical water extraction (SWE) have been considered. Qualitative and quantitative analysis of phenolic compounds from the A. uva-ursi herbal dust extracts was performed using HPLC-DAD. Results Extraction temperature had a major influence on the values of TPC and TFC of A. uva-ursi herbal dust extract, as the maximum values of these responses were obtained at a temperature of 80 °C, 15.37 g GAE/100 g and 2.82 g CE/100 g, respectively. The major phenolic compounds in A. uva-ursi herbal dust determined at different extraction conditions were hyperoside, followed by gallic acid and arbutin, whereas isoquercitrin and rutin represented the minor compound. Resultantly, a significantly higher content of arbutin, rutin and hyperoside was observed when the extraction was accomplished with UAE. SLE resulted in higher yields of gallic acid and isoquercitrin, whereas by application of SWE the highest concentration of arbutin and gallic acid in one extract was achieved. Conclusions These research findings indicate promising opportunities for UAE and SWE methods with respect to SLE to produce A. uva-ursi herbal dust extract for food and pharmaceutical applications. Graphical Abstract