Effect of ultrasound on extraction and stability of polyphenols from Berberis jaeschkeana C.K. Schneid fruits: A comparative study

The extraction of bioactive compounds from plant sources has always posed the question of stability, which largely depends on the extraction conditions. This study is, therefore, designed to evaluate the stability of polyphenolics from Berberis jaeschkeana fruit extracted under optimal ultrasonic-assisted extraction (UAE) conditions, and make comparisons with conventional extraction (CE). Ultrasonic temperature, solvent concentration and sample-to-solvent ratio were found to significantly affect the extraction yield. Under the optimal UAE conditions, significantly higher polyphenolic contents and antioxidant activity were recorded than CE. The stability of polyphenols varied in UAE and CE conditions, and compounds, such as rutin, vanillic acid, 3hydroxybenzoic acid and trans cinnamic acid, showed higher stability under UAE, while caffeic, chlorogenic, p-coumaric and 4-hydroxybenzoic acid were completely degraded under ultrasonication. The results revealed that the stability of polyphenolic compounds under UAE depend on the physio-chemical properties of the individual polyphenolic compounds, extraction type and process factors.