Sophora japonica Nanoemulsion: Ultrasound-Assisted Extraction and Characterization

Abstract

Sophora japonica, a member of the Fabaceae family, is recognized for its medicinal properties, particularly in traditional Asian medicine. This study aimed to investigate the efficiency of ultrasound-assisted extraction techniques in obtaining bioactive compounds from S. japonica and to formulate these extracts into stable nanoemulsions with enhanced antioxidant activity. The extraction methods employed included ethanolic maceration followed by ultrasound-assisted extraction, with the latter producing a total phenolic content of 65.57 mg gallic acid equivalent per milliliter, compared to 51.18 mg for the maceration method. Antioxidant activity was assessed using the DPPH scavenging assay, revealing that the ultrasound-assisted extract exhibited a scavenging efficiency of 67%, whereas the ethanolic extract demonstrated a scavenging efficiency of 59%. The resultant nanoemulsions, formulated from the ultrasound-assisted extracts, showed an average particle size of 252.92 nm and a zeta potential of −36.68 mV, indicating favorable stability. Visual inspections and peroxide value assessments during a 5-day oxidative stability study indicated that the water-based nanoemulsion experienced minimal changes, maintaining its stability, while the ethanolic nanoemulsion exhibited significant signs of separation and oxidation. These findings suggest that ultrasound-assisted extraction not only enhances the recovery of bioactive compounds from S. japonica but also contributes to the formation of stable nanoemulsions, which hold potential applications in the food and pharmaceutical industries.