Enhancement of The Sappanwood Extract Yield by Aqueous Ultrasound-Assisted Extraction Using Water Solvent

Sappanwood (Caesalpinia sappan L) is a member of Leguminosae plant, which is popular for its function as a natural source of red dye and has been traditionally used to prepare food and beverage in Southeast Asia. From the pharmacological point of view, the heartwood extract of this plant exhibits various biological activities, such as antibacterial, anti-photoaging, anti-allergic, anti-inflammatory, antioxidant, etc. Brazilin as the main antioxidant compound can be efficiently extracted by the ultrasound-assisted extraction (UAE) method. This study aimed to evaluate the effect of temperature (30 to 60°C), time (5 to 25 minutes), and solid-liquid ratio (1:5 to 1:8 g/mL) on the batch ultrasound-assisted extraction of antioxidant compounds from sappanwood heartwood. The results showed that the feasible extraction process was at 30°C using the solid-liquid ratio of 1:5 g/mL for 15 minutes to obtain an extract yield of 3.0%. The yield was 1.50 times compared to the conventional extraction without ultrasound. The increase in temperature and solvent resulted in higher yields. However, considering the energy for extraction and product purification, extraction at ambient temperature with minimum solvent volume was favorable. Meanwhile, the pseudo-second-order mass transfer model exhibited good statistical parameters, and R2 was higher than 0.99 with lower RSMD values. This model can be used to describe the kinetics of UAE of antioxidant compounds from sappanwood. The model was meaningful in determining the efficient extraction time with reasonable antioxidant performance.