Ultrasound-assisted extraction optimisation of Bajakah Tampala ( <i>Spatholobus littoralis</i> Hassk.) wood using response surface methodology

Bajakah tampala (Spatholobus littoralis Hassk.) (BT), a native medicinal plant, is renowned for its rich phytochemical profile and therapeutic potential. Green technology extraction can protect heat-sensitive compounds. This study aimed to optimise the ultrasound-assisted extraction (UAE) and profile the extract’s compounds. The optimisation process employed response surface methodology (RSM) with box-behnken design (BBD) to determine the effects of ethanol concentration, temperature, and time on total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activity (AA). The results demonstrated that optimal extraction conditions (ethanol concentration: 54.19%, temperature: 64.38°C, and time: 29.02 min) yielded high levels of TPC (18.78 mg GAE/g), TFC (6.67 mg QE/g), and AA (80.79%). LC-HRMS analysis identified five dominant compounds with antioxidant relevance. A group of phenolic, flavonoid, and alkaloid compounds, including scopoletin, cianidanol, yohimbine, hercynine, and rhynchophylline. Those compounds are known for their potent antioxidant properties, which may contribute to the traditional therapeutic use of BT.