Efficient extraction of quassinoids and alkaloids from Eurycoma longifolia Jack roots using natural deep eutectic solvents and microwave-assisted extraction

Eurycoma longifolia Jack (EL) extracts have immunomodulatory and anti-inflammatory effects and are utilized in the treatment of male sexual dysfunctions. Water-based extraction methods for hydrophobic and bioactive components of EL are often inefficient and energy-intensive. Therefore, this study aimed to develop an efficient and environmentally friendly method for extracting EL quassinoids and alkaloids using natural deep eutectic solvents (NADESs) and microwave-assisted extraction (MAE). The NADES-based MAE method employed an optimized NADES comprising choline chloride, citric acid, glucose, and water (CCGW). CCGW provided higher extraction yields of eurycomanone (EU, 1.608 +/- 0.004 mg/g) and 9-methoxy-canthin-6-one (9MCO, 0.3022 +/- 0.0007 mg/g) than water-based extraction under optimal MAE conditions, as determined using Box-Behnken Design of Response Surface Methodology. CCGW effectively extracted both polar quassinoids and less-polar alkaloids from EL roots. While concentrated NADES had an impact on RAW264.7 cell viability, the use of diluted CCGW did not enhance the cytotoxicity of both EU and 9MCO compared to their preparation in water. The anti-inflammatory activity of 9MCO, prepared in diluted CCGW, was equivalent to that of the compound prepared in water. The cytotoxicity of both compounds in Vero cells was higher when coupled with CCGW than their preparation in water. The NADES-based MAE method is an efficient approach for extracting bioactive components from EL.