OPTIMIZING FLAVONOID EXTRACTION FROM Curcuma xanthorrhiza WITH A SIMPLEX CENTROID DESIGN

Curcuma xanthorrhiza is a species of the genus Curcuma which is a medicinal ingredient in high demand in Indonesia and other countries. Chemical compounds such as flavonoids and their diverse bioactivity have triggered research that prioritizes quality and efficiency. This study was designed to optimize the extraction solvent in producing flavonoids from the rhizome of C. xanthorrhiza based on a simplex centroid design using Design Expert 13.0. Extractor solvents (water, acetone, ethanol, and methanol), as well as their combinations, were studied to test the total flavonoid content using the calorimetric aluminum chloride method by spectrophotometer. The experimental results with the special cubic model are a good and reliable fit for recovering flavonoids. The optimal conditions obtained were highly accurate at the desirability value of 1.00 with a mixed solvent of methanol (0.445) and ethanol (0.555), which resulted in total flavonoid content of 144.665 mg quercetin equivalent per gram dry weight. Methanol and ethanol combined can be an effective solvent option for extracting high amounts of active compounds (especially flavonoids) in C. xanthorrhiza rhizome.