In this study, an environmentally friendly extraction method for flavonoid compound from Ixora javanica, as a new raw material candidate for herbal medicine and cosmetics, was developed. The objectives of the present work were to provide recommendations for the optimal extraction conditions and to investigate the effects of any extraction parameters on flavonoid yields from the I. javanica flower. The extraction process was performed using deep eutectic solvent (DES) (choline chloride and propylene glycol at molar ratio of 1 : 1) and the ultrasound-assisted extraction method. Both single-factor and response surface analyses using three-level and three-factor Box Behnken designs were conducted to obtain the optimum flavonoid concentrations. The results showed that the optimum extraction conditions for total flavonoids featured an extraction time of 40 min, 25% water content in DES and a solid-to-liquid ratio of 1 : 25 g ml⁻¹. An extract obtained under optimum extraction conditions showed higher total flavonoid yields than an ethanolic extract which was used for comparison. Scanning electron microscope images demonstrated that both of the solvents also showed different effects on the outer surface of the I. javanica flower during the extraction process. In summary, our work succeeded in determining the optimum conditions for total flavonoids in the I. javanica flower using a green extraction method.

本研究开发了一种从龙船花中提取黄酮类化合物的环保方法，作为草药和化妆品的新原料候选物。本工作的目的是为最佳提取条件提供建议，并研究任何提取参数对爪哇花中黄酮类化合物产量的影响。提取过程使用低共熔溶剂（DES）（氯化胆碱和丙二醇摩尔比为1:1）和超声辅助提取方法进行。使用三水平和三因素 Box Behnken 设计进行单因素分析和响应面分析，以获得最佳黄酮类化合物浓度。结果表明，总黄酮的最佳提取条件为提取时间40 min、DES含水量25%、料液比1：25 g ml ^-1 。在最佳提取条件下获得的提取物显示出比用于比较的乙醇提取物更高的总黄酮产量。扫描电子显微镜图像表明，两种溶剂在提取过程中对爪哇花的外表面也表现出不同的影响。总之，我们的工作成功地利用绿色提取方法确定了爪哇花中总黄酮的最佳条件。