A green extraction design for enhancing flavonoid compounds from the Ixora javanica flowers using a deep eutectic solvent

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 ultrasound-assisted extraction (UAE) 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. An extract
obtained under optimum extraction conditions showed higher total flavonoid
yields than an ethanolic extract which was used for comparison. Scanning
electron microscope (SEM) images demonstrated that both of the solvents
also showed different effects on the outer surface of the I. javanica
flower during extraction process. In sum, our work succeeded in
determining the optimum conditions for total flavonoids in the I. javanica
flower using a green extraction method.