Optimization of Microwave-Assisted Green Method for Enhanced Solubilization of Water-Soluble Curcuminoids Prepared Using Steviol Glycosides

Abstract

In this study, the optimization and modeling of microwave-assisted extraction (MAE) of water-soluble curcuminoids prepared using novel steviol glycosides (SGs) was carried out using four independent process variables at varying levels—X1: microwave power (50–200 W), X2: stevioside concentration (50–200 mg/mL), X3: curcumin concentration (20–200 mg/mL), and X4: time (1–10 min)—in response surface methodology configuration. Moreover, the effects of stevioside, as the most cost-effective natural solubilizer, were also evaluated. The water solubility of curcuminoids increased from 11 to 1320 mg/L with the addition of stevioside as a natural solubilizer. Moreover, microwave heating synergistically with stevioside addition significantly (p < 0.05) increased the solubility up to 5400 mg/L. Based on the results, the optimum conditions providing the maximum solubilization of 16,700 mg/L were 189 W microwave power, 195 g/L stevioside concentration, 183 g/L curcuminoid concentration, and 9 min of incubation time. Moreover, MAE of curcuminoids using SGs might render a significant advantage for its wide-scale application to solubilizing the multitude of insoluble functional flavonoids in fruits, plants, and food materials.

Technologies for Solubility, Dissolution and Permeation Enhancement of Natural Compounds

“…Analytical and in silico study was of the inclusion complexes between tropane alkaloids atropine and scopolamine with cyclodextrins [87]. The most recent study by Ko et al (2021) also highlighted the use of steviol glycosides for the conversion of poorly water soluble curcumin into water soluble curcuminoids (Curcumin-steviol glycosides complex) for antiviral theapy. Moreover, the author reported the novel method of Microwave-assisted extraction and stated that by using in conjunction with the Curcumin-steviol glycosides complex several folds enhanced solubility (11 mg/L to 1320 mg/L) was achieved [53].…”

Solubilized curcuminoid complex prevents extensive immunosuppression through immune restoration and antioxidant activity: Therapeutic potential against SARS-CoV-2 (COVID-19)

“…Following this trend, we recently reported a new method for increasing the solubility of curcuminoids using stevioside, a known natural solubilizer, and a microwave-assisted method. Here, water-soluble curcuminoids (named C—S/M) prepared using stevioside are made in nanoparticle form (average particle size of approximately 190 nm) [19] . Importantly, recent studies demonstrated that using biomaterials encapsulated in stevioside can usually improve bioactivity, stability, and cell-to-nanoparticle interaction [20] , [21] .…”