Ultrasound-Assisted Extraction of Isoquercetin from Ephedra alata (Decne): Optimization Using Response Surface Methodology and In Vitro Bioactivities

Abstract

Isoquercetin (ISQ) is reported to be a powerful antioxidant with extremely high bioavailability and structural stability compared to aglycone quercetin. Despite this, it is not well studied due to the limited methods for its extraction. With the growing interest in the research and analysis of ISQ-rich herbs, there is a need to optimize an efficient and rapid method for their extraction. In the present study, the ultrasound-assisted extraction of ISQ from Ephedra alata Decne was optimized by a response surface methodology (RSM) using high-performance liquid chromatography as a separation method. The best possible ranges for extraction time (10–30 min), temperature (50–70 °C), ultrasonic power (60–90 W), solvent-to-solid ratio (50–70 mL/g), and ethanol concentration (50–70%) were determined using a single factor analysis. Subsequently, an optimization of the extraction conditions was performed with RSM using the Box–Behnken design. An ultrasonication time of 10 min, a temperature of 60 °C, a power of 75 W, a solvent-to-solid ratio of 60 mL/g, and an ethanol concentration of 70% were determined to be the optimal conditions for the highest recovery of isoquercetin (1033.96 ± 3.28 µg/g). Furthermore, E. alata powder morphology (using a scanning electron microscope), antioxidant activities, and the inhibition potential of key enzymes involved in skin aging (elastase and collagenase), hyperpigmentation (tyrosinase), diabetes (α-amylase), inflammation (hyaluronidase), and neurodegenerative disorders (cholinesterase) were determined and compared with those using the Soxhlet method. This study established a highly efficient method for ISQ extraction and suggested several potential applications of ISQ in the pharmaceutical and cosmetics industries.

Ethnobotanical Uses and Pharmacological Activities of Moroccan Ephedra Species

“…E. alata is located in North Africa and West Asia (▶ Fig. 2 a) [33], and was cited among the flora of Morocco [34][35][36], Algeria [37], Tunisia [38,39], and Palestine [40]. E. altissima is limited to North Africa and the south of Europe [41] (▶ Fig.…”

“…The enriched extract showed a higher inhibitory efficiency against different enzymes, such as elastase and collagenase implicated in skin aging, tyrosinase involved in hyperpigmentation, α-amylase playing a role in diabetes, hyaluronidase involved in inflammation processes, and cholinesterase implicated in some neurodegenerative disorders. The content of isoquercetin was largely enhanced and the associated bioactivities reinforced [35]. Isoquercetin (quercetin 3-glucoside, also called isoquercitrin) (▶ Fig.…”

“…3 E. alata with the extraction and purification process developed to efficiently extract isoquercetin [35] (photo of the plant from POWO [https://powo.science.kew.org]).…”

“…distachya (stems) from which the polysaccharides ephedrans A-E can be isolated. These water-soluble polymers exhibit antioxidant and hypoglycemic properties [35] (photo of the plant from https://inpn.mnhn.fr; photo credit: P. Rouveyrol). [152].…”

“…The dried aerial parts of a sample of E. alata collected from the Laâyoune Sakia El Hamra region (Morocco) have been used to prepare a plant extract via an ultrasound-assisted extraction process with the objective of optimizing the yield of the main active ingredient from the extract, the flavonoid glycoside isoquercetin [35]. The process afforded more than 1 mg of isoquercetin per gram of extract.…”