Optimization and Comparison of Ultrasound and Microwave-Assisted Extraction of Phenolic Compounds from Cotton-Lavender (Santolina chamaecyparissus L.)

Abstract

The interest in natural phenolic compounds has increased because of their attractive use especially as antioxidant and antimicrobial agents in foods. The large content in phenolic compounds of interest in Santolina chamaecyparissus L. (S. chamaecyparissus) makes this plant a target source that is worthy of note. In this work, new extraction technologies comprising ultrasound (UAE) and microwave (MAE) assisted extraction of the phenolic compounds in S. chamaecyparissus have been developed, optimized, and compared. Several extraction factors have been optimized based on a Box-Behnken design. Such optimized factors include the percentage of methanol in water (25–75%), the temperature (10–70 °C), the ultrasound amplitude (20–80%), the ultrasound cycle (0.2–1 s), the solvent pH (2–7) and the solvent-sample ratio (5/0.2–15/0.2 mL/g) with regard to UAE, while the percentage of methanol in water (50–100%), the temperature (50–100 °C), the pH (2–7) and the solvent-sample ratio (5/0.2–15/0.2 mL/g) were optimized for MAE. The solvent composition was the most influential parameter both on MAEs (64%) and UAEs (74%). The extraction optimum time was established as 15 min for MAE and 25 min for UAE. Five major phenolic compounds were detected and identified by Ultra-High-Performance Liquid Chromatography—Quadrupole Time of Flight—Mass Spectrometry (UHPLC-QToF-MS) in the extracts: chlorogenic acid, quercetin 3-O-galactoside, quercetin 3-O-glucoside, isoorientin, and cynarin. With the exception of chlorogenic acid, the other four compounds have been identified for the first time in S. chamaecyparissus. The findings have confirmed that MAE is a significantly more efficient extraction method than UAE to extract phenolic compounds from S. chamaecyparissus.

Optimization of an Ultrasound-Assisted Extraction Method for the Analysis of Major Anthocyanin Content in Erica australis Flowers

“…While for the intermediate precision study, 4 extractions were performed on each one of three con- As it can be observed, the maximum amount of anthocyanins was extracted when the extraction time was 15 min, with a noticeable difference in relation to the 5 min extractions and no significant differences with regard to any other of the extraction times. This fact is in agreement with the extraction time required for the extraction of anthocyanins from other matrices [19,35,36]. Moreover, no decreasing trend in anthocyanins recoveries was observed when longer extraction times (over 15 min) were applied, which suggests that no anthocyanin degradation took place under such time conditions [50].…”

“…Similarly, the temperature should not be above 70 • C because the solvent would start boiling and this would affect the final recovery. Some authors have observed that percentages of methanol near 70% were more optimal for the extraction of anthocyanins, especially from plant materials [19,35,49]. Finally, higher levels of methanol in the solvent were assayed while the rest of optimal extraction conditions according to the BBD were applied, i.e., 70 • C, 20 mL of solvent per 0.5 g of sample and pH = 5.…”

“…The percentage of MeOH, the extraction temperature, and the solvent ratio were determined based on previous investigations carried out in the research group and bibliograpy [32,35,36]. Regarding the pH of the solvent, in aqueous solution, anthocyanins undergo structural re-arrangements in response to changes in pH in four molecular structures: quinoidal base (blue), flavylium cation (red), carbinol (colorless) and chalcone (yellowish) forms.…”

Influences of Microwave-Assisted Extraction Parameters on Antioxidant Activity of the Extract from Akebia trifoliata Peels

“…The solvent-to-material ratio was considered to be one of the most important factors affecting the extraction yields of phenolic compounds [ 20 , 21 ]. A larger ratio of solvent-to-material was conducive to the rapid release of the intracellular substances and enhanced extraction yield [ 22 ]. Nevertheless, it was also found that a much large ratio of solvent-to-material would lead to a decline in the recovery efficiency [ 19 ].…”

Extraction and Analysis of Natural Product in Plant

“…Thanks to these non-conventional methods, the time required for a substantial extraction of the compounds of interest was reduced to just a few minutes (2-10 min). Aurach et al [5] used both ultrasound-assisted extraction (UAE) and microwave-assisted extraction (MAE) for the extraction of the phenolic compounds that are found in Cotton-Lavender (Santolina chamaecyparissus L.). The largest phenolic compounds' extraction yields from this matrix were achieved when MAE was employed.…”