High-Performance Green Extraction of Polyphenolic Antioxidants from Salvia fruticosa Using Cyclodextrins: Optimization, Kinetics, and Composition

Abstract

S. fruticosa, collectively known as Cretan sage, is a medicinal plant to which a number of bioactivities have been attributed. In spite of its importance in nutrition and pharmacy, reports on the extraction of major polyphenols using sustainable processes are particularly limited. In this study, three common cyclodextrins, namely, methyl β-cyclodextrin (m-β-CD), hydroxypropyl β-cyclodextrin (HP-β-CD), and β-cyclodextrin (β-CD), were tested as green boosters of aqueous extraction of polyphenols from aerial parts of S. fruticosa. To examine simultaneously important extraction parameters, including the concentration of cyclodextrins (CCD), pH, and liquid-to-solid ratio (RL/S), a Box–Behnken design was chosen, with three central points. Temperature effects on the extraction yield were also considered, by carrying out kinetics. The results showed that m-β-CD was the most effective extraction booster, providing total polyphenols yields that amounted to 98.39 mg gallic acid equivalents g−1 dry mass. The kinetic assay demonstrated that extraction was highly effective at 80 °C, increasing significantly polyphenol yield, as well as the ferric-reducing power and antiradical activity of the extracts. It was also proven that extraction with m-β-CD was the least energy-demanding process. Liquid chromatography-tandem mass spectrometry examination revealed that m-β-CD might possess higher affinity for luteolin 7-O-glucuronide extraction, but β-CD for rosmarinic acid extraction.

Hydroxypropyl-β-Cyclodextrin as a Green Co-Solvent in the Aqueous Extraction of Polyphenols from Waste Orange Peels

“…However, no statistical difference was seen compared to the Y TP achieved at the other pH tested. This is in contrast to recent studies on the importance of the pH in the HP-β-CD-aided extraction of polyphenols [15,16], where pH effects on polyphenol extraction performance was found to be significant. Optimum pH value for HP-β-CD-aided extraction of S. fruticosa polyphenols was shown to be 3.90 [16], very close to pH 4 determined in this study.…”

“…Construction of the predictive model was performed by deploying a response surface methodology via a Box-Behnken design with three central points. The basis for choosing the process variables was literature data [15,16] illustrating their profound influence on the extraction yield in total polyphenols (Y TP ), which was the response. The actual and codified levels of the variables are analytically presented in Table 1.…”

Batch Stirred-Tank Green Extraction of Salvia fruticosa Mill. Polyphenols Using Newly Designed Citrate-Based Deep Eutectic Solvents and Ultrasonication Pretreatment

“…For the screening process, all DES were tested as 70% (w/v) aqueous mixtures. Control solvents were 60% (v/v) ethanol, 60% (v/v) methanol and deionized water [14,16]. Extractions were accomplished in a 20-mL glass vial, using 15 mL of each solvent and 0.375 g of plant material, for 150 min.…”

“…Previous studies on the extraction of polyphenols from S. fruticosa using methyl β-cyclodextrin (m-β-CD) showed that extracts with increased polyphenol concentration and improved antioxidant characteristics could be obtained at 80 • C [14]. However, a following investigation with a 60% (w/v) hydroglycerolic mixture demonstrated that Y TP displayed a gradual decrease when extraction temperature varied from 50 to 80 • C [42], although differences were non-significant (p < 0.05).…”

“…To further bring out the efficiency of LA-SCDB15, the characteristics of an extract obtained under optimized conditions were compared to those from two preexisting green extraction methods, one performed with methyl β-cyclodextrin (m-β-CD) [14] and one with 60% (w/v) glycerol/water mixture (GL) [42], but also 60% (v/v) aqueous ethanol and 60% (v/v) aqueous methanol (Table 4). The LA-SCDB15 extract was found to have significantly higher Y TP , which demonstrated its high extraction capacity.…”