Alternative Assisted Extraction Methods of Phenolic Compounds Using NaDESs

Abstract

A renewed understanding of eco-friendly principles is moving the industrial sector toward a shift in the utilization of less harmful solvents as a main strategy to improve manufacturing. Green analytical chemistry (GAC) has definitely paved the way for this transition by presenting green solvents to a larger audience. Among the most promising, surely DESs (deep eutectic solvents), NaDESs (natural deep eutectic solvents), HDESs (hydrophobic deep eutectic solvents), and HNaDESs (hydrophobic natural deep eutectic solvents), with their unique features, manifest a wide-range of applications, including their use as a means for the extraction of small bioactive compounds. In examining recent advancements, in this review, we want to focus our attention on some of the most interesting and novel ‘solvent-free‘ extraction techniques, such as microwave-assisted extraction (MAE) and ultrasound-assisted extraction (UAE) in relation to the possibility of better exploiting DESs and NaDESs as plausible extracting solvents of the phenolic compounds (PCs) present in different matrices from olive oil components, such as virgin olive pomace, olive leaves and twigs, virgin and extra virgin olive oil (VOO and EVOO, respectively), and olive cake and olive mill wastewaters (OMWW). Therefore, the status of DESs and NaDESs is shown in terms of their nature, efficacy and selectivity in the extraction of bioactive phytochemicals such as secoiridoids, lignans, phenolic acids and alcohols. Related studies on experimental design and processes’ optimization of the most promising DESs/NaDESs are also reviewed. In this framework, an extensive list of relevant works found in the literature is described to consider DESs/NaDESs as a suitable alternative to petrochemicals in cosmetics, pharmaceutical, or food applications.

Combination of Natural Deep Eutectic Solvents and Nano-Liquid Chromatography towards White Analytical Chemistry: A Practical Application

“…However, in the oil extracts, shown in Figure 4b-d, a large band of more than a minute wide can be seen, and its intensity is much higher than that of the compounds of interest. As it can be observed, all tested NADES were able to extract most of the target compounds from the model matrix, which demonstrates their potential to extract polar compounds from fatty matrices, as has also been remarked in other works [39][40][41]. The most polar analytes included in this study (phenol and BPA) are very affected by the tail of the co-extracted matrix components.…”

A Review on the Use of Deep Eutectic Solvents in Protection Reactions

“…DESs are defined as systems composed of a binary mixture of two components—a hydrogen bond acceptor (HBA), including choline chloride and betaine as quaternary ammonium, sulfonium or phosphonium salts and metal halides, and a hydrogen bond donor (HBD), including urea, renewable carboxylic acids, polyols and saccharides—which are capable of self-associating to form a new eutectic phase with a melting point lower than the individual melting points of their constituent components. The production of DESs from natural sources, together with almost no toxicity, total biodegradability and a low cost, makes these solvents suitable for extraction and chemical synthesis processes [ 12 , 13 , 14 , 15 ].…”

Green Solvent Extraction of Antioxidants from Herbs and Agro-Food Wastes: Optimization and Capacity Determination

“…Interestingly, herb residues and agro-food by-products still contain high amounts of bioactive components, such as polyphenols, vitamins, carotenoids, tannins, and other phytochemicals (minerals, dietary fibers, fatty acids, amino acids, prebiotics) with high nutritional value and antioxidant properties. Recently, the antioxidant potential of phenolic extracts from various by-products such as the distillation solid wastes of Greek oregano, rosemary, Greek sage, lemon balm, and spearmint [6], chestnut shell [7][8][9], berry biowaste [10], chokeberry pomace [11], grape pomace and skin [9,12], rapeseed, mustard, sesame meals and cakes [13,14], olive pomace and leaves, spent coffee grounds, brewer's spent grain, fruit and vegetable leaves, pulp, peel, pomace and seeds [9,15,16], gray and black alder bark [17], and buckwheat hulls [18,19] have been investigated.…”

“…These antioxidant properties of biologically active substances isolated from plant wastes can also be of interest to cosmetic and pharmaceutical applications for the enhancement of therapeutic agent stability, photostability and protection of skin from UV rays, and formulation of new functional cosmetic and pharmaceutical ingredients [9]. It is known that different techniques and solvents, including traditional procedures and innovative processes, can be applied to extract antioxidant compounds from plant materials and by-products of agro-food industries [6][7][8][9][10][11][12][13][14][15][16][17][18][19]. Among them, solid-liquid extraction, Soxhlet extraction, heating-stirring extraction, ohmic heating extraction, homogenization-assisted extraction, heat refluxing extraction, high hydrostatic pressure-assisted extraction, supercritical and subcritical extraction, accelerated solvent extraction (ASE), microwave-assisted extraction (MAE), and ultrasound-assisted extraction (UAE) were employed.…”