The Utilization of an Aloe Vera Rind By-Product: Deep Eutectic Solvents as Eco-Friendly and Recyclable Extraction Media of Polyphenolic Compounds.

In this study, an optimized environmentally friendly procedure was employed to enhance the sustainable utilization of phenolic antioxidants derived from aloe vera rind by-products. The procedure involved the application of ultrasound-assisted extraction (UAE) in combination with deep eutectic solvents (DESs). Eleven different DESs and three conventional solvents were employed as extraction media for polyphenolic compounds. Choline chloride-citric acid (ChCl-CA) was selected as the most suitable extractant, considering its extraction efficiency in relation to the total phenolic content. The operating conditions of UAE were optimized and modeled by the use of response surface methodology in order to maximize the yield of total phenolics and antioxidant capacity. The optimal operational parameters for the UAE procedure were determined to be 16.5 min, 74% (v/v) DES in water, and a solvent-to-solid ratio equal to 192. HPLC analysis, which was performed on the optimum extract, revealed significant levels of phenolics present in the aloe rind. Efficient recovery of the extracted antioxidants was obtained by the use of solid-phase extraction (SPE) and polyamide cartridges. The ChCl-CA DES exhibited excellent recycling capability with a yield of over 90% through SPE. Finally, the greenness of the method was evaluated using the green AGREE and AGREEprep metrics. The results highlighted the sustainability and the greenness of the proposed extraction procedure for the aloe by-product.

Novel supramolecular deep eutectic solvent (SUPRADES) as a sole chiral selector in capillary electrophoresis for the enantiomeric separation of fluorine-substituted amphetamine analogs.

In this study, a novel supramolecular deep eutectic solvent consisting of sulfated-ß-CD and citric acid (S-ß-CD-CA) is reported for the first time. This innovative system was evaluated as a sole chiral selector in capillary electrophoresis for the enantioseparation of six fluorine-substituted amphetamine analogs, yielding remarkable outcomes. Baseline separations of all amphetamine analogs under study were achieved in less than 21.00 min using the S-ß-CD-CA as the chiral selector. It was observed that the addition of 0.050 % v/v S-ß-CD-CA into the background electrolyte resulted in the baseline separation of five out of the six fluorine-substituted amphetamine analogs, while in the case of the para-substituted amphetamine analog, 4-fluoramphetamine (4-FA), a higher percentage (0.15 % v/v) was required to achieve baseline enantioseparation. These findings emphasized the potential of this new supramolecular system in providing a class of solvents with promising chiral recognition properties.

Stereoselective separation of psychoactive substances: Multivariate optimization and validation of a capillary electrophoresis method using carboxymethyl-ß-CD/deep eutectic solvent dual system.

A comprehensive study was performed to determine an optimum enantioseparation method for fluorine-substituted amphetamine and cathinone derivatives (fluor-amphetamine and fluor-cathinone derivatives), using a binary system consisting of carboxymethyl-ß-CD (CM-ß-CD) and a deep eutectic solvent (DES), namely choline chloride-ethylene glycol (ChCl-EG). Under this framework, the optimization and modeling of the separation conditions in a binary system were performed with the objective of maximizing resolution and minimizing analysis time. This was achieved through the application of response surface methodology. In particular, the effect of chiral selector concentration and percentage of DES on resolution and analysis time were investigated and optimized using a complete experimental design. The optimum enantioseparation conditions were determined to be 13.84 mM CM-ß-CD and 0.15% v/v ChCl-EG for fluorine-substituted amphetamine derivatives and 14.36 mM and 0.75% v/v ChCl-EG for fluorine-substituted cathinone derivatives, respectively. This combination resulted in a baseline separation for eight out of the nine analytes studied. Overall, the results demonstrated the synergistic effect of the CM-ß-CD/DES dual system and highlighted the significance of DESs as additives in capillary electrophoresis.

Ultrasound-Assisted Extraction of Taro Leaf Antioxidants Using Natural Deep Eutectic Solvents: An Eco-Friendly Strategy for the Valorization of Crop Residues.

Colocasia esculenta L. leaves are considered a by-product of taro cultivation and are discarded as environmental waste, despite their valuable phenolic composition. Their valorization to obtain value-added substances for medicinal, food, and cosmetic applications is the aim of the current work. An ultrasound-assisted extraction was developed for the environmentally friendly and sustainable isolation of taro leaf antioxidants using natural deep eutectic solvents (NaDESs). Among the utilized solvents, the NaDES based on betaine and ethylene glycol provided the best extraction efficiencies in terms of polyphenolic content and antioxidant activity. Multi-response optimization suggested a solvent-to-solid ratio of 10 mL g-1, a processing time of 60 min, an extraction temperature of 60 °C, and a water content of 33.8% (w/w) as optimal extraction parameters. Leaf extract obtained under these optimum operational parameters demonstrated a strong radical scavenging activity against 2,2-diphenyl-1-picrylhydrazyl (65.80 ± 0.87%), a high ferric reducing antioxidant power (126.62 ± 1.92 µmol TE g-1 sample), and significant protection against oxidative stress-induced DNA damage. The chromatographic characterization of the optimum extract revealed its richness in flavonoids (flavones and flavonols). The outcomes of the present study suggest that the proposed method could serve as a highly efficient and green alternative for the recovery of polyphenols from agricultural wastes.

The potential of the use of deep eutectic solvents and amino acid-based ionic liquids to enhance the chiral discrimination ability of different chiral selectors in capillary electrophoresis.

The effect of the combined use of amino acid-based ionic liquids (AAILs) and deep eutectic solvents (DESs) with either cyclodextrin- (CD) or cyclofructan- (CF) based chiral selectors for the chiral separation of amphetamine derivatives was investigated in the present study. A non-significant improvement in enantiomeric separation of target analytes was observed when AAILs were combined with either CF or CD. On the other side, a markedly improved chiral separation of enantiomers was obtained using the dual carboxymethyl-ß-cyclodextrin/DES system, highlighting the existence of a synergistic effect. After the addition of 0.5% v/v of choline chloride-ethylene glycol, the resolution of the enantiomers of amphetamine, methamphetamine and 3-fluorethamphetamine, increased from 1.4, 1.1, 1.0 to 1.8, 1.8, and 1.5 min, and the analysis times increased from 19.54, 20.48, 18.71 to 35.71, 35.78 and 32.90 min, respectively. This was not the case for the CF/DES dual system, in which the separation of amphetamines worsened, indicating an antagonistic effect. In conclusion, DESs are a very promising additive in capillary electrophoresis that can improve the separation of chiral molecules in combination with CDs but not CFs.

Phenolic Profile, Antioxidant Activity, and Chemometric Classification of Carob Pulp and Products.

In recent years, carob and its derived products have gained wide attention due to their health-promoting effects, which are mainly attributed to their phenolic compounds. Carob samples (carob pulps, powders, and syrups) were analyzed to investigate their phenolic profile using high-performance liquid chromatography (HPLC), with gallic acid and rutin being the most abundant compounds. Moreover, the antioxidant capacity and total phenolic content of the samples were estimated through DPPH (IC50 98.83-488.47 mg extract/mL), FRAP (48.58-144.32 µmol TE/g product), and Folin-Ciocalteu (7.20-23.18 mg GAE/g product) spectrophotometric assays. The effect of thermal treatment and geographical origin of carobs and carob-derived products on their phenolic composition was assessed. Both factors significantly affect the concentrations of secondary metabolites and, therefore, samples' antioxidant activity (p-value < 10-7). The obtained results (antioxidant activity and phenolic profile) were evaluated via chemometrics, through a preliminary principal component analysis (PCA) and orthogonal partial least square-discriminant analysis (OPLS-DA). The OPLS-DA model performed satisfactorily, differentiating all samples according to their matrix. Our results indicate that polyphenols and antioxidant capacity can be chemical markers for the classification of carob and its derived products.

Evaluation of cyclodextrin- and cyclofructan-based chiral selectors for the enantioseparation of psychoactive substances in capillary electrophoresis.

During this study, a simple and easy-to-prepare electrophoretic method was developed for the enantioseparation of amphetamine and cathinone derivatives. Different types of ß-cyclodextrin and cyclofructan-based chiral selectors (CSs), both native and derivatized, were utilized, and the most effective ones, in terms of resolution and analysis time, were identified. In addition, several electrophoretic parameters, such as background electrolyte concentration and pH, and CS concentration, were examined to optimize the separation conditions. Under the optimal electrophoretic conditions, 10 psychoactive substances were enantiomerically separated using 1 mM sulfated cyclofructan-6 (SCF-6) for the amphetamine derivatives and 1 mM sulfated cyclofructan-7 (SCF-7) for the cathinone derivatives dissolved in an aqueous solution of 20-mM monobasic sodium phosphate at pH 2.5, a temperature of 25°C, and an applied voltage of 25 kV. In addition, the method was validated by estimating the intra- and interday precision.

Anti-Cancer Activity and Phenolic Content of Extracts Derived from Cypriot Carob (Ceratonia siliqua L.) Pods Using Different Solvents.

Extracts derived from the Ceratonia siliqua L. (carob) tree have been widely studied for their ability to prevent many diseases mainly due to the presence of polyphenolic compounds. In this study, we explored, for the first time, the anti-cancer properties of Cypriot carobs. We produced extracts from ripe and unripe whole carobs, pulp and seeds using solvents with different polarities. We measured the ability of the extracts to inhibit proliferation and induce apoptosis in cancer and normal immortalized breast cells, using the MTT assay, cell cycle analysis and Western Blotting. The extracts' total polyphenol content and anti-oxidant action was evaluated using the Folin-Ciocalteu method and the DPPH assay. Finally, we used LC-MS analysis to identify and quantify polyphenols in the most effective extracts. Our results demonstrate that the anti-proliferative capacity of carob extracts varied with the stage of carob maturity and the extraction solvent. The Diethyl-ether and Ethyl acetate extracts derived from the ripe whole fruit had high Myricetin content and also displayed specific activity against cancer cells. Their mechanism of action involved caspase-dependent and independent apoptosis. Our results indicate that extracts from Cypriot carobs may have potential uses in the development of nutritional supplements and pharmaceuticals.

Combined use of ß-cyclodextrin and ionic liquid as electrolyte additives in EKC for separation and determination of carob's phenolics-A study of the synergistic effect.

In this work, a simple, reliable, and fast capillary electrophoretic method was developed and validated for the simultaneous determination of 12 polyphenolic compounds, the most frequently found in carob's pulp and seeds. The present work deals with the development of a novel dual electrophoretic system based on the combined use of ß-CD and ionic liquid (IL) as buffer additives. A baseline separation of the target analytes was achieved in less than 10 min by using a BGE consisting of 35 mM borate along with 15 mM ß-CD and 3 mM l-alanine tert butyl ester lactate (l-AlaC4 Lac) IL as buffer additives at pH 9.5, a temperature of 25°C, and an applied voltage of 30 kV. The application of the developed electrophoretic method to real samples enabled the identification and quantification of the main phenolic constituents of both ripe and unripe carob pulp extracts. The results revealed the predominance of gallic acid in both ripe (183.92 µg/g carob pulp) and unripe (205.10 µg/g carob pulp) carob pulp and highlighted the great influence of the ripening stage on carobs polyphenolic composition, with unripe pods being more enriched in polyphenols (total phenolics detected: 912.58 and 283.13 µg/g unripe and ripe carob pulp).

Continuous and pulsed ultrasound-assisted extraction of carob's antioxidants: Processing parameters optimization and identification of polyphenolic composition.

Polyphenols in carobs have recently attracted great attention due to their wide range of biological and health promoting effects. A comprehensive study was conducted to find an optimum method for the extraction, purification and characterization of these valuable bioactive substances. Under this framework, the ultrasound-assisted extraction (UAE) of polyphenols from carob pulp was optimized by the maximization of the yield in total phenolics using response surface methodology. In particular, the effects of solid-solvent ratio, solvent concentration, extraction time, sonication amplitude, and sonication mode were investigated and optimized using a complete experimental design. In comparison to conventional extraction techniques, UAE offered a higher yield of antioxidants and a shorter processing time. Solid-phase extraction was evaluated as a clean-up strategy prior to the electrophoretic analysis of extracts. The results from the analysis of real samples revealed the predominance of gallic acid and highlighted the great influence of the ripening stage on carobs composition.

Polyphenols in carobs: A review on their composition, antioxidant capacity and cytotoxic effects, and health impact.

Carob (Ceratonia Siliqua L., tree of the pea family Fabaceae) and its products have recently attracted great interest due to their polyphenolic composition. This review summarizes the polyphenolic compounds that are contained in different carob parts (leaves, pod, seeds, barks) and products (syrup, flour, fiber). It also states the main differences of polyphenolic composition due to environmental and natural reasons, such as region, variety, and gender, and due to the processes used for preparation, extraction and analysis. The gender, along with the extraction procedure, proved to be the most important factors affecting the polyphenolic composition. Supercritical fluid extraction is the most efficient technique used because it protects polyphenols from decomposition. Due to the relatively low number of publications, it is concluded that further development of optimum methods for extraction, analysis and isolation of polyphenols should be carried over to assess their antioxidant capacity and their food technological and pharmaceutical industry.