Response surface modeling and optimization of the extraction conditions using lactic acid-based deep eutectic solvents as green alternative extraction media for Mentha pulegium

Selective extraction of plant bioactive compounds with deep eutectic solvents: Iris sibirica L. as example

INTRODUCTION

Deep eutectic solvents (DESs) are promising extractants with tuneable properties. However, there is a lack of reports about the influence of the nature of the original DES on obtaining the metabolomic profile of a plant.

OBJECTIVE

The aim of this study is to investigate the possibility of obtaining Iris sibirica L. chromatographical profiles with DESs based on various hydrogen bond donors and acceptors as extraction solvents.

METHODOLOGY

DESs were prepared by mixing choline chloride or tetrabutylammonium bromide with various hydrogen bond donors and investigated for the extraction of bioactive substances from biotechnological raw materials of I. sibirica L. The obtained extracts were analysed by HPLC with diode array detector (DAD) and Q-MS.

RESULTS

Chromatographic profiles for I. sibirica L. extracts by eight choline chloride DESs and six tetrabutylammonium DESs have been obtained. It has been found that selective recovery of bioactive substances can be achieved by varying the composition of DESs. Eleven phenolic compounds were identified in I. sibirica L. using HPLC-MS. Phase separation was observed with acetonitrile for four DESs. New flavonoid derivatives have been found in DES extracts compared with methanol extracts.

CONCLUSION

The results showed the possibility of DES usage for extraction without water addition. Selectivity of DESs varies depending on the chemical composition of hydrogen bond donors and acceptors. Choline chloride is a more suitable hydrogen bond acceptor for the flavonoid extraction. Choline chloride-lactic acid (1:1) DES has demonstrated a metabolic profile that was the closest to the methanol one and enhanced the extraction up to 2.6-fold.

Recovery of Polyphenols from Rosehip Seed Waste Using Natural Deep Eutectic Solvents and Ultrasonic Waves Simultaneously

Rosehips are processed and consumed in numerous forms, such as juice, wine, herbal tea, yogurt, preserved fruit, and canned products. The seeds share in fruit is 30-35% and they have recently been recognized as an important source of oil rich in unsaturated fatty acids. However, after defatting, seed waste may still contain some polar polyphenolic compounds, which have been scarcely investigated. The aim of this study was to examine the potential of the defatted seed waste as a source of polyphenols. For the defatting process, supercritical carbon dioxide extraction at 300 bar and 40 °C was applied. The capacity of eight different natural deep eutectic solvents (NADES) for the recovery of phenolics from defatted rosehip seed powder (dRSP) was examined. In the extracts obtained with ultrasound-assisted NADES extraction, twenty-one phenolic compounds were identified with LC-MS/MS, among which the most abundant were quinic acid (22.43 × 103 µg/g dRSP) and catechin (571.93 µg/g dRSP). Ternary NADES formulations based on lactic acid proved to be superior. Potential correlations between identified chemical compounds, solvent polarity and viscosity, as well as the compound distributions across studied solvent combinations in PCA hyperspace, were also investigated. PCA demonstrated that more polar NADES mixtures showed improved extraction potential. The established environmentally friendly process represents an approach of transforming rosehip seed waste into value-added products with the potential to be applied in the food industry and to contribute to sustainable production.

Optimization of Cyclodextrin-Assisted Extraction of Phenolics from Helichrysum italicum for Preparation of Extracts with Anti-Elastase and Anti-Collagenase Properties

Helichrysum italicum is a plant traditionally used for skin-related disorders that is becoming an increasingly popular ingredient in cosmetic products. In this work, a "green" ultrasound-assisted extraction method for H. italicum phenolics was developed using skin-friendly cyclodextrins (CDs). Extraction conditions needed for the greatest yield of target compounds (total phenolics, phenolic acids, and flavonoids) were calculated. The composition of the extracts was determined using LC-MS and spectrophotometric methods. Among the tested CDs, 2-hydroxylpropyl-beta-CD (HP-β-CD) was the best suited for extraction of target phenolics and used to prepare two optimized extracts, OPT 1 (the extract with the highest phenolic acid content) and OPT 2 (the extract with the highest total phenol and flavonoid content). The extracts were prepared at 80 °C, using 0.089 g of plant material/g solvent (0.6 mmol of HP-β-CD), with or without addition of 1.95% (w/w) lactic acid. The main metabolite in both extracts was 3,5-O-dicaffeoylquinic acid. It was found that the addition of lactic acid greatly contributes to the extraction of arzanol, a well-known anti-inflammatory agent. IC₅₀ values of the anti-elastase (22.360 ± 0.125 μL extract/mL and 20.067 ± 0.975 for OPT-1 and OPT-2, respectively) and anti-collagenase (12.035 ± 1.029 μL extract/mL and 14.392 ± 0.705 μL extract/mL for OPT-1 and OPT-2, respectively) activities of the extracts surpassed those of the applied positive controls, namely ursolic and gallic acids. This activity deems the prepared extracts promising ingredients for natural cosmetics, appropriate for direct use in cosmetic products, removing the need for the evaporation of conventional solvents.

Elaboration and Characterization of Natural Deep Eutectic Solvents (NADESs): Application in the Extraction of Phenolic Compounds from pitaya

In this paper, natural deep eutectic solvents (NADESs) with lactic acid, glycine, ammonium acetate, sodium acetate, and choline chloride were prepared with and without the addition of water. NADES formation was evaluated using FTIR and Raman, where hydrogen bonds were identified between the hydroxyl group of lactic acid and the amino and carboxyl groups of glycine. Acetate and ammonium ions were also identified as forming bonds with lactic acid. The addition of water did not cause changes in the vibrational modes of the FTIR and Raman spectra but contributed to a reduction in NADES viscosity and density. Viscosity ranged from 0.335 to 0.017 Pa s^-1, and density ranged from 1.159 to 0.785 g mL^-1. The best results for the extraction of phenolic compounds from pitaya (dragon fruit) were achieved with an organic solvent (450. 41 mg 100 g^-1 dry bases-db) in comparison to NADESs lactic acid:glycine (193.18 mg 100 g^-1 db) and lactic acid:ammonium acetate (186.08 mg 100 g^-1 db). The antioxidant activity of the extracts obtained with the NADESs was not statistically different from that of the extract obtained with organic solvents.