A hydrophobic deep eutectic solvents-based integrated method for efficient and green extraction and recovery of natural products from Rosmarinus officinalis leaves, Ginkgo biloba leaves and Salvia miltiorrhiza roots

Rapid screening and isolation of 5-lipoxygenase inhibitors in Inonotus obliquus and mechanism of action in the treatment of asthma

Accurate screening and targeted preparative isolation of active substances in natural medicines have long been two technical challenges in natural medicine research. This study outlines a new approach to improve the efficiency of natural product preparation, focusing on rapidly and accurately screening potential active ingredients in Inonotus obliquus as well as efficiently preparing 5-lipoxidase (5-LOX) inhibitors, to provide new ideas for the treatment of asthma with Inonotus obliquus. First, we used ultrafiltration (UF) mass spectrometry to screen for three potential inhibitors of 5-LOX in Inonotus obliquus. Subsequently, the inhibitory effect of the active ingredients screened in the UF assay on 5-LOX was verified using the molecular docking technique, and the potential role of the active compounds in Inonotus obliquus for the treatment of asthma was analyzed by network pharmacology. Finally, based on the above activity screening guidelines, we used semi-preparative liquid chromatography and consecutive high-speed countercurrent chromatography to isolate three high-purity 5-LOX inhibitors such as betulin, lanosterol, and quercetin. Obviously, through the above approach, we have seamlessly combined rapid discovery, screening, and centralized preparation of the active ingredient with molecular-level interactions between the active ingredient and the protease.

Recovery and separation of glycyrrhizic acid from Natural Deep Eutectic Solvent (NADES) extract by macroporous resin: adsorption kinetics and isotherm studies

Natural Deep Eutectic Solvents (NADESs) have emerged as a green and sustainable alternative to conventional organic solvents to extract bioactive compounds. However, the recovery of bioactive compounds from the NADES extracts is challenging, restricting their large-scale applications. The present work investigated the recovery of glycyrrhizic acid (GA) from choline-chloride/lactic acid NADES extract using macroporous resins. GA possesses a wide spectrum of biological activities, and it is extracted from the well-known herb Glycyrrhiza glabra. During resin screening, DIAIONTM SP700 showed high adsorption and desorption capacities. The adsorption kinetics study demonstrated that the adsorption of GA on SP700 followed Pseudo First-order kinetic model. Moreover, the adsorption behaviors were elucidated by the Freundlich isotherm using a correlation coefficient based on a static adsorption study at different temperatures and pH. Furthermore, the thermodynamic parameters, for instance, the change of Gibbs free energy (ΔG*), entropy (ΔS*), and enthalpy (ΔH*), showed that the adsorption process was spontaneous, favorable and exothermic. In addition, the sample after macroporous resin treatment, which is enriched with GA exhibited good anticancer potential analyzed by SRB assay. The regenerated NADES solvent was recycled twice, keeping more than 90% extraction efficiency, indicating good reusability of NADES in the GA extraction process by using macroporous resin.

A countercurrent chromatography solvent system based on deep eutectic solvents for separation of cis- and trans-crocetin from Gardenia jasminoides Ellis

Due to the structural similarity and large difference in concentration, the separation of trans- and cis-crocetin has been challenging, and the cis-crocetin is usually neglected. In this work, a countercurrent chromatography method was developed for the quick separation of trans-crocetin and cis-crocetin from the hydrolytic extract of Gardenia jasminoides Ellis. High purity of trans-crocetin (>95%) and cis-crocetin (>91%) were prepared simultaneously for the first time through a novel biphasic system based on deep eutectic solvents, n-heptane/n-butyl alcohol/13 mmol/L Na2 CO3 in water/acetamide-benzyltrimethylammonium chloride (4:1, mol/mol) (4:7:9:1, v/v). The addition of deep eutectic solvent significantly improved the separation efficiency. The two targets can be easily recovered from the separation system through simple acidification and precipitation. It has potential for preparative separations on a large scale.

An effervescence-assisted switchable deep eutectic solvent based liquid-phase microextraction of triazole fungicides in drinking water and beverage

A new effervescence-assisted switchable deep eutectic solvent-based liquid phase microextraction (EA-SDES-LPME) combined with HPLC-UV was developed for determination of common triazole fungicides in drinking water and beverages, including myclobutanil, flusilazole, hexaconazole and bitertanol. The alternative extraction solvent was prepared with hexafluoroisopropanol and dipropylamine with the merits of time-saving, easy to collect and cost-effectiveness. The SDES can be reversibly switched between hydrophilic and hydrophobic states by pH adjustment. The homogeneous extraction was achieved under the hydrophilic form of SDES, and the bi-phase separation was obtained easily by adjusting pH value to restore the original hydrophobicity. Moreover, the characterization of SDES was investigated by FTIR and 1H NMR. The main variables affecting extraction efficiency were optimized in detail. Under the optimal conditions, the proposed method shows desirable precision (RSDs less than 18.5%) and acceptable recovery (72.6-95.4%). The lower limits of detection and limits of quantitation were found to be in the range of 1-2 μg L-1 and 5-10 μg L-1, respectively. The formation mechanism of SDES and the extraction mechanism for target analytes were investigated by density functional theory. The proposed methodology was simplicity, sensitive, time-saving and successfully applied to determine triazole fungicides in drinking water and beverages, making it an alternative technique for the analysis of trace analytes with satisfactory sensitivity.

Identification of an effective fraction from Ampelopsis Radix with anti-dengue virus activities in vitro and in vivo

ETHNOPHARMACOLOGICAL RELEVANCE

Dengue virus (DENV) infection is a global public health issue without effective therapeutic interventions. Chinese medicine with heat-clearing and detoxifying properties has been frequently used in the treatment of viral infection. Ampelopsis Radix (AR) is a traditional Chinese medicine for clearing heat and detoxification that has been widely used in the prevention and treatment of infectious diseases. However, no studies on the effects of AR against viral infection have been reported, thus far.

AIM OF THE STUDY

To explore the anti-DENV activities of the fraction (AR-1) obtained from AR both in vitro and in vivo.

MATERIALS AND METHODS

The chemical composition of AR-1 was identified by liquid chromatography-tandem MS (LC‒MS/MS). The antiviral activities of AR-1 were studied in baby hamster kidney fibroblast BHK-21 cells, ICR suckling mice and induction of interferon α/β (IFN-α/β) and IFN-γ R^-/- (AG129) mice.

RESULTS

Based on LC‒MS/MS analysis, 60 compounds (including flavonoids, phenols, anthraquinones, alkaloids and other types) were tentatively characterized from AR-1. AR-1 inhibited the cytopathic effect, the production of progeny virus and the synthesis of viral RNA and proteins by blocking DENV-2 binding to BHK-21 cells. Moreover, AR-1 significantly attenuated weight loss, decreased clinical scores and prolonged the survival of DENV-infected ICR suckling mice. Critically, the viral load in blood, brain and kidney tissues and the pathological changes in brain were remarkably alleviated after AR-1 treatment. Further study on AG129 mice showed that AR-1 obviously improved the clinical manifestations and survival rate, reduced viremia, attenuated gastric distension and relieved the pathological lesions caused by DENV.

CONCLUSIONS

In summary, this is the first report that AR-1 exhibits anti-DENV effects both in vitro and in vivo, which suggests that AR-1 may be developed as a therapeutic candidate against DENV infection.

Isolation of the Main Biologically Active Substances and Phytochemical Analysis of Ginkgo biloba Callus Culture Extracts

The work reveals the results of studying the content of biologically active substances in samples of extracts of Ginkgo biloba callus cultures. Callus cultures grown in vitro on liquid nutrient media were the objects of the study. Considering various factors affecting the yield of the target components during extraction, the volume fraction of the organic modifier in the extracting mixture, the temperature factor, and the exposure time were identified as the main ones. The maximum yield of extractive substances (target biologically active substances with a degree of extraction of at least 50%) from the samples of callus culture extracts was detected at a ratio of extragent of 70% ethanol, a temperature of 50 °C, and exposure time of 6 h. Flavonoids, such as luteolin, quercetin, isoramentin, kaempferol, and amentoflavone, were isolated in the extract samples. As a result of column chromatography, fractions of individual biologically active substances (bilobalide, ginkgolide A, B, and C) were determined. The proposed schemes are focused on preserving the nativity while ensuring maximum purification from associated (ballast) components. Sorbents (Sephadex LH-20, poly-amide, silica gel) were used in successive stages of chromatography with rechromatography. The degree of purity of individually isolated substances was at least 95%.

Optimization of mechanically assisted coamorphous dispersion extraction of hydrophobic compounds from plant tea (Citri Reticulatae Pericarpium) using water

This study aimed to establish a novel mechanically assisted coamorphous dispersion extraction (MADE) method for the extraction of hydrophobic compounds (hesperidin, nobiletin and tangeretin) from Citri Reticulatae Pericarpium using water. The surface morphology, particle size distributions, phase states and functional groups of the coground product surface were characterized by Scanning Electron Microscopy, X-ray diffraction and Fourier transform infrared spectroscopy. The parameters affecting the efficiency of extraction method were optimized by single-factor experiments and response surface methodology. The method showed good linear relationships in the range of 1-500 μg/mL with correlation coefficients (R²) ≥ 0.9990, low limits of detection ranging from 3.0 to 28.3 ng/mL, and acceptable recoveries ranging from 87.0 to 91.0%. Therefore, the proposed MADE method is a promising, efficient and organic solvent-free method for the extraction of hydrophobic compounds from plant tea.

Untargeted Metabolomics by Using UHPLC–ESI–MS/MS of an Extract Obtained with Ethyl Lactate Green Solvent from Salvia rosmarinus

Salvia rosmarinus (Lamiaceae), previously known as Rosmarinus officinalis, is a plant cultivated worldwide, native to the Mediterranean region. Its leaves are traditionally used for cooking. This species possesses numerous biological activities, including antioxidant, antimicrobial, anticancer, anti-inflammatory, and hepatoprotective properties. These biological properties are due to the presence of phenolic compounds, including rosmarinic acid and phenolic diterpenoids, such as carnosic acid and carnosol. In this study, we investigated the chemical composition of a green extract obtained by maceration with ethyl lactate for the first time. Seventy-five compounds were tentatively identified by UHPLC–ESI–MS/MS, including six organic acids, six cinnamic acid derivatives, five fatty acids, eighteen flavonoids, and thirty-eight terpenoids. Thus, abietane-type diterpenoids from the ethyl lactate extract were the predominant diterpenoids in the Chilean S. rosmarinus species, in contrast to the Chinese species, in which labdane and isopimarane-type diterpenoids were found for the first time. Finally, our study confirms that the extraction of S. rosmarinus with green ethyl lactate as a solvent is efficient and sustainable for the identification of flavonoids, phenols, and terpenoids from leaves.

Tetrabutylammonium bromide-based hydrophobic deep eutectic solvent for the extraction and separation of dihydromyricetin from vine tea and its inhibitory efficiency against xanthine oxidase

In this study, deep eutectic solvent oscillation-assisted extraction (DES-OS) combined with macroporous resin adsorption and desorption technology was used to achieve the rapid green extraction and separation of the characteristic component dihydromyricetin (DMY) from vine tea. Multivariate data analysis showed that the DES system composed of tetrabutylammonium bromide (N₄₄₄Br) and pyruvic acid (molar ratio 1 : 2) had good extraction performance for DMY. The influence parameters of DES-OS were studied, and optimized by the single-factor test and response surface methodology (RSM) with Box–Behnken design (BBD). The extraction model of DMY was established and verified. The results showed that the extraction yield of DMY could reach 40.1 mg g⁻¹ under the optimal conditions (DES water contents of 71.18%, extraction time of 2.80 h, extraction temperature of 46.40 °C), which is in good agreement with the predicted value. In addition, Fourier transform infrared spectroscopy (FT-IR) was used to characterize the solvent before and after extraction. Scanning electron microscopy (SEM) results further confirmed that tetrabutylammonium bromide:pyruvate enhanced the destruction of the cell wall structure, resulting in the release of more DMY. Furthermore, different macroporous resins were selected for the separation of DMY for the DES-OS extract, and it was found that the DM301 resin had the ideal recovery performance under optimized dynamic condition. Finally, the product was found to have an inhibitory effect against xanthine oxidase (XO) as a mixed-type competitive inhibitor with IC50 values of (5.79 ± 0.22) × 10⁻⁵ mol L⁻¹. The inhibitory mechanisms of DMY on XO were explored by enzyme kinetics, spectroscopy, molecular docking and molecular dynamics analysis approaches, which provided a theoretical basis for the above inhibition assays.

In this study, deep eutectic solvent oscillation-assisted extraction (DES-OS) combined with macroporous resin adsorption and desorption technology was used to achieve the rapid green extraction and separation of dihydromyricetin (DMY) from vine tea.

Selective extraction and stabilization of bioactive compounds from rosemary leaves using a biphasic NADES

Rosemary (Rosmarinus officinalis) is a natural source of bioactive compounds that have high antioxidant activity. It has been in use as a medicinal herb since ancient times, and it currently is in widespread use due to its inherent pharmacological and therapeutic potential, in the pharmaceutical, food, and cosmetic industries. Natural deep eutectic systems (NADESs) have recently been considered as suitable extraction solvents for bioactive compounds, with high solvent power, low toxicity, biodegradability, and low environmental impact. The present work concerns the extraction of compounds such as rosmarinic acid, carnosol, carnosic acid, and caffeic acid, from rosemary using NADESs. This extraction was carried out using heat and stirring (HS) and ultrasound-assisted extraction (UAE). A NADES composed of menthol and lauric acid at a molar ratio of 2:1 (Me:Lau) extracted carnosic acid and carnosol preferentially, showing that this NADES exhibits selectivity for nonpolar compounds. On the other hand, a system of lactic acid and glucose (LA:Glu (5:1)) extracted preferentially rosmaniric acid, which is a more polar compound. Taking advantage of the different polarities of these NADESs, a simultaneous extraction was carried out, where the two NADESs form a biphasic system. The system LA:Glu (5:1)/Men:Lau (2:1) presented the most promising results, reaching 1.00 ± 0.12 mg of rosmarinic acid/g rosemary and 0.26 ± 0.04 mg caffeic acid/g rosemary in the more polar phase and 2.30 ± 0.18 mg of carnosol/g of rosemary and 17.54 ± 1.88 mg carnosic acid/g rosemary in the nonpolar phase. This work reveals that is possible to use two different systems at the same time and extract different compounds in a single-step process under the same conditions. NADESs are also reported to stabilize bioactive compounds, due to their interactions established with NADES components. To determine the stability of the extracts over time, the compounds of interest were quantified by HPLC at different time points. This allows the conclusion that bioactive compounds from rosemary were stable in NADESs for long periods of time; in particular, carnosic acid presented a decrease of only 25% in its antioxidant activity after 3 months, whereas the carnosic acid extracted and kept in the methanol was no longer detected after 15 days. The stabilizing ability of NADESs to extract phenolic/bioactive compounds shows a great promise for future industrial applications.

Study of the Preparation and Properties of Chrysin Binary Functional Monomer Molecularly Imprinted Polymers

Chrysin is a natural bioactive molecule with various groups, and it has been a challenge to separate and enrich chrysin from natural products. Molecularly imprinted polymers have been widely used in the extraction of natural products, but the number and type of functional monomers limits the separation effect. The synergistic action of multiple functional monomers can improve the separation effect. In this paper, molecularly imprinted polymers (Bi-MIPs) were prepared using methacrylic acid and acrylamide as binary functional monomers for the separation and enrichment of chrysin. The Bi-MIPs were characterized using thermogravimetric analyzer (TGA), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscope (SEM). The performances of Bi-MIPs were assessed, which included adsorption isotherms, selective recognition and adsorption kinetics. The experimental results show that Bi-MIPs are shaped as a uniform sphere with an abundant pocket structure on its surface. The adsorption of chrysin on the Bi-MIPs followed a pseudo-second-order and adapted Langmuir–Freundlich isotherm models. The adsorption performance of the Bi-MIPs was determined at different temperatures, and the Bi-MIPs showed excellent adsorption performance at 30 °C. The initial decomposition temperature of the Bi-MIPs was 220 °C. After five times of adsorption and desorption, the adsorption performance of the Bi-MIPs decreased by only 7%. In contrast with single functional monomer molecularly imprinted polymers (Si-MIPs), the Bi-MIPs showed excellent specificity, with an imprinting factor of 1.54. The Bi-MIPs are promising materials in the separation and enrichment of chrysin for their high adsorption capacity, low cost and being environmentally friendly.

Eutectic Thin-Layer Chromatography as a New Possibility for Quantification of Plant Extracts-A Case Study

Deep eutectic solvents (DES), compared to classic ones, have interesting properties, such as the ability to solubilize compounds differing in polarity or increased dissolution of selected chemical compounds. They also offer specific interactions between the mobile and stationary phases. Those features make them promising solvents in chromatographic techniques, including the use in the separation of complicated samples. The first quantitative analysis with eutectic thin-layer chromatography (TLC) is presented in the paper. As a case study, five alkaloids from Chelidonium maius were selected as target compounds. A wide range of terpene-based DESs was investigated to develop the chromatographic system, both pure and after dilution. Moreover, a novel approach was employed to adjust polarity, involving mixing DESs differing in chromatographic properties. This procedure has proved to be effective. The best results were obtained with a 2:1 (wt/wt) mixture of DESs: camphor + phenol and menthol + limonene, with a 20% addition of methanol. The chromatographic system was validated and checked on the real sample, which made it the first applicable and operational quantitative eutectic TLC system.