Application of Ionic Liquid-Based Ultrasonic-Assisted Extraction of Flavonoids from Bamboo Leaves

Endogenous crude Scutellaria baicalensis polysaccharide robustly enhances one-pot extraction and deglycosylation of baicalin

With the extensive application of baicalein in the treatment of cardiovascular and cerebrovascular diseases, its clinical and market demand has gradually expanded. But the natural yield of baicalein is very low, and it is mainly prepared by the deglycosylation of baicalin. However, the insolubility of baicalin in water significantly limits the deglycosylation of it under biocatalysis. To make biocatalysis of baicalin more efficient and environmental, a strategy was designed to enhance its water solubility through the solubilization mechanism of endogenous biological macromolecules, and the effect on the activity of glucuronidase was further explored. The results showed that wrapping with Scutellaria baicalensis polysaccharide (SBP) significantly improved the solubility of baicalin in water (the water solubility of baicalin increased by 23 times, BI/SBP = 1/12, w/w). It was not only contributed to the efficient production of baicalein by one-pot method, but also effectively improved the deglycosylation rate of baicalin (increase by 47.04 % in aqueous solution). With the help of the solubilization of endogenous polysaccharide on baicalin in aqueous solution, a green, low-cost and efficient method (one-pot method) was designed to simultaneously extract and enzymatic hydrolyze baicalin to prepare baicalein. Under the same conditions, the yield of one-pot method is 87.17 %, which was much higher than that of the conventional method (29.38 %). In addition, one-pot method with the aid of endogenous polysaccharide could simply and conveniently prepare aglycone of other insoluble natural flavonoids, which has a wide range of industrial application value.

Separation and Purification of Bamboo Leaf Flavones by Polyvinylpolypyrrolidone Adsorption

In view of the adsorption performance of polyvinylpolypyrrolidone (PVPP) to flavones, the adsorption and purification of bamboo leaf flavones (BLFs) by PVPP were studied. The flavones solution was adsorbed by PVPP column chromatography, and then establish a relatively effective method for elution and purification of flavones from bamboo leaf. The optimal separation conditions of column chromatography were determined as the following: the feed concentration of 10 mg/mL, the ratio of diameter to height of 1:1.9, eluents of deionized water (21 mL) and 70% ethanol (800 mL) with a flow rate of 0.33 mL/min. The purity of flavones obtained from ethanol eluents (80-480 mL) was 96.2%. This showed that the PVPP had an ideal adsorption and purification effect on BLFs.

Overwintering performance of bamboo leaves, and establishment of mathematical model for the distribution and introduction prediction of bamboos

Bamboo has great economic values and is used extensively in many industries, and their natural distribution range was divided into 12 zones in China according to the temperature of their geographical distribution in previous works. Different bamboo species had significantly different abilities in low-temperature tolerance, which need to be considered carefully during ex-situ introduction. In this paper, we observed and evaluated the low-temperature damage of 19 bamboo species in winter, and measured the physiological changes of bamboo leaves. A total of 3060 leaf samples were obtained from 102 core collections in 34 bamboo species from the 5 regions of Chinese mainland for anatomical comparison, in order to screen out the key anatomical indicators related to their low-temperature tolerance and to establish a mathematical prediction model for bamboo introduction. The results showed that the low-temperature resistance of clustered bamboos was generally lower than that of the scattered bamboos. The decreased temperature led to the constant decrease of net photosynthetic rate and transpiration rate, but the increase of soluble sugar content in all bamboo species. There was no dormancy for all bamboo species in winter. The temperate bamboos showed lower photosynthesis as compared to tropical bamboos in winter. The leaf shape of bamboos was closely related to their distribution. A total of 13 leaf indicators were screened and more suitable to estimate the low-temperature tolerant abilities of bamboos and to predict their distribution. The MNLR (multiple nonlinear regression) mathematical model showed the highest fitting degree and the optimal prediction ability in the potential northernmost introduction range of bamboos. This study lay a foundation for bamboo introduction, and could also reduce the economic losses caused by the wrong introduction.

Deep eutectic solvent-ultrasound assisted extraction as a green approach for enhanced extraction of naringenin from Searsia tripartita and retained their bioactivities

Background

Naringenin (NA) is a natural flavonoid used in the formulation of a wide range of pharmaceutical, fragrance, and cosmetic products. In this research, NA was extracted from Searsia tripartita using an environmentally friendly, high efficiency extraction method: an ultrasound-assisted extraction with deep eutectic solvents (UAE-DES).

Methods

Six natural deep eutectic solvent systems were tested. Choline chloride was used as the hydrogen bond acceptor (HBA), and formic acid, ethylene glycol, lactic acid, urea, glycerol, and citric acid were used as hydrogen bond donors (HBD).

Results

Based on the results of single-factor experiments, response surface methodology using a Box-Behnken design was applied to determine the optimal conditions for UAE-DES. According to the results, the optimal NA extraction parameters were as follows: DES-1 consisted of choline chloride (HBA) and formic acid (HBD) in a mole ratio of 2:1, an extraction time of 10 min, an extraction temperature of 50°C, an ultrasonic amplitude of 75 W, and a solid-liquid ratio of 1/60 g/mL. Extracted NA was shown to inhibit the activity of different enzymes in vitro, including α-amylase, acetylcholinesterase, butyrylcholinesterase, tyrosinase, elastase, collagenase, and hyaluronidase.

Conclusion

Thus, the UAE-DES technique produced high-efficiency NA extraction while retaining bioactivity, implying broad application potential, and making it worthy of consideration as a high-throughput green extraction method.

Separation of Flavonoids and Purification of Chlorogenic Acid from Bamboo Leaves Extraction Residues by Combination of Macroporous Resin and High-Speed Counter-Current Chromatography

Flavonoids are major active small-molecule compounds in bamboo leaves, which can be easily obtained from the bamboo leaves extraction residues (BLER) after the polysaccharides extraction. Six macroporous resins with different properties were screened to prepare and enrich isoorientin (IOR), orientin (OR), vitexin (VI), and isovitexin (IVI) from BLER, and the XAD-7HP resin with the best adsorption and desorption performance was selected for further evaluation. Based on the static adsorption experiments, the experimental results showed that the adsorption isotherm fitted well with the Langmuir isotherm model, and the adsorption process was better explained by the pseudo-second-order kinetic model. After the dynamic trial of resin column chromatography, 20 bed volume (BV) of upload sample and 60% ethanol as eluting solvent was used in a lab scale-up separation, and the results demonstrated that the content of four flavonoids could be increased by 4.5-fold, with recoveries between 72.86 and 88.21%. In addition, chlorogenic acid (CA) with purity of 95.1% was obtained in water-eluted parts during dynamic resin separation and further purified by high-speed countercurrent chromatography (HSCCC). In conclusion, this rapid and efficient method can provide a reference to utilize BLER to produce high-value-added food and pharmaceutical products.

Advances of Imidazolium Ionic Liquids for the Extraction of Phytochemicals from Plants

In this review, we present the research from 2013 to 2022 about the character of ionic liquids, the categories of phytochemicals, and the reasons for selecting imidazolium ionic liquids for phytochemical extraction. Then we introduce the structural formulae of the imidazolium ionic liquids commonly used in the extraction of phytochemicals, the methods used to prepare imidazolium ionic liquids, and a comprehensive introduction of how imidazolium ionic liquids are applied to extract phytochemicals from plants. Importantly, we discuss the strategies for studying the extraction mechanisms of imidazolium ionic liquids to extract phytochemicals, and the recovery methods regarding imidazolium ionic liquids and their recyclability are analyzed. Then the toxicity in imidazolium ionic liquids is pointed out. Finally, the challenges and prospects of extracting phytochemicals by imidazolium ionic liquids are summarized, and they are expected to provide some references for researchers.

Botanical characteristics, chemical components, biological activity, and potential applications of mangosteen

Garcinia mangostana L. (Mangosteen), a functional food, belongs to the Garcinaceae family and has various pharmacological effects, including anti-oxidative, anti-inflammatory, anticancer, antidiabetic, and neuroprotective effects. Mangosteen has abundant chemical constituents with powerful pharmacological effects. After searching scientific literature databases, including PubMed, Science Direct, Research Gate, Web of Science, VIP, Wanfang, and CNKI, we summarized the traditional applications, botanical features, chemical composition, and pharmacological effects of mangosteen. Further, we revealed the mechanism by which it improves health and treats disease. These findings provide a theoretical basis for mangosteen's future clinical use and will aid doctors and researchers who investigate the biological activity and functions of food.

Phytochemical Characterization for Quality Control of Phyllostachys pubescens Leaves Using High-Performance Liquid Chromatography Coupled with Diode Array Detector and Tandem Mass Detector

Phyllostachys pubescens leaves are cultivated in a number of Asian countries and have been used for antipyretic and diuretic effects since ancient times, especially in Korea. The purpose of this study was to develop and validate of analytical method for quality control of P. pubescens leaves using high-performance liquid chromatography with diode array detector (HPLC–DAD) and liquid chromatography with tandem mass spectrometry (LC–MS/MS) detection. HPLC–DAD analysis was conducted with a Gemini C₁₈ column, and distilled water–acetonitrile (both with 0.1% (v/v) formic acid) mobile-phase system. For the LC–MS/MS analysis, all markers were separated with a Waters ACQUITY UPLC BEH C₁₈ column and gradient flow system of distilled water containing 0.1% (v/v) formic acid and 5 mM ammonium formate–acetonitrile. In both method, major components were detected at 2.13–11.63 mg/g (HPLC–DAD) and 0.12–19.20 mg/g (LC–MS/MS). These methods were validated with respect to linearity (coefficient of determination >0.99), recovery (95.22–118.81%), accuracy (90.52–116.96), and precision (<4.0%), and were successfully applied for the quantitative analysis of P. pubescens leaves.

A targeted extraction with solvent-free pressurized method based on analyte-like oxonium salts: An example for simultaneous determination of bamboo-leaf flavonoids by ultra-performance liquid chromatography/ultraviolet detection

By using novel oxonium salts in "Sandwich" mode, an improved approach of targeted enrichment through a pressurized solvent-free extraction coupled with ultra-performance liquid chromatography/ultraviolet detection (UPLC-UV) analysis was developed for main bioactive flavonoids in bamboo leaves. As solid extractants, these salts have the same structural nucleus with analytes. By comparison, the yield of this new method was higher than that of reported ways, and the highest enrichment factor reached 394.22. The whole process was more consistent with pseudo-second order model (R²=0.9994) with the rate constant of 0.0537 (g/mg·min). Moreover, ideal selectivity, linearity, repeatability, limit of detection, limit of quantification, and recovery were all achieved.

An Efficient Ionic Liquid-Mediated Extraction and Enrichment of Isoimperatorin from Ostericum koreanum (Max.) Kitagawa

Ionic liquids (ILs) have attracted significant interest because of their desirable properties. These characteristics have improved their application to overcome the shortcomings of conventional separation techniques for phytochemicals. In this study, several ILs were investigated for their capacity to extract isoimperatorin, a bioactive furanocoumarin, from the roots of Ostericum koreanum. Herein, 1-Butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF4]) was selected as a promising IL for separating isoimperatorin. A central composite design was applied to optimize the extraction conditions. Under the optimal conditions, the yield of isoimperatorin reached 97.17 ± 1.84%. Additionally, the recovery of isoimperatorin from the [Bmim][BF4] solution was successfully achieved (87.73 ± 2.37%) by crystallization using water as an antisolvent. The purity of the isoimperatorin was greatly enhanced, from 0.26 ± 0.28% in the raw material to 26.94 ± 1.26% in the product, in a one-step crystallization process. Namely, an enhancement of approximately 103-folds was reached. The developed approach overcomes the shortcomings of conventional separation methods applied for gaining isoimperatorin by significantly reducing the laboriousness of the process and the consumption of volatile organic solvents. Moreover, the simplicity and effectiveness of the method are assumed to be valuable for producing isoimperatorin-enriched products and for promoting its purification. This work also confirms the efficiency of ILs as a promising material for the separation of phytochemicals.

Homogenate-Ultrasound-Assisted Ionic Liquid Extraction of Total Flavonoids from Selaginella involven: Process Optimization, Composition Identification, and Antioxidant Activity

In this paper, an efficient approach to extract total flavonoids (TFs) from Selaginella involvens (Sw.) Spring using homogenate-ultrasound-assisted ionic liquid (IL) extraction (HUA-ILE) was first developed. The results indicated that EPyBF4 was selected as the suitable extractant. According to the single factor experiment and response surface methodology, the IL concentration of 0.10 mol/L, the extraction time of 160 s, the liquid/solid ratio of 13:1 mL/g, and the extraction power of 300 W were concluded as the best conditions. A yield of 8.48 ± 0.27 mg/g TF content was obtained. Compared with HUA ethanol extraction, ultrasound-assisted IL extraction, and percolation extraction, the TF content obtained by the HUA-ILE method could be increased by 2 to 4 times, and the extraction time could be reduced by 100 times. Furthermore, 16 compounds of the TF extract were finally identified through ultra-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry, among which 11 compounds were first discovered in S. involven. The contents of six biflavonoids in S. involven were determined simultaneously adopting high-performance liquid chromatography, including amentoflavone, hinokiflavone, bilobetin, ginkgetin, isoginkgetin, and heveaflavone. The TF extract in S. involven was proved to have potent antioxidant activity through the four antioxidant experiments. In conclusion, HUA-ILE was applied for the first time to exploit a green, efficient, and novel approach to extract TFs, and the research also provided promising prospects for applications of S. involven.

Facile and Rapid Isolation of Oxypeucedanin Hydrate and Byakangelicin from Angelica dahurica by Using [Bmim]Tf2N Ionic Liquid

Ionic liquids (ILs) have sparked much interest as alternative solvents for plant materials as they provide distinctive properties. Therefore, in this study, the capacity of ILs to extract oxypeucedanin hydrate and byakangelicin from the roots of Angelica dahurica (A. dahurica) was investigated. The back-extraction method was examined to recover target components from the IL solution as well. Herein, [Bmim]Tf2N demonstrated outstanding performance for extracting oxypeucedanin hydrate and byakangelicin. Moreover, factors including solvent/solid ratio, extraction temperature and time were investigated and optimized using a statistical approach. Under optimum extraction conditions (solvent/solid ratio 8:1, temperature 60 °C and time 180 min), the yields of oxypeucedanin hydrate and byakangelicin were 98.06% and 99.52%, respectively. In addition, 0.01 N HCl showed the most significant ability to back-extract target components from the [Bmim]Tf2N solution. The total content of both oxypeucedanin hydrate (36.99%) and byakangelicin (45.12%) in the final product exceeded 80%. Based on the data, the proposed approach demonstrated satisfactory extraction ability, recovery and enrichment of target compounds in record time. Therefore, the developed approach is assumed essential to considerably reduce drawbacks encountered during the separation of oxypeucedanin hydrate and byakangelicin from the roots of A. dahurica.

Simultaneous Natural Deep Eutectic Solvent-Based Ultrasonic-Assisted Extraction of Bioactive Compounds of Cinnamon Bark and Sappan Wood as a Dipeptidyl Peptidase IV Inhibitor

Cinnamon bark (Cinnamomum burmannii) and sappan wood (Caesalpinia sappan) have been reported to be beneficial for Type-2 Diabetes Mellitus (T2DM) and the combination is commonly used by Indonesian herbal industries. In the present study, the simultaneous extraction of bioactive compounds from both plants was conducted using natural deep eutectic solvent (NADES), their content analyzed using high-performance liquid chromatography (HPLC), and their dipeptidyl peptidase IV (DPP IV) inhibitory activity evaluated. An additional in silico molecular docking analysis was conducted to ensure their activity. The results showed that NADES (with a composition of choline chloride–glycerol) extraction from cinnamon and sappan wood had DPP IV inhibitory activity of 205.0 and 1254.0 µg/mL, respectively. Brazilin as a marker substance from sappan wood was responsible for the DPP IV inhibitory activity, while none of the marker substances chosen for cinnamon bark (trans-cinnamaldehyde, coumarin, and trans-cinnamic acid) were found to have significant DPP IV inhibitory activity. These results were confirmed by molecular docking conducted in brazilin, trans-cinnamaldehyde, coumarin, and trans-cinnamic acid.

Bamboo leaf flavone changed the community of cecum microbiota and improved the immune function in broilers

It has been shown that bamboo leaf flavone (BLF) displays biological and pharmacological activities in mammals. However, the effects of BLF on broiler gut microbiota and related immune function have not been investigated. The aim of this study was to test our hypothesis that BLF can improve the health status of broilers by modulating the gut microbiota. A total of 300 one-day-old Arbor Acres (AA) broilers were used to characterize their gut microbiota and immune status after feeding diet supplemented with BLF. The V4 hypervariable region of the 16S rRNA gene from cecal bacteria was sequenced via the Illumina MiSeq platform. The Immune status and related parameters were assessed, including the immune organ index (the spleen, thymus, and bursa), serum concentrations of IL-2 and INF-γ, and spleen IL-2 and INF-γ gene expressions. The results showed the BLF diet had an Immune enhancement effect on broilers. In addition, BFL caused the changes of the gut microbial community structure, resulting in greater proportions of bacterial taxa belonging to Lactobacillus, Clostridiales, Ruminococcus, and Lachnospiraceae. These bacteria have been used as probiotics for producing short chain fatty acids in hosts. These results indicate that BLF supplement improves immune function in chicken via modulation of the gut microbiota.

Ionic Liquid-Based Ultrasonic-Assisted Extraction Coupled with HPLC and Artificial Neural Network Analysis for Ganoderma lucidum

Ganoderma lucidum is widely used in traditional Chinese medicine (TCM). Ganoderic acid A and D are the main bioactive components with anticancer effects in G. lucidum. To obtain the maximum content of two compounds from G. lucidum, a novel extraction method, an ionic liquid-based ultrasonic-assisted method (ILUAE) was established. Ionic liquids (ILs) of different types and parameters, including the concentration of ILs, ultrasonic power, ultrasonic time, rotational speed, solid–liquid ratio, were optimized by the orthogonal experiment and variance analysis. Under these optimal conditions, the total extraction yield of the two compounds in G. lucidum was 3.31 mg/g, which is 36.21% higher than that of the traditional solvent extraction method. Subsequently, an artificial neural network (ANN) was developed to model the performance of the total extraction yield. The Levenberg–Marquardt back propagation algorithm with the sigmoid transfer function (logsig) at the hidden layer and a linear transfer function (purelin) at the output layer were used. Results showed that single hidden layer with 9 neurons presented the best values for the mean squared error (MSE) and the correlation coefficient (R), with respectively corresponding values of 0.09622 and 0.93332.

Some Features of the Ultrasonic Liquid Extraction of Metal Ions

The non-linear equation of the radial oscillations of a liquid ball in an immiscible liquid under the exposure of time-varying sound pressure was obtained. The behavioral features of a liquid spherical drop placed in such a media were analyzed in the presence of ultrasound irradiations. The slowing-down effect of the extracted metal ions under its exposure has been studied for the first time, using theoretical and experimental approaches. This phenomenon mechanism was revealed, and analytical equations for the mass transfer rate as a function of the sound pressure oscillations amplitude and the substrate ultrasonic treatment time are presented. Experimental studies of Fe3+ ions extracted from chloride and nitrate solutions in systems based on water-soluble polymers were carried out, and a convincing coincidence with the results of theoretical calculations was established. The conditions for achieving the desired extraction efficiency when applying the ultrasonic stimulating effect are specified. The derived result opens the complementary possibility in operations, with the separateness of extraction processes, that which has the essential practical importance.

Efficient Extraction of Anti-Inflammatory Active Ingredients from Schefflera octophylla Leaves Using Ionic Liquid-Based Ultrasonic-Assisted Extraction Coupled with HPLC

Schefflera octophylla (Lour.) Harms, a kind of traditional Chinese medicine (TCM), is commonly used for anti-inflammatory, analgesic, rheumatism, fever, and hemostasis therapy. In our previous studies, two major triterpenoids were isolated and identified from leaves of S. octophylla, and evaluated for their inhibitory effects on lipopolysaccharide (LPS)-induced nitric oxide production in RAW264.7 cells; both of them displayed significant anti-inflammatory activities at their noncytotoxic concentrations. Therefore, it is very useful to establish an efficient and green extraction method to isolated the two major triterpenoids from leaves of S. octophylla. In this paper, ionic liquid based ultrasonic-assisted extraction (ILUAE) was successfully applied to extract the two major triterpenoids from leaves of S. octophylla. Four single factors (ionic liquids (ILs) concentration, solid–liquid ratio, centrifugal speed, mesh number), with a greater impact on extraction rate, were selected from a variety of influencing factors, and the optimal conditions were obtained by Box–Behnken response surface methodology (RSM). Under optimal conditions, the total extraction yield and extraction rate of two triterpenoids were 288.03 mg/g and 28.80%, respectively, which was 6.80% higher than that of 70% Ethanol (220 mg/g and 22%, respectively).

Rapid and Efficient Separation of Decursin and Decursinol Angelate from Angelica gigas Nakai using Ionic Liquid, (BMIm)BF4, Combined with Crystallization

Ionic liquids (ILs) have gained much attention as alternative solvents to volatile organic solvents due to their attractive properties. This study aimed to develop an efficient method for the selective separation of decursin (D) and decursinol angelate (DA) from Angelica gigas Nakai (A. gigas) using ILs and crystallization. The IL 1-butyl-3-methylimidazolium tetrafluoroborate ((BMIm)BF₄) was the most efficient at extracting D and DA. Parameters including solid-to-liquid ratio, time, and temperature were optimized by response surface methodology (RSM). Under optimal extraction conditions (1 g/6.5 mL solid-to-liquid ratio, 60 °C temperature, and 120 min time), the extraction yields of D and DA were 43.32 mg/g (97.06%) and 17.87 mg/g (97.12%), respectively. Moreover, drowning out crystallization using deionized water (DW) as an anti-solvent offered an excellent ability to recover D and DA from the A. gigas–(BMIm)BF₄ extraction solution. The rates of recovery and the total purity of D and DA were found to be greater than 97%. Therefore, a rapid and efficient method of combining ILs with crystallization was effectively achieved for the selective separation of D and DA. This approach is assumed to be beneficial in the pharmaceutical industry for the effective obtention of D- and DA-enriched products.

Ionic Liquid⁻Ultrasound-Based Extraction of Biflavonoids from Selaginella helvetica and Investigation of Their Antioxidant Activity

As a new and green solvent, ionic liquids (ILs) have received more attention during the green extraction and separation process for natural medicines. In this paper, IL-ultrasound-assisted extraction (IL-UAE) of total biflavonoids (TBFs) from Selaginella helvetica was firstly developed, and different ILs were employed and compared. Based on single-factor experiment, solid⁻liquid ratio (1:10⁻1:14 g/mL), IL concentration (0.6⁻1.0 mmol/mL), and extract temperature (40⁻60 °C) were further explored, according to response surface methodology (RSM), with TBF yields as the index. Moreover, antioxidant activity of TBF extract was analyzed by four methods, i.e., 2,2-di(4-tert-octylphenyl)-1-picrylhydrazyl (DPPH) and 2,2'-azinobis-(3-ethylbenzth-iazoline-6-sulphonate (ABTS) free radical scavenging assay, ferric ion reducing power assay, and chelation of ferrous ions assay. The results indicated that [C₆mim]PF₆ had a high selectivity and efficiency. Moreover, important parameters for the extraction process were investigated and optimized. Through parameter optimization (0.8 mmol/L, 250 W, 40 min, 1:12.7 g/mL, and 47 °C), a yield of 18.69 mg/g biflavonoids was obtained from the extract of S. helvetica. Compared with ethanol-UAE, heat-reflux extraction, Soxhlet extraction, and percolation extraction, IL-UAE could not only obtain higher yield in a shorter time, but also reduce the solvent consumption. In addition, TBF extract showed potential antioxidant activity based on the above four antioxidant methods. In short, IL-UAE was first employed to develop a novel and green extraction method for TBF content, and this experiment provides valuable references for further utilization of S. helvetica.