Ionic Liquid-Microwave-Based Extraction of Biflavonoids from Selaginella sinensis

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.

Sea Buckthorn Flavonoid Extracted by High Hydrostatic Pressure Inhibited IgE-Stimulated Mast Cell Activation through the Mitogen-Activated Protein Kinase Signaling Pathway

Sea buckthorn (Hippophaë rhamnoides L.), as one of the Elaeagnaceae family, has the significant function of anti-tumor, anti-inflammation, anti-oxidation, and other physiological activities. High hydrostatic pressure (HHP) extraction has the advantages of being easy and efficient, while maintaining biological activity. In this study, sea buckthorn flavonoid (SBF) was extracted with HHP and purified sea buckthorn flavonoid (PSBF) was isolated by AB-8 macroporous resin column. HPLC analysis was used to quantified them. In addition, the effect of anti-allergy in RBL-2H3 cells by SBF, PSBF, and their flavonoid compounds was evaluated. The results demonstrate the conditions for obtaining the maximum flavonoid amount of SBF: 415 MPa for 10 min, 72% ethanol concentration, and a liquid to solid ratio of 40 mL/g, which increased the purity from 1.46% to 13.26%. Both SBF and PSBF included rutin, quercitrin, quercetin, isorhamnetin, and kaempferol. In addition, quercitrin, kaempferol, and SBF could regulate Th1/Th2 cytokine balance. Moreover, extracellular Ca2+ influx was reduced by quercitrin and PSBF. Furthermore, rutin, quercetin, iso-rhamnetin, and SBF could also inhibit P-p38 and P-JNK expression, thereby suppressing the phosphorylation of the MAPK signaling pathways. Overall, SBF is effective for relieving food allergy and might be a promising anti-allergic therapeutic agent.

Flavonoids: Overview of Biosynthesis, Biological Activity, and Current Extraction Techniques

Recently, increased attention has been paid to natural sources as raw materials for the development of new added-value products. Flavonoids are a large family of polyphenols which include several classes based on their basic structure: flavanones, flavones, isoflavones, flavonols, flavanols, and anthocyanins. They have a multitude of biological properties, such as anti-inflammatory, antioxidant, antiviral, antimicrobial, anticancer, cardioprotective, and neuroprotective effects. Current trends of research and development on flavonoids relate to identification, extraction, isolation, physico-chemical characterization, and their applications to health benefits. This review presents an up-to-date survey of the most recent developments in the natural flavonoid classes, the biological activity of representative flavonoids, current extraction techniques, and perspectives.

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.

Enzymolysis-Microwave-Assisted Hydrodistillation for Extraction of Volatile Oil from Atractylodes Chinensis and Its Hypoglycemic Activity in vitro

BACKGROUND

Atractylodes chinensis (family Asteraceae) is a perennial herb with many pharmacological effects.

OBJECTIVE

Extraction of volatile oil from Atractylodes chinensis was optimized and its hypoglycemic activities were studied.

METHODS

Enzymolysis-microwave-assisted hydrodistillation (EMAHD) was adopted to extract the volatile oil, and the technology was optimized using a single-factor experiment that incorporated response surface methodology (RSM). The extraction rates of volatile oil by EMAHD, microwave-assisted hydrodistillation (MAHD), and hydrodistillation (HD) methods were compared at different times. The ingredients of Atractylodes chinensis volatile oil were analyzed by gas chromatography-mass spectrometry. Scanning electron microscopy (SEM) were used to analyze the microstructural changes in Atractylodes chinensis residue before and after extraction. The inhibition of α-amylase activity was determined.

RESULTS

The obtained optimal extraction conditions for EMAHD were as follows: enzyme concentration 1.6%, pH 7, enzymolysis time 20 min, enzymolysis temperature 50°C, liquid-solid ratio 30:1, microwave power 455 W, and microwave time 40 min. The levels of the main ingredients and the in vitro inhibition of α-amylase activities were higher for Atractylodes chinensis volatile oil extracted by EMAHD than by HD or MAHD. The powder residue of Atractylodes chinensis remaining after EMAHD showed a ruptured and collapsed cell structure, indicating accelerated dissolution of the volatile oil.

CONCLUSIONS AND HIGHLIGHTS

EMAHD is deemed a method with many advantages for extraction of volatile oil from Atractylodes chinensis. The volatile oil of Atractylodes chinensis is a promising component for treating hyperglycemia.

Binary Eluent Based Vortex-Assisted Matrix Solid-Phase Dispersion for the Extraction and Determination of Multicomponent from Musk by Gas Chromatography-Mass Spectrometry

A green, flexible, and effective strategy was proposed to quantify four target compounds (muscone, ethyl palmitate, ethyl oleate, and ethylparaben) from musk by binary eluent based vortex-assisted matrix solid-phase dispersion (MSPD) extraction coupled with GC/MS. Single-factor tests and orthogonal design were employed to optimize the MSPD parameters. In addition, the binary eluent system, methanol, and ethyl acetate 3 : 7 (v/v) were used to extract the target analytes. Finally, C ₁₈ was applied as the easily available dispersant and the sample powder was ground for 2 min. Thereafter, the mixture was rapidly extracted with the binary eluents under whirling for 3 min. Eventually, the analysis of the samples was completed within 12 min by GC/MS. All correlation coefficients (r) of four targets were more than 0.9991. The recoveries of all target compounds ranged from 92.8% to 101% while their RSDs were less than 6.94%. There was no significant matrix interference for the analysis. Thus, the combination of vortex-assisted MSPD with GC/MS was considered as a novel, rapid, and environmentally friendly quantitative approach for musk samples.

Hinokiflavone and Related C-O-C-Type Biflavonoids as Anti-cancer Compounds: Properties and Mechanism of Action

Biflavonoids are divided in two classes: C-C type compounds represented by the dimeric compound amentoflavone and C-O-C-type compounds typified by hinokiflavone (HNK) with an ether linkage between the two connected apigenin units. This later sub-group of bisflavonyl ethers includes HNK, ochnaflavone, delicaflavone and a few other dimeric compounds, found in a variety of plants, notably Selaginella species. A comprehensive review of the anticancer properties and mechanism of action of HNK is provided, to highlight the anti-proliferative and anti-metastatic activities of HNK and derivatives, and HNK-containing plant extracts. The anticancer effects rely on the capacity of HNK to interfere with the ERK1-2/p38/NFκB signaling pathway and the regulation of the expression of the matrix metalloproteinases MMP-2 and MMP-9 (with a potential direct binding to MMP-9). In addition, HNK was found to function as a potent modulator of pre-mRNA splicing, inhibiting the SUMO-specific protease SENP1. As such, HNK represents a rare SENP1 inhibitor of natural origin and a scaffold to design synthetic compounds. Oral formulations of HNK have been elaborated to enhance its solubility, to facilitate the compound delivery and to enhance its anticancer efficacy. The review shed light on the anticancer potential of C-O-C-type biflavonoids and specifically on the pharmacological profile of HNK. This compound deserves further attention as a regulator of pre-mRNA splicing, useful to treat cancers (in particular hepatocellular carcinoma) and other human pathologies.

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.

Biflavonoid as potential 3-chymotrypsin-like protease (3CLpro) inhibitor of SARS-Coronavirus

3CL protease is one of the key proteins expressed by SARS-Coronavirus-2 cell, the potential to be targeted in the discovery of antivirus during this COVID-19 pandemic. This protein regulates the proteolysis of viral polypeptide essential in forming RNA virus. 3CL protease (3CLpro) was commonly targeted in the previous SARS-Coronavirus including bat and MERS, hence, by blocking this protein activity, the coronavirus should be eradicated. This study aims to review the potency of biflavonoid as the SARS-Coronavirus-2 3CLpro inhibitor. The review was initiated by describing the chemical structure of biflavonoid and followed by listing its natural source. Instead, the synthetic pathway of biflavonoid was also elaborated. The 3CLpro structure and its function were also illustrated followed by the list of its 3D-crystal structure available in a protein data bank. Lastly, the pharmacophores of biflavonoid have been identified as a protease inhibitor, was also discussed. This review hopefully will help researchers to obtain packed information about biflavonoid which could lead to the study in designing and discovering a novel SARS-Coronavirus-2 drug by targetting the 3CLpro enzyme.

Ultrasonic-Assisted Ionic Liquid Extraction of Two Biflavonoids from Selaginella tamariscina

Selaginella tamariscina, a traditional Chinese medicine, contains a variety of bioactive components, among which biflavonoids are the main active ingredients and have antioxidant, antitumor, and anti-inflammatory properties. In this study, ultrasonic-assisted ionic liquid extraction (UAILE) is used for the first time to extract two main biflavonoids (amentoflavone (AME) and hinokiflavone (HIN)) from S. tamariscina. A high-performance liquid chromatography method is used for the simultaneous determination of AME and HIN in S. tamariscina. Then, three novel ILs are synthesized for the first time by a one-step method using benzoxazole and three acids or acid salts as raw materials, and the structures of the synthesized ILs are characterized by elemental analysis, infrared spectroscopy, and NMR spectroscopy, as well as the thermal stability of the ILs is evaluated by thermogravimetric analysis. After screening the extraction effects of three benzoxazole ILs, three pyridine ILs, and three imidazole ILs, it is found that [Bpy]BF4 is the best and therefore selected as the extractant. The optimal extraction process is explored in terms of the yields of AME and HIN from S. tamariscina by a single-factor experiments and response surface analysis. Under the optimal level of each influencing factor (IL concentration of 0.15 mol/L, solid-liquid ratio of 1:12 g/mL, ultrasonic power of 280 W, ultrasonic time of 30 min, and three extraction cycles), the extraction rates of AME and HIN from S. tamariscina are 13.51 and 6.74 mg/g, respectively. Moreover, the recovery experiment of [Bpy]BF4 on the extraction of biflavonoids shows that the recovered IL can repeatedly extract targets six times and the extraction rate is about 90%, which indicates that the IL can be effectively reused. UAILE can effectively and selectively extract AME and HIN, laying the foundation for the application of S. tamariscina.