Extraction kinetics, thermodynamics, rheological properties and anti-BVDV activity of the hot water assisted extraction of Glycyrrhiza polysaccharide

A review of polysaccharides from Ganoderma lucidum: Preparation methods, structural characteristics, bioactivities, structure-activity relationships and potential applications

Ganoderma lucidum (G. lucidum), commonly known as "fairy grass", is a saprophyte fungus belonging to the Polyporaceae family with a lengthy history of use as a food ingredient and traditional medicine in China. G. lucidum is abundant in diverse chemical compounds that encompass polysaccharides, alkaloids, steroids, terpenoids, proteins, as well as amino acids. Among these, polysaccharides as the main active ingredients prepared from G. lucidum have exhibited a multitude of biological activities, such as anti-tumor effect, antioxidant activity, antidiabetic effect, anti-inflammatory effect, immune regulation and so forth. The main methods for extracting GLPs are hot water extraction, ultrasound-assisted extraction, microwave-assisted extraction and enzyme-assisted extraction. The research on GLPs poses challenges, especially in optimizing extraction and purification processes to enhance the yield and preserve the structural characteristics. Furthermore, it remains ambiguous whether the bioactivities of GLPs are closely related to their extraction methods and structural characteristics, necessitating further exploration and elucidation of the structure-activity relationships. This review comprehensively and systematically outlines an overview of the preparation methods, structural characteristics, bioactivities, structure-activity relationships and potential applications of GLPs. The review emphasizes their therapeutic potential and health functions, providing a reference for further exploitation and application in various fields of GLPs.

Immunomodulation of Glycyrrhiza Polysaccharides In Vivo Based on Microbiome and Metabolomics Approaches

Glycyrrhiza uralensis Fisch. is a medicinal herb that can be added to food to provide therapeutic effects and reduce the burden of medications. Herein, the immunomodulatory effects of Glycyrrhiza polysaccharides (GPs) were verified and illustrated by intervening immunocompromised rats treated with different doses of GPs, which were reflected for adjusting the composition and structure of the intestinal microbiota and altering the metabolic profile. The immunomodulatory effects of GPs were exerted by regulating the intestinal microenvironment. In particular, GPs could promote the growth of probiotic bacteria Allobaculum, norank__o_Clostridia_UCG-014, Dubosiella, and g__norank_o___RF39 and curb the growth of harmful bacteria Enterococcus. The results showed that GPs had a prebiotic effect, which contributed to improving the intestinal environment and maintaining intestinal health. In addition, the content of beneficial differential metabolites was up-regulated, especially short-chain fatty acids, with alanine, aspartate, and glutamate metabolism; arginine biosynthesis; glyoxylate and dicarboxylate metabolism being the most enriched pathways. These metabolic pathways imply the metabolic process of GPs, and the metabolic pathways and differential effector metabolites of it are focused. Overall, the purpose of this article lies in providing support for the application of GPs for regulating immune function.

Comprehensive understanding of impacts of steam explosion on facilitated extraction and transformation of flavonoids from Astragali Radix

Recalcitrant structure of cell walls restricts the extraction of bioactive components from edible plants. In this study, the impacts of steam explosion (SE) on the release and transformation of flavonoids in Astragali Radix (AR) were evaluated. Results revealed that SE destroyed the compact structure of cell walls. Furthermore, the porous network was reformed due to the degradation of hemicelluloses and water-soluble components. The maximum extraction contents of ethanol-soluble and water-soluble flavonoids of 6.34 and 1.48 mg/g were obtained from the pretreated AR (1.5 MPa, 5 min), which were 5.22 and 2.88 times higher than those obtained from the untreated AR, respectively. SE not only released bound flavonoids from cell walls by cleaving glycoside or ester bonds, but also transformed some flavonoid glycosides into aglycones through deglycosylation. In conclusion, SE can reduce mass transfer hindrance and facilitate flavonoid transformation, thus providing a green and facile processing method for traditional edible plants.

Designing green and recyclable switchable supramolecular deep eutectic solvents for efficient extraction of flavonoids from Scutellariae Radix and mechanism exploration

A green and recyclable switchable supramolecular deep eutectic solvent (SS-DES) was designed and prepared for effective extraction of flavonoids from Scutellariae Radix. The novel SS-DES has both excellent extraction performance of DES and the host guest inclusion of cyclodextrin, thereby showing superior extraction efficiency and selectivity. The characteristic of polarity switching can endow the SS-DES with achieving homogeneous extraction and rapid two-phase separation, shorting per-treatment time largely. Parameters affecting the extraction performance were investigated by the response surface methodology. The results indicated that the SS-DES showed better extraction yield of total flavonoids (157.95 mg/g) compared with pure DES (135 mg/g) and traditional organic solvent (60 % ethanol, 104.87 mg/g). Moreover, the switching mechanism of SS-DES was characterized by FT-IR and 1H NMR, and the extraction mechanism was studied by density functional theory and molecular docking analysis. After evaluating the ecological impact of the method, the cytotoxicity of SS-DES was investigated and the result displayed that its toxicity was very low or even negligible with the EC50>2000 mg/L. After being adsorbed by macroporous AB-8 resin, the regenerated SS-DES was recycled 5 times and the extraction efficiency still remained above 90 %, indicating the desirable reusability. Therefore, the proposed method was efficient and sustainable, and revealed favorable application prospect for the extraction of bio-active compounds from plant materials.

Study on the Optimization, Extraction Kinetics and Thermodynamics of the Ultrasound-Assisted Enzymatic Extraction of Tremella fuciformis Polysaccharides

In this study, Tremella fuciformis polysaccharides (TFPs) were extracted by ultrasound-assisted enzymatic extraction (UAE) at different extraction parameters in order to explore the potential of ultrasound in intensifying the extraction yield. The effects of experimental conditions on the extraction yields were optimized using response surface methodology, with the optimal ultrasonic power of 700 W, temperature of 45 °C and time of 50 min. The kinetic analysis revealed that UAE significantly promoted the dissolution, diffusion and migration with the maximum yield of 26.39%, which was enhanced by 40.45% and 156.96% compared with individual ultrasonic extraction (UE) and enzymatic extraction (EE). According to the modified Fick's second law of diffusion, the extraction process of TFPs illustrated a good linear correlation (R2 ≥ 0.9), and the rate constant gradually elevated as the temperature increased from 25 to 45 °C, while the presence of ultrasound exerted a vital role in extracting TFPs. Regarding to the thermodynamic results, the positive values of ΔH and ΔG demonstrated that UAE, UE and EE were endothermic and unspontaneous processes. This study provides a theoretical basis for polysaccharide extraction processing.

Eco-friendly and efficient extraction of polyphenols from Ligustrum robustum by deep eutectic solvent assisted ultrasound

An eco-friendly and efficient extraction method using deep eutectic solvents assisted ultrasound extraction (DESs-UAE) for the polyphenols from Ligustrum robustum was developed. Among the 34 kinds of DESs prepared, tetraethyl ammonium bromide: 1,2,4-butanol (Teab: 1,2,4-But) was proved to be a suitable extraction solvent based on the extraction efficiency. The extraction parameters including temperature, water content, liquid-solid ratio were optimized with response surface methodology (RSM). Under the optimal conditions, the total phenolic content (TPC) and total flavonoid content (TFC) were 101.46 ± 2.96 mg GAE/g DW and 264.17 ± 5.39 mg RE/g DW, respectively. Furthermore, the extraction mechanism of DESs-UAE was investigated by extraction kinetics, molecular dynamic simulation and theory calculations of interaction. In particular, 9 kinds of polyphenols compounds from Ligustrum robustum were firstly identified by UPLC-Q-TOF-MS. Moreover, the recovered polyphenols exhibited significant antioxidant, α-glucosidase inhibition, acetylcholinesterase inhibition and anticancer activity.

Effects of slit dual-frequency ultrasound-assisted pulping on the structure, functional properties and antioxidant activity of Lycium barbarum proteins and in situ real-time monitoring process

To improve the protein dissolution rate and the quality of fresh Lycium barbarum pulp (LBP), we optimized the slit dual-frequency ultrasound-assisted pulping process, explored the dissolution kinetics of Lycium barbarum protein (LBPr), and established a near-infrared spectroscopy in situ real-time monitoring model for LBPr dissolution through spectral information analysis and chemometric methods. The results showed that under optimal conditions (dual-frequency 28-33 kHz, 300 W, 31 min, 40 °C, interval ratio 5:2 s/s), ultrasonic treatment not only significantly increased LBPr dissolution rate (increased by 71.48 %, p < 0.05), improved other nutrient contents and color, but also reduced the protein particle size, changed the amino acid composition ratio and protein structure, and increased the surface hydrophobicity, zeta potential, and free sulfhydryl content of protein, as well as the antioxidant activity of LBPr. In addition, ultrasonication significantly improved the functional properties of the protein, including thermal stability, foaming, emulsification and oil absorption capacity. Furthermore, the real-time monitoring model of the dissolution process was able to quantitatively predict the dissolution rate of LBPr with good calibration and prediction performance (Rc = 0.9835, RMSECV = 2.174, Rp = 0.9841, RMSEP = 1.206). These findings indicated that dual-frequency ultrasound has great potential to improve the quality of LBP and may provide a theoretical basis for the establishment of an intelligent control system in the industrialized production of LBP and the functional development of LBPr.

Total biflavonoids extraction from Selaginella chaetoloma utilizing ultrasound-assisted deep eutectic solvent: Optimization of conditions, extraction mechanism, and biological activity in vitro

In this study, the deep eutectic solvent based ultrasound-assisted extraction (DES-UAE) was investigated for the efficient and environmentally friendly extraction of Selaginella chaetoloma total biflavonoids (SCTB). As an extractant for optimization, tetrapropylaminium bromide-1,4-butanediol (Tpr-But) was employed for the first time. 36 DESs were created, with Tpr-But producing the most effective results. Based on response surface methodology (RSM), the greatest extraction rate of SCTB was determined to be 21.68 ± 0.78 mg/g, the molar ratio of HBD to HBA was 3.70:1, the extraction temperature was 57 °C, and the water content of DES was 22 %. In accordance with Fick's second rule, a kinetic model for the extraction of SCTB by DES-UAE has been derived. With correlation coefficients 0.91, the kinetic model of the extraction process was significantly correlated with the general and exponential equations of kinetics, and some important kinetic parameters such as rate constants, energy of activation and raffinate rate were determined. In addition, molecular dynamics simulations were used to study the extraction mechanisms generated by different solvents. Comparing the effect of several extraction methods on S.chaetoloma using ultrasound-assisted extraction and conventional methods, together with SEM examination, revealed that DES-UAE not only saved time but also enhanced SCTB extraction rate by 1.5-3 folds. SCTB demonstrated superior antioxidant activity in three studies in vitro. Furthermore, the extract could suppress the growth of A549, HCT-116, HepG2, and HT-29 cancer cells. Alpha-Glucosidase (AG) inhibition experiment and molecular docking studies suggested that SCTB exhibited strong inhibitory activity against AG and potential hypoglycemic effects. The results of this study indicated that a Tpr-But-based UAE method was suitable for the efficient and environmentally friendly extraction of SCTB, and also shed light on the mechanisms responsible for the increased extraction efficiency, which could aid in the application of S.chaetoloma and provide insight into the extraction mechanism of DES.

Beyond cellulose: pharmaceutical potential for bioactive plant polysaccharides in treating disease and gut dysbiosis

Polysaccharides derived from plants, algae, or fungi serve as the major components of some human diets. Polysaccharides have been shown to exhibit diverse biological activities in improving human health, and have also been proposed to function as potent modulators of gut microbiota composition, thus playing a bi-directional regulatory role in host health. Here, we review a variety of polysaccharide structures potentially linked to biological functions, and cover current research progress in characterizing their pharmaceutical effects in various disease models, including antioxidant, anticoagulant, anti-inflammatory, immunomodulatory, hypoglycemic, and antimicrobial activities. We also highlight the effects of polysaccharides on modulating gut microbiota via enrichment for beneficial taxa and suppression of potential pathogens, leading to increased microbial expression of carbohydrate-active enzymes and enhanced short chain fatty acid production. This review also discusses polysaccharide-mediated improvements in gut function by influencing interleukin and hormone secretion in host intestinal epithelial cells.

Glycyrrhiza Polysaccharide Inhibits Pseudorabies Virus Infection by Interfering with Virus Attachment and Internalization

Pseudorabies virus (PRV) is one of the most important pathogens causing serious diseases and leads to huge economic losses in the global swine industry. With the continuous emergence of PRV variants and the increasing number of cases of human infection, there is an urgent need to develop antiviral drugs. In this study, we discover that Glycyrrhiza polysaccharide (GCP) has anti-PRV infection activity in vitro, and 600 μg/mL GCP can completely block viral infection. The addition of GCP simultaneously with or after PRV infection had a significant inhibitory effect on PRV. Addition of GCP at different times of the virus life cycle mainly led to the inhibition of the attachment and internalization of PRV but does not affect viral replication and release. Our findings suggest that GCP has potential as a drug against PRV infection.

Isolation, Characterization, Pharmacology and Biopolymer Applications of Licorice Polysaccharides: Review

Licorice is known as "Gan-Cao" in traditional Chinese Medicine (TCM), belonging to the genus Glycyrrhiza (Family: Fabaceae/Leguminosae). It has a long medicinal history and wide applications in China. Polysaccharides of licorice (LPs) are one of the key bioactive components. As herbal polysaccharides attracted increasing interest in the past several decades, their extraction, isolation, structural characterization, pharmacological activities, and medicinal application have been explored extensively. It is worth heeding that the method of extraction and purification effects LPs, apart from specie and origin specificity. This review evaluates the method of extraction and purification and demonstrates its performance in gaining specific composition and its structure-activity relationship, which might lead the readers to a fresh horizon for developing advanced treatment strategies. It is recently reported that the conformation of LPs plays a vital role as biopolymers, such as selenized modification, microencapsulation, nanocomposite, liposome formulation, drug/hydrogel combinations, biosensor device, and synergistic effect with a vaccine. In addition, LPs showed a good thermodynamics profile, as these properties enable them to interact with additional supramolecular interaction by chemical modifications or copolymerization. Functional polymers that are responsive to various external stimuli, such as physical, chemical, and biological signals, are a promising study topic. Thus, LPs are emerging as a new biomaterial that can enhance intended formulation along exerting its inherent medicinal effects. It is hoped that this review will provide a basis for the utilization and further developments of licorice polysaccharides in the vast medium.

Extraction kinetics, physicochemical properties and immunomodulatory activity of the novel continuous phase transition extraction of polysaccharides from Ganoderma lucidum

Ganoderma lucidum polysaccharides (GLP) possess remarkable bioactivity and have been studied widely. However, the application of new technologies in the polysaccharide extraction has not been investigated. Herein, a novel continuous phase transition extraction (CPTE) technology was applied for the extraction of polysaccharides from Ganoderma lucidum. The extraction kinetics, physicochemical properties and immunomodulatory activity of GLP were evaluated. The kinetics results showed that the extraction process could be fitted to a two-site kinetic model due to the high R² values in the range of 0.9939-0.9999. Polysaccharides extracted by different technologies showed that GLP yield by CPTE could be significantly improved, which was 3.34 times and 2.68 times that of hot water and ultrasonic-assisted extraction, respectively. Molecular weight distribution analysis indicated that high molecular mass polysaccharide proportion by CPTE was the highest among the three extraction methods, which was 2.03 times and 3.41 times as much as that of the hot water and ultrasonic-assisted extraction. Morphology analysis showed that CPTE treatment caused disruption of most of the cells and effective release of intracellular components, implying that CPTE was beneficial to extract polysaccharides. Furthermore, the immunomodulatory assays demonstrated that GLP significantly enhanced the proliferation and production of NO, TNF-α and IL-6 in macrophages. Therefore, CPTE was more effective for extracting polysaccharides from Ganoderma lucidum than the common extraction.

Development of Broad-Spectrum Antiviral Agents-Inspiration from Immunomodulatory Natural Products

Developing broad-spectrum antiviral drugs remains an important issue as viral infections continue to threaten public health. Host-directed therapy is a method that focuses on potential targets in host cells or the body, instead of viral proteins. Its antiviral effects are achieved by disturbing the life cycles of pathogens or modulating immunity. In this review, we focus on the development of broad-spectrum antiviral drugs that enhance the immune response. Some natural products present antiviral effects mediated by enhancing immunity, and their structures and mechanisms are summarized here. Natural products with immunomodulatory effects are also discussed, although their antiviral effects remain unknown. Given the power of immunity and the feasibility of host-directed therapy, we argue that both of these categories of natural products provide clues that may be beneficial for the discovery of broad-spectrum antiviral drugs.

Extraction assisted by far infrared radiation and hot air circulation with deep eutectic solvent for bioactive polysaccharides from Poria cocos (Schw.) wolf

In this study, a new ternary choline chloride-deep eutectic solvent was used to efficiently extract bioactive polysaccharides from poria cocos assisted by the new tool of the far infrared radiation (FIR) together with hot air circulation (HAC).