Phenolic composition, antioxidant and cytoprotective effects of aqueous‐methanol extract from Anneslea fragrans leaves as affected by drying methods

The influences of extraction methods on the chemical constituents of Lyonia ovalifolia (wall.) Drude and intracellular protective effects based on metabolomics analysis

Lyonia ovalifolia (Wall.) Drude (LO) is mainly distributed in China with health benefits. In this study, LO buds (LOB) were extracted by ultrasonic extraction (UE) with or without ultra-high-pressure (UHP-UE), microwave (MW-UE), subcritical (SC-UE) techniques. The metabolomic result showed that a total of 960 chemical compounds and 117 differential compounds were identified from LOB extracts. The UHP-UE extract was rich in total polyphenol and flavonoid contents, followed by MW-UE, UE and SC-UE extracts, respectively. All LOB extracts increased superoxide dismutase (SOD) and catalase (CAT) activities, and glutathione (GSH) content, decreased reactive oxygen species (ROS) accumulation, levels of interleukin-6 (IL-6), interleukin-1β (IL-1β), tumor necrosis factor -α (TNF-α), and nitric oxide (NO), and alleviated apoptosis in cells. The cellular protective effect was UHP-UE > MW-UE > UE > SC-UE. This study revealed that higher pressure and lower temperature may be key factors for increasing bioactivities of LOB extracts.

Protective effect of hot-water and ethanol-aqueous extracts from Anneslea fragrans against acetaminophen-induced acute liver injury in mice

Anneslea fragrans Wall. (AF) is an important medicinal and edible plant in China. The principal objectives of this study are to explore the hepatoprotective effect of ethanol-aqueous (AFE) and hot-water (AFW) extracts in vitro and in vivo. UPLC-ESI-MS/MS analysis showed that AFW and AFE are rich in dihydrochalcones. Both AFW and AFE significantly up-regulated the expressions of SOD, CAT and GSH, reduced the MDA content in acetaminophen (APAP)-induced HepG2 cells, and suppressed the expressions of NO, TNF-α, IL-1β, and IL-6 in LPS-induced RAW246.7 cells. In APAP-induced mice, AFW and AFE administration significantly decreased the plasma levels of AST and ALT, and improved liver tissue damage, the collagen deposition and fibrosis formation. Moreover, AFW and AFE decreased the MDA and ROS accumulations via activating Nrf2 pathway to increase the hepatic GSH contents and activities of SOD, CAT, HO-1, and NQO-1, reduced the levels of NO, TNF-α, IL-1β, and IL-6 by suppressing the JNK/p38/ERK/NF-κB pathways, and alleviated apoptosis via regulating Bcl-2, Bax, caspase-3/9 protein expressions. This study provides a new sight that AFW and AFE may have a potential natural resource for the treatment of liver injury.

A Comparative Analysis of Chemical Constituents and Antioxidant Effects of Dendrobium fimbriatum Hook Fractions with Different Polarities

The aim of this study was to investigate the chemical composition and antioxidant capacity of various polar fractions obtained from Dendrobium fimbriatum Hook (DH). First, a 90% ethanol-aqueous extract of DH (CF) was subjected to sequential fractionation using different organic solvents, resulting in the isolation of a methylene chloride fraction (DF), an ethyl acetate fraction (EF), an n-butanol fraction (BF), and a remaining water fraction (WF) after condensation. Additionally, the CF was also subjected to column chromatography via a D101 macroreticular resin column, eluted with ethanol-aqueous solution to yield six fractions (0%, 20%, 40%, 60%, 80%, and 100%). UPLC-Q-Exactive Orbitrap-MS/MS analysis identified a total of 47 chemical compounds from these polar fractions, including fatty acids, amino acids, phenolic acids, flavonoids, organic heterocyclic molecules, and aromatic compounds. Moreover, DF, EF, and the 60%, 80%, and 100% ethanol-aqueous fractions had higher total phenol content (TPC) and total flavonoid content (TFC) values and greater 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS-) and 1,1-diphenyl-2-picrylhydrazyl (DPPH)-scavenging abilities. In H2O2-induced HepG2 cells, the aforementioned fractions could increase the activities of antioxidative enzymes NAD(P)H: quinone oxidoreductase 1 (NQO1), superoxide dismutase (SOD), heme oxygenase-1 (HO-1) and catalase (CAT), stimulate glutathione (GSH) synthesis by increasing the activities of glutamic acid cysteine ligase (GCL) and glutathione synthetase (GS), regulate GSH metabolism by increasing glutathione peroxidase (GSH-Px) and glutathione reductase (GR) activities, and reduce levels of reactive oxygen species (ROS) and malondialdehyde (MDA). Furthermore, the antioxidative stress effect of the DH fractions was found to be positively correlated with the activation of nuclear factor-erythroid 2-related factor 2 (Nrf2) protein and the presence of antioxidative chemical constituents. In conclusion, this study highlights the efficacy of both liquid-liquid extraction and macroporous resin purification techniques in the enrichment of bioactive compounds from natural food resources. The comprehensive analysis of chemical constituents and antioxidant effects of different polar fractions from Dendrobium fimbriatum Hook contributes to the understanding of its potential application in functional foods and nutraceuticals.

Chemical Constituents, Antioxidant, and α-Glucosidase Inhibitory Activities of Different Fermented Gynostemma Pentaphyllum Leaves and Untargeted Metabolomic Measurement of the Metabolite Variation

To assess the effects of microbial fermentation on Gynostemma pentaphyllum leaves (GPL), four probiotics were used to ferment GPL (FGPL) for 7 days. At different stages of fermentation, changes in the active components and biological activities of FGPL were determined. The findings suggest that short-term fermentation with probiotics can enhance both the content and bioactivity of active components in GPL. However, prolonged fermentation may lead to a decline in these aspects. Among them, the best effect was observed with SWFU D16 fermentation for 2 days. This significantly improved the total phenolic and total flavonoid content, antioxidant capacity, and inhibitory ability against α-glucosidase activity with an increase of 28%, 114.82%, 7.42%, and 31.8%, respectively. The high-performance liquid chromatography (HPLC) analysis results also supported this trend. Untargeted metabolomics analysis revealed metabolite changes between GPL and FGPL and the key metabolites associated with these functional activities. These key metabolites are mainly organic acids, flavonoids, carbohydrates, terpenoids, and other substances. KEGG analysis demonstrated that microbial metabolism in diverse environments and carbon metabolism were the most significantly enriched pathways. Among them, 3-(3-hydroxyphenyl) propanoic acid, d-glucose, gallic acid, gluconic acid, l-lactic acid, and l-malic acid were mostly involved in the microbial metabolism of diverse environmental pathways. In contrast, D-glucose, gluconic acid, and l-malic acid were mainly related to the carbon metabolism pathway. This study revealed the positive effect of probiotic fermentation on GPL and its potential metabolism mechanism, which could provide supporting data for further research.

Phytochemicals from Anneslea fragrans Wall. and Their Hepatoprotective and Anti-Inflammatory Activities

Anneslea fragrans Wall., popularly known as "Pangpo tea", is an edible, medicinal, and ornamental plant of the Family Theaceae. The leaves of A. fragrans were historically applied for the treatment of liver and intestinal inflammatory diseases in China. This study aimed to explore the hepatoprotective agents from A. fragrans leaves through hepatoprotective and anti-inflammatory assessment. The phytochemical investigation of the leaves of A. fragrans resulted in the isolation and identification of a total of 18 chemical compounds, including triterpenoids, aliphatic alcohol, dihydrochalcones, chalcones, flavanols, phenolic glycoside, and lignans. Compounds 1-2, 4-6, 11-12, and 16-18 were identified from A. fragrans for the first time. Compounds 7 and 14 could significantly alleviate hepatocellular damage by decreasing the contents of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) and inhibit the hepatocellular apoptosis in the HepG2 cells induced by N-acetyl-p-aminophenol (APAP). In addition, compounds 7 and 14 inhibited reactive oxygen species (ROS) and malondialdehyde (MDA) contents and increased the catalase (CAT) superoxide dismutase (SOD), and glutathione (GSH) levels for suppressing APAP-induced oxidative stress. Additionally, compounds 7, 13, and 14 also had significant anti-inflammatory effects by inhibiting interleukin-6 (IL-6), interleukin-1β (IL-1β), and tumor necrosis factor-α (TNF-α) productions on LPS-induced RAW246.7 cells.

Influence of Ultra-High-Pressure Pretreatment Method on Chemical Constituents, Antioxidant and Cytoprotective Activities of Free, Esterified, and Bound Phenolics from Anneslea Fragrans Wall. Leaves

Anneslea fragrans Wall., an edible and medicinal plant, is traditionally used to treat liver and gastrointestinal diseases. This paper aimed to investigate the influence of ultra-high pressure (UHP) pretreatment on the phenolics profiling, antioxidant, and cytoprotective activities of free (FP), esterified (EP), and bound (BP) phenolics from A. fragrans leaves. A total of 32 compounds were characterized and quantified. The davidigenin (44.46 and 113.37 mg/g extract) was the highest in A. fragrans leaves. The vitexin (9), afzelin (10), coreopsin (15), and davidigenin (28) were analyzed with MS² fragment pathways. Results showed that UHP treated A. fragrans leaves had higher total phenolic (TPC) and total flavonoid (TFC) contents of FP, EP, and BP fractions than those in the raw leaves. Moreover, UHP pretreated A. fragrans leaves had higher scavenging activities on DPPH⁺• and ABTS⁺•, and inhibitory effects on the intracellular ROS generation in H₂O₂-induced HepG2 cells. UFP showed the highest inhibition of ROS production among the samples. Therefore, UHP pretreatment method might be used as an effective strategy for elevating the availabilities of A. fragrans leaves to develop functional foods.

Effect of ultra-high pressure pretreatment on the phenolic profiles, antioxidative activity and cytoprotective capacity of different phenolic fractions from Que Zui tea

This study aims to explore whether ultra-high pressure (UHP) pre-treatment strengthened the bioaccessibility and bioactivities of the free (QF), esterified (QE) and insoluble-bound phenolics (QIB) from Que Zui tea (QT). The results revealed that the extraction yields, the total phenolic (TPC) and total flavonoid contents (TFC) of three phenolic fractions from QT were markedly increased after ultra-high pressure (UHP) processing (p < 0.05). A total of 19 and 20 compounds were characterized and quantified in non- and UHP-treated QT, respectively, including the content of 6'-O-caffeoylarbutin (11775.68 and 13248.87 μg/g of dry extract) was highest in QF, the content of caffeic acid was highest in QE (2131.58 and 7362.99 μg/g of dry extract) and QIB (9151.89 and 10930.82 μg/g of dry extract). QF, QE and QIB from QT after UHP processing had better antioxidant, ROS scavenging, and anti-apoptosis effects. The possible mechanism of cytoprotective effect was related to Keap1-Nrf2 pathway.

Confusoside, a dihydrochalcone glucoside, prevents acetaminophen-induced liver injury by modulating the Nrf2/NF-κB/caspase signaling pathway

Dihydrochalcones are important bioactive ingredients in plants. Anneslea fragrans is an edible and medicinal plant, and its leaves are rich in dihydrochalcones. Confusoside (CF) is the most abundant dihydrochalcone in A. fragrans leaves, which is traditionally used in the treatment of liver diseases. The aim of this study was to investigate the hepatoprotective effect of CF on acetaminophen (APAP)-induced hepatic injury in mice. CF could reduce the levels of AST, ALT, and LDH in the serum and enhance the antioxidant activity by activating the Nrf2 signaling pathway to increase the activities of antioxidant enzymes (SOD and CAT), and the GSH content but decrease the MDA accumulation in liver tissues. Immunofluorescence assay and western blotting analysis showed that CF can regulate Nrf2 into the cell nucleus, thereby promoting the expression of downstream antioxidant-related proteins, including NQO1 and HO-1. In addition, CF could inhibit the liver inflammatory response by suppressing the activation of the NF-κB signaling pathway to reduce the expressions of TNF-α, IL-1β, IL-6, and NO. Molecular docking results showed that there was good binding between the CF and Keap1-Nrf2 protein. Western blotting and TUNEL analysis also revealed CF-inhibited cell apoptosis-related protein expression (Bcl2 and caspase-3/9 proteins). Thus, the CF from A. fragrans leaves could be served as an alternative hepaprotective agent for the treatment and prevention of APAP-induced liver injury.

Electrochemical Characterization of the Antioxidant Properties of Medicinal Plants and Products: A Review

Medicinal plants are an important source of bioactive compounds with a wide spectrum of practically useful properties. Various types of antioxidants synthesized in plants are the reasons for their application in medicine, phytotherapy, and aromatherapy. Therefore, reliable, simple, cost-effective, eco-friendly, and rapid methods for the evaluation of antioxidant properties of medicinal plants and products on their basis are required. Electrochemical methods based on electron transfer reactions are promising tools to solve this problem. Total antioxidant parameters and individual antioxidant quantification can be achieved using suitable electrochemical techniques. The analytical capabilities of constant-current coulometry, potentiometry, various types of voltammetry, and chrono methods in the evaluation of total antioxidant parameters of medicinal plants and plant-derived products are presented. The advantages and limitations of methods in comparison to each other and traditional spectroscopic methods are discussed. The possibility to use electrochemical detection of the antioxidants via reactions with oxidants or radicals (N- and O-centered) in solution, with stable radicals immobilized on the electrode surface, via oxidation of antioxidants on a suitable electrode, allows the study of various mechanisms of antioxidant actions occurring in living systems. Attention is also paid to the individual or simultaneous electrochemical determination of antioxidants in medicinal plants using chemically modified electrodes.

Confusoside from Anneslea fragrans Alleviates Acetaminophen-Induced Liver Injury in HepG2 via PI3K-CASP3 Signaling Pathway

Confusoside (CF), a major chemical compound in the leaves of Anneslea fragrans Wall., is a dihydrochalcone glycoside with excellent antioxidant and anti-inflammatory effects. However, the hepatoprotective effect of CF has not been described. This study aimed to explore the hepatoprotective effect of CF against acetaminophen (APAP)-induced hepatic injury in HepG2 cells. First, the potential hepatoprotective effect mechanisms of CF were predicted by network pharmacology and were thought to involve reducing inflammation and inhibiting apoptosis. Target proteins (phosphatidylinositol3-kinase (PI3K) and caspase-3 (CASP3)) were found via molecular docking analysis. To verify the predicted results, an analysis of biological indicators was performed using commercial kits and Western blotting. The results showed that CF significantly decreased the levels of liver injury biomarkers (ALT, AST, and LDH), strongly inhibited the production of inflammatory cytokines (IL-1β, IL-6, and TNF-α) and the NO level via inhibiting the activation of the NF-κB signaling pathway, and markedly regulated the expression levels of Bcl2, Bax, and cleaved-CASP3/9 proteins by activating the PI3K-CASP3 apoptosis pathway. The results demonstrated that CF has a therapeutic effect on APAP-induced liver injury by inhibiting intracellular inflammation and cell apoptosis, indicating that CF may be used as a potential reagent for the prevention and treatment of APAP-induced liver injury.

Ultra-High Hydrostatic Pressure Pretreatment on White Que Zui Tea: Chemical Constituents, Antioxidant, Cytoprotective, and Anti-Inflammatory Activities

Herbal tea has numerous biological activities and exhibits broad benefits for human health. In China, the flower buds of Lyonia ovalifolia are traditionally processed as herbal tea, namely White Que Zui tea (WQT). This study was aimed to evaluate the effect of ultra-high hydrostatic pressure (UHHP) pretreatment on the chemical constituents and biological activities of free, esterified, and insoluble-bound phenolic fractions from WQT. A total of 327 chemical constituents were identified by a quasi-targeted metabolomics analysis. UHHP pretreatment extremely inhibited reactive oxygen species (ROS) production and cell apoptosis in H2O2-induced HepG2 cells, and it increased the activities of intracellular antioxidant enzymes (SOD and CAT) and GSH content in different phenolic fractions from WQT. In addition, after UHHP pretreatment, the anti-inflammatory effects of different phenolic fractions from WQT were improved by inhibiting the production of nitric oxide (NO) and pro-inflammatory cytokines (TNF-α, IL-6, and IL-1β) in LPS-induced RAW264.7 cells. Thus, the UHHP method might be a potential pretreatment strategy for improving the bioavailability of phytochemicals from natural plants.

Electrochemical Methodologies for Investigating the Antioxidant Potential of Plant and Fruit Extracts: A Review

In recent years, the growing research interests in the applications of plant and fruit extracts (synthetic/stabilization materials for the nanomaterials, medicinal applications, functional foods, and nutraceuticals) have led to the development of new analytical techniques to be utilized for identifying numerous properties of these extracts. One of the main properties essential for the applicability of these plant extracts is the antioxidant capacity (AOC) that is conventionally determined by spectrophotometric techniques. Nowadays, electrochemical methodologies are emerging as alternative tools for quantifying this particular property of the extract. These methodologies address numerous drawbacks of the conventional spectroscopic approach, such as the utilization of expensive and hazardous solvents, extensive sample pre-treatment requirements, long reaction times, low sensitivity, etc. The electrochemical methodologies discussed in this review include cyclic voltammetry (CV), square wave voltammetry (SWV), differential pulse voltammetry (DPV), and chronoamperometry (CAP). This review presents a critical comparison between both the conventional and electrochemical approaches for the quantification of the parameter of AOC and discusses the numerous applications of the obtained bioextracts based on the AOC parameter.

Ethanolic Extract from Pteris wallichiana Alleviates DSS-Induced Intestinal Inflammation and Intestinal Barrier Dysfunction by Inhibiting the TLR4/NF-κB Pathway and Regulating Tight Junction Proteins

The aim of the research was to determine the protective effect and mechanism of Pteris wallichiana J. Agardh extract (PWE) on DSS-induced ulcerative colitis (UC) in mice. In this research, PWE is rich in flavonoids and diterpenoids by UPLC-MS/MS analysis. In LPS-induced RAW264.7 cells, PWE reduced the productions of inflammatory factors (i.e., NO, TNF-α, IL-6, and IL-1β). In DSS-induced UC in mice, PWE improved disease activity index (DAI) score, attenuated oxidative stress by decreasing MPO and MDA activities and activating GSH and SOD levels, and inhibited TNF-α, IL-6, and IL-1β expressions in the colonic tissues. PWE also improved the intestinal barrier by upregulating the expressions of tight junction proteins, including occludin and ZO-1. Moreover, PWE extract alleviated intestinal inflammation by suppressing the TLR4/MyD88/NF-κB signaling pathway. Conclusion: PWE can alleviate DSS-induced UC in mice by increasing the expressions of intestinal tight junction proteins and inhibiting the TLR4/NF-κB inflammatory pathway.

Complexation of ellagic acid with α-lactalbumin and its antioxidant property

Ellagic acid possesses numerous bioactivities such as antioxidant activity and anti-inflammatory effect. In this work, the binding interaction between ellagic acid and α-lactalbumin was investigated by multi-spectroscopy and the results suggested that ellagic acid could change the conformation of α-lactalbumin. Chromatographic analysis proved the interaction of α-lactalbumin with ellagic acid taken place in less than 30 min and this interaction was stable. Computer simulations showed that both aromatic clusters Ⅰ and Ⅱ of α-lactalbumin were active sites for ellagic acid. Interestingly, both the results of molecular docking and molecular dynamics simulations suggested that ellagic acid tended to bind to aromatic cluster Ⅱ rather than aromatic cluster Ⅰ. Moreover, α-lactalbumin could enhance the antioxidant property of ellagic acid, indicating that the solubility of ellagic acid might be improved by combining α-lactalbumin. Overall, this work suggested that α-lactalbumin exhibited binding affinity for ellagic acid and enhanced its antioxidant property.

The effect of ultra-high pretreatment on free, esterified and insoluble-bound phenolics from mango leaves and their antioxidant and cytoprotective activities

Ultra-high pressure (UHP) is a novel non-thermal pretreatment method in food processing for improving the extraction yield of polyphenols and functional properties. The present work investigated the phenolic profiles, antioxidant activities, and cytoprotective effects of the free, esterified, and insoluble-bound phenolic fractions from mango leaves before and after ultra-high pressure (UHP) treatment. UHPLC-Q-Orbitrap-MS/MS analysis resulted in the identification of 42 phenolic compounds in the different phenolic forms. UHP pretreatment could significantly influence the contents of total phenols, total flavonoids and individual compounds in the different phenolic fractions (p < 0.05). After UHP pretreatment, these phenolic fractions exhibited greater antioxidant activity, and inhibited reactive oxygen species production and cell apoptosis (p < 0.05). Meanwhile, IBP were the most potential antioxidative and cytoprotective ingredients. Therefore, UHP pretreated mango leaves with enhanced bioactivity could be used as biological agents in the health food industry to improve its application and economic values.

Dietary phytochemicals as modulators of human pregnane X receptor

As a promiscuous xenobiotic sensor, pregnane X receptor (PXR) plays a crucial role in drug metabolism. Since dietary phytochemicals exhibit the potential to modulate human PXR, this review aims to summarize the plant-derived PXR modulators, including agonists, partial agonists, and antagonists. The crystal structures of the apo and ligand-bound forms of PXR especially that of PXR complexed with binary mixtures are summarized, in order to provide the structural basis for PXR binding promiscuity and synergistic activation of PXR by composite ligands. Furthermore, this review summarizes the characterized agonists, partial agonists, and antagonists of human PXR from botanical source. Contrary to PXR agonists, there are only a few antagonists obtained from botanical source due to the promiscuity of PXR. It is worth noting that trans-resveratrol and a series of methylindoles have been identified as partial agonists of PXR, both in activating PXR function, but also inhibiting the effect of other PXR agonists. Since antagonizing PXR function plays a crucial role in the prevention of drug-drug interactions and improvement of therapeutic efficacy, further research is necessary to screen more plant-derived PXR antagonists in the future. In summary, this review may contribute to understanding the roles of phytochemicals in food-drug and herb-drug interactions.

Activity Guided Isolation of Phenolic Compositions from Anneslea fragrans Wall. and Their Cytoprotective Effect against Hydrogen Peroxide Induced Oxidative Stress in HepG2 Cells

Anneslea fragrans Wall., commonly known as “Pangpo Tea”, is traditionally used as a folk medicine and healthy tea for the treatment of liver and intestine diseases. The aim of this study was to purify the antioxidative and cytoprotective polyphenols from A. fragrans leaves. After fractionation with polar and nonpolar organic solvents, the fractions of aqueous ethanol extract were evaluated for their total phenolic (TPC) and flavonoid contents (TFC) and antioxidant activities (DPPH, ABTS, and FRAP assays). The n-butanol fraction (BF) showed the highest TPC and TFC with the strongest antioxidant activity. The bio-guided chromatography of BF led to the purification of six flavonoids (1–6) and one benzoquinolethanoid (7). The structures of these compounds were determined by NMR and MS techniques. Compound 6 had the strongest antioxidant capacity, which was followed by 5 and 2. The protective effect of the isolated compounds on hydrogen peroxide (H₂O₂)-induced oxidative stress in HepG2 cells revealed that the compounds 5 and 6 exhibited better protective effects by inhibiting ROS productions, having no significant difference with vitamin C (p > 0.05), whereas 6 showed the best anti-apoptosis activity. The results suggest that A. fragrans could serve as a valuable antioxidant phytochemical source for developing functional food and health nutraceutical products.