Recrystallization of dihydromyricetin from Ampelopsis grossedentata and its anti-oxidant activity evaluation

Phenolic Compound Profiles, Antioxidant, and Cytoprotective Activity of Elaeagnus conferta Roxb. Fruit

In this paper, three varieties of Elaeagnus conferta Roxb fruits prepared by ultrasonic-assisted extraction from a subtropical region southwest of China were utilized as raw materials to investigate their phenolic profiles, antioxidant activities, and protective effects on injured human umbilical vein endothelial cells (HUVECs). The ultra performance liquid chromatography-electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS) findings revealed that fifteen substances, including seven phenolic acids, seven flavonoids, and one gallic acid derivative, were discovered. The dihydromyricetin, ellagic acid, gallic acid were the predominant phenolic compounds in all E.conferta fruits. These E.conferta fruits extracts shown excellent antioxidant activity varied from 2.258±0.03~7.844±0.39 μM Trolox/g and protective effect on HUVECs injured by H2O2 through decrease the level of ROS, MDA, LDH and enhance the SOD level. These finding indicate that E.conferta is a valuable source of high-capacity antioxidants that might be used as an alternative material for food industries.

Molecular Mechanism of Exogenous ABA to Enhance UV-B Resistance in Rhododendron chrysanthum Pall. by Modulating Flavonoid Accumulation

With the depletion of the ozone layer, the intensity of ultraviolet B (UV-B) radiation reaching the Earth's surface increases, which in turn causes significant stress to plants and affects all aspects of plant growth and development. The aim of this study was to investigate the mechanism of response to UV-B radiation in the endemic species of Rhododendron chrysanthum Pall. (R. chrysanthum) in the Changbai Mountains and to study how exogenous ABA regulates the response of R. chrysanthum to UV-B stress. The results of chlorophyll fluorescence images and OJIP kinetic curves showed that UV-B radiation damaged the PSII photosystem of R. chrysanthum, and exogenous ABA could alleviate this damage to some extent. A total of 2148 metabolites were detected by metabolomics, of which flavonoids accounted for the highest number (487, or 22.67%). KEGG enrichment analysis of flavonoids that showed differential accumulation by UV-B radiation and exogenous ABA revealed that flavonoid biosynthesis and flavone and flavonol biosynthesis were significantly altered. GO analysis showed that most of the DEGs produced after UV-B radiation and exogenous ABA were distributed in the cellular process, cellular anatomical entity, and catalytic activity. Network analysis of key DFs and DEGs associated with flavonoid synthesis identified key flavonoids (isorhamnetin-3-O-gallate and dihydromyricetin) and genes (TRINITY_DN2213_c0_g1_i4-A1) that promote the resistance of R. chrysanthum to UV-B stress. In addition, multiple transcription factor families were found to be involved in the regulation of the flavonoid synthesis pathway under UV-B stress. Overall, R. chrysanthum actively responded to UV-B stress by regulating changes in flavonoids, especially flavones and flavonols, while exogenous ABA further enhanced its resistance to UV-B stress. The experimental results not only provide a new perspective for understanding the molecular mechanism of the response to UV-B stress in the R. chrysanthum, but also provide a valuable theoretical basis for future research and application in improving plant adversity tolerance.

A comprehensive review of vine tea: Origin, research on Materia Medica, phytochemistry and pharmacology

ETHNOPHARMACOLOGICAL RELEVANCE

Vine tea is a popular folk tea that has been consumed in China for more than 1200 years. It is often used in ethnic medicine by ethnic groups in southwest China with at least 35 aliases in 10 provinces. In coastal areas, vine tea is mostly used to treat heatstroke, aphtha, aphonia, toothache, etc. In contrast, in the southwest inland regions, vine tea is mostly used to clear away heat and toxic materials, antiphlogosis and relieving sore-throat, lowering blood pressure and lipid levels, and alleviating fatigue. Three main species have been used as the source of vine tea, Nekemias grossedentata, Nekemias cantonensis and Nekemias megalophylla. Among them, the leaves of Nekemias grossedentata were considered as new food resource in complicance with regulations, according to the Food Safety Standards published by the Monitoring and Evaluation Department of the National Health and Family Planning Commission in China.

AIM OF THE STUDY

At present, the comprehensively summary of Materia Medica on the history and source of vine tea is currently unavailable. The current article summed up the Materia Medica, species origin and pharmacological effects of all 3 major species used in vine tea to fill the knowledge gaps. We also aim to provide a reference for future research on historical textual, resource development and medicinal utilization of vine tea.

MATERIALS AND METHODS

Adhering to the literature screening methodology outlined by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), this review encompasses 148 scholarly research papers from three database, paper ancient books, local chronicles and folklore through field investigations. We then comprehensively summarized and discussed research progresses in scientific and application studies of vine tea.

RESULTS

The historical records indicated that vine tea could have been used as early as Southern and Northern Dynasties (AC 420-589). Nekemias grossedentata, Nekemias cantonensis and Nekemias megalophylla, were used to considered as vine tea in the ethnic medicine. The main phytochemicals found in three plants are flavonoids, polyphenols and terpenoids, among which dihydromyricetin (DHM) is the most important and most studied active substance. The key words "Ampelopsis grossedentata" (Synonym of Nekemias grossedentata) and "dihydromyricetin/DHM" showed the highest frequency over the last 27 year based on the research trend analysis. And the ethnopharmacology studies drawn the main activities of vine tea are antioxidant, antibacterial, hepatoprotective, neuroprotective and anti-atherosclerosis activities.

CONCLUSIONS

This review systematically summarized and discussed vine tea from the following five aspects, history, genetic relationship, phytochemistry, research trend and ethnopharmacology. Vine tea has a long historical usage in Chinese ethnic medicine. Its outstanding therapeutic efficacies have attracted extensive attention in other places in the world at present. Nekemias cantonensis and Nekemias megalophylla are quite similar to Nekemias grossedentata in terms of many aspects. However, the current research has a narrow focus on mainly Nekemias grossedentata and DHM. We propose that future studies could be carried out to determine the synergistic effect of multi-components and multi-targets of vine tea including all 3 species to provide valuable knowledge.

An efficient cocrystallization strategy for separation of dihydromyricetin from vine tea and enhanced its antibacterial activity for food preserving application

The objective of this study was to optimize the separation and purification of dihydromyricetin (DMY) from vine tea to obtain high purity, antibacterial and antioxidant crystal forms. We developed a cocrystallization approach for separation of DMY from vine tea with easy operation and high efficiency. The type and concentration of co-formers as well as solvent for separation have been investigated in detail. Under the optimal conditions, DMY with a purity of 92.41% and its two co-crystal forms (purity >97%) can be obtained. Three DMY crystal forms had consistent and good antioxidant activities according to DPPH radical scavenging results. DMY had effective antibacterial activity against the two kinds of drug-resistant bacteria including CRAB and MRSA, and DMY co-crystals had a greater advantage than DMY itself on CRAB. This work implies that cocrystallization can be used for the DMY separation and enhanced its anti-drug-resistant bacteria activity in food preservation.

Dihydromyricetin functions as a tumor suppressor in hepatoblastoma by regulating SOD1/ROS pathway

Background

Hepatoblastoma has an unsatisfactory prognosis, and traditional chemotherapy has strong side effects. Dihydromyricetin is a flavonoid extracted from a woody vine of the genus Serpentine in the family Vitaceae, with effects such as preventing alcoholic liver and reducing the incidence of liver cancer. However, the effect of DHM on hepatoblastoma and its specific pathway are still unclear.

Purpose

The purpose of this study was to investigate the effects of DHM on children's hepatoblastoma and its related mechanisms.

Methods

CCK-8 assays were used to measure proliferation. Apoptosis and reactive oxygen species (ROS) were analyzed by flow cytometry. Apoptotic cells were observed using Hoechst 33342 staining and fluorescence microscopy. Protein expression levels in HuH-6 and HepG2 cells were determined by western blotting.

Results

We found that DHM was able to inhibit the growth and increase cellular mortality in HuH-6 and HepG2 cells. Furthermore, DHM decreased the intracellular ROS level and increased the expression of SOD1. ROS scavenger NAC promoted apoptosis, while the use of SOD1 inhibitor LCS-1 weakened the ROS scavenging effect of DHM , and to some extent reduced the killing effect of DHM on hepatoblastoma cells.

Conclusion

These results suggest that regulating SOD1/ROS pathway to induce apoptosis is one of the potential mechanisms of DHM as a tumor suppressor in hepatoblastoma. Therefore, DHM may be a novel candidate for inhibiting hepatoblastoma growth and deserves further study.

Molecular mechanisms and promising role of dihydromyricetin in cardiovascular diseases

Vine tea, a Chinese herbal medicine, is widely used in traditional Asian medicine to treat common health problems. Dihydromyricetin (DMY) is the main functional flavonoid compound extracted from vine tea. In recent years, preclinical studies have focused on the potential beneficial effects of dihydromyricetin, including glucose metabolism regulation, lipid metabolism regulation, neuroprotection, and anti-tumor effects. In addition, DMY may play a role in cardiovascular disease by resisting oxidative stress and participating in the regulation of inflammation. This review is the first review that summaries the applications of dihydromyricetin in cardiovascular diseases, including atherosclerosis, myocardial infarction, myocardial hypertrophy, and diabetic cardiomyopathy. We also clarified the underlying mechanisms and signaling pathways involved in the above process. The aim of this review is to provide a better understanding and quick overview for future researches of dihydromyricetin in the field of cardiovascular diseases, and more detailed and robust researches are needed for evaluation and reference.

Dihydromyricetin Inhibited Migration and Invasion by Reducing S100A4 Expression through ERK1/2/β-Catenin Pathway in Human Cervical Cancer Cell Lines

Cervical cancer has a poor prognosis and is the fourth most common cancer among women. Dihydromyricetin (DHM), a flavonoid compound, exhibits several pharmacological activities, including anticancer effects; however, the effects of DHM on cervical cancer have received insufficient research attention. This study examined the antitumor activity and underlying mechanisms of DHM on human cervical cancer. Our results indicated that DHM inhibits migration and invasion in HeLa and SiHa cell lines. Mechanistically, RNA sequencing analysis revealed that DHM suppressed S100A4 mRNA expression in HeLa cells. Moreover, DHM inhibited the protein expressions of β-catenin and GSK3β through the regulated extracellular-signal-regulated kinase (ERK)1/2 signaling pathway. By using the ERK1/2 activator, T-BHQ, reverted β-catenin and S100A4 protein expression and cell migration, which were reduced in response to DHM. In conclusion, our study indicated that DHM inhibited cell migration by reducing the S100A4 expression through the ERK1/2/β-catenin pathway in human cervical cancer cell lines.

LC-ESI-QTOF/MS characterization of antimicrobial compounds with their action mode extracted from vine tea (Ampelopsis grossedentata) leaves

Vine tea (Ampelopsis grossedentata) is a tea plant cultivated south of the Chinese Yangtze River. It has anti-inflammatory properties and is used to normalize blood circulation and detoxification. The leaves of vine tea are the most abundant source of flavonoids, such as dihydromyricetin and myricetin. However, as the main bioactive flavonoid in vine tea, dihydromyricetin was the main focus of previous research. This study aimed to explore the antibacterial activities of vine tea against selected foodborne pathogens. The antimicrobial activity of vine tea extract was evaluated by the agar well diffusion method. Cell membrane integrity and bactericidal kinetics, along with physical damage to the cell membrane, were also observed. The extract was analyzed using a high-performance liquid chromatography-diode array detector (HPLC-DAD), and the results were confirmed using a modified version of a previously published method that combined liquid chromatography and electrospray-ionized quadrupole time-of-flight mass spectrometry (LC-ESI-QTOF/MS). Cell membrane integrity and bactericidal kinetics were determined by releasing intracellular material in suspension and monitoring it at 260 nm using an ultraviolet (UV) spectrophotometer. A scanning electron microscope (SEM) was used to detect morphological alterations and physical damage to the cell membrane. Six compounds were isolated successfully: (1) myricetin (C15H10O8), (2) myricetin 3-O-rhamnoside (C21H20O12), (3) 5,7,8,3,4-pentahydroxyisoflavone (C15H10O7), (4) dihydroquercetin (C15H12O7), (5) 6,8-dihydroxykaempferol (C15H10O8), and (6) ellagic acid glucoside (C20H16O13). Among these bioactive compounds, C15H10O7 was found to have vigorous antimicrobial activity against Bacillus cereus (AS11846) and Staphylococcus aureus (CMCCB26003). A dose-dependent bactericidal kinetics with a higher degree of absorbance at optical density 260 (OD260) was observed when the bacterial suspension was incubated with C15H10O7 for 8 h. Furthermore, a scanning electron microscope study revealed physical damage to the cell membrane. In addition, the action mode of C15H10O7 was on the cell wall of the target microorganism. Together, these results suggest that C15H10O7 has vigorous antimicrobial activity and can be used as a potent antimicrobial agent in the food processing industry.

Dihydromyricetin Improves Cognitive Impairments in d-Galactose-Induced Aging Mice through Regulating Oxidative Stress and Inhibition of Acetylcholinesterase

SCOPE

Alzheimer's disease (AD) is a neurodegenerative disease with phenomena of cognitive impairments. Oxidative stress and cholinergic system dysfunction are two widely studied pathogenesis of AD. Dihydromyricetin (DMY) is a natural dihydroflavonol with many bioactivities. In this study, it is aimed to investigate the effects of DMY on cognitive impairment in d-galactose (d-gal) induced aging mice.

METHODS AND RESULTS

Mice are intraperitoneally injected with d-gal for 16 weeks, and DMY is supplemented in drinking water. The results show that DMY significantly improves d-gal-induced cognitive impairments in novel object recognition and Y-maze studies. H&E and TUNEL staining show that DMY could improve histopathological changes and cell apoptosis in mice brain. DMY effectively induces the activities of catalase, superoxide dismutase and glutathione peroxidase, and reduces malondialdehyde level in mice brain and liver. Furthermore, DMY reduces cholinergic injury by inhibiting the activity of Acetylcholinesterase (AChE) in mice brain. In vitro studies show that DMY is a non-competitive inhibitor of AChE with IC50 value of 161.2 µg mL^-1 .

CONCLUSION

DMY alleviates the cognitive impairments in d-gal-induced aging mice partly through regulating oxidative stress and inhibition of acetylcholinesterase.

The modulation of SIRT1 and SIRT3 by natural compounds as a therapeutic target in doxorubicin-induced cardiotoxicity: A review

Doxorubicin (DOX) is a potent antitumor agent with a broad spectrum of activity; however, irreversible cardiotoxicity resulting from DOX treatment is a major issue that limits its therapeutic use. Sirtuins (SIRTs) play an essential role in several physiological and pathological processes including oxidative stress, apoptosis, and inflammation. It has been reported that SIRT1 and SIRT3 can act as a protective molecular against DOX-induced myocardial injury through targeting numerous signaling pathways. Several natural compounds (NCs), such as resveratrol, sesamin, and berberine, with antioxidative, anti-inflammation, and antiapoptotic effects were evaluated for their potential to suppress the cardiotoxicity induced by DOX via targeting SIRT1 and SIRT3. Numerous NCs exerted their therapeutic effects on DOX-mediated cardiac damage via targeting different signaling pathways, including SIRT1/LKB1/AMPK, SIRT1/PGC-1α, SIRT1/NLRP3, and SIRT3/FoxO. SIRT3 also ameliorates cardiotoxicity by enhancing mitochondrial fusion.

Antibacterial Effect of Dihydromyricetin on Specific Spoilage Organisms of Hybrid Grouper

This study aimed to investigate the mechanism of antibacterial activity level inhibition of dihydromyricetin (DMY) against specific spoilage bacteria of grouper. Firstly, the specific spoilage bacteria of grouper in the cold storage process are Pseudomonas antarctica (P. antarctica), which are selected by calculating the spoilage metabolite yield factor. It was determined that the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of DMY against grouper spoilage bacteria were 2.0 mg/mL and 6.4 mg/mL, respectively. DMY was added to the matrix of chitosan and sodium alginate, and DMY emulsions of different concentrations (0 MIC, 1 MIC, 2 MIC, 4 MIC) were prepared and characterized by differential calorimetry methods. Through analyzing cell permeability, enzyme activity, and images of the confocal laser scanning microscope (CLSM), we further studied the antibacterial mechanism of DMY emulsion on specific spoilage bacteria. The results showed that, with the increase of DMY concentration in the treatment group, the leakage of nucleic acid and protein increased significantly, the activity of ATPase and three critical enzymes in the Embden-Meyerhof-Parnas (EMP) pathway decreased significantly, and the activity of AKPase did not decrease significantly, . The metabolic activity and viability are reduced considerably. Analysis of the above results shows that DMY inhibits the growth and reproduction of P. antarctica by interfering with the metabolic activity of bacteria and destroying the function of bacterial cell membranes but has no inhibitory effect on the activity of AKPase. This study proves that DMY could be an effective and natural antibacterial agent against specific spoilage bacteria in aquatic products.

Dihydromyricetin Acts as a Potential Redox Balance Mediator in Cancer Chemoprevention

Dihydromyricetin (DHM) is a flavonoid extracted from the leaves and stems of the edible plant Ampelopsis grossedentata that has been used for Chinese Traditional Medicine. It has attracted considerable attention from consumers due to its beneficial properties including anticancer, antioxidative, and anti-inflammatory activities. Continuous oxidative stress caused by intracellular redox imbalance can lead to chronic inflammation, which is intimately associated with the initiation, promotion, and progression of cancer. DHM is considered a potential redox regulator for chronic disease prevention, and its biological activities are abundantly evaluated by using diverse cell and animal models. However, clinical investigations are still scanty. This review summarizes the current potential chemopreventive effects of DHM, including its properties such as anticancer, antioxidative, and anti-inflammatory activities, and further discusses the underlying molecular mechanisms of DHM in cancer chemoprevention by targeting redox balance and influencing the gut microbiota.

Leading individual features of antioxidant systematically classified by the ORAC assay and its single electron transfer and hydrogen atom transfer reactivities; analyzing ALS therapeutic drug Edaravone

Many natural compounds mop up radicals and limit radical reactions and may prove useful in reducing or preventing oxidative stress-related diseases in vivo. Several assays have been developed to measure antioxidant or anti-radical activity. Here, we measured the anti-radical activities of representative antioxidants using different assays. The oxygen radical absorption capacity (ORAC) assay has two mechanistic stages. We classified antioxidant behavior using two characteristic values thought to be related to the two stages - peroxyl radical formation time (lag time) and fluorescein annihilation rate (k _obs) - by applying Voronoi polyhedral division. We focused on four class-representative antioxidants, Trolox ®, vitamin C, l-cysteine, and 2,6-di‑tert‑butyl‑p-cresol, and compared their characteristic activities with those of edaravone. Our analysis indicates that edaravone is in the same group as cysteine and may function via a similar mechanism. Our results suggest that analyzing lag time and k _obs is a useful method to characterize antioxidants.

Serum Cholesterol-Lowering Activity of β-Sitosterol Laurate Is Attributed to the Reduction of Both Cholesterol Absorption and Bile Acids Reabsorption in Hamsters

The research was performed to delineate how β-sitosterol laurate (β-SLE) consumption influenced serum and hepatic lipids. The results showed that 220 mg/5 mL oil/kg body weight of β-SLE robustly reduced serum total triglyceride and cholesterol levels and the epididymal adipocyte size, and efficiently protected hepatic polyunsaturated fatty acids against lipid peroxidation through superoxide dismutase and glutathione transferase activity enhancement and malondialdehyde level reduction. Based on the changes of fecal cholesterol contents, fecal and hepatic bile acid (BAs) levels, and related protein expression, it was concluded that the mechanisms for lowering serum cholesterol by β-SLE involved (i) the enhanced excretion of fecal cholesterol via down-regulation of intestinal Niemann-Pick C1-like 1 protein; (ii) the increased conversion from cholesterol to primary BAs via up-regulation of cholesterol-7α-hydroxylase and sterol 27-hydroxylase, which was induced by the reduced BAs reabsorption through up-regulating ileal apical sodium-dependent bile acid transporter and ileal bile acid-binding protein.

Peroxiredoxin of Arthrospira platensis derived short molecule YT12 influences antioxidant and anticancer activity

This study demonstrates both the antioxidant and anticancer potential of the novel short molecule YT12 derived from peroxiredoxin (Prx) of spirulina, Arthrospira platensis (Ap). ApPrx showed significant reduction in reactive oxygen species (ROS) against hydrogen peroxide (H₂ O₂ ) stress. The complementary DNA sequence of ApPrx contained 706 nucleotides and its coding region possessed 546 nucleotides between position 115 and 660. Real-time quantitative reverse transcription polymerase chain reaction analysis confirmed the messenger RNA expression of ApPrx due to H₂ O₂ exposure in spirulina cells at regular intervals, in which the highest expression was noticed on Day 20. Cytotoxicity assay was performed using human peripheral blood mononuclear cells, and revealed that at 10 μM, the YT12 did not exhibit any notable toxicity. Furthermore, ROS scavenging activity of YT12 was performed using DCF-DA assay, in which YT12 scavenged a significant amount of ROS at 25 μM in H₂ O₂ -treated blood leukocytes. The intracellular ROS in human colon adenocarcinoma cells (HT-29) was regulated by oxidative stress, where the YT12 scavenges ROS in HT-29 cells at 12.5 μM. Findings show that YT12 peptide has anticancer activity, when treated against HT-29 cells. Through the MTT assay, YT12 showed vital cytotoxicity against HT-29 cells. These finding suggested that YT12 is a potent antioxidant molecule which defends ROS against oxidative stress and plays a role in redox balance.

New Method for Extracting and Purifying Dihydromyricetin from Ampelopsis grossedentata

Dihydromyricetin (DMY) is a kind of flavone. It has a variety of physiological effects, and its content in Ampelopsis grossedentata is as high as 35%. There are two shortcomings in the traditional batch extraction process commonly used in a laboratory: long extraction time and low extraction rate. In this study, a new chelating extraction method was proposed, that is, Zn2+ was introduced into the extraction and purification process to chelate with DMY, and the yield and purity were taken as evaluation indices for a comparative study with the traditional batch extraction method. In addition, 1H NMR, single-crystal X-ray diffraction, IR, and UV were used to analyze the product structure; thermogravimetry and differential thermal analysis was utilized to examine the thermal stability of DMY. The results were shown as follows. Compared with the batch extraction method, the chelation extraction method could effectively avoid the oxidation of DMY by air during the extraction and purification process, and the yield of the DMY also increased. Furthermore, this method was time-saving. Through investigating the extraction process and characterizing the structure and thermal stability of DMY, the chelating extraction method could be considered to provide a reference for commercial applications of DMY.

Antibacterial Activity and Mode of Action of Dihydromyricetin from Ampelopsis grossedentata Leaves against Food-Borne Bacteria

Dihydromyricetin (DMY) has recently attracted increased interest due to its considerable health-promoting activities but there are few reports on its antibacterial activity and mechanism. In this paper, the activity and mechanisms of DMY from Ampelopsis grossedentata leaves against food-borne bacteria are investigated. Moreover, the effects of pH, thermal-processing, and metal ions on the antibacterial activity of DMY are also evaluated. The results show that DMY exhibits ideal antibacterial activity on five types of food-borne bacteria (Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Salmonella paratyphi, and Pseudomonas aeruginosa). The activities of DMY against bacteria are extremely sensitive to pH, thermal-processing, and metal ions. The morphology of the tested bacteria is changed and damaged more seriously with the exposure time of DMY. Furthermore, the results of the oxidative respiratory metabolism assay and the integrity of the cell membrane and wall tests revealed that the death of bacteria caused by DMY might be due to lysis of the cell wall, leakage of intracellular ingredients, and inhibition of the tricarboxylic acid cycle (TCA) pathway.

Dietary Supplementation of Vine Tea Ameliorates Glucose and Lipid Metabolic Disorder via Akt Signaling Pathway in Diabetic Rats

A traditional Chinese tea with many pharmacological effects, vine tea (VT) is considered a potential dietary supplement to improve type 2 diabetes (T2D). To investigate the effect and mechanism of VT on glucose and lipid metabolic disorders in T2D rats, Wistar rats fed a normal diet served as the normal control, while rats fed a high-fat diet combined with low-dose streptozotocin (STZ)-induced T2D were divided into three groups: The model group (MOD); the positive control group (MET, metformin at 200 mg/kg/d); and the VT-treated group (VT500, allowed to freely drink 500 mg/L VT). After four weeks of intervention, biochemical metrics indicated that VT significantly ameliorated hyperglycemia, hyperlipidemia and hyperinsulinemia in T2D rats. Metabolomics research indicated that VT regulated the levels of metabolites closely related to glucose and lipid metabolism and promoted glycogen synthesis. Furthermore, VT had a significant influence on the expression of key genes involved in the Akt signaling pathway, inhibited gluconeogenesis through the Akt/Foxo1/Pck2 signaling pathway, and reduced fatty acid synthesis via the SREBP1c/Fasn signaling pathways. In conclusion, VT has great potential as a dietary supplement to ameliorate glucose and lipid metabolic disorders via the Akt signaling pathway in T2D rats.

Design and characterization of a novel Arthrospira platensis glutathione oxido-reductase-derived antioxidant peptide GM15 and its potent anti-cancer activity via caspase-9 mediated apoptosis in oral cancer cells

Glutathione oxido-reductase (GR) is a primary antioxidant enzyme of most living forms which protects the cells from oxidative metabolism by reducing glutathione (GSH) from its oxidized form (GSSG). Although the antioxidant role of the enzyme is well characterized, the specific role of conserved N' peptide sequence in antioxidant mechanism remains unclear. In this study, we have identified an RNA sequence encoding GR enzyme from spirulina, Arthrospira platensis (Ap) and the changes in its gene expression profile was analysed during H₂O₂ stress. Results showed that H₂O₂ (10 mM) stimulated the expression of ApGR throughout the timeline of study (0, 5, 10, 15 and 20 days) with highest expression at 5^th day post-exposure which confirmed the antioxidant role of ApGR in spirulina during H₂O₂ induced oxidative stress. A dithiol containing short antioxidant peptide, ³⁹GGTCVIRGCVPKKLM⁵³ (GM15) from ApGR was predicted and its radicals (superoxide and hydroxyl radical) scavenging potential was confirmed by in vitro cell-free assays. GM15 (12.5 μM) reduced the intracellular generalized oxidative stress level, as measured using DCFDA assay in H₂O₂ exposed leucocytes without affecting any of the cellular population. Further, the biomedical application of the radical scavenging property of GM15 was validated in oral carcinoma (KB) cells where GM15 exhibited significant cytotoxicity. Also, GM15 exhibited heterogenous effects on intracellular oxidative stress level in KB cells: at lower concentration (6.25 μM), the peptide reduced oxidative stress whereas, at higher concentration (25 μM) it increased the intensity of oxidative stress. GM15 (25 μM) induced caspase-9 mediated apoptosis in KB cells along with membrane disruption and DNA degradation which are confirmed by propidium iodide (PI) internalization and comet assays, respectively. Overall, the study shows that GM15 peptide i) scavenges superoxide, hydroxyl radicals, and influences intracellular oxidative stress, and ii) has anti-cancer effect in oral cancer cells.

Protective effects of p-coumaric acid against oxidant and hyperlipidemia-an in vitro and in vivo evaluation

Dietary phenols are antioxidants with diverse physiological functions that are beneficial for human health. The objective of this research work was to investigate antioxidant activity of p-coumaric acid (p-CA) using four in vitro methods, the protective effects against oxidative stress in PC12 cells, and hypolipidemic effects on High fat-diet (HFD) mice model. The p-CA exhibited moderate antioxidant activity in the selected in vitro assay. The highest chelating activity of p-CA at 50 μg/mL was found to be 52.22%. Pretreatment with p-CA significantly enhanced cell viability of PC12 cell and suppressed AAPH-induced intracellular ROS generation and AAPH-induced LDH release. The hypolipidemic effects of p-CA (100 mg/kg BW) was directly linked to the increased expression of nuclear factor erythroid 2-related factor (Nrf2) by 2.0-fold, Glutathione peroxidase (Gpx) by 3.8-fold, Superoxide dismutase (SOD-1) by 1.6-fold, Heme oxygenase (HO-1) by 1.72-fold and NAD(P)H Quinone Dehydrogenase 1 (NQO-1) by 1.5-fold compared with HFD group. In addition to these effects, p-CA decreased total cholesterol and atherosclerosis index levels, and increased catalase (CAT) level in serum, total antioxidant capacity (T-AOC) and glutathione peroxidase (GSH-Px) levels in liver as compared HFD group. Administration of p-CA also promoted the recovery of hyperlipidemia steatohepatitis in mice by ameliorating lipid peroxidation. These results suggested that p-CA is a potent antioxidant with potential therapeutic efficacy for treating hyperlipidemia symptoms.

Chemical Compositions, Antiobesity, and Antioxidant Effects of Proanthocyanidins from Lotus Seed Epicarp and Lotus Seed Pot

Lotus seed epicarp (LSE) and lotus seed pot (LSP) were characterized, and a total of 5 and 7 proanthocyanidins (PAs) were identified in purified LSE and LSP extract, respectively. Purified LSE and LSP PAs significantly suppressed the body weight and weight gain of white adipose tissue (WAT) and decreased the WAT cell size in high-fat diet-induced obese mice regardless of the daily food intake. LSE or LSP administration significantly lowered the serum leptin level and improved the serum and liver lipid profiles (including total cholesterol (TC), triglycerides (TG), high-density lipoprotein-cholesterol (HDL-C), and low-density lipoprotein-cholesterol (LDL-C) levels), increased activities of antioxidant enzymes (superoxide dismutase (SOD) and glutathione transferase (GST)) and reduced glutathione (GSH) concentration, and suppressed lipid peroxidation in hepatic tissue. LSP PAs were generally more effective than LSE PAs. Both extracts ameliorated obesity, insulin resistance, and oxidative damage in obese mice, suggesting they are good candidates for value-added functional food and nutraceutical ingredients.

Interactions of Dihydromyricetin, a Flavonoid from Vine Tea (Ampelopsis grossedentata) with Gut Microbiota

Dihydromyricetin (DMY) is the main bioactive constituent in vine tea (Ampelopsis grossedentata), which was predominantly distributed in the gastrointestinal tract and showed poor oral bioavailability. Our aim was to systematically investigate the interactions of DMY with gut microbiota. Through the metabolism study of DMY by fecal microflora in vitro, it was found that DMY could be metabolized into three metabolites by fecal microflora via reduction and dehydroxylation pathways, and the dehydroxylation metabolite was the dominant one. Meanwhile, in order to consider the influence of gut microbiota metabolism on the pharmacokinetics of DMY, the pharmacokinetics of DMY in control and pseudo-germ-free rats were compared. It was shown that area under the curve (AUC) could only slightly increase, however, peak concentration (C_max ) could significantly increase in the pseudo-germ-free rats compared with the control rats, which indicated the gut microbiota metabolism played an important role in the pharmacokinetics of DMY. In addition, the long-term influence of DMY on gut microbiota composition by using 16S rRNA pyrosequencing was further investigated. And it was found that DMY could markedly alter the richness and diversity of the gut microbiota and modulate the gut microbiota composition. The present findings will be helpful for the future development and clinical application of DMY.

PRACTICAL APPLICATION

The gut microbiota plays an important role in the pharmacokinetics of flavonoids. As well, the long-term supplements of flavonoids could alter the gut microbiota composition in turn. The study aims to clarify the mutual interaction of DMY with gut microbiota, which may lead to new information with respect to the mechanism study and clinical application of DMY.

Unraveling the inhibitory effect of dihydromyricetin on heterocyclic aromatic amines formation

BACKGROUND

Heterocyclic aromatic amines (HAAs) are mutagens and rodent carcinogens. Flavonoids have attracted considerable attention for development into effective inhibitors against the formation of genotoxic HAAs in thermally processed foods.

RESULTS

The inhibitory effect of dihydromyricetin (DMY) on the formation of key HAAs, including 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), 2-amino-3,8-dimethylimidazo[4,5-f]-quinoxaline (MeIQx), and 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (4,8-DiMeIQx), was significant. In chemical models, DMY (0.05 mmol, 0.1 mmol, and 0.2 mmol) significantly decreased the amount of PhIP formed (43.0%, 54.7%, and 75.7% respectively). A significant inhibitory effect on the formation of MeIQx and 4,8-DiMeIQx was also observed. Moreover, DMY (0.05%, 0.1%, and 0.2%) reduced the generation of PhIP (by 48.0%, 59.0%, and 80.1% respectively) and that of MeIQx (by 45.8%, 62.0%, and 76.7% respectively) in fried beef patties.

CONCLUSION

The results indicate that DMY could be converted into myricetin during thermal processing, and both DMY and myricetin could trap phenylacetaldehyde, a major Strecker aldehyde of phenylalanine, in a similar manner to thus inhibit the generation of PhIP. This study provides valuable information for the development of effective strategies to minimize HAA content in thermally processed foods and also sheds light on the mechanism that accounts for the inhibitory effect. © 2017 Society of Chemical Industry.

Antioxidant and anti-inflammatory effects of polyphenols extracted from Ilex latifolia Thunb

To promote the rational and effective application of Ilex latifolia Thunb., a Chinese bitter tea widely consumed as a health beverage, polyphenols were extracted from its leaves and their cellular antioxidant activity (CAA) and anti-inflammatory effect against mouse macrophage RAW 264.7 cells were analyzed. Results showed that the antioxidant capacity of polyphenols was high, and their CAA values in PBS wash and no PBS wash protocols were 6871.42 ± 85.56 and 25161.61 ± 583.55 μmol QE (quercetin equivalents)/100 g phenolic extracts, respectively. In addition, polyphenols from I. latifolia displayed strong inhibition on LPS-induced NO-production in RAW 264.7 cells. Polyphenol treatment inhibited the release of pro-inflammatory cytokines (TNF-α, IL-1β and IL-6) induced by LPS in a dose-dependent manner by ELISA and mRNA expression analysis. Western blot results showed that the anti-inflammatory activity of polyphenols from I. latifolia might be exerted through inhibiting the activation of MAPKs (ERK and JNK) and NF-κB to decrease NO, COX-2 and pro-inflammatory cytokines production. Thus, the polyphenol enriched extracts from I. latifolia are a good source of natural antioxidants with a beneficial effect against inflammation, and they may be applied as a food supplement and/or functional ingredient.

The cardioprotective effect of dihydromyricetin prevents ischemia-reperfusion-induced apoptosis in vivo and in vitro via the PI3K/Akt and HIF-1α signaling pathways

Reperfusion therapy is widely used to treat acute myocardial infarction (AMI). However, further injury to the heart induced by rapidly initiating reperfusion is often encountered in clinical practice. A lack of pharmacological strategies in clinics limits the prognosis of patients with myocardial ischemia-reperfusion injury (MIRI). Dihydromyricetin (DMY) is one of the most abundant components in vine tea, commonly known as the tender stems and leaves of Ampelopsis grossedentata. The aim of this study was to evaluate the cardioprotection of DMY against myocardial ischemia-reperfusion (I/R) injury and to further investigate the underlying mechanism. An I/R injury was induced by left anterior descending coronary artery occlusion in adult male rats in vivo and a hypoxia-reoxygenation (H/R) injury in H9c2 cardiomyocytes in vitro. We found that DMY pretreatment provided significant protection against I/R-induced injury, including enhanced antioxidant capacity and inhibited apoptosis in vivo and in vitro. This effect correlated with the activation of the PI3K/Akt and HIF-1α signaling pathways. Conversely, blocking Akt activation with the PI3K inhibitor LY294002 effectively suppressed the protective effects of DMY against I/R-induced injury. In addition, the PI3K inhibitor partially blocked the effects of DMY on the upregulation of Bcl-2, Bcl-xl, procaspase-3, -8, and -9 protein expression and the downregulation of HIF-1α, Bnip3, Bax, Cyt-c, cleaved caspase-3, -8, and -9 protein expression. Collectively, these results showed that DMY decreased the apoptosis and necrosis by I/R treatment, and PI3K/Akt and HIF-1α plays a crucial role in protection during this process. These observations indicate that DMY has the potential to exert cardioprotective effects against I/R injury and the results might be important for the clinical efficacy of AMI treatment.

Dihydromyricetin-mediated inhibition of the Notch1 pathway induces apoptosis in QGY7701 and HepG2 hepatoma cells

AIM

To investigate whether Dihydromyricetin (DHM) inhibits cell proliferation and promotes apoptosis by downregulating Notch1 expression.

METHODS

The correlation between Notch1 and Hes1 (a Notch1 target molecule) expression in hepatoma samples was confirmed by qRT-PCR. In addition, MTT assays, flow cytometry and TUNEL analysis showed that DHM possessed strong anti-tumor properties, evidenced not only by reduced cell proliferation but also by enhanced apoptosis in QGY7701 and HepG2 hepatocellular carcinoma (HCC) cells. The expressions of Notch1, Hes1, Bcl-2 and Bax were determined by Western blot.

RESULTS

Among the tested samples (n = 64), the expression levels of Notch1 (75% of patients) and Hes1 (79.7% of patients) mRNA in tumor tissues were higher than in the normal liver tissues. There was a negative correlation between the expression of Notch1 and the degree of differentiation and positively correlated with the Alpha Fetal Protein concentration. The viability of HCC cells treated with DHM was significantly inhibited in a dose and time-dependent manner. Apoptosis was induced in HepG2 and QGY7701 cell lines following 24 h of DHM treatment. After treatment with DHM, the protein expression of Notch1 was downregulated, the apoptosis-related protein Bax was upregulated and Bcl2 was downregulated. Notch1 siRNA further enhanced the anti-tumor properties of DHM.

CONCLUSION

Notch1 is involved in the development of HCC and DHM inhibits cell proliferation and promotes apoptosis by down-regulating the expression of Notch1.

Anti‑inflammatory effects of dihydromyricetin in a mouse model of asthma

Dihydromyricetin (DHM) is a plant flavonoid and is the primary active ingredient isolated from the medicinal herb, Ampelopsis grossedentata. DHM has been shown to possess various pharmacological activities, including anti-inflammatory effects. However, the possible role of DHM in asthma treatment remains to be elucidated. The present study aimed to investigate its anti-inflammatory properties in mice with symptoms of allergic asthma. The C57BL/6 mice were sensitized and challenged with ovalbumin (OVA) to induce asthma. DHM or phosphate-buffered saline treatment was administered 1 h prior to the OVA challenge. The levels of interleukin (IL)-4, IL-5 and IL-13 in the bronchoalveolar lavage (BAL) fluid were measured by enzyme-linked immunosorbent assay (ELISA), and OVA-specific serum IgE and IgG1 levels were also determined by ELISA. Histopathological staining was performed to evaluate the infiltration of inflammatory cells into the BAL fluid, lung tissues and goblet cell hyperplasia. DHM treatment significantly reduced the total number of inflammatory cells, including eosinophils, neutrophils, lymphocytes and macrophages, in the BAL fluid. DHM also reduced the levels of IL-4, IL-5 and IL-13 in the BAL fluid, and reduced the secretion of OVA-specific IgE and IgG1 in the serum. The histological staining demonstrated that DHM treatment effectively suppressed the OVA-induced inflammatory cells in the lung tissues and in the mucus hypersecreted by goblet cells in the airway. These results showed that DHM had a potent anti-inflammatory effect in an OVA-induced mouse model of asthma, offering potential as an anti-inflammatory agent for the treatment of asthma.

Biotransformation of vine tea (Ampelopsis grossedentata) by solid-state fermentation using medicinal fungus Poria cocos

Vine tea was bio-transformed using Poria cocos by solid-state fermentation in order to improve its taste and quality. Volatile components in vine tea were also identified by GC-MS. The changes of flavonoid, tea polyphenols and polysaccharides in fermented vine tea were evaluated. Flavonoid and polyphenols in vine tea were remained unchanged even after biotransformation, but content of polysaccharides increased to 3.9-fold than that of unfermented vine tea. Antioxidant activity such as DPPH free radical scavenging capacity (SR) was determined that there was a positive correlation between SR and content of polysaccharides in vine tea. Methyl 2-methylvalerate-a new volatile compound was identified and gave the vine tea rich delicate fragrance of fruits. The content of linolenic acid increased from 0.88 to 19.59 %. Biotransformation improved the taste and quality of vine tea.

Antioxidant Mechanism of Betaine without Free Radical Scavenging Ability

Betaine (BET) is a native compound widely studied as an antioxidant in agriculture and human health. However, the antioxidant mechanism of BET remains unclear. In this research, radical scavenging assays showed that BET had little free radical scavenging activity. However, the antioxidant activity of BET was confirmed by cellular antioxidant activity (CAA) and erythrocyte hemolysis assays. The results of quantitative PCR (qPCR) and enzyme activity determination kits showed that the antioxidant activity of BET was not due to the gene expression and activity of antioxidases. High-pressure liquid chromatography (HPLC) assessment of the effect of BET on sulfur-containing amino acid metabolism showed that BET increased the levels of nonenzymatic antioxidants,S-adenosylmethionine (SAM) and methionine (p < 0.05), via the regulation of the methionine-omocysteine cycle. Additionally, the three methyl groups of BET were found to play a key role in its antioxidant activity. The possible reason was that because of the hydrophobicity of the three methyl groups and hydrophilicity of the carboxyl of BET, a tight protective membrane was formed around cells to prevent oxidative stress inducer from inducing ROS generation and cell damage. In conclusion, the antioxidant mechanism of BET was found to enhance nonenzymatic antioxidant defenses via the methionine-homocysteine cycle and form a protective membrane around cells.

Dihydromyricetin protects neurons in an MPTP-induced model of Parkinson's disease by suppressing glycogen synthase kinase-3 beta activity

AIM

It is general believed that mitochondrial dysfunction and oxidative stress play critical roles in the pathology of Parkinson's disease (PD). Dihydromyricetin (DHM), a natural flavonoid extracted from Ampelopsis grossedentata, has recently been found to elicit potent anti-oxidative effects. In the present study, we explored the role of DHM in protecting dopaminergic neurons.

METHODS

Male C57BL/6 mice were intraperitoneally injected with 1-methyl4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) for 7 d to induce PD. Additionally, mice were treated with either 5 or 10 mg/kg DHM for a total of 13 d (3 d before the start of MPTP, during MPTP administration (7 d) and 3 d after the end of MPTP). For the saline or DHM alone treatment groups, mice were injected with saline or DHM for 13 d. On d 14, behavioral tests (locomotor activity, the rotarod test and the pole test) were administered. After the behavioral tests, the mice were sacrificed, and brain tissue was collected for immunofluorescence staining and Western blotting. In addition, MES23.5 cells were treated with MPP⁺ and DHM, and evaluated using cell viability assays, reactive oxygen species (ROS) measurements, apoptosis analysis and Western blotting.

RESULTS

DHM significantly attenuated MPTP-induced mouse behavioral impairments and dopaminergic neuron loss. In the MES23.5 cells, DHM attenuated MPP⁺-induced cell injury and ROS production in a dose-dependent manner. In addition, DHM increased glycogen synthase kinase-3 beta phosphorylation in a dose- and time-dependent manner, which may be associated with DHM-induced dopaminergic neuronal protection.

CONCLUSION

The present study demonstrated that DHM is a potent neuroprotective agent for DA neurons by modulating the Akt/GSK-3β pathway, which suggests that DHM may be a promising therapeutic candidate for PD.

Lactobacillus paracasei subsp. paracasei M5L induces cell cycle arrest and calreticulin translocation via the generation of reactive oxygen species in HT-29 cell apoptosis

Lactobacillus paracasei subsp. paracasei M5L (L. paracasei M5L) was isolated and co-cultured with HT-29 colon cancer cells to study its anti-colorectal cancer effects and mechanism. Using the MTT assay we found that L. paracasei M5L significantly inhibits HT-29 cell proliferation. Morphological and biochemical characteristics of apoptosis were observed and confirmed by hematoxylin and eosin (HE) staining and transmission electron microscopy (TEM). Lactobacilli could change the cell cycle distribution and induce calreticulin (CRT) translocation from the endoplasmic reticulum to the surface of the cytomembrane. We also determine that vast reactive oxygen species (ROS) were generated, while the activities of superoxide dismutase (SOD) and catalase (CAT) were noticeably diminished following L. paracasei M5L treatment. This study reveals that L. paracasei M5L induces apoptosis in HT-29 cells through ROS generation followed by CRT accompanied endoplasmic reticulum (ER) stress and S phase arrest. These results provide new insights into the possible molecular mechanism of L. paracasei M5L as a novel probiotic with the potential for further application.

Protective effects of kaempferol against reactive oxygen species-induced hemolysis and its antiproliferative activity on human cancer cells

The protective effects of kaempferol against reactive oxygen species (ROS)-induced hemolysis and its antiproliferative activity on human cancer cells were evaluated in this study. Kaempferol exhibited strong cellular antioxidant ability (CAA) with a CAA value of 59.80 ± 0.379 μM of quercetin (QE)/100 μM (EC50 = 7.74 ± 0.049 μM). Pretreatment with kaempferol significantly attenuated the ROS-induced hemolysis of human erythrocyte (87.4% hemolysis suppressed at 100 μg/mL) and reduced the accumulation of toxic lipid peroxidation product malondialdehyde (MDA). The anti-hemolytic activity of kaempferol was mainly through scavenging excessive ROS and preserving the intrinsic antioxidant enzymes (superoxide dismutase, SOD; catalase, CAT; and glutathione peroxidase, GPx) activities in normal levels. Additionally, kaempferol showed significant antiproliferative activity on a panel of human cancer cell lines including human breast carcinoma (MCF-7) cells, human stomach carcinoma (SGC-7901) cells, human cervical carcinoma (Hela) cells and human lung carcinoma (A549) cells. Kaemperol induced apoptosis of MCF-7 cells accompanied with nuclear condensation and mitochondria dysfunction.

Analysis of the quantitative structure–activity relationship of glutathione-derived peptides based on different free radical scavenging systems

In the present study, eleven glutathione-derived peptides, including Glu-Cys-His, Pro-Leu-Gly, Pro-Cys-Gly, Phe-Lys-Leu, Leu-His-Gly, Lys-Leu-Glu, Lys-Val-His, Tyr-Glu-Gly, Tyr-His-Leu, Gly-Glu-Leu and Gly-Pro-Glu, were designed.

Biofunctionalization of Selenium Nanoparticle with Dictyophora Indusiata Polysaccharide and Its Antiproliferative Activity through Death-Receptor and Mitochondria-Mediated Apoptotic Pathways

Bio-functionalized nanoparticles with semiconducting/metallic core encapsulated in a bio- or bio-derived materials are promising for applications in biology and especially in cancer diagnostic and healing. In this report, we report a facile, single-step, first-time synthesis and in-situ functionalization strategy for the preparation of monodispersed selenium nanoparticles (SeNPs) functionalized using a novel polysaccharide (DP1) extracted from Dictyophora indusiata (a fungus). The DP1 functionalized SeNPs (DP1-SeNPs), where DP1 is attached to the surface via Se-O bond as well as physic-sorption had, an average diameter of 89 nm, and were highly uniform, extremely stable compared to bare SeNPs. Detailed investigation of the biological properties of DP1-SeNP illustrated that they exhibit unprecedented, enhanced, and selective antiproliferative activity through inducing cell apoptosis confirmed by nuclear condensation, DNA cleavage, and accumulation of S phase cell arrest. The mechanism of the induced apoptosis was found to be a combination of the activation of caspases 3, 8, and 9, the Fas-associated death domain protein (FADD), reactive oxygen species (ROS) overproduction, as well as mitochondrial dysfunction. It is envisioned that the reported DP1-SeNPs will offer a new phase space for high-efficiency anticancer treatment with little side effect.