Dihydromyricetin induces apoptosis and inhibits proliferation in hepatocellular carcinoma cells

Multiple molecular and cellular mechanisms of the antitumour effect of dihydromyricetin (Review)

Dihydromyricetin (DHM) is a natural flavonoid compound with multiple antitumour effects, including inhibition of proliferation, promotion of apoptosis, inhibition of invasion and migration, clearance of reactive oxygen species (ROS) and induction of autophagy. For example, DHM can effectively block the progression of the tumour cell cycle and inhibit cell proliferation. In different types of cancer cells, DHM can regulate the PI3K/Akt pathway, mTOR, and NF-κB pathway components, such as p53, and endoplasmic reticulum stress can alter the accumulation of ROS or induce autophagy to promote the apoptosis of tumour cells. In addition, when DHM is used in combination with various known chemotherapy drugs, such as paclitaxel, nedaplatin, doxorubicin, oxaliplatin and vinblastine, it can increase the sensitivity of tumour cells to DHM and increase the therapeutic effect of chemotherapy drugs. In the present review, the multiple molecular and cellular mechanisms underlying the antitumour effect of DHM, as well as its ability to increase the effects of various traditional antitumour drugs were summarized. Through the present review, it is expected by the authors to draw attention to the potential of DHM as an antitumour drug and provide valuable references for the clinical translation of DHM research and the development of related treatment strategies.

Mechanisms of dihydromyricetin against hepatocellular carcinoma elucidated by network pharmacology combined with experimental validation

CONTEXT

Dihydromyricetin (DMY) is extracted from vine tea, a traditional Chinese herbal medicine with anti-cancer, liver protection, and cholesterol-lowering effects.

OBJECTIVE

This study investigated the mechanism of DMY against hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

Potential DMY, HCC, and cholesterol targets were collected from relevant databases. PPI networks were created by STRING. Then, the hub genes of co-targets, screened using CytoHubba. GO and KEGG pathway enrichment, were performed by Metascape. Based on the above results, a series of in vitro experiments were conducted by using 40-160 μM DMY for 24 h, including transwell migration/invasion assay, western blotting, and Bodipy stain assay.

RESULTS

Network pharmacology identified 98 common targets and 10 hub genes of DMY, HCC, and cholesterol, and revealed that the anti-HCC effect of DMY may be related to the positive regulation of lipid rafts. Further experiments confirmed that DMY inhibits the proliferation, migration, and invasion of HCC cells and reduces their cholesterol levels in vitro. The IC₅₀ is 894.4, 814.4, 467.8, 1,878.8, 151.8, and 156.9 μM for 97H, Hep3B, Sk-Hep1, SMMC-7721, HepG2, and Huh7 cells, respectively. In addition, DMY downregulates the expression of lipid raft markers (CAV1, FLOT1), as well as EGFR, PI3K, Akt, STAT3, and Erk.

DISCUSSION AND CONCLUSION

The present study reveals that DMY suppresses EGFR and its downstream pathways by reducing cholesterol to disrupt lipid rafts, thereby inhibiting HCC, which provides a promising candidate drug with low toxicity for the treatment of HCC.

Natural Acetogenins, Chatenaytrienins-1, -2, -3 and -4, Mitochondrial Potential Uncouplers and Autophagy Inducers-Promising Anticancer Agents

The present paper details the complete stereoselective synthesis of four natural acetogenins, chatenaytrienins-1, -2, -3 and -4, previously isolated from the roots of fruit trees of the family Annonaceae (A. nutans and A. muricata), as an inseparable mixture. The novel organometallic reactions, developed by the authors, of Ti-catalyzed cross-cyclomagnesiation of O-containing and aliphatic allenes using available Grignard reagents were applied at the key stage of synthesis. We have studied the biological activity of the synthesized individual chatenaytrienins-1, -2, -3 and -4 in vitro, including their cytotoxicity in a panel of tumor lines and their ability to induce apoptosis, affect the cell cycle and mitochondria, and activate the main apoptotic signaling pathways in the cell, applying modern approaches of flow cytometry and multiplex analysis with Luminex xMAP technology. It has been shown that chatenaytrienins affect mitochondria by uncoupling the processes of mitochondrial respiration, causing the accumulation of ROS ions, followed by the initiation of apoptosis. The most likely mechanism for the death of cortical neurons from the consumption of tea from the seeds of Annona fruit is long-term chronic hypoxia, which leads to the development of an atypical form of Parkinson's disease that is characteristic of the indigenous inhabitants of Guam and New Caledonia.

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.

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.

Anticancer and antibacterial flavonoids from the callus of Ampelopsis grossedentata; a new weapon to mitigate the proliferation of cancer cells and bacteria

A new flavonoid angelioue (1) together with five known compounds cuminatanol (2), myricetin (3), epigallocatechin (4), taxifolin (5) and dihydromyricetin (6) was isolated from the callus extract of Ampelopsis grossedentata (Hand.-Mazz.) W. T. Wang and the structures were elucidated based on their detailed spectroscopic data. Among the compounds, the new compound angelioue (1) displayed significant antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA) with the MIC value of 6.68 μg mL-1 and MBC value of 53.42 μg mL-1; in contrast the other compounds showed moderate to no antibacterial activity. In addition, known dihydromyricetin (6) exhibited potent cytotoxic activities against mouse breast cancer cells (4T1), human lung adenocarcinoma (A549) and human non-small cell lung cancer (NCI-H1975) tumor cell lines with GI50 values of 17.47, 18.91 and 20.50 μM mL-1, respectively. The compounds 1-5 exhibited low micro-molar inhibitory activities. Moreover, the structure-activity relationships of the most active compounds for antibacterial and cytotoxic activities are discussed. The present findings clearly suggest that the A. grossedentata callus is a good source of bioactive compounds.

Present Status, Challenges, and Prospects of Dihydromyricetin in the Battle against Cancer

Dihydromyricetin (DHM) is a natural flavonoid compound extracted from Ampelopsis grossedentata that has been used for centuries in traditional Chinese medicine. DHM has attracted intensive attention due to its numerous beneficial activities, such as hepatoprotection, cardioprotection, antioxidant, and anti-inflammation. In addition, DHM inhibits the progression of cancers such as lung cancer, hepatocellular cancer, breast cancer, melanoma, and malignant reproductive systems through multiple mechanisms, including antiangiogenesis, antiproliferation, apoptosis, and inhibition of invasion and migration. Notably, DHM also activates autophagy at different levels, exerting a dual-regulatory effect on cancers. Mechanistically, DHM can effectively regulate mammalian target of rapamycin (mTOR), noncoding RNA-mediated signaling, phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) pathway, nuclear factor-κB (NF-κB), p53, and endoplasmic reticulum stress (ER stress)-driven signaling in different types of cancers. DHM has also been shown to have inhibitory effects on various regulators that trigger epithelial–mesenchymal transition (EMT). Furthermore, DHM exhibits a remarkable anticancer reversal ability when used in combination with drugs such as adriamycin, nedaplatin, and other drugs. However, the low bioavailability of DHM limits its potential applications, which are improved through structural modification and the exploration of novel dosage forms. Therefore, DHM may become a promising candidate for treating malignancies alone or combined with conventional anticancer strategies used in clinical practice.

The Synergistic Effect of Triterpenoids and Flavonoids-New Approaches for Treating Bacterial Infections?

Currently, the pharmaceutical industry is well-developed, and a large number of chemotherapeutics are being produced. These include antibacterial substances, which can be used in treating humans and animals suffering from bacterial infections, and as animal growth promoters in the agricultural industry. As a result of the excessive use of antibiotics and emerging resistance amongst bacteria, new antimicrobial drugs are needed. Due to the increasing trend of using natural, ecological, and safe products, there is a special need for novel phytocompounds. The compounds analysed in the present study include two triterpenoids ursolic acid (UA) and oleanolic acid (OA) and the flavonoid dihydromyricetin (DHM). All the compounds displayed antimicrobial activity against Gram-positive (Staphylococcus aureus ATCC 6538, Staphylococcus epidermidis ATCC 12228, and Listeria monocytogenes ATCC 19115) and Gram-negative bacteria (Escherichia coli ATCC 25922, Proteus hauseri ATCC 15442, and Campylobacter jejuni ATCC 33560) without adverse effects on eukaryotic cells. Both the triterpenoids showed the best antibacterial potential against the Gram-positive strains. They showed synergistic activity against all the tested microorganisms, and a bactericidal effect with the combination OA with UA against both Staphylococcus strains. In addition, the synergistic action of DHM, UA, and OA was reported for the first time in this study. Our results also showed that combination with triterpenoids enhanced the antimicrobial potential of DHM.

Recent advances in research on vine tea, a potential and functional herbal tea with dihydromyricetin and myricetin as major bioactive compounds

Vine tea has been used as an herbal tea by several ethnic minorities for hundreds of years in China. Flavonoids, a kind of indispensable component in a variety of nutraceutical, pharmaceutical and cosmetic applications, are identified to be the major metabolites and bioactive ingredients in vine tea. Interestingly, vine tea exhibits a wide range of significant bioactivities including anti-oxidant, anti-inflammatory, anti-tumor, antidiabetic, neuroprotective and other activities, but no toxicity. These bioactivities, to some extent, enrich the understanding about the role of vine tea in disease prevention and therapy. The health benefits of vine tea, particularly dihydromyricetin and myricetin, are widely investigated. However, there is currently no comprehensive review available on vine tea. Therefore, this report summarizes the most recent studies investigating bioactive constituents, pharmacological effects and possible mechanisms of vine tea, which will provide a better understanding about the health benefits and preclinical assessment of novel application of vine tea.

Molecular mechanisms and therapeutic implications of dihydromyricetin in liver disease

Recent studies demonstrated that dihydromyricetin (DHM) has prominent therapeutic effects on liver injury and liver cancer. By summarizing the current preclinical in vitro and in vivo studies, the present review examines the preventive and therapeutic effects of DHM on liver disorders as well as its potential mechanisms. Briefly, in both chemical- and alcohol-induced liver injury models, DHM ameliorates hepatocyte necrosis and steatosis while promoting liver regeneration. In addition, DHM can alleviate nonalcoholic fatty liver disease (NAFLD) via regulating lipid/glucose metabolism, probably due to its anti-inflammatory or sirtuins-dependent mechanisms. Furthermore, DHM treatment inhibits cell proliferation, induces apoptosis and autophagy and regulates redox balance in liver cancer cells, thus exhibiting remarkable anti-cancer effects. The pharmacological mechanisms of DHM may be associated with its anti-inflammatory, anti-oxidative and apoptosis-regulatory benefits. With the accumulating interests in utilizing natural products to target common diseases, our work aims to improve the understanding of DHM acting as a novel drug candidate for liver diseases and to accelerate its translation from bench to bedside.

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.

Dihydromyricetin inhibits cell proliferation, migration, invasion and promotes apoptosis via regulating miR-21 in Human Cholangiocarcinoma Cells

Dihydromyricetin, the most abundant natural flavonoid isolated from Ampelopsis grossedentata, exhibits broad anti-tumor effects. However, the effects of dihydromyricetin on cholangiocarcinoma remain unclear. This study examined the anti-tumor effects of dihydromyricetin in two human cholangiocarcinoma cell lines HCCC9810 and TFK-1, and the underlying mechanism was also investigated. Our study was the first to show that dihydromyricetin significantly inhibited cell proliferation, migration, invasion and promoted apoptosis in cholangiocarcinoma cells. By analyzing the TCGA dataset, we found that expression of miR-21, an oncogene and a potential target of anticancer drugs for cholangiocarcinoma, was upregulated in cholangiocarcinoma tissues compared to paired control tissues. Moreover, dihydromyricetin significantly reduced the expression of miR-21 in a dose-dependent manner. Overexpression of miR-21 remarkably abolished the inhibitory effects of dihydromyricetin on cell proliferation, migration, invasion and abrogated its effect of promoting cell apoptosis in both HCCC9810 and TFK-1 cells. Dihydromyricetin remarkably increased the expression of PTEN and decreased the expression of phosphorylated Akt, while overexpression of miR-21 abrogated the modulation of PTEN/ Akt pathway by dihydromyricetin. Taken together, our study demonstrates that dihydromyricetin inhibits cell proliferation, migration, invasion and promotes apoptosis in cholangiocarcinoma cells via regulating miR-21.

Dihydromyricetin Protects the Liver via Changes in Lipid Metabolism and Enhanced Ethanol Metabolism

Background

Excess alcohol (ethanol, EtOH) consumption is a significant cause of chronic liver disease, accounting for nearly half of the cirrhosis‐associated deaths in the United States. EtOH‐induced liver toxicity is linked to EtOH metabolism and its associated increase in proinflammatory cytokines, oxidative stress, and the subsequent activation of Kupffer cells. Dihydromyricetin (DHM), a bioflavonoid isolated from Hovenia dulcis, can reduce EtOH intoxication and potentially protect against chemical‐induced liver injuries. But there remains a paucity of information regarding the effects of DHM on EtOH metabolism and liver protection. As such, the current study tests the hypothesis that DHM supplementation enhances EtOH metabolism and reduces EtOH‐mediated lipid dysregulation, thus promoting hepatocellular health.

Methods

The hepatoprotective effect of DHM (5 and 10 mg/kg; intraperitoneal injection) was evaluated using male C57BL/6J mice and a forced drinking ad libitum EtOH feeding model and HepG2/VL‐17A hepatoblastoma cell models. EtOH‐mediated lipid accumulation and DHM effects against lipid deposits were determined via H&E stains, triglyceride measurements, and intracellular lipid dyes. Protein expression of phosphorylated/total proteins and serum and hepatic cytokines was determined via Western blot and protein array. Total NAD⁺/NADH Assay of liver homogenates was used to detect NAD + levels.

Results

DHM reduced liver steatosis, liver triglycerides, and liver injury markers in mice chronically fed EtOH. DHM treatment resulted in increased activation of AMPK and downstream targets, carnitine palmitoyltransferase (CPT)‐1a, and acetyl CoA carboxylase (ACC)‐1. DHM induced expression of EtOH‐metabolizing enzymes and reduced EtOH and acetaldehyde concentrations, effects that may be partly explained by changes in NAD⁺. Furthermore, DHM reduced the expression of proinflammatory cytokines and chemokines in sera and cell models.

Conclusion

In total, these findings support the utility of DHM as a dietary supplement to reduce EtOH‐induced liver injury via changes in lipid metabolism, enhancement of EtOH metabolism, and suppressing inflammation responses to promote liver health.

Annotation of genes involved in high level of dihydromyricetin production in vine tea (Ampelopsis grossedentata) by transcriptome analysis

BACKGROUND

Leaves of the medicinal plant Ampelopsis grossedentata, which is commonly known as vine tea, are used widely in the traditional Chinese beverage in southwest China. The leaves contain a large amount of dihydromyricetin, a compound with various biological activities. However, the transcript profiles involved in its biosynthetic pathway in this plant are unknown.

RESULTS

We conducted a transcriptome analysis of both young and old leaves of the vine tea plant using Illumina sequencing. Of the transcriptome datasets, a total of 52.47 million and 47.25 million clean reads were obtained from young and old leaves, respectively. Among 471,658 transcripts and 177,422 genes generated, 7768 differentially expressed genes were identified in leaves at these two stages of development. The phenylpropanoid biosynthetic pathway of vine tea was investigated according to the transcriptome profiling analysis. Most of the genes encoding phenylpropanoid biosynthesis enzymes were identified and found to be differentially expressed in different tissues and leaf stages of vine tea and also greatly contributed to the biosynthesis of dihydromyricetin in vine tea.

CONCLUSIONS

To the best of our knowledge, this is the first formal study to explore the transcriptome of A. grossedentata. The study provides an insight into the expression patterns and differential distribution of genes related to dihydromyricetin biosynthesis in vine tea. The information may pave the way to metabolically engineering plants with higher flavonoid content.

Effects of dihydromyricetin on ARPE-19 cell migration through regulating matrix metalloproteinase-2 expression

Dihydromyricetin (DHM), a flavanonol compound in Ampelopsis grossedentata, possesses several biological activities. However, the molecular mechanism underlying the effects of DHM on human proliferative vitreoretinopathy (PVR) remains unclear. We explored the effects of DHM on cell migration and the metastasis-promoting proteins in human retinal pigment epithelial (RPE) cells (ARPE-19 cells). Our results revealed that DHM attenuated ARPE-19 cell invasion and migration by reducing matrix metalloproteinase-2 (MMP-2) expression. Furthermore, a Western blot analysis revealed that DHM significantly reduced levels of phosphorylated c-Jun N-terminal kinase 1/2, but not those of extracellular signal-regulated kinase 1/2 and p38. In conclusion, our findings shown that DHM inhibits human RPE cell migration through the inhibition of MMP-2 expression; therefore, DHM may have potential therapeutic value in treating PVR as adjuvant therapy.

Dihydromyricetin from ampelopsis grossedentata protects against vascular neointimal formation via induction of TR3

Vine tea has been used as a medicinal herb in traditional Chinese medicine for hundreds of years. As the most abundant ingredient in vine tea, Dihydromyricetin (DHM) has been reported to exert anti-inflammatory, antioxidant, and anti-cardiovascular disease. However, the role of DHM in injury-induced neointimal formation remains poorly characterized. We determined the effects of DHM on ligation-induced carotid artery neointimal formation. We found that ligation-induced carotid artery neointimal formation could be significantly attenuated by DHM treatment. We provide evidence that DHM increases orphan nuclear receptor TR3 expression in smooth muscle cell (SMC) and carotid artery. Moreover, overexpression and loss-of-function strategies of TR3 were done to overexpression and knockdown of TR3, and demonstrate that DHM promotes SMC differentiation, however, inhibits SMC proliferation and migration, via regulating expression of TR3. Collectively, we reveal that DHM may be a therapeutic agent for the treatment of injury-induced vascular diseases.

Astragalin and dihydromyricetin as adjuncts to histidine‑tryptophan‑ketoglutarate cardioplegia enhances protection during cardioplegic arrest

The present study used an in vitro model of cold cardioplegia in isolated working rat hearts to evaluate the possible effects of two flavonoids, astragalin and dihydromyricetin, as adjuncts to histidine‑tryptophan‑ketoglutarate (HTK) cardioplegia. The following three groups of male Sprague Dawley rats were evaluated: The HTK group, treated with HTK alone; the HTK‑A group, treated with 10 µmol/l astragalin; and the HTK‑D group, treated with 10 µmol/l dihydromyricetin. Isolated rat hearts were perfused with Krebs‑Henseleit buffer for 30 min and incubated with the respective cardioplegic solution for 6 h at 4˚C. Subsequently, astragalin or dihydromyricetin was added to the cardioplegic solutions. Following 30 min of reperfusion, the left ventricular developed pressure (LVDP), maximum up/down rate of left ventricular pressure (±dp/dtmax) and heart rate were documented as indices of myocardial function using a physiological recorder. Myocardial infarct size (IS) was estimated using 2,3,5‑triphenyltetrazolium chloride staining. Lactate dehydrogenase (LDH) and creatine kinase (CK) levels were also determined to assess the degree of cardiac injury. Cardiomyocyte apoptosis analysis was performed using an in situ cell death detection kit. In addition, malondialdehyde (MDA), superoxide dismutase (SOD), interleukin‑6 (IL‑6), tumor necrosis factor‑α (TNF‑α), C‑reactive protein (CRP) levels, as well as the glutathione/glutathione disulfide (GSH/GSSG) ratio were determined and analyzed using ELISA kits. The protein levels of caspase‑9 and B‑cell lymphoma‑2 (Bcl‑2) were determined using western blot analysis. The results demonstrated that exposure to astragalin or dihydromyricetin significantly improved the recovery of LVDP (P<0.05 and P<0.01, respectively), the +dP/dtmax (P<0.05 for dihydromyricetin only) and the ‑dP/dtmax (P<0.05 and P<0.01, respectively), increased SOD levels (P<0.05 and P<0.01, respectively) and GSH/GSSG ratios (P<0.05), reduced myocardial IS (P<0.05 and P<0.01, respectively), decreased CK, LDH, IL‑6 (all P<0.05 and P<0.01, respectively), MDA (P<0.05), CRP (P<0.05) and TNF‑α levels (P<0.05 and P<0.01, respectively), increased Bcl‑2 levels (P<0.01) and decreased caspase‑9 levels (P<0.01). The results indicated that the addition of either flavonoid (particularly dihydromyricetin) to HTK enhances protection during ischemia, decreases myocardial dysfunction by enhancing anti‑inflammatory activities, attenuates myocardial oxidative injury and prevents apoptosis during ischemia/reperfusion.

Dihydromyricetin Attenuates TNF-α-Induced Endothelial Dysfunction through miR-21-Mediated DDAH1/ADMA/NO Signal Pathway

Accumulating studies demonstrate that dihydromyricetin (DMY), a compound extracted from Chinese traditional herb, Ampelopsis grossedentata, attenuates atherosclerotic process by improvement of endothelial dysfunction. However, the underlying mechanism remains poorly understood. Thus, the aim of this study is to investigate the potential mechanism behind the attenuating effects of DMY on tumor necrosis factor alpha- (TNF-α-) induced endothelial dysfunction. In response to TNF-α, microRNA-21 (miR-21) expression was significantly increased in human umbilical vein endothelial cells (HUVECs), in line with impaired endothelial dysfunction as evidenced by decreased tube formation and migration, endothelial nitric oxide synthase (eNOS) (ser1177) phosphorylation, dimethylarginine dimethylaminohydrolases 1 (DDAH1) expression and metabolic activity, and nitric oxide (NO) concentration as well as increased asymmetric dimethylarginine (ADMA) levels. In contrast, DMY or blockade of miR-21 expression ameliorated endothelial dysfunction in HUVECs treated with TNF-α through downregulation of miR-21 expression, whereas these effects were abolished by overexpression of miR-21. In addition, using a nonspecific NOS inhibitor, L-NAME, also abrogated the attenuating effects of DMY on endothelial dysfunction. Taken together, these data demonstrated that miR-21-mediated DDAH1/ADMA/NO signal pathway plays an important role in TNF-α-induced endothelial dysfunction, and DMY attenuated endothelial dysfunction induced by TNF-α in a miR-21-dependent manner.

Dihydromyricetin protects against liver ischemia/reperfusion induced apoptosis via activation of FOXO3a-mediated autophagy

Liver ischemia and reperfusion (I/R) injury is characterized by defective liver autophagy accompanied by alterations to the endogenous defense system. Dihydromyricetin (DHM) is a natural flavonoid that demonstrates a wide range of physiological functions, and has been implicated as a regulator of autophagy. This study investigates the protective effects of DHM pretreatment on liver injury caused by ischemia/reperfusion (I/R) and elucidates the potential mechanism of DHM-mediated protection. Mice were subjected to 60 minutes of ischemia followed by 5 hours of reperfusion. DHM (100 mg/kg bw/day) or the vehicle was administered daily by gavage 7 days before ischemia and immediately before reperfusion. In this study, DHM markedly decreased serum aminotransferase activity and inhibited liver I/R -stimulated apoptosis. Moreover, DHM exerted hepatoprotective effects by upregulating mRNA levels of various essential autophagy-related genes including ATG5, ATG12, BECN1, and LC3. Autophagy inhibitor chloroquine or Atg5 knockdown blocked DHM -mediated elevation in liver function. Specifically, DHM significantly increased FOXO3a expression, and enhanced FOXO3a nuclear translocation and Ser588 phosphorylation modification. Importantly, the inhibition of FOXO3a with FOXO3a-siRNA in mice decreased DHM-induced autophagy-related genes and diminished the protective effects of DHM against liver I/R injury. In summary, these findings identify DHM as a novel hepatoprotective small molecule by elevating FOXO3a expression and nuclear translocation, stimulating autophagy-related genes and suppressing liver I/R-induced apoptosis, suggesting FOXO3a may have therapeutic value in liver cell protection in liver I/R injury.

In vitro inhibitory effects of dihydromyricetin on human liver cytochrome P450 enzymes

CONTEXT

Dihydromyricetin (DHM) is the most abundant and active flavonoid component isolated from Ampelopsis grossedentata (Hand-Mazz) W.T. Wang (Vitaceae) and it possesses numerous pharmacological activities. However, whether DHM affects the activity of human liver cytochrome P450 (CYP) enzymes remains unclear.

MATERIALS AND METHODS

The inhibitory effects of DHM on eight human liver CYP isoforms (i.e., 1A2, 3A4, 2A6, 2E1, 2D6, 2C9, 2C19 and 2C8) were investigated in vitro using human liver microsomes (HLMs).

RESULTS

The results showed that DHM could inhibit the activity of CYP3A4, CYP2E1 and CYP2D6, with IC₅₀ values of 14.75, 25.74 and 22.69 μM, respectively, but that other CYP isoforms were not affected. Enzyme kinetic studies showed that DHM was not only a non-competitive inhibitor of CYP3A4 but also a competitive inhibitor of CYP2E1 and CYP2D6, with Ki values of 6.06, 9.24 and 10.52 μM, respectively. In addition, DHM is a time-dependent inhibitor for CYP3A4 with K_I/K_inact value of 12.17/0.057 min^-1μM^-1.

DISCUSSION AND CONCLUSION

The in vitro studies of DHM with CYP isoforms indicate that DHM has the potential to cause pharmacokinetic drug interactions with other co-administered drugs metabolized by CYP3A4, CYP2E1 and CYP2D6. Further clinical studies are needed to evaluate the significance of this interaction.

The Versatile Effects of Dihydromyricetin in Health

Dihydromyricetin is a flavonoid isolated from Ampelopsis grossedentata, which is traditionally used in China. Dihydromyricetin exhibits health-benefiting activities with minimum adverse effects. Dihydromyricetin has been demonstrated to show antioxidative, anti-inflammatory, anticancer, antimicrobial, cell death-mediating, and lipid and glucose metabolism-regulatory activities. Dihydromyricetin may scavenge ROS to protect against oxidative stress or potentiate ROS generation to counteract cancer cells selectively without any effects on normal cells. However, the low bioavailability of dihydromyricetin limits its potential applications. Recent research has gained positive and promising data. This review will discuss the versatile effects and clinical prospective of dihydromyricetin.

Molecular mechanisms of ampelopsin from Ampelopsis megalophylla induces apoptosis in HeLa cells

Ampelopsin (AMP) is an active ingredient of flavonoid compounds that is extracted from Ampelopsis megalophylla Diels et Gilg. The present study aimed at investigating the antitumor activities of AMP and the possible underlying molecular mechanisms in HeLa cells. A total of three types of tumor cell were selected to screen antitumor activities for AMP using the MTT assay. Flow cytometry was used to analyze the cell apoptotic proportion and the cell cycle. Rhodamine 123 staining was used to determine changes in mitochondrial transmembrane potential. Western blot analysis was used to determine the expression of apoptosis-associated proteins. The results of the present study demonstrated that AMP may inhibit the viability of HeLa cells in a dose- and time-dependent manner. Changes in morphology were observed using fluorescence microscopy. In addition, Annexin V-fluorescein isothiocyanate/propidium iodide (PI) double staining revealed that AMP induced apoptosis in a concentration-dependent manner and PI staining indicated that HeLa cells were arrested in S phase. Furthermore, western blot analysis demonstrated that AMP treatment induced apoptosis through activation of caspases 9 and 3, which was validated by the increasing ratio of B-cell lymphoma 2 (Bcl-2)-associated X protein to Bcl-2. Additionally, the loss of mitochondrial transmembrane potential and the release of cytochrome c suggested that AMP-induced apoptosis was associated with the mitochondrial pathway. Taken together, these results indicate that AMP may induce apoptosis via the mitochondrial signaling pathway in HeLa cells.

Solamargine inhibits the migration and invasion of HepG2 cells by blocking epithelial-to-mesenchymal transition

Solamargine (SM), a steroidal alkaloid glycoside purified from the Chinese traditional herb Solanum incanum, is known to possess various biological activities. However, only a few previous studies have reported the anti-metastatic activity of SM. In the present study, the inhibitory effects of SM on metastatic action were investigated in human HepG2 cells. The proliferation effects of SM on the HepG2 cells was evaluated by MTT and colony formation assays. Wound-healing and Transwell assays were performed to examine the migration and invasion effects on SM-treated HepG2 cells. The epithelial-to-mesenchymal transition (EMT)-associated markers (E-cadherin, Vimentin and N-cadherin) were detected by western blotting analysis. In the present study, MTT and colony formation assays indicated that SM suppressed HepG2 cell viability in a dose-dependent manner. The wound-healing and Transwell assays revealed that the migration and invasion activities were significantly inhibited following exposure to SM. EMT has been demonstrated to be essential for promoting migration and invasion in tumor cells and has often been characterized with a loss of epithelial markers (E-cadherin) and an increase of mesenchymal markers (Vimentin and N-cadherin). In the western blotting analysis, the expression level of E-cadherin was significantly upregulated compared with that in the control group, whereas the expression levels of N-cadherin and Vimentin were downregulated. Thus, it was suggested that the underlying mechanism of SM inhibits migration and invasion in HepG2 cells and is associated with suppression of EMT.

Dihydromyricetin Induces Apoptosis and Reverses Drug Resistance in Ovarian Cancer Cells by p53-mediated Downregulation of Survivin

Ovarian cancer is one of the leading causes of death in gynecological malignancies, and the resistance to chemotherapeutic agents remains a major challenge to successful ovarian cancer chemotherapy. Dihydromyricetin (DHM), a natural flavonoid derived from Ampeopsis Grossdentata, has been widely applied in food industry and medicine for a long time. However, little is known about the effects of DHM on ovarian cancer and the underlying mechanisms. In this study, we demonstrated that DHM could effectively inhibit the proliferation of ovarian cancer cells and induce cell apoptosis. Survivin, an inhibitor of apoptosis (IAPs) family member, exhibited a decreased expression level after DHM treatment, which may be attributed to the activation of p53. Moreover, DHM markedly sensitized paclitaxel (PTX) and doxorubicin (DOX) resistant ovarian cancer cells to PTX and DOX by inhibiting survivin expression. Collectively, our findings highlight a previously undiscovered effect of DHM, which induces apoptosis and reverses multi-drug resistance against ovarian cancer cells through downregulation of survivin.

Dihydromyricetin attenuated Ang II induced cardiac fibroblasts proliferation related to inhibitory of oxidative stress

Dihydromyricetin (DMY) is one of the most important flavonoids in vine tea, which showed several pharmacological effects. However, information about the potential role of DMY on angiotensin II (Ang II) induced cardiac fibroblasts proliferation remains unknown. In the present study, cardiac fibroblasts isolated from neonatal Sprague-Dawley rats were pretreated with different concentrations of DMY (0-320μM) for 4h, or DMY (80μM) for different time (0-24h), followed by Ang II (100nM) stimulation for 24h, Then number of cardiac fibroblasts and content of hydroxyproline was measured. The level of cellular reactive oxygen species, malondialdehyde (MDA), activity of superoxide dismutase (SOD) and total antioxidant capacity (T-AOC) were also evaluated. Expression of type I, type III collagen, α-smooth muscle actin (α-SMA), p22^phox (one vital subunit of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase), SOD and thioredoxin (Trx) were detected with real time PCR or/and western blot. We found that pre-incubation with DMY (20μM, 40μM, 80μM) for 4h, 12h or 24h attenuated the proliferation of cardiac fibroblasts induced by Ang II. Expression of type I and type III collagen, as well as α-SMA were inhibited by DMY at both mRNA and protein level. DMY also significantly decreased cellular reactive oxygen species production and MDA level, while increased the SOD activity and T-AOC. DMY suppressed p22^phox, while enhanced antioxidant SOD and Trx expression in Ang II stimulated cardiac fibroblasts. Thus, dihydromyricetin attenuated Ang II induced cardiac fibroblasts proliferation related to inhibitory of oxidative stress.

Highly Efficient Enzymatic Acylation of Dihydromyricetin by the Immobilized Lipase with Deep Eutectic Solvents as Cosolvent

A novel deep eutectic solvent (DES)-DMSO cosolvent system has been, for the first time, successfully used as the reaction medium for the enzymatic acylation of dihydromyricetin (DMY) catalyzed by the immobilized lipase from Aspergillus niger (ANL). The cosolvent mixture, ChCl:Glycerol-DMSO (1:3, v/v) proved to be the optimal medium. With the newly developed cosolvent, the initial reaction rate of enzymatic acylation of DMY achieved 11.1 mM/h and the conversion of DMY was 91.6%. ANL@PD-MNPs is stable and recyclable in this cosolvent, offering 90% conversion rate after repeated use of 5 times. The lipid-solubility of DMY-16-acetate was 10 times higher than that of its raw materials DMY. The results showed that the DMY-16-acetate product exhibits good antioxidative activity. The present research illustrated that the use of DES-DMSO cosolvent may become a feasible alternative for the synthesis of DMY ester.

Targeting of growth factors in the treatment of hepatocellular carcinoma: The potentials of polysaccharides

Hepatocellular carcinoma (HCC) has become a leading cause of cancer-associated mortality worldwide and is thus of great concern. Although various chemotherapeutic drugs are currently used for the treatment of HCC, severe side effects associated with these treatments have prompted interest in novel therapies, including the use of certain biological macromolecules such as polysaccharides. Several studies have shown that polysaccharides have anticancer and antiproliferative effects on HCC. Vascular endothelial growth factor, transforming growth factor β, epidermal growth factor and fibroblast growth factor may be effective targets for polysaccharides and may modulate tumor growth and immunity through increasing the expression levels of cytokines. The present review focuses on the ways in which growth factors contribute to the development of HCC, and on the anti-growth factor activities of natural and synthetic polysaccharides, as well as their effect on proinflammatory cytokines.

Dihydromyricetin induces mitochondria-mediated apoptosis in HepG2 cells through down-regulation of the Akt/Bad pathway

The plant flavonol dihydromyricetin (DHM) was reported to induce apoptosis in human hepatocarcinoma HepG2 cells. This study was undertaken to elucidate the underlying molecular mechanism of action of DHM. In the study, DHM down-regulated Akt expression and its phosphorylation at Ser473, up-regulated the levels of mitochondrial proapoptotic proteins Bax and Bad, and inhibited the phosphorylation of Bad at Ser136 and Ser112. It also inhibited the expression of the antiapoptotic protein Bcl-2 and enhanced the cleavage and activation of caspase-3 as well as the degradation of its downstream target poly(ADP-ribose) polymerase. Our results for the first time suggest that DHM-induced apoptosis in HepG2 cells may come about by the inhibition of the Akt/Bad signaling pathway and stimulation of the mitochondrial apoptotic pathway. Dihydromyricetin may be a promising therapeutic medication for hepatocellular carcinoma.

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.

Diosmetin inhibits cell proliferation and induces apoptosis by regulating autophagy via the mammalian target of rapamycin pathway in hepatocellular carcinoma HepG2 cells

Hepatocellular carcinoma (HCC), which is a type of malignant tumor, is the fifth most common cancer in men and ninth in women worldwide. The aim of the present study was to investigate the antitumor effect of diosmetin (DIOS) in hepatocellular carcinoma HepG2 cells. The proliferation, apoptosis and autophagy rates of HepG2 cells were measured following treatment with DIOS. The effects of DIOS treatment on HepG2 cell proliferation and apoptosis rates were analyzed using MTT assays and Annexin V staining, respectively. The effect of DIOS treatment on autophagy levels was assessed using transmission electron microscopy, green fluorescent protein (GFP)-microtubule-associated protein 1 light chain (LC3) transfection and LysoTracker Red staining. Furthermore, bafilomycin A1 (BA1), an autophagy inhibitor, was used to assess the association between DIOS and cell autophagy, proliferation and apoptosis. In addition, the expression of autophagy-related proteins [mammalian target of rapamycin (mTOR), phosphatidylinositol 3-kinase, P70S6K, phosphoinositide-dependent kinase-1, extracellular signal-regulated kinase, 5′-AMP-activated protein kinase and Akt] and apoptosis-related proteins [B-cell lymphoma (Bcl)-2-associated X protein, Bak, p53, Bcl-2 and caspase-3] were analyzed by western blotting. The results revealed that DIOS significantly inhibited proliferation (P<0.01) and induced apoptosis (P<0.001) in HepG2 cells. It was also demonstrated that DIOS triggered autophagy by regulating the mTOR pathway in HepG2 cells. Notably, following treatment of HepG2 cells with the autophagy inhibitor, BA1, the expression of apoptosis-related proteins, including Bax, Bak and p53, were significantly decreased (P<0.05), and cell viability was recovered to a certain extent. In conclusion, DIOS inhibits cell proliferation and induces apoptosis in HepG2 cells via regulation of the mTOR pathway. Thus, the results of the current study indicate that DIOS may present a potential therapeutic agent for HCC treatment.

Optimization of the Ultrasonic-Assisted Extraction of Bioactive Flavonoids from Ampelopsis grossedentata and Subsequent Separation and Purification of Two Flavonoid Aglycones by High-Speed Counter-Current Chromatography

The fermented leaf of Ampelopsis grossedentata has been used as a beverage and folk medicine called "vine tea" in the southern region of China. In this paper, the optimum extraction conditions for the maximum recovery amounts of total flavonoids (TF), dihydromyricetin (DMY), myricitrin (MYG) and myricetin (MY) from natural Ampelopsis grossedentata leaves subjected to ultrasonic-assisted extraction (UAE) were determined and optimized by using response surface methodology. The method was employed by the Box-Behnken design (BBD) and Derringer's desirability function using methanol concentration, extraction time, liquid/solid ratio as factors and the contents of TF, DMY, MYG and MY as responses. The obtained optimum UAE conditions were as follows: a solvent of 80.87% methanol, an extraction time of 31.98 min and a liquid/solid ratio of 41.64:1 mL/g. Through analysis of the response surface, it implied that methanol concentration and the liquid/solid ratio had significant effects on TF, DMY, MYG and MY yields, whereas extraction time had relatively little effects. The established extraction and analytical methods were successfully applied to determine the contents of the total flavonoids and three individual flavonoids in 10 batches of the leaf samples of A. grossedentata from three counties in Fujian Province, China. The results suggested the variability in the quality of A. grossedentata leaves from different origins. In addition, high purities of dihydromyricetin and myricetin were simultaneously separated and purified from the extract subjected to optimized UAE, by high-speed counter-current chromatography using a solvent system of N-hexane-ethyl acetate-methanol-water (1:3:2:4; v/v/v/v). In a single operation, 200 mg of the extract were separated to yield 86.46 mg of dihydromyricetin and 3.61 mg of myricetin with the purity of 95.03% and 99.21%, respectively. The results would be beneficial for further exploiting the herbal products and controlling the quality of the herb and its derived products.

Chrysin induces cell apoptosis via activation of the p53/Bcl-2/caspase-9 pathway in hepatocellular carcinoma cells

Chrysin is a major active ingredient of flavonoids, known to exhibit protective effects against various types of cancer. However, the anticancer role of chrysin against hepatocellular carcinoma (HCC) and the underlying molecular mechanisms remain unclear. In order to evaluate the effects of chrysin on cell viability and apoptosis in human HCC, HepG2 and QGY7701 cells were used in the present study. Cell viability was monitored using an MTT assay. In addition, an Annexin V-fluorescein isothiocyanate/propidium iodide kit was used for the labeling of the apoptotic cells, which were then measured using flow cytometry. Western blotting was used to examine the protein expression of p53, B-cell lymphoma-2 (Bcl-2), Bcl-2-associated X (Bax), Bcl-2-associated death promoter (Bad), Bcl-2 homologous antagonist/killer (Bak), caspases-3 and -9, and cleaved-caspases-3 and -9. The results of the present study revealed that chrysin suppressed the cell viability of HepG2 and QGY7701 cells in a concentration-dependent manner. In addition, chrysin induced significant apoptosis in HepG2 and QGY7701 cells. Furthermore, it was demonstrated that chrysin treatment increased the expression of proapoptotic proteins, including p53, Bax, Bad and Bak, while it decreased the protein level of antiapoptotic protein Bcl-2. It was also demonstrated that chrysin induced apoptosis in the HCC cells by regulating the p53/Bcl-2/caspase-9 signaling pathway. In conclusion, the results of the present study suggested that chrysin may be a potential candidate agent for the induction of cell apoptosis in human HCC.

Diosmetin inhibits the metastasis of hepatocellular carcinoma cells by downregulating the expression levels of MMP-2 and MMP-9

Hepatocellular carcinoma (HCC) is one of the most malignant types of tumor worldwide with a high rate of mortality. Diosmetin (DIOS) exhibits various activities, including anticancer activities. However, the role of DIOS in the metastasis of HCC, and its underlying molecular mechanism, remain to be fully elucidated. In the present study, the antimetastatic effects of DIOS were investigated in SK‑HEP‑1 and MHcc97H HCC cell lines. Cell proliferation, wound healing, motility, invasion and adhesion capacities were examined to evaluate the inhibitory effect of DIOS on the metastasis of HCC cells. Cell viability was detected using an MTT assay in order to verify the inhibitory effect of DIOS on the proliferation of HCC cells. Cell migration was assessed using would healing and motility assays in order to verify the inhibitory effect of DIOS on the migration of HCC cells. Cell invasion and adhesion assays were performed in order to verify the inhibitory effect of DIOS on the invasion and adhesion of HCC cells. Matrix metalloproteinase (MMP)‑2/9, proteins of the mitogen‑activated protein kinase (MAPK) pathway (c‑Jun N‑terminal kinase, extracellular signal‑regulated kinase and p38 MAPK) and protein kinase C‑δ were detected in order to verify the potential molecular mechanisms of DIOS in the inhibition of the metastasis of HCC cells. DIOS was observed to inhibit the metastasis of SK‑HEP‑1 and MHcc97H cells by downregulating the expression of MMP‑2/9 via the PKC/MAPK/MMP pathways. DIOS also inhibited the migration and invasion of the HCC cells, and may serve as a potential candidate agent for the prevention of HCC metastasis.