Cytotoxic, antioxidant, and antimicrobial activities of Ampelopsis brevipedunculata and Parthenocissus tricuspidata (Vitaceae)

Effect of Ampelopsis brevipedunculata (Maxim.) Trautv extract on a model of atopic dermatitis in HaCaT cells and mice

Ampelopsis brevipedunculata (Maxim.) Trautv. has been used for a long time as a folk remedy. According to studies, it possesses anti-inflammatory, antioxidant, and antibacterial properties. However, its effects on atopic dermatitis (AD) are poorly studied. Thus, we investigated the therapeutic effect of A. brevipedunculata (Maxim.) Trautv. extract (ABE-M) on 2,4-dinitrochlorobenzene (DNCB)-induced AD. For in vitro analysis, keratinocytes cell lines (HaCaT cells) were used. To evaluate the gene and protein expression levels of cytokines and chemokines, TNF-α/IFN-γ-stimulated HaCaT cells were treated with ABE-M. The cells and the supernatant were collected, then gene and protein levels were analyzed by real-time polymerase chain reaction and enzyme-linked immunosorbent assay analysis. For in vivo analysis, BALB/c mice (6 weeks) were randomly separated into five groups (n = 5). The mice were applied DNCB and phosphate-buffered saline, dexamethasone (DX) or ABE-M (50, 100, and 200 mg/kg) was orally administrated for 28 days. At the end, ear tissues and blood were collected for histological analysis and evaluation of cytokines and chemokines. In keratinocytes, ABE-M inhibited the protein and mRNA levels of chemokines, and cytokines exposed by TNF-α/IFN-γ. Similarly, the expression of chemokines was suppressed by ABE-M in AD animal model induced by DNCB and the level of pro-inflammatory cytokines was decreased in a dose-dependent manner. Our research indicates that ABE-M could be a candidate material that can be used to improve skin immunity enhancement, health, and beauty.

The Effect of Dihydromyricetin, a Natural Flavonoid, on Morphine-induced Conditioned Place Preference and Physical Dependence in Mice

Objective Dihydromyricetin (DHM), a natural flavonoid, is used to reduce alcohol hangover. It has a modulatory role on GABAA receptors with significant effects on seizure and anxiety in animal models. We aimed to evaluate the effect of DHM on morphine conditioned place preference (CPP) and withdrawal sings following morphine dependence using animal models.

Methods The effect of DHM (1, 2 and 5 mg/kg, intraperitoneal; ip) on the acquisition and expression of morphine-induced CPP was evaluated in male mice. Administration of morphine for three consecutive days induced physical dependence. The withdrawal signs such as jumping and defecation were precipitated by administration of naloxone (8 mg/kg, ip). The effect of DHM on the development of physical dependence was assessed by injection of DHM before morphine administrations.

Results DHM, at the dose of 5 mg/kg, reduced expression of morphine CPP with an increase in the locomotor activity. DHM, at the doses of 2 and 5 mg/kg, also reduced development of morphine CPP. DHM alleviated development of morphine-induced physical dependence at the dose of 1, 2, and 5 mg/kg by decreasing jumping and defecation.

Conclusion These results indicated that DHM decreased acquisition and expression of morphine CPP and inhibited development of morphine-induced physical dependence.

Protective effects of Ampelopsis brevipedunculata against in vitro hepatic stellate cells system and thioacetamide-induced liver fibrosis rat model

CONTEXT

Ampelopsis brevipedunculata Maxim (Vitaceae) is a traditional medicinal herb used for treating liver disorders.

OBJECTIVE

The hepatoprotective effects of A. brevipedunculata ethanol extract (ABE) was investigated in experimental models of fibrosis.

MATERIALS AND METHODS

Hepatic stellate cells (HSCs) system in vitro and thioacetamide (TAA)-induced liver fibrosis rat model in vivo were used. Sprague-Dawley rats were divided into five groups of eight each (control, TAA, TAA with ABE 10 mg/kg, ABE 100 mg/kg and silymarin 50 mg/kg groups, respectively). Fibrosis was induced except to the control group by TAA (200 mg/kg, i.p.) twice per week for 13 weeks. ABE and silymarin was administered orally six times per week from the 7th week to the 13th week.

RESULTS

In HSC-T6 cells, ABE (0.1 mg/mL) and silymarin (0.05 mg/mL) significantly (p < 0.01) induced apoptosis (12.94 ± 5.72% and 14.9 ± 3.8%, respectively) compared with control group (7.51 ± 1.26%). The expression of fibrosis related genes (TGF-β, α-SMA and Col1A1) in HSC-T6 cells were significantly (p < 0.01) downregulated in ABE-treated groups compared with control group. In in vivo studies, ABE (10 and 100 mg/kg) treatment ameliorated the altered levels of serum biomarkers significantly (p < 0.01 and p < 0.001) in TAA-induced groups. Further, ABE (10 and 100 mg/kg) significantly (p < 0.01) attenuated the altered histopathological findings, glutathione content and the accumulation of hydroxyproline.

CONCLUSION

These results collectively indicate that ABE can potentially be developed as a therapeutic agent in the treatment of hepatic fibrosis.

Dihydromyricetin Improves Hypobaric Hypoxia-Induced Memory Impairment via Modulation of SIRT3 Signaling

Inadequate oxygen availability-for instance at high altitudes-leads to hippocampal neurodegeneration and memory impairment. Although oxidative stress is one factor, the mechanism underlying the effects of hypobaric hypoxia (HH) are unclear, and effective strategies for preventing the resultant damage to the brain are limited. In the present study, we demonstrate that ingesting dihydromyricetin (DM) protects against memory impairment in adult rats subjected to HH for 7 days, equivalent to an altitude of 5000 m above sea level. Moreover, DM treatment stimulated mitochondrial biogenesis and improved mitochondrial morphology and function, suppressed the generation of reactive oxygen species, and reduced lipid peroxidation in the hippocampus. In HT-22 cells exposed to hypoxic conditions, the neuroprotective effects of DM were shown to be exerted via attenuation of oxidative stress through sirtuin 3-induced forkhead box O3 deacetylation.

A reduction in reactive oxygen species contributes to dihydromyricetin-induced apoptosis in human hepatocellular carcinoma cells

Reactive oxygen species (ROS) and cellular oxidant stress are considered inducers of carcinogenesis. However, the association of ROS with cancer is both complex and, at times, paradoxical. We assessed the effects of dihydromyricetin (DHM) on the induction of ROS accumulation and on the activation of the mitochondrial signaling pathway in human hepatoma HepG2 cells. The results indicated that DHM could reduce ROS accumulation in a concentration-dependent manner. Additionally, with increasing concentrations of DHM, the expression of proteins that participate in the cell apoptosis program increased in a concentration-dependent manner. Furthermore, we found that a low dose of H2O2 (10 nM) could reverse DHM-induced cell apoptosis. We observed the following critical issues: first, the cellular redox balance is vital in DHM-induced apoptosis of human hepatocellular carcinoma (HCC) cells, and second, ROS could function as a redox-active signaling messenger to determine DHM-induced cell apoptosis. In this study, we demonstrated that low levels of ROS are also critical for the function of HCC cells.

Dihydromyricetin induces mouse hepatoma Hepal-6 cell apoptosis via the transforming growth factor-β pathway

Dihydromyricetin (DHM) is a flavonoid compound which possesses potent antitumor activity. In the present study, it was demonstrated that DHM significantly inhibited proliferation and induced apoptosis in mouse hepatocellular carcinoma Hepal-6 cells. Transforming growth factor β (TGF-β) is recognized as a major profibrogenic cytokine and is therefore a common target for drugs in the treatment of liver disease. The present study aimed to investigate whether TGF-β was involved in DHM-triggered cell-viability inhibition and apoptosis induction. An MTT assay was used to evaluate the viability of Hepal-6 cells following DHM treatment. TGF-β signalling is mediated by Smads and nicotinamide adenine dinucleotide phosphate oxidase 4 (NOX4) is a crucial regulator of reactive oxygen species ROS production. TGF-β, Smad3, phosphorylated (p)-Smad2/3 and NOX4 protein expression levels were evaluated by western blot analysis. TGF-β and NOX4 gene expression levels were determined by quantitative polymerase chain reaction. The results indicated that DHM downregulated TGF-β, Smad3, p-Smad2/3 and NOX4 in a concentration-dependent manner. A cell counting assay indicated that DHM also inhibited Hepal-6 cell growth in a concentration-dependent manner. TGF-β expression was significantly decreased following DHM treatment. In conclusion, the results of the present study defined and supported a novel function for DHM, indicating that it induced cell apoptosis by downregulating ROS production via the TGF-β/Smad3 signaling pathway in mouse hepatocellular carcinoma Hepal-6 cells.

Dihydromyricetin reduced Bcl-2 expression via p53 in human hepatoma HepG2 cells

Dihydromyricetin (DHM) is a major active ingredient of flavonoids compounds. It exhibited anticancer activity and induced apoptosis in human hepatocellular carcinoma HepG2 cells according to our previous data. In this study, we investigated whether p53 is involved in DHM-triggered viability inhibition and apoptosis induction in cancer cells. MTT [3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide] assay was employed to evaluate the viability of HepG2 cells after DHM treatment. Meanwhile, p53 small interfering RNA (siRNA) was adopted to silence p53 expression. Protein level of p53 and Bax/Bcl-2 were evaluated by western blot analysis. Cell counting assay showed that DHM inhibited HepG2 cell growth effectively in a time- and dose-dependent manner. P53 expression was significantly increased after DHM treatment, whereas Bcl-2 was reduced potently. Furthermore, after co-treatment with Pifithrin-α (PFT-α, p53 inhibitor), Bcl-2 expression was reversed. The expression of Bax was no significant change, which was also observed after p53 silence. These findings defined and supported a novel function that DHM could induce human hepatocellular carcinoma HepG2 cells apoptosis by up-regulating Bax/Bcl-2 expression via p53 signal pathway.

Evaluation of the Combined Effects of Stilbenoid from Shorea gibbosa and Vancomycin against Methicillin-Resistant Staphylococcus aureus (MRSA)

The aim of this study is to determine the combined effects of stilbenoids from Shorea gibbosa and vancomycin against methicillin-resistant Staphylococcus aureus (MRSA). A total of nine pure compounds, five stilbenoid dimers ε-viniferin, ampelopsin A, balanocarpol, laevifonol and diptoindonesin G and four stilbenoid trimers α-viniferin, johorenol A, ampelopsin E and vaticanol G were evaluated for their antibacterial activities against ATCC 33591 and a HUKM clinical isolate. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) for each active compound were determined using the serial microdilution and plate-streak techniques. The combined effect of stilbenoids with vancomycin against MRSA was evaluated using the checkerboard assay to determine their fractional inhibitory concentration (FIC) index values. The MIC value of α-viniferin on both MRSA strains was 100 μg/mL, whereas those of johorenol A on ATCC 33591 and HUKM strain were 100 μg/mL and 200 μg/mL, respectively. The MIC values of ampelopsin E and vaticanol G were higher than 400 μg/mL. Out of the five stilbenoid dimers, only ε-viniferin was capable of inhibiting the growth of both MRSA strains at MIC 400 μg/mL. The MBC value of ε-viniferin, α-viniferin and johorenol A showed bacteriostatic action against MRSA. The FIC index value of ε-viniferin and α-viniferin in combination with vancomycin showed an additive effect (0.5 < FIC ≤ 2.0) against both MRSA strains. Johorenol A-vancomycin combination was also additive against HUKM strain, but it showed synergistic interaction with vancomycin against ATCC 33591 (FIC < 0.5). Stilbenoid compounds from Shorea gibbosa have anti-MRSA activity and huge potential as an alternative phytotherapy in combating MRSA infections.

Microemulsion drug delivery system: for bioavailability enhancement of ampelopsin

Ampelopsin, one of the most common flavonoids, reported to possess numerous pharmacological activities and shows poor aqueous solubility. The purpose of this study was to enhance the dissolution rate and bioavailability of this drug by developing a novel delivery system that is microemulsion (ME) and to study the effect of microemulsion (ME) on the oral bioavailability of ampelopsin. Capmul MCM-based ME formulation with Cremophor EL as surfactant and Transcutol as cosurfactant was developed for oral delivery of ampelopsin. Optimised ME was evaluated for its transparency, viscosity, percentage assay and so forth. Solubilisation capacity of the ME system was also determined. The prepared ME was compared with the pure drug solution and commercially available tablet for in vitro drug release. The optimised ME formulation containing ampelopsin, Capmul MCM (5.5%), Cremophor EL (25%), Transcutol P (8.5%), and distilled water showed higher in vitro drug release, as compared to plain drug suspension and the suspension of commercially available tablet. These results demonstrate the potential use of ME for improving the bioavailability of poor water soluble compounds, such as ampelopsin.