Ampelopsin A

Control of Reactive Oxygen Species for the Prevention of Parkinson's Disease: The Possible Application of Flavonoids.[Pubmed:32635299]

Antioxidants (Basel). 2020 Jul 3;9(7). pii: antiox9070583.

Oxidative stress reflects an imbalance between the production of reactive oxygen species (ROS) and antioxidant defense systems, and it can be associated with the pathogenesis and progression of neurodegenerative diseases such as multiple sclerosis, stroke, and Parkinson's disease (PD). The application of antioxidants, which can defend against oxidative stress, is able to detoxify the reactive intermediates and prevent neurodegeneration resulting from excessive ROS production. There are many reports showing that numerous flavonoids, a large group of natural phenolic compounds, can act as antioxidants and the application of flavonoids has beneficial effects in the adult brain. For instance, it is well known that the long-term consumption of the green tea-derived flavonoids catechin and epigallocatechin gallate (EGCG) can attenuate the onset of PD. Also, flavonoids such as Ampelopsin And pinocembrin can inhibit mitochondrial dysfunction and neuronal death through the regulation of gene expression of the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway. Additionally, it is well established that many flavonoids exhibit anti-apoptosis and anti-inflammatory effects through cellular signaling pathways, such as those involving (ERK), glycogen synthase kinase-3beta (GSK-3beta), and (Akt), resulting in neuroprotection. In this review article, we have described the oxidative stress involved in PD and explained the therapeutic potential of flavonoids to protect the nigrostriatal DA system, which may be useful to prevent PD.

Screening of Natural Stilbene Oligomers from Vitis vinifera for Anticancer Activity on Human Hepatocellular Carcinoma Cells.[Pubmed:32492881]

Antioxidants (Basel). 2020 Jun 1;9(6). pii: antiox9060469.

The characterization of bioactive resveratrol oligomers extracted from Vitis vinifera canes has been recently reported. Here, we screened six of these compounds (Ampelopsin A, trans-epsilon-viniferin, hopeaphenol, isohopeaphenol, R2-viniferin, and R-viniferin) for their cytotoxic activity to human hepatocellular carcinoma (HCC) cell lines p53 wild-type HepG2 and p53-null Hep3B. The cytotoxic efficacy depended on the cell line. R2-viniferin was the most toxic stilbene in HepG2, with inhibitory concentration 50 (IC50) of 9.7 +/- 0.4 microM at 72 h, 3-fold lower than for resveratrol, while Hep3B was less sensitive (IC50 of 47.8 +/- 2.8 microM). By contrast, hopeaphenol (IC50 of 13.1 +/- 4.1 microM) and isohopeaphenol (IC50 of 26.0 +/- 3.0 microM) were more toxic to Hep3B. Due to these results, and because it did not exert a large cytotoxicity in HH4 non-transformed hepatocytes, R2-viniferin was selected to investigate its mechanism of action in HepG2. The stilbene tended to arrest cell cycle at G2/M, and it also increased intracellular reactive oxygen species (ROS), caspase 3 activity, and the ratio of Bax/Bcl-2 proteins, indicative of apoptosis. The distinctive toxicity of R2-viniferin on HepG2 encourages research into the underlying mechanism to develop the oligostilbene as a therapeutic agent against HCC with a particular genetic background.

Grape Cane Extracts as Multifunctional Rejuvenating Cosmetic Ingredient: Evaluation of Sirtuin Activity, Tyrosinase Inhibition and Bioavailability Potential.[Pubmed:32397228]

Molecules. 2020 May 8;25(9). pii: molecules25092203.

Grape canes are waste biomass of viticulture containing bioactive polyphenols valuable in cosmetics. Whereas several studies reported the cosmetic activities of E-resveratrol, only few described the potential of E-epsilon-viniferin, the second major constituent of grape cane extracts (GCE), and none of them investigated GCE as a natural blend of polyphenols for cosmetic applications. In this study, we considered the potential of GCE from polyphenol-rich grape varieties as multifunctional cosmetic ingredients. HPLC analysis was performed to quantify major polyphenols in GCE i.e., catechin, epicatechin, E-resveratrol, E-piceatannol, Ampelopsin A, E-epsilon-viniferin, hopeaphenol, isohopeaphenol, E-miyabenol C and E-vitisin B from selected cultivars. Skin whitening potential through tyrosinase inhibition assay and the activation capacity of cell longevity protein (SIRT1) of GCE were compared to pure E-resveratrol and E-epsilon-viniferin. Drug-likeness of GCE polyphenols were calculated, allowing the prediction of skin permeability and bioavailability. Finally, the present data enabled the consideration of GCE from polyphenol-rich varieties as multifunctional cosmetic ingredients in accordance with green chemistry practices.

A stilbene dimer and flavonoids from the aerial parts of Chromolaena odorata with proprotein convertase subtilisin/kexin type 9 expression inhibitory activity.[Pubmed:32335358]

Bioorg Chem. 2020 Jun;99:103869.

Investigation of components of the chloroform-soluble and ethyl acetate-soluble extracts of the aerial parts of Chromolaena odorata L. selected by PCSK9 mRNA expression monitoring assay in HepG2 cells led to the isolation of a new stilbene dimer, (+)-8b-epi-Ampelopsin A (1), and 30 known compounds (2-31). The structures of the isolates were established by interpretation of NMR spectroscopic data and the stereochemistry of the new stilbene (1) was proposed based on ECD and NMR calculations. Among the isolates, 1, 5,6,7,4'-tetramethoxyflavanone (6), 5,6,7,3',4'-pentamethoxyflavanone (7), acacetin (18), and uridine (21) were found to inhibit PCSK9 mRNA expression with IC50 values of 20.6, 21.4, 31.7, 15.0, and 13.7 microM, respectively. Furthermore, the most abundant isolate among the selected compounds, 6, suppressed PCSK9 and low-density lipoprotein receptor protein expression in addition to downregulating the mRNA expression of HNF-1alpha.

Inhibition of the type III secretion system of Pseudomonas syringae pv. tomato DC3000 by resveratrol oligomers identified in Vitis vinifera L.[Pubmed:31994325]

Pest Manag Sci. 2020 Jul;76(7):2294-2303.

BACKGROUND: The bacterial type III secretion system (T3SS) is one of the virulence determinants of Gram-negative bacteria through which various effector and virulence proteins are translocated into host cells. RESULTS: We constructed an assay system to screen inhibitors of hrpA gene expression (a structural gene of Hrp pili) in Pseudomonas syringae pv. tomato DC3000. In a plant extract library screening, the root extract of Vitis vinifera L. displayed the most prominent activity. Three resveratrol oligomers, hopeaphenol, isohopeaphenol and Ampelopsin A, were identified in grapevine root extract, which significantly reduced the transcription levels of the hrpA, hrpL and hopP1 genes without growth retardation. Additional resveratrol derivatives identified in other plant extracts were also examined for their inhibitory effect on hrpA expression. Another resveratrol oligomer, kobophenol A, also inhibited the transcription of the hrpA gene and other T3SS-related genes, while resveratrol monomers (resveratrol and piceatannol) were not effective. The severity of bacterial specks was reduced by each hopeaphenol, isohopeaphenol and Ampelopsin A treatment. CONCLUSION: These results show the potential of resveratrol derivatives as anti-virulence agents for the control of plant diseases.

Ampelopsin alleviates sevoflurane-induced cognitive dysfunction by mediating NF-kappaB pathway in aged rats.[Pubmed:31902108]

Genes Genomics. 2020 Apr;42(4):361-369.

BACKGROUND: Cancer-induced bone pain (CIBP) is the pain caused by bone metastasis from malignant tumors, and the largest source of pain for cancer patients. miR-300 is an important miRNA in cancer. It has been shown that miR-300 regulates tumorigenesis of various tumors. PURPOSE: This study aims to investigate the role of miR-300 in CIBP and its underlying molecular mechanisms in vitro and in vivo. METHODS: We constructed CIBP model in rats and investigated the mechanism through which miR-300 affects CIBP. We first examined expression level of miR-300 in CIBP rats and then tested the effect of its overexpression. Next, we identified the target of miR-300 using TargetScan analysis and double luciferase assay. Finally, we studied genetic interactions between miR-300 and its target and their roles in CIBP. RESULTS: We found that miR-300 was downregulated in CIBP rats. Overexpression of miR-300 significantly attenuated cancer-induced neuropathic pain (p < 0.01). Furthermore, TargetScan analysis and double luciferase assay show High Mobility Group Box 1 (HMGB1) is a target of miR-300. Notably, HMGB1 is overexpressed in CIBP rats, while up-regulation of miR-300 significantly suppresses expression of HMGB1 (p < 0.01). Moreover, knockdown of HMGB1 by siRNA significantly relieves cancer-induced neuropathic pain in rats (p < 0.01). On the other hand, HMGB1 overexpression partially blocked the effect of miR-300 on cancer-induced nerve pain. CONCLUSION: miR-300 relieves cancer-induced neuropathic pain by inhibiting HMGB1 expression. These results may be beneficial for the treatment of CIBP in clinical practice.