Showing papers on "Isovitexin published in 2019"

Isovitexin reduces carcinogenicity and stemness in hepatic carcinoma stem-like cells by modulating MnSOD and FoxM1

Abstract: Manganese superoxide dismutase (MnSOD) upregulating FoxM1 have previously been demonstrated promoting lung cancer stemness. Isovitexin exhibits antitumor activities in various cancers. This study aimed to assess whether isovitexin inhibits hepatic carcinoma stem-like cells (HCSLCs) features via regulating MnSOD and FoxM1 expression. Second-generation spheres from the hepatic carcinoma cell lines, respectively, were used as HCSLCs. Protein amounts of MnSOD, FoxM1 and stemness-associated markers (CD133, CD44, ALDH1, Bmi1, Nanog and Oct4) were determined by immunoblotting. In vitro carcinogenicity was evaluated by sphere- and colony-formation assays. The effects of isovitexin on HCSLC carcinogenicity and stemness were examined in vitro and in xenograft models. An adenoviral delivery system was employed to manipulate MnSOD and/or FoxM1. Luciferase reporter assay was performed to verify isovitexin downregulated FoxM1 by inhibiting MnSOD-mediated effects of E2F1 and/or Sp1 on activation of FoxM1 promoter. FoxM1 upregulation by MnSOD contributed to carcinogenicity and stemness, with increased sphere- and colony-formation capabilities, upregulated stemness-associated markers and CD133+ subpopulation as well as elevated oncogenicity in vivo in HCSLCs compared with hepatic carcinoma cells. Isovitexin substantially decreased sphere and colony formation rates, and stemness-associated markers in cultured HCSLCs by suppressing MnSOD and FoxM1 expression. Importantly, isovitexin significantly inhibited tumor growth of in nude mice bearing HCSLCs and reduced CD133 protein expression of xenograft in nude mice. MnSOD or FoxM1 knockdown enhanced the effects of isovitexin suppression on carcinogenicity and stemness in HCSLC. MnSOD or FoxM1 overexpression attenuated the effects of isovitexin. Additionally, isovitexin and MnSOD knockdown could inhibit FoxM1 reporter activity via a decreased binding of E2F1 and/or Sp1 onto FoxM1 promoter. FoxM1 overexpression reversed the effects of isovitexin combined with MnSOD knockdown, without affecting MnSOD expression. Moreover, MnSOD knockdown plus thiostrepton, a FoxM1 specific inhibitor, cooperated with isovitexin to repress xenograft tumor growth and downregulate MnSOD and FoxM1 in nude mice bearing HCSLCs from MHCC97H cells. Isovitexin inhibits carcinogenicity and stemness in HCSLCs by downregulating FoxM1via inhibition of MnSOD.

Developing and Validating a Method for Separating Flavonoid Isomers in Common Buckwheat Sprouts Using HPLC-PDA.

Abstract: Buckwheat sprouts that are synthesized during the germination process are rich in flavonoids, including orientin, vitexin, rutin, and their isomers (isoorientin, isovitexin, and quercetin-3-O-robinobioside, respectively). The purpose of this study was to optimize and validate an analytical method for separating flavonoid isomers in common buckwheat sprout extract (CSE). Factors, such as range, linearity, precision, accuracy, limit of detection, and limit of quantification, were evaluated for each standard using high-performance liquid chromatography (HPLC). On the basis of resolution and symmetry, a column temperature of 40 °C with 0.1% (v/v) acidic water and acetonitrile as mobile phases, at a flow rate of 1 mL min−1 were determined to be the optimal analytical conditions. Calibration curves for orientin, isoorientin, vitexin, isovitexin, and rutin exhibited good linearity with correlation coefficients of 0.9999 over the 6.25–100.00 μg mL−1 range. Recovery values of 96.67–103.60% confirmed that the method was accurate for all flavonoids. The relative standard deviations of intra-day repeatability and inter-day reproducibility confirmed method preciseness, with values of less than 5.21% and 5.40%, respectively. The developed method was used to analyze flavonoids in CSE, with isomers satisfactorily separated and simultaneously quantified. We demonstrated that the developed HPLC method can be used to monitor flavonoids in buckwheat sprouts.

Flavonoid composition, cellular antioxidant activity and (myelo)peroxidase inhibition of a Bryonia alba L. (Cucurbitaceae) leaves extract.

Abstract: Objectives The aim of the present study consisted in the isolation of flavonoids from the leaves of Bryonia alba L. and evaluation of their antioxidant activity and inhibition on peroxidase-catalysed reactions. Methods Flavonoids were isolated by preparative HPLC-DAD and their structures were elucidated by MS and NMR. Inhibitory effect was tested by the horseradish peroxidase and the myeloperoxidase assays. Cellular antioxidant assays consisted in testing the inhibitory activity on the reactive oxygen species released upon activation of neutrophils freshly isolated ex vivo from equine blood and of human monocytes-derived macrophages in vitro. Whole organism toxicity was assessed on zebrafish larvae. Key findings Four flavonoids (lutonarin, saponarin, isoorientin and isovitexin) were isolated. The performed assays showed significant antioxidant activity and inhibition for the peroxidase-catalysed reactions. Absence of cellular and zebrafish toxicity was confirmed. Conclusions Bryonia alba L. leaves are particularly interesting for their flavonoids content and showed significant inhibitory effect on peroxidase-catalysed oxidation of substrates (Amplex Red and L012), as well as antioxidant/antiradical activity, proving that this species has a medicinal potential. Moreover, the present study highlights the absence of the toxicity of these leaves and offers though a novel perspective on the species, previously known as being toxic.

Flavonoids Isolated from Vitex grandifolia, an Underutilized Vegetable, Exert Monoamine A & B Inhibitory and Anti-inflammatory Effects and Their Structure-activity Relationship.

Abstract: Objectives Vitex grandifolia belongs to family Lamiaceae; it consists of flowering plants and it is also called the mint family. The Yoruba people of southwest Nigeria called it "Oriri" or "Efo oriri". This plant is classified as an underutilized vegetable and little is known about its phytochemistry or its biological evaluations. Materials and Methods Methanol extracts of the dried leaves and stem of the plant were subjected to fractionation and isolation using vacuum layer and column chromatography methods. The structures of the compounds were elucidated using spectroscopic techniques including IR, 1D-, and 2D-NMR and by comparison with the data reported in the literature. They were evaluated in vitro for the inhibition of monoamine recombinant human MAO-A and -B and anti-inflammatory activities. Results Three known flavonoids were isolated from the methanolic extract of the leaves of V. grandifolia for the first time to the best of our knowledge, i.e. isoorientin (1), orientin (2), and isovitexin (3). Most of the isolated compounds showed selective inhibition of monoamine oxidase B, inhibition of MAO-B by isoorientin (1) and orientin (2) were 9-fold more potent (IC50 (μg/mL) of 11.08 and 11.04) compared to the inhibition of MAO-A (IC50 (μg/mL) of ˃100), while clorgyline and deprenyl were used as positive standards. The isolated flavonoids displayed good activity against the NF-ﭏb assay with IC50 (μg/mL) of 8.9, 12, and 18. This study establishes a link between the structure and the biological activities on the basis of the different patterns of substitution, particularly the C2=C3 double bond and the position of glucose moiety. Conclusion This study is the first to establish the phytochemistry of the polar part of V. grandifolia and the anti-inflammatory and neuroprotective role of these isolated compounds.

Flavonoid Analysis and Antioxidant Activities of the Bryonia alba L. Aerial Parts

Abstract: Bryonia alba L. is the only Bryonia species found in Romanian flora, being known as a remedy for inflammatory pathologies or for its hepatoprotective and adaptogen activities. The present investigation studied the flavonoid composition and antioxidant activities of the aerial parts of this species. Flavonoid profile was evaluated by HPLC coupled with Diode Array Detection (DAD), while antioxidant capacity was assessed by various methods, testing different antioxidant mechanisms: DPPH (2,2-diphenyl-1-picrylhydrazyl), CUPRAC (cupric reducing antioxidant capacity), FRAP (ferric reducing ability of plasma), TEAC (Trolox equivalent antioxidant capacity), EPR (electron paramagnetic resonance method) and SNPAC (silver nanoparticles antioxidant capacity). Cytotoxicity was tested on human cancerous and healthy cell lines. Anti-plasmodial tests were performed on two strains of Plasmodium falciparum. Whole organism toxicity was assessed on zebrafish larvae. The HPLC-DAD analysis proved the presence of lutonarin, saponarin, isoorientin, and isovitexin as the major flavonoids in the composition of tested samples. Significant results were obtained for all antioxidant capacity assays. The cytotoxicity tests proved the absence of cellular and parasitic toxicity and these results were confirmed by the lack of toxicity on the zebrafish larvae model. This study proves a promising potential of the aerial parts of Bryonia alba L. as antioxidant agents.

Apoptosis Caused by Triterpenes and Phytosterols and Antioxidant Activity of an Enriched Flavonoid Extract from Passiflora mucronata.

Abstract: Background P. mucronata (Pm) comes from South America, Brazil and is characterized as "Maracuja de Restinga". It is used in folk medicine for its soothing properties and in treating insomnia. Objective The present study for the first time analyzed the antioxidant and cytotoxicity of the hydroalcoholic leaves extract and fractions from Pm. Method The cytotoxicity test will be evaluated by different assays (MTT and CV) against human prostate cancer (PC3) and mouse malignant melanoma (B16F10) cell lines, and the antioxidant test by DPPH method. Results β-Amyrin, oleanolic acid, β-sitosterol and stigmasterol were isolated of the most active, hexane fraction. These substances were tested against the tumor cell lines: β-sitosterol and stigmasterol showed the most relevant activity to PC3 in CV assay and, oleanolic acid to B16F10 by the MTT assay. In addition, it was possible to indicate that the mode of cell death for stigmasterol, presumably is apoptosis. In terms of antioxidant activity, the hydroalcoholic leaves extract presented higher activity (EC50 133.3 µg/mL) compared to the flower (EC50 152.3 µg/mL) and fruit (EC50 207.9 µg/mL) extracts. By the HPLC-MS, it was possible to identify the presence of flavones in the leaf extract (isoschaftoside, schaftoside, isovitexin, vitexin, isoorientin, orientin). Conclusions P. mucronata hexane fraction showed promising cytotoxic effect against cancer cell lines, and stigmasterol contributes to this activity, inducing apoptosis of these cells. Furthermore, as other Passiflora species, Pm extract showed antioxidant activity and flavones are its major phenolic compounds.

A Newly Isolated Human Intestinal Bacterium Strain Capable of Deglycosylating Flavone C-glycosides and Its Functional Properties

Abstract: Flavone C-glycosides are difficult to be deglycosylated using traditional chemical methods due to their solid carbon–carbon bond between sugar moieties and aglycones; however, some bacteria may easily cleave this bond because they generate various specific enzymes. A bacterial strain, named W12-1, capable of deglycosylating orientin, vitexin, and isovitexin to their aglycones, was isolated from human intestinal bacteria in this study and identified as Enterococcus faecalis based on morphological examination, physiological and biochemical identification, and 16S rDNA sequencing. The strain was shown to preferentially deglycosylate the flavone C-glycosides on condition that the culture medium was short of carbon nutrition sources such as glucose and starch, and its deglycosylation efficiency was negatively correlated with the content of the latter two substances. This study provided a new bacterial resource for the cleavage of C-glycosidic bond of flavone C-glycosides and reported the carbon nutrition sources reduction induced deglycosylation for the first time.

Antibacterial activity of apigenin, luteolin, and their C-glucosides

Abstract: Apigenin (4′,5,7-trihydroxyflavone) and luteolin (3′,4′,5,7-tetrahydroxyflavone) are among the most widely distributed flavone aglycones in flowering plants. These metabolites often occur in the form of O- and C-glycosides. In this group, four C-glucosides pay special attention: vitexin (apigenin 8-C-glucoside) and isovitexin (apigenin 6-C-glucoside) as well as orientin (luteolin 8-C-glucoside) and isoorientin (luteolin 6-C-glucoside). The above-mentioned compounds show various biological activities, including antioxidant, anti-inflammatory, immunomodulatory, anticancer as well as neuro-, cardio-, and hepatoprotective effects. The aim of the present work was to determine the antibacterial activity of these flavones. In the in vitro tests, there were investigated clinical strains of two Gram-positive (Staphylococcus aureus, Enterococcus faecalis) and Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa). The antimicrobial activity of chosen substances was determined by the micro-dilution method according to recommendations of the Clinical and Laboratory Standards Institute (CLSI). Curcumin was used as a positive control. Our results exhibited a relatively low sensitivity of the tested strains to the plant metabolites. In the case of curcumin – natural compound with known strong antibacterial effect, the minimal inhibitory concentration (MIC) for all species of bacteria was 500 μg/mL. The same level of biological activity was observed for apigenin, luteolin, and their glucosides against E. coli and P. aeruginosa. Among Gram-positive bacteria, the obtained results showed significant variability. Strains of S. aureus demonstrated a weak sensitivity to apigenin (MIC = 500-1000 μg/mL), and were resistant to its derivatives: vitexin and isovitexin (>1000 μg/mL). Additionally, these compounds poorly inhibited the growth of E. faecalis (1000 μg/mL). In turn, luteolin and its C-glucosides (orientin, isoorientin) reached the same values of the MICs: moderate against S. aureus (500 μg/mL) and weak for E. faecalis (1000 μg/mL). Our research points to the problem of varied sensitivity and even resistance of some clinical strains of common pathogens to the widespread natural plant compounds, such as flavonoids and other phenolics (e.g., curcumin). It is interesting that apigenin, luteolin, and their C-glucosides were generally more potent against Gram-negative bacteria than Gram-positive ones. A pair of analysed flavone aglycones has a very similar chemical structure, and they did not differ significantly in the antibacterial activity. Similarly, the presence and location of the sugar group in the flavone glucosides usually did not affect the values of the MICs.

Anti-oxidant activity of avicularin and isovitexin from Lespedeza cuneata

Abstract: This study evaluated the anti-oxidant activity of avicularin and isovitexin from Lespedeza cuneata using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl (OH) scavenging assays. The results showed that among the four fractions, the highest OH radical scavenging activity was exhibited by the n-butanol fraction. The DPPH radical scavenging activities of avicularin and isovitexin were higher than 50% at a concentration of 100 μg/mL. Moreover, one hundred micrograms per liter of avicularin and isovitexin exhibited effective anti-oxidant activity, with the OH radical scavenging rates being 87.54 and 91.48%, respectively. These results suggest that Lespedeza cuneata would be useful anti-oxidant agents from natural sources.

Chemical profile and pancreatic lipase inhibitory activity of Sinobambusa tootsik (Sieb.) Makino leaves

Abstract: Background Sinobambusa tootsik (Sieb.) Makino (S. tootsik) is one species of bamboo distributed in China, Japan and Vietnam. The chemical profile of its leaves and its potential application was unknown yet. Methods The chemical profile of S. tootsik was studied by HPLC and UPLC-DAD-QTOF-MS. The S. tootsik extract was prepared by extraction with 50% aqueous ethanol, followed by H103 macroporous resins adsorption and desorption processes. Pancreatic lipase inhibitory activity was determined using p-nitrophenyl palmitate as the substance, which was hydrolyzed by lipase to form coloured p-nitrophenol. Results Eighteen compounds were identified in S. tootsik. Most of them were the C-glycosylated derivatives of luteolin and apigenin, such as isoorientin, isoorientin-2″-O-rhamnoside and isovitexin. Isoorientin-2″-O-rhamnoside was the most dominant flavonoid in the sample. S. tootsik extract was prepared through resin adsorption/desorption with yield of 1.12 ± 015% and total flavonoids content of 82 ± 2 mg/g (in term of isoorientin). The extract exhibited pancreatic lipase inhibitory activity with IC50 value of 0.93 mg/mL. Conclusion The chemical profile of S. tootsik leaves was uncovered for the first time. C-glycosyl flavonoids were the main constituents in the plant. The extract exhibited pancreatic lipase inhibitory activity and may have potential for use as a food supplement for controlling obesity.

Isovitexin Increases Stem Cell Properties and Protects Against PM2.5 in Keratinocytes.

Abstract: Background/Aim: Fine airborne particles of Particular Matter of less than 2.5 micrometers (PM 2.5 ) have been recognized as a dominant air contamination causing critical health concerns. Herein, we determined whether isovitexin, a natural plant-derived compound could protect PM2.5-mediated oxidative stress and induce stemness in epidermal cells. Materials and Methods: Cell viability was detected by the 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide (MTT) assay. Reactive oxygen species (ROS) were determined by flow cytometry with 2',7'-dichlorofluorescin diacetate (DCFH-DA). Protein hallmarks of stem cells were examined by western blot analysis. Results: PM2.5 treatment for 30 min increased the levels of intracellular ROS. Pre-treatment of cells with 10-50 μM of isovitexin dramatically inhibited the ROS induced by PM2.5. Antioxidant efficacy of isovitexin was also determined by the ROS scavenging activity against 2,2-diphenyl-2-picrylhydrazyl (DPPH), ABTS and superoxide anion radicals. In addition, we found that isovitexin enhanced the stem cell properties of keratinocytes, indicated by the significant increase in the levels of stem cell proteins. Conclusion: Isovitexin can be potentially used as an effective compound for preventing skin damage.

First insight into the phenolic content of Spartina maritima: isolation, characterization and quantification of four C-glycosidic flavonoids

Abstract: The phenolic content of Spartina maritima was investigated using chromatographic and spectroscopic techniques. Aqueous methanolic extracts were prepared from plant collected in different seasons in the Bay of Arcachon (French Atlantic coast). High performance liquid chromatography (HPLC) with diode array detection (DAD) coupled with mass spectrometry allowed identification of four major phenolics in the aerial tissue, all belonging to the C-glycosidic-flavonoid class. They were isolated from the crude extracts, and their structures were assigned to isovitexin, isoscoparin and their respective 2″-O-glucosides on the basis of NMR, mass and UV spectroscopies. The seasonal variation of the flavonoid content was quantified over the period January 2013 to May 2015. The total concentration found ranged from 1.73 to 4.60 mg g⁻¹ dry wt for isovitexin derivatives, and 0.88–2.66 mg g⁻¹ dry wt for isoscoparin derivatives. The phenolic content of the rhizomes was very low and mainly dominated by coumaric acid (0.03–0.08 mg g⁻¹), along with ferulic acid (≤0.06 mg g⁻¹). The lack of significant concentrations of flavonoids in the rhizome contrasts with the aerial tissue. This work constitutes the first phenolic profiling of S. maritima and should provide a foundation for further studies, considering the reported biological activities of C-glycosidic flavonoids, and the lack of knowledge of the phenolic chemistry of the genus Spartina.

Local orbital locator analysis of isomeric compounds of luteolin and apigenin

Abstract: The density functional theory (DFT) protocol together with B3LYP/6-311G(d,p) level of theory has been utilized to explore and compare the structural features of two naturally occurring flavonoid isomeric compounds of luteolin and apigenin. To understand the structural activity of these C-glycosides their charge density, bonding nature and dispersion are analysed using localized orbital locator (LOL) analysis. From the delocalization pattern the antioxidant capability of flavonoid isovitexin and isoorientin is found to be superior to their isomers vitexin and orientin.

ERRATUM: "In silico modeling and in vitro activity of vitexin and isovitexin against SGLT2"

Abstract: The homology model of hSGLT2 (human sodium dependent glucose co-transporter 2) was used as a target for diabetes mellitus. Molecular docking and dynamics simulations were carried out on vitexin- an...

Method for producing fermented barley sprout with enhanced saponarin isovitexin and luteolin using novel Lactobacillus fermentum strain

Abstract: The present invention relates to a method for producing a sprout barley fermentation product with the increased content of luteolin, isovitexin, and saponarin, and a sprout barley fermentation product with the increased content of luteolin, isovitexin, and saponarin produced by the method. The method comprises: a step (1) of preparing pulverized sprout barley pulverized by adding water to sprout barley, adding a complex enzyme, in which viscozyme and pectinex ultra SP-L are mixed, to the prepared pulverized product, and then performing hydrolysis; a step (2) of preparing a sprout barley enzyme mixture by adding banana concentrate to a sprout barley fermentation decomposer hydrolyzed in the step (1), heating the same, and then inactivating the enzyme; and a step (3) of inoculating Lactobacillus fermentum strains to the sprout barley fermentation mixture prepared in the step (2) and then, fermenting the same.

Method for extracting high-purity vitexin and isovitexin from santati album leaves

Abstract: The invention provides a method for extracting high-purity vitexin and isovitexin from santati album leaves. The method comprises the steps: repeatedly extracting dried and smashed santati album leaves through ethyl alcohol or methyl alcohol for twice to three times, combining filtrates, decolorizing through a decolorizing agent, performing vacuum concentration and sequentially utilizing petroleumether and ethyl acetate to extract concentrate for twice to three times; combining ethyl acetate extract liquor, concentrating, freeze drying, fully dissolving in water bath and centrifuging to divide into precipitate and supernatant; centrifuging the precipitate in 75 to 85 DEG C water bath and freeze drying the obtained precipitate to obtain the vitexin; concentrating the supernatant and utilizing a cooling crystallization mode to obtain isovitexin. The purity of the vitexin and the isovitexin prepared by the method is higher than 98%; furthermore, the method has the advantages of being simple and convenience in operation, low cost and high extracting efficiency; the obtained product has a high purity, and large-scale production is achieved.