Displaying publications 141 - 160 of 586 in total

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  1. Flavonoids from the Bark of Artocarpus integer var. silvestris and their Anti-inflammatory Properties
    Shaha MKK, Sirata HM, Jamil S, Jalil J
    Nat Prod Commun, 2016 Sep;11(9):1275-1278.
    PMID: 30807020
    A new pyranoflavone, methoxycyclocommunol (1) together with four known flavonoids, artonin F (2), heteroflavanone A (3), cudraflavone C (4) and cyclocommunol (5) were isolated from the bark of Artocarpus integer var. silvestris Corner. Their structures were elucidated through extensive spectroscopic- techniques (UV, IR, MS, 1D-NMR and 2D-NMR) and by comparison with literature data. All the pure compounds were tested for their anti-inflammatory activities by using screening kit and radioimmunoassay methods. In a 15-lipoxygenase (15-LOX) inhibitory assay, compounds 1, 2, 4 and 5 gave weak percentages of inhibition, 16.5, 18.3, 17.6, 10.2%, respectively at the concentration of 100 μM. Compounds 1, 3 and 4, however, showed strong dose- dependent inhibition towards prostaglandin E₂ (PGE₂) production in lipopolysaccharide-induced human whole blood using a radioimmunoassay method with IC₅₀ values of 4.3, 0.8, and 0.07 μM, respectively suggesting that they strongly exhibited cyclooxygenase-2 (COX-2) activity.
    Matched MeSH terms: Flavonoids/isolation & purification; Flavonoids/pharmacology*
  2. Fulltext Factors Affecting Cell Biomass and Flavonoid Production of Ficus deltoidea var. kunstleri in Cell Suspension Culture System
    Haida Z, Syahida A, Ariff SM, Maziah M, Hakiman M
    Sci Rep, 2019 07 02;9(1):9533.
    PMID: 31267036 DOI: 10.1038/s41598-019-46042-w
    A study was conducted to establish in vitro culture conditions for maximum production of biomass and flavonoid content for Ficus deltoidea var. kunstleri, locally named as Mas Cotek, known to have a wide variety of potential beneficial attributes for human health. Size of initial inoculum, cell aggregate and initial pH value have been suggested to influent content of biomass and flavonoid for cell suspension culture in several plant species. In the present study, leaf explants were cultured by cell suspension culture procedures in MSB5 basal medium supplemented with predetermined supplements of 30 g/L sucrose, 2.75 g/L gelrite, 2 mg/L picloram and 1 mg/L kinetin with continuous agitation of 120 rpm in a standard laboratory environment. Establishment of cell suspension culture was accomplished by culturing resulting callus in different initial fresh weight of cells (0.10, 0.25, 0.50, 1.0, and 2.0 g/25 mL of media) using similar basal medium. The results showed that the highest production of biomass (0.65 g/25 mL of media) was recorded from an initial inoculum size of 2.0 g/25 mL media, whereas the highest flavonoid (3.3 mg RE/g DW) was found in 0.5 g/25 mL of media. Cell suspension fractions classified according to their sizes (500-750 µm, 250-500 µm, and <250 µm). Large cell aggregate size (500-750 µm) cultured at pH 5.75 produced the highest cell biomass (0.28 g/25 mL media) and flavonoid content (3.3 mg RE/g DW). The study had established the optimum conditions for the production of total antioxidant and flavonoid content using DPPH and FRAP assays in cell suspension culture of F. deltoidea var. kunstleri.
    Matched MeSH terms: Flavonoids/analysis; Flavonoids/metabolism*
  3. Phenolic profiling and evaluation of in vitro antioxidant, α-glucosidase and α-amylase inhibitory activities of Lepisanthes fruticosa (Roxb) Leenh fruit extracts
    Salahuddin MAH, Ismail A, Kassim NK, Hamid M, Ali MSM
    Food Chem, 2020 Nov 30;331:127240.
    PMID: 32585546 DOI: 10.1016/j.foodchem.2020.127240
    The present study focused on the phytochemical profiling along with evaluation of in vitro antioxidant, α-glucosidase and α-amylase inhibitory activities of various crudes and fractions obtained from Lepisanthes fruticosa (Roxb) Leenh fruit. Ethanolic seed crude extract exhibited the strongest radical scavenging, β-carotene bleaching activity, α-glucosidase inhibition and the highest total phenolic content (TPC). Column chromatography afforded various fractions with fraction M4 being the most potent due to the strongest radical scavenging, β-carotene bleaching, α-glucosidase inhibition and greatest amount of TPC. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis of ethanolic seed crude extract and fraction M4 showed the presence of various phytochemicals with antioxidant and antidiabetic properties, which include mostly flavonoids and tannins. The results may suggest that the ethanolic crude seed extract and its fraction could be an excellent source of bioactive phytochemicals with antioxidant and antidiabetic potential.
    Matched MeSH terms: Flavonoids/analysis; Flavonoids/chemistry
  4. Fulltext Effects of Cocoa Polyphenols and Dark Chocolate on Obese Adults: A Scoping Review
    Halib H, Ismail A, Mohd Yusof BN, Osakabe N, Mat Daud ZA
    Nutrients, 2020 Nov 30;12(12).
    PMID: 33266002 DOI: 10.3390/nu12123695
    Obesity remains a major public health problem due to its increasing prevalence. Natural products have become common as adjunct therapeutic agents for treating obesity and preventing metabolic diseases. Cocoa and its products are commonly consumed worldwide. Dark chocolate, a rich source of polyphenols, has received attention lately for its beneficial role in the management of obesity; however, conflicting results are still being reported. This scoping review aims to provide a comprehensive understanding of the existing literature on the relationship and effects of cocoa and dark chocolate intake among obese adults. We searched multiple databases for research investigating the consumption of cocoa and/or dark chocolate in managing obesity among adults. This review includes epidemiological and human studies that were published in English over the last 10 years. Our review of the current literature indicates that epidemiological and human trials with obese adults have shown inconsistent results, which may be due to the different populations of subjects, and different types of cocoa products and doses used for intervention. Studies among obese adults are mainly focusing on obese individuals with comorbidities, as such more studies are needed to elucidate the role of cocoa polyphenols in weight control and preventing the risk of chronic diseases among obese individuals without comorbidities as well as healthy individuals. Careful adjustment of confounding factors would be required. The effects of cocoa and dark chocolate intake on obese adults were discussed, and further research is warranted to identify the gaps.
    Matched MeSH terms: Flavonoids/analysis; Flavonoids/pharmacology
  5. Antiviral activity of selected flavonoids against Chikungunya virus
    Lani R, Hassandarvish P, Shu MH, Phoon WH, Chu JJ, Higgs S, et al.
    Antiviral Res, 2016 Sep;133:50-61.
    PMID: 27460167 DOI: 10.1016/j.antiviral.2016.07.009
    This study focuses on the antiviral activity of selected flavonoids against the Chikungunya virus (CHIKV), a mosquito-transmitted virus that can cause incapacitating arthritis in infected individuals. Based on the results of screening on Vero cells, the tested compounds were evaluated further with various assays, including cytotoxicity assay, virus yield assay by quantitative reverse transcription polymerase chain reaction (qRT-PCR), virus RNA replication assay with a CHIKV replicon cell line, Western blotting, and quantitative immunofluorescence assay. Baicalein, fisetin, and quercetagetin displayed potent inhibition of CHIKV infection, with 50% inhibitory concentrations [IC50] of 1.891 μg/ml (6.997 μM), 8.444 μg/ml (29.5 μM), and 13.85 μg/ml (43.52 μM), respectively, and with minimal cytotoxicity. The time-of-addition studies and various antiviral assays demonstrated that baicalein and quercetagetin mainly inhibited CHIKV binding to the Vero cells and displayed potent activity against extracellular CHIKV particles. The qRT-PCR, immunofluorescence assay, and Western blot analyses indicated that each of these flavonoids affects CHIKV RNA production and viral protein expression. These data provide the first evidence of the intracellular anti-CHIKV activity of baicalein, fisetin, and quercetagetin.
    Matched MeSH terms: Flavonoids/pharmacology*; Flavonoids/chemistry
  6. Insight into the molecular mechanism of P-glycoprotein mediated drug toxicity induced by bioflavonoids: an integrated computational approach
    Wongrattanakamon P, Lee VS, Nimmanpipug P, Sirithunyalug B, Chansakaow S, Jiranusornkul S
    Toxicol. Mech. Methods, 2017 May;27(4):253-271.
    PMID: 27996361 DOI: 10.1080/15376516.2016.1273428
    In this work, molecular docking, pharmacophore modeling and molecular dynamics (MD) simulation were rendered for the mouse P-glycoprotein (P-gp) (code: 4Q9H) and bioflavonoids; amorphigenin, chrysin, epigallocatechin, formononetin and rotenone including a positive control; verapamil to identify protein-ligand interaction features including binding affinities, interaction characteristics, hot-spot amino acid residues and complex stabilities. These flavonoids occupied the same binding site with high binding affinities and shared the same key residues for their binding interactions and the binding region of the flavonoids was revealed that overlapped the ATP binding region with hydrophobic and hydrophilic interactions suggesting a competitive inhibition mechanism of the compounds. Root mean square deviations (RMSDs) analysis of MD trajectories of the protein-ligand complexes and NBD2 residues, and ligands pointed out these residues were stable throughout the duration of MD simulations. Thus, the applied preliminary structure-based molecular modeling approach of interactions between NBD2 and flavonoids may be gainful to realize the intimate inhibition mechanism of P-gp at NBD2 level and on the basis of the obtained data, it can be concluded that these bioflavonoids have the potential to cause herb-drug interactions or be used as lead molecules for the inhibition of P-gp (as anti-multidrug resistance agents) via the NBD2 blocking mechanism in future.
    Matched MeSH terms: Flavonoids/toxicity*; Flavonoids/chemistry
  7. Fulltext The Potential Role of Flavonoids in Ameliorating Diabetic Cardiomyopathy via Alleviation of Cardiac Oxidative Stress, Inflammation and Apoptosis
    Jubaidi FF, Zainalabidin S, Taib IS, Hamid ZA, Budin SB
    Int J Mol Sci, 2021 May 12;22(10).
    PMID: 34065781 DOI: 10.3390/ijms22105094
    Diabetic cardiomyopathy is one of the major mortality risk factors among diabetic patients worldwide. It has been established that most of the cardiac structural and functional alterations in the diabetic cardiomyopathy condition resulted from the hyperglycemia-induced persistent oxidative stress in the heart, resulting in the maladaptive responses of inflammation and apoptosis. Flavonoids, the most abundant phytochemical in plants, have been reported to exhibit diverse therapeutic potential in medicine and other biological activities. Flavonoids have been widely studied for their effects in protecting the heart against diabetes-induced cardiomyopathy. The potential of flavonoids in alleviating diabetic cardiomyopathy is mainly related with their remedial actions as anti-hyperglycemic, antioxidant, anti-inflammatory, and anti-apoptotic agents. In this review, we summarize the latest findings of flavonoid treatments on diabetic cardiomyopathy as well as elucidating the mechanisms involved.
    Matched MeSH terms: Flavonoids/pharmacology*; Flavonoids/therapeutic use
  8. Fulltext Impact of soil field water capacity on secondary metabolites, phenylalanine ammonia-lyase (PAL), maliondialdehyde (MDA) and photosynthetic responses of Malaysian kacip fatimah (Labisia pumila Benth)
    Jaafar HZ, Ibrahim MH, Mohamad Fakri NF
    Molecules, 2012 Jun 13;17(6):7305-22.
    PMID: 22695235 DOI: 10.3390/molecules17067305
    A randomized complete block design 2 × 4 experiment was designed and conducted for 15 weeks to characterize the relationships between production of total phenolics, flavonoid, anthocyanin, leaf gas exchange, total chlorophyll, phenylalanine ammonia-lyase (PAL) and malondialdehyde (MDA) activity in two varieties of Labisia pumila Benth, namely the var. alata and pumila, under four levels of evapotranspiration replacement (ER) (100%; well watered), (75%, moderate water stress), (50%; high water stress) and (25%; severe water stress). The production of total phenolics, flavonoids, anthocyanin, soluble sugar and relative leaf water content was affected by the interaction between varieties and SWC. As the ER levels decreased from 100% to 25%, the production of PAL and MDA activity increased steadily. At the highest (100%) ER L. pumila exhibited significantly higher net photosynthesis, apparent quantum yield, maximum efficiency of photosystem II (f(v)/f(m)) and lower dark respiration rates compared to the other treatment. The production of total phenolics, flavonoids and anthocyanin was also found to be higher under high water stress (50% ER replacement) compared to severe water stress (25% ER). From this study, it was observed that as net photosynthesis, apparent quantum yield and chlorophyll content were downregulated under high water stress the production of total phenolics, flavonoids and anthocyanin were upregulated implying that the imposition of high water stress can enhance the medicinal properties of L. pumila Benth.
    Matched MeSH terms: Flavonoids/metabolism; Flavonoids/chemistry
  9. Fulltext Phenolics, flavonoids, antioxidant activity and cyanogenic glycosides of organic and mineral-base fertilized cassava tubers
    Omar NF, Hassan SA, Yusoff UK, Abdullah NA, Wahab PE, Sinniah U
    Molecules, 2012;17(3):2378-87.
    PMID: 22370524 DOI: 10.3390/molecules17032378
    A field study was conducted to determine the effect of organic and mineral-based fertilizers on phytochemical contents in the tubers of two cassava varieties. Treatments were arranged in a split plot design with three replicates. The main plot was fertilizer source (vermicompost, empty fruit bunch compost and inorganic fertilizer) and sub-plot was cassava variety (Medan and Sri Pontian). The amount of fertilizer applied was based on 180 kg K(2)O ha-1. The tubers were harvested and analyzed for total flavonoids, total phenolics, antioxidant activity and cyanogenic glucoside content. Total phenolic and flavonoid compounds were determined using the Folin-Ciocalteu assay and aluminium chloride colorimetric method, respectively. Different sources of fertilizer, varieties and their interactions were found to have a significant effect on phytochemical content. The phenolic and flavonoid content were significantly higher (p < 0.01) in the vermicompost treatment compared to mineral fertilizer and EFB compost. The total flavonoids and phenolics content of vermicompost treated plants were 39% and 38% higher, respectively, than those chemically fertilized. The antioxidant activity determined using the DPPH and FRAP assays were high with application of organic fertilizer. Cyanogenic glycoside levels were decreased with the application of organic fertilizer. Among the two types of compost, vermicompost resulted in higher nutritional value of cassava tubers. Medan variety with application of vermicompost showed the most promising nutritional quality. Since the nutritional quality of cassava can be improved by organic fertilization, organic fertilizer should be used in place of chemical fertilizer for environmentally sustainable production of better quality cassava.
    Matched MeSH terms: Flavonoids/isolation & purification; Flavonoids/chemistry
  10. In vitro modulatory effects of flavonoids on human cytochrome P450 2C8 (CYP2C8)
    Pang CY, Mak JW, Ismail R, Ong CE
    Naunyn Schmiedebergs Arch Pharmacol, 2012 May;385(5):495-502.
    PMID: 22307090 DOI: 10.1007/s00210-012-0731-5
    The inhibitory effects of five flavonoids with distinct chemical classes (flavones [luteolin], flavonols [quercetin and quercitrin], and flavanones [hesperetin and hespiridin]) on cDNA-expressed CYP2C8 were investigated. CYP2C8 was co-expressed with NADPH-cytochrome P450 reductase in Escherichia coli and used to characterise potency and mechanism of these flavonoids on the isoform. Tolbutamide 4-methylhydroxylase, a high-performance liquid chromatography-based assay, was selected as marker activity for CYP2C8. Our results indicated that the flavonoids inhibited CYP2C8 with different potency. The order of inhibitory activities was quercetin > luteolin > hesperetin > hesperidin > quercitrin. All of these compounds however exhibited mechanism-based inhibition. A number of structural factors were found to be important for inhibition; these include the molecular shape (volume to surface ratio), the number of hydroxyl groups as well as glycosylation of the hydroxyl group. Quercetin was the most potent inhibitor among the flavonoids examined in this study, and our data suggest that it should be examined for potential pharmacokinetic drug interactions pertaining to CYP2C8 substrates in vivo.
    Matched MeSH terms: Flavonoids/pharmacology*; Flavonoids/chemistry
  11. Fulltext Phenolics and flavonoids compounds, phenylanine ammonia lyase and antioxidant activity responses to elevated CO₂ in Labisia pumila (Myrisinaceae)
    Jaafar HZ, Ibrahim MH, Karimi E
    Molecules, 2012 May 25;17(6):6331-47.
    PMID: 22634843 DOI: 10.3390/molecules17066331
    A split plot 3 × 3 experiment was designed to examine the impact of three concentrations of CO₂ (400, 800 and 1,200 μmol·mol⁻¹) on the phenolic and flavonoid compound profiles, phenylalanine ammonia lyase (PAL) and antioxidant activity in three varieties of Labisia pumila Benth. (var. alata, pumila and lanceolata) after 15 weeks of exposure. HPLC analysis revealed a strong influence of increased CO₂ concentration on the modification of phenolic and flavonoid profiles, whose intensity depended on the interaction between CO₂ levels and L. pumila varieties. Gallic acid and quercetin were the most abundant phenolics and flavonoids commonly present in all the varieties. With elevated CO₂ (1,200 μmol·mol⁻¹) exposure, gallic acid increased tremendously, especially in var. alata and pumila (101-111%), whilst a large quercetin increase was noted in var. lanceolata (260%), followed closely by alata (201%). Kaempferol, although detected under ambient CO₂ conditions, was undetected in all varieties after exposure. Instead, caffeic acid was enhanced tremendously in var. alata (338~1,100%) and pumila (298~433%). Meanwhile, pyragallol and rutin were only seen in var. alata (810 μg·g⁻¹ DW) and pumila (25 μg·g⁻¹ DW), respectively, under ambient conditions; but the former compound went undetected in all varieties while rutin continued to increase by 262% after CO₂ enrichment. Interestingly, naringenin that was present in all varieties under ambient conditions went undetected under enrichment, except for var. pumila where it was enhanced by 1,100%. PAL activity, DPPH and FRAP also increased with increasing CO₂ levels implying the possible improvement of health-promoting quality of Malaysian L. pumila under high CO₂ enrichment conditions.
    Matched MeSH terms: Flavonoids/metabolism*; Flavonoids/chemistry
  12. Fulltext Baicalin, a metabolite of baicalein with antiviral activity against dengue virus
    Moghaddam E, Teoh BT, Sam SS, Lani R, Hassandarvish P, Chik Z, et al.
    Sci Rep, 2014 Jun 26;4:5452.
    PMID: 24965553 DOI: 10.1038/srep05452
    Baicalin, a flavonoid derived from Scutellaria baicalensis, is the main metabolite of baicalein released following administration in different animal models and human. We previously reported the antiviral activity of baicalein against dengue virus (DENV). Here, we examined the anti-DENV properties of baicalin in vitro, and described the inhibitory potentials of baicalin at different steps of DENV-2 (NGC strain) replication. Our in vitro antiviral experiments showed that baicalin inhibited virus replication at IC50 = 13.5 ± 0.08 μg/ml with SI = 21.5 following virus internalization by Vero cells. Baicalin exhibited virucidal activity against DENV-2 extracellular particles at IC50 = 8.74 ± 0.08 μg/ml and showed anti-adsorption effect with IC50 = 18.07 ± 0.2 μg/ml. Our findings showed that baicalin as the main metabolite of baicalein exerting in vitro anti-DENV activity. Further investigations on baicalein and baicalin to deduce its antiviral therapeutic effects are warranted.
    Matched MeSH terms: Flavonoids/administration & dosage*; Flavonoids/metabolism
  13. Fulltext Phytochemical constituents, nutritional values, phenolics, flavonols, flavonoids, antioxidant and cytotoxicity studies on Phaleria macrocarpa (Scheff.) Boerl fruits
    Lay MM, Karsani SA, Mohajer S, Abd Malek SN
    BMC Complement Altern Med, 2014;14:152.
    PMID: 24885709 DOI: 10.1186/1472-6882-14-152
    The edible fruits of Phaleria macrocarpa (Scheff.) Boerl are widely used in traditional medicine in Indonesia. It is used to treat a variety of medical conditions such as - cancer, diabetes mellitus, allergies, liver and heart diseases, kidney failure, blood diseases, high blood pressure, stroke, various skin diseases, itching, aches, and flu. Therefore, it is of great interest to determine the biochemical and cytotoxic properties of the fruit extracts.
    Matched MeSH terms: Flavonoids/analysis*; Flavonoids/pharmacology
  14. Fulltext Combined effect of CO(2) enrichment and foliar application of salicylic acid on the production and antioxidant activities of anthocyanin, flavonoids and isoflavonoids from ginger
    Ghasemzadeh A, Jaafar HZ, Karimi E, Ibrahim MH
    BMC Complement Altern Med, 2012 Nov 23;12:229.
    PMID: 23176249 DOI: 10.1186/1472-6882-12-229
    BACKGROUND: The increase in atmospheric CO(2) concentration caused by climate change and agricultural practices is likely to affect biota by producing changes in plant growth, allocation and chemical composition. This study was conducted to evaluate the combined effect of the application of salicylic acid (SA, at two levels: 0 and 10-3 M) and CO(2) enrichment (at two levels: 400 and 800 μmol·mol-1) on the production and antioxidant activities of anthocyanin, flavonoids and isoflavonoids from two Malaysian ginger varieties, namely Halia Bentong and Halia Bara.

    METHODS: High-performance liquid chromatography (HPLC) with photodiode array detection and mass spectrometry was employed to identify and quantify the flavonoids and anthocyanins in the ginger extracts. The antioxidant activity of the leaf extracts was determined by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and thiobarbituric acid (TBA) assays. The substrate specificity of chalcone synthase, the key enzyme for flavonoid biosynthesis, was investigated using the chalcone synthase (CHS) assay.

    RESULTS: CO(2) levels of 800 μmol·mol-1 significantly increased anthocyanin, rutin, naringenin, myricetin, apigenin, fisetin and morin contents in ginger leaves. Meanwhile, the combined effect of SA and CO(2) enrichment enhanced anthocyanin and flavonoid production compared with single treatment effects. High anthocyanin content was observed in H Bara leaves treated with elevated CO(2) and SA. The highest chalcone synthase (CHS) activity was observed in plants treated with SA and CO(2) enrichment. Plants not treated with SA and kept under ambient CO(2) conditions showed the lowest CHS activity. The highest free radical scavenging activity corresponded to H Bara treated with SA under high CO(2) conditions, while the lowest activity corresponded to H Bentong without SA treatment and under atmospheric CO(2) levels. As the level of CO(2) increased, the DPPH activity increased. Higher TBA activity was also recorded in the extracts of H Bara treated with SA and grown under high CO(2) conditions.

    CONCLUSIONS: The biological activities of both ginger varieties were enhanced when the plants were treated with SA and grown under elevated CO(2) concentration. The increase in the production of anthocyanin and flavonoids in plants treated with SA could be attributed to the increase in CHS activity under high CO(2) levels.

    Matched MeSH terms: Flavonoids/analysis*; Flavonoids/metabolism
  15. Flavonoids and linderone from Lindera oxyphylla and their bioactivities
    Hosseinzadeh M, Hadi AH, Mohamad J, Khalilzadeh MA, Cheahd SC, Fadaeinasab M
    Comb Chem High Throughput Screen, 2013 Feb;16(2):160-6.
    PMID: 23173924
    A new linderone A, namely 2-cinnamoyl-3-hydroxy-4, 5-dimethoxycyclopenta-2, 4-dienone (5), together with three known flavonoids (1-3) and one linderone (4), were isolated from the bark of Lindera oxyphylla. Extensive spectroscopic analysis including 1D and 2D-NMR spectra determined their sturctures. In addition, the antioxidant activity of all the compounds has been determined using 2, 2-diphenyl-1-picrylhydrazyl radical scavenging (DPPH), ferric reducing antioxidant power (FRAP) and ferrous ion chelating (FIC) methods. Compound 3 showed excellent DPPH scavenging activity with IC50% value of 8.5 ± 0.004% (μg/mL) which is comparable with vitamin C. This compound, also showed an absorbance value of 1.00 ± 0.06% through FRAP test when compared with Butyl Hydroxy Aniline (BHA). However, FIC showed low activity for all the isolated compounds (chelating activity less than 50%) in comparison with ethylene diamine tetra acetic acid (EDTA). Anticancer activity for all compounds has also been measured on A375 human melanoma, HT-29 colon adenocarcinoma, MCF-7 human breast adenocarcinoma cells, WRL-68 normal hepatic cells, A549 non-small cell lung cancer cells and PC-3 prostate adenocarcinoma cell line. Compound 1 showed A549=65.03%, PC-3=30.12%, MCF-7=47.67, compound 2 showed PC-3=90.13%, compound 3 showed MCF-7=79.57 and for compound 5 MCF-7 is 96.33.
    Matched MeSH terms: Flavonoids/pharmacology; Flavonoids/chemistry*
  16. Isolation and identification of radical scavenging and tyrosinase inhibition of polyphenols from Tibouchina semidecandra L
    Sirat HM, Rezali MF, Ujang Z
    J Agric Food Chem, 2010 Oct 13;58(19):10404-9.
    PMID: 20809630 DOI: 10.1021/jf102231h
    Phytochemical and bioactivity studies of the leaves and stem barks of Tibouchina semidecandra L. have been carried out. The ethyl acetate extract of the leaves yielded four flavonoid compounds, identified as quercetin, quercetin 3-O-α-l-(2''-O-acetyl) arabinofuranoside, avicularin, and quercitrin, while the stem barks gave one ellagitannin, identified as 3,3'-O-dimethyl ellagic acid 4-O-α-l-rhamnopyranoside. Evaluation of the antioxidative activity on the crude extracts and pure compounds by electron spin resonance (ESR) and ultraviolet-visible (UV-vis) spectrophotometric assays showed that the pure isolated polyphenols and the EtOAc extract possessed strong antioxidative capabilities. Quercetin was found to be the most active radical scavenger in DPPH-UV and ESR methods with SC(50) values of 0.7 μM ± 1.4 and 0.7 μM ± 0.6 μM, respectively, in the antioxidant assay. A combination of quercetin and quercitrin was tested for synergistic antioxidative capacity;, however, there was no significant improvement observed. Quercetin also exhibited strong antityrosinase activity with a percent inhibition of 95.0% equivalent to the positive control, kojic acid, in the tyrosinase inhibition assay.
    Matched MeSH terms: Flavonoids/isolation & purification*; Flavonoids/pharmacology*
  17. In vitro modulation of naturally occurring flavonoids on cytochrome P450 2A6 (CYP2A6) activity
    Tiong KH, Yiap BC, Tan EL, Ismail R, Ong CE
    Xenobiotica, 2010 Jul;40(7):458-66.
    PMID: 20402563 DOI: 10.3109/00498251003786749
    1. The effect of flavonoids on coumarin 7-hydroxylation, an activity marker of an important human liver cytochrome P450 isoform, cytochrome P450 2A6 (CYP2A6), was investigated in this study. 2. Coumarin 7-hydroxylase activity was measured fluorometrically in reaction mixtures containing cDNA-expressed CYP2A6, nicotinamide adenine dinucleotide phosphate generating system and 10 uM coumarin, at various concentrations of flavonoids. 3. Among the 23 compounds tested, most of the active members were from flavonol group of hydroxylated flavonoids, with myricetin being the most potent inhibitor followed by quercetin, galangin, and kaempferol. 4. Further exploration of the inhibition mechanism of these compounds revealed that myricetin, galangin, and kaempferol exhibited mixed-type of inhibition pattern while quercetin was observed to exhibit competitive mode of inhibition. 5. Structure-function analyses revealed that degree of inhibition was closely related to the number and location of hydroxyl groups, glycosylation of the free hydroxyl groups, degree of saturation of the flavane nucleus as well as the presence of the alkoxylated function.
    Matched MeSH terms: Flavonoids/metabolism*; Flavonoids/pharmacology
  18. 6th COSTAM/SFRR (ASEAN/Malaysia) International Workshop on Micronutrients, Oxidative Stress, and the Environment
    Nesaretnam K, Sies H
    Antioxid Redox Signal, 2006 10 13;8(11-12):2175-7.
    PMID: 17034360
    The 6(th) COSTAM/SFRR (ASEAN/Malaysia) workshop, "Micronutrients, Oxidative Stress, and the Environment," was held from June 29 to July 2 at Holiday Inn Damai Beach Resort in Kuching, Sarawak. Two hundred twenty participants from 17 countries presented recent advances on natural antioxidants in the area of oxidative stress and molecular aspects of nutrition. Natural products and research are an important program in academic institutions and are experiencing unprecedented interest and growth by the scientific community and public health authorities. Progress is being driven by better understanding of the molecular mechanisms of the relation between oxidative stress and micronutrient action. The gathering of scientists from around the world was fruitful, and we hope that future work will be developed by the formal and informal interactions that took place in this beautiful tropical setting.
    Matched MeSH terms: Flavonoids/pharmacology; Flavonoids/therapeutic use
  19. Fulltext Antimetastatic effects of Phyllanthus on human lung (A549) and breast (MCF-7) cancer cell lines
    Lee SH, Jaganath IB, Wang SM, Sekaran SD
    PLoS One, 2011;6(6):e20994.
    PMID: 21698198 DOI: 10.1371/journal.pone.0020994
    Current chemotherapeutic drugs kill cancer cells mainly by inducing apoptosis. However, they become ineffective once cancer cell has the ability to metastasize, hence the poor prognosis and high mortality rate. Therefore, the purpose of this study was to evaluate the antimetastatic potential of Phyllanthus (P. niruri, P. urinaria, P. watsonii, and P. amarus) on lung and breast carcinoma cells.
    Matched MeSH terms: Flavonoids/analysis; Flavonoids/pharmacology
  20. Fulltext Apoptotic effects of chrysin in human cancer cell lines
    Khoo BY, Chua SL, Balaram P
    Int J Mol Sci, 2010;11(5):2188-99.
    PMID: 20559509 DOI: 10.3390/ijms11052188
    Chrysin is a natural flavonoid currently under investigation due to its important biological anti-cancer properties. In most of the cancer cells tested, chrysin has shown to inhibit proliferation and induce apoptosis, and is more potent than other tested flavonoids in leukemia cells, where chrysin is likely to act via activation of caspases and inactivation of Akt signaling in the cells. Moreover, structure-activity relationships have revealed that the chemical structure of chrysin meets the key structural requirements of flavonoids for potent cytotoxicity in leukemia cells. It is possible that combination therapy or modified chrysin could be more potent than single-agent use or administration of unmodified chrysin. This study may help to develop ways of improving the effectiveness of chrysin in the treatment of leukemia and other human cancers in vitro.
    Matched MeSH terms: Flavonoids/pharmacology*; Flavonoids/chemistry
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