[Show abstract][Hide abstract] ABSTRACT: The aim of the present study was to investigate the biological activity of 20 essential oils (EOs) derived from herbal plants and citrus fruits. The in vitro anti-allergic and anti-inflammatory activities of these oils were investigated, and the EO which was found to have the strongest activity of the 20 EOs examined, was investigated further to identify its components and bioactive compounds. The in vitro anti-allergic activity was determined by measuring the release of β-hexosaminidase from rat basophilic leukemia (RBL-2H3) cells treated with the calcium ionophore, A23187. The in vitro anti-inflammatory activity was determined by measuring the production of tumor necrosis factor-α (TNF-α) in RAW264.7 murine macrophages treated with lipopolysaccharide. Among the EOs examined, lemongrass [Cymbopogon citratus (DC.) Stapf] elicited the strongest anti-allergic and anti-inflammatory effects. A principal component of this EO is citral (3,7-dimethyl-2,6-octadien-1-al) (74.5%), a mixture of the stereoisomers, geranial (trans‑citral, 40.16%) and neral (cis-citral, 34.24%), as determined by chromatography-mass spectrometry analysis. The activities of citral and geranial are similar to those of lemongrass EO. These compounds elicited significant in vivo anti-allergic and anti-inflammatory effects, suppressing an immunoglobulin E (IgE)-induced passive cutaneous anaphylactic reaction in mice and a 12-O-tetradecanoylphorbol-13-acetate-induced inflammatory mouse ear edema, respectively. Our data demonstrate that lemongrass EO and its constituents, citral and geranial, may be a therapeutic candidate for allergic and inflammatory diseases.
International Journal of Molecular Medicine 03/2014; 33(6). DOI:10.3892/ijmm.2014.1720 · 2.09 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: During the screening of selective DNA polymerase (pol) inhibitors from more than 50 plant food materials, we found that the extract from steamed germinated soybeans (Glycine max L.) inhibited human pol λ activity. Among the three processed soybean samples tested (boiled soybeans, steamed soybeans, and steamed germinated soybeans), both the hot water extract and organic solvent extract from the steamed germinated soybeans had the strongest pol λ inhibition. We previously isolated two glucosyl compounds, a cerebroside (glucosyl ceramide, AS-1-4, compound ) and a steroidal glycoside (eleutheroside A, compound ), from dried soybean, and these compounds were prevalent in the extracts of the steamed germinated soybeans as pol inhibitors. The hot water and organic solvent extracts of the steamed germinated soybeans and compounds and selectively inhibited the activity of eukaryotic pol λ in vitro but did not influence the activities of other eukaryotic pols, including those from the A-family (pol γ), B-family (pols α, δ, and ε), and Y-family (pols η, ι, and κ), and also showed no effect on the activity of pol β, which is of the same family (X) as pol λ. The tendency for in vitro pol λ inhibition by these extracts and compounds showed a positive correlation with the in vivo suppression of TPA (12-O-tetradecanoylphorbol-13-acetate)-induced inflammation in mouse ear. These results suggest that steamed germinated soybeans, especially the glucosyl compound components, may be useful for their anti-inflammatory properties.
[Show abstract][Hide abstract] ABSTRACT: We previously found that vitamin K3 (menadione, 2-methyl-1,4-naphthoquinone) inhibits the activity of human mitochondrial DNA polymerase γ (pol γ). In this study, we focused on plumbagin (5-hydroxy-2-methyl-1,4-naphthoquinone), and chemically synthesized novel plumbagins conjugated with C2:0 to C22:6 fatty acids (5-O-acyl plumbagins). These chemically modified plumbagins enhanced mammalian pol inhibition and their cytotoxic activity. Plumbagin conjugated with chains consisting of more than C18-unsaturated fatty acids strongly inhibited the activities of calf pol α and human pol γ. Plumbagin conjugated with oleic acid (C18:1-acyl plumbagin) showed the strongest suppression of human colon carcinoma (HCT116) cell proliferation among the ten synthesized 5-O-acyl plumbagins. The inhibitory activity on pol α, a DNA replicative pol, by these compounds showed high correlation with their cancer cell proliferation suppressive activity. C18:1-Acyl plumbagin selectively inhibited the activities of mammalian pol species, but did not influence the activities of other pols and DNA metabolic enzymes tested. This compound inhibited the proliferation of various human cancer cell lines, and was the cytotoxic inhibitor showing strongest inhibition towards HT-29 colon cancer cells (LD50 = 2.9 µM) among the nine cell lines tested. In an in vivo anti-tumor assay conducted on nude mice bearing solid tumors of HT-29 cells, C18:1-acyl plumbagin was shown to be a promising tumor suppressor. These data indicate that novel 5-O-acyl plumbagins act as anti-cancer agents based on mammalian DNA replicative pol α inhibition. Moreover, the results suggest that acylation of plumbagin is an effective chemical modification to improve the anti-cancer activity of vitamin K3 derivatives, such as plumbagin.
PLoS ONE 02/2014; 9(2):e88736. DOI:10.1371/journal.pone.0088736 · 3.23 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The present study focused on variation in the fatty acid (FA) composition of the different lipids in black, red and green rice brans. Total lipids were fractionated using TLC into nine subfractions. The lipids comprised mainly triacylglycerols (TAG: 78.0 - 81.6 wt%), free FA (FFA: 5.6 - 8.8 wt%), and phospholipids (PL: 6.3 - 7.0 wt%). The PL components included phosphatidyl choline (52.6 - 57.2 wt%), phosphatidyl inositol (22.3 - 25.2 wt%) and phosphatidyl ethanolamine (11.4 - 16.4 wt%). Comparison of these cultivars showed no significant differences (P > 0.05) in FA composition of TAG, FFA and PL. FA composition of TAG among the three cultivars was characterized in the rice brans: unsaturated FA were predominantly concentrated at the sn-2 position (97.7 - 98.5 wt%) and saturated FA primarily occupied the sn-1 or sn-3 position (29.8 - 31.8 wt%). Comparison of individual PLs revealed significant differences (P < 0.05) in FA composition. Black and red rice brans were very similar, with green rice bran exhibiting a few differences. The results revealed no significant differences (P > 0.05) in the proportional composition of FA with increased degree of milling.
Food Science and Technology Research 01/2014; 20(1):121-127. DOI:10.3136/fstr.20.121 · 0.35 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Variotin (1) and three novel compounds, formosusin A (2), B (3), and C (4), were isolated from the cultures of the fungus Paecilomyces formosus, and their structures were determined by spectroscopic analyses. Compound 2 is (6Z,8E,10E)-variotin, a new cis-olefin analog of compound 1. Compound 2 selectively inhibited the activity of mammalian DNA polymerase β (pol β) in vitro, with an IC50 of 35.6μM. By contrast, compounds 1, 3, and 4 did not influence the activity of pol β. These four compounds showed no effect on the activities of other 10 mammalian pols (i.e., pols α, γ, δ, ε, η, ι, κ, λ, and μ, and terminal deoxynucleotidyl transferase). These compounds also did not inhibit the activities of fish, insect, plant, and prokaryotic pols and other DNA metabolic enzymes tested. These results suggested that compound 2 could be a selective inhibitor of mammalian pol β. The compound 2-induced inhibition of rat pol β activity was competitive and non-competitive with respect to the DNA template-primer substrate and the dNTP substrate, respectively. On the basis of these results, the relationship between the three-dimensional structure and pol β inhibitory mechanism of compound 2 is discussed.
[Show abstract][Hide abstract] ABSTRACT: The objective of this study was to evalute the tocochromanol distributions, lipid components and molecular species of triacylglycerols (TAG) in three colored rice bran cultivars. The dominant tocochromanol were gama-tocotrienol, alpha-tocopherol and alpha-tocotrienol with smaller amounts of gama-tocopherol, delta-tocopherol and delta-tocotrienol. These lipids comprised mainly TAG (78.0-81.6 wt%), free fatty acids (FFA: 5.6-8.8 wt%), and phospholipids (PL: 6.3-7.0 wt%), while other components were present in minor proportions (0.4-2.3 wt%). Sixteen different TAG molecular species were detected and quantified by successive applications of AgNO3-TLC and GC. The major TAG molecular species were SM2 (6.1-9.8%), S2D (4.8-7.3%)?M3 (16.4-18.7%), SMD (6.2-9.2%), SD2 (6.5-9.5%), SMT (6.3-7.7%), M2D (12.3-15.5%.), MD2 (8.4-10.4%), SDT (4.3-5.4%) and D3 (10.2-15.2%) (where S, M, D, and T denote saturated FA, monoene, diene, and triene, respectively). The results showed that colored rice bran lipids contain large amounts of nutraceutical with proven positive health effects.
[Show abstract][Hide abstract] ABSTRACT: During the screening of selective DNA polymerase (pol) inhibitors, we isolated cycloartenyl trans-ferulate (CAF), which is a major component of γ-oryzanol, which is a byproduct formed during the production of Japanese rice wine "sake". CAF selectively inhibited the activity of mammalian A, B, and X pol families, but Y family pols were not affected. CAF did not influence the activities of plant or prokaryotic pols, nor the activity of other DNA metabolic enzymes tested. Individual chemical components of CAF, including cycloartenol (CA) and ferulic acid (FA), did not inhibit pol enzyme activities. CAF suppressed TPA (12-O-tetradecanoylphorbol-13-acetate)-induced inflammation in the mouse ear, but CA and FA did not. The ability to inhibit mammalian pol enzymes in vitro was positively correlated with their propensity to suppress inflammation in vivo. These results suggest that this byproduct formed during the sake-brewing process is useful as an anti-inflammatory agent.
[Show abstract][Hide abstract] ABSTRACT: Ustusorane D and penicisochromans B-D are natural isochromans isolated from Aspergillus ustus 094102 and Penicillium sp. PSU-F40, respectively. Herein, we report the syntheses of (-)-ustusorane D and (+)-penicisochroman B and the structures of penicisochromans C and D. The relative configuration of natural ustusorane D and the absolute configuration of natural penicisochroman B were determined. Two plausible structures for penicisochroman C were evaluated through synthesis, but their (1)H and (13)C NMR data were not in agreement with those of the natural product. The structural revision and the determination of the absolute configuration of natural penicisochroman D were achieved. Structure-activity relationship studies of the synthetic compounds as well as a series of related isochromans indicated that the enone of the furanone moiety was essential for the cytotoxicity of these compounds toward HCT116 human colon cancer cells. Pseudodeflectusin, the related natural isochroman, suppressed cell growth and induced apoptosis in HCT116 cells.
[Show abstract][Hide abstract] ABSTRACT: In this study, the inhibitory activities against mammalian DNA polymerases (pols) of 16 major bioflavonoids were investigated. Myricetin (3,3',4',5,5',7-hexahydroxyflavone) was the most potent inhibitor of pols amongst the compounds tested, with IC50 values of 21.3-40.9μM. This compound did not affect the activities of plant (cauliflower) pol α or prokaryotic pols. Myricetin also inhibited human DNA topoisomerase II (topo II) activity with an IC50 value of 27.5μM, but did not inhibit the activities of other DNA metabolic enzymes tested. Myricetin also did not influence the direct binding to double stranded DNA as determined by thermal transition analysis. It was found to prevent the proliferation of human colon HCT116 carcinoma cells with an LD50 of 28.2μM, halt the cell cycle in G2/M phase, and induce apoptosis. These results suggest that the decrease of proliferation may be a result of the inhibition of cellular topoisomerase (topo) II rather than pols.
[Show abstract][Hide abstract] ABSTRACT: The inhibitory activity of 3 soy isoflavones (daidzein, genistein and glycitein) and their glycosides (daidzin, genistin and glycitin) on mammalian DNA polymerases (pols) and topoisomerases (topos) was investigated. Of the compounds tested, only genistein selectively inhibited human topo II activity and had an IC50 value of 37.5 µM. These isoflavones had no effect on the activity of human topo I; mammalian pols α, β, γ and κ; or on any other DNA metabolic enzyme tested. Thermal transition analysis indicated that genistein did not influence the direct binding to double-stranded DNA. Genistein prevented the proliferation of HCT116 human colon carcinoma cells with an LD50 of 94.0 µM and it halted the cell cycle in G2/M phase. These results suggest that decreases in cell proliferation due to genistein may result from the inhibition of cellular topo II and that genistein, a major soy isoflavone, may be an anticancer food component. The relationship between the structures and these bioactivities of soy isoflavones is discussed.
International Journal of Oncology 07/2013; 43(4). DOI:10.3892/ijo.2013.2032 · 3.03 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Carotenoids are organic pigments that are found in the chloroplasts and chromoplasts of plants and some other photosynthetic organisms like algae, bacteria, and fungi. There are over 600 known carotenoids; they are divided into two classes, xanthophylls (which contain oxygen) and carotenes (which are purely hydrocarbons, and contain no oxygen).
All carotenoids are tetraterpenoids, meaning that they are produced from 8 isoprene (2-methyl-1,3-butadiene) molecules and contain 40 carbon atoms. In humans, four carotenoids (beta-carotene, alpha-carotene, gamma-carotene, and beta-crypoxanthin) have vitamin A activity (meaning they can be converted to retinal). Bixin ((2E,4E,6E,8E,10E,12E,14E,16Z,18E)-20-methoxy-4,8,13,17-tetramethyl-20-oxoicosa 2,4,6,8,10,12,14, 16,18-nonaenoic acid) is an polyunsaturated, norcarotenoid, red dye from the main fruit of annatto, its seeds reduced to powder are widely used to color food and sunscreen. The annatto seeds contain about 5% pigment, which consist of 70-80% of bixin. The bixin is soluble in fats but insoluble in water. When exposed to alkalis, the methyl ester is hydrolyzed and produces the norbixin dicarboxylic acid, a water soluble derivative. It is a chemically unstable compound when isolated and is converted, via
isomerization, in bixin trans-(β-bixin), the cis-trans isomer of bixin. Carotenoids bixin and norbixin have two stereo configurations, i.e., cis and trans. In extracts, under normal conditions, the cis-bixin or cis-norbixin are more unstable. The cis-bixin or cis-norbixin solution under heating are partially converted into the trans configuration, which is more stable and known as isobixin and isonorbixin. Brazil is one of the major producers of annatto and its planting occurs primarily in the North and Northeast regions, although its
cultivation in the last decades expanded to other regions, in the Southeast, especially Sao Paulo and Rio de Janeiro. The international market growing demand is justified by the prohibition of synthetic dyes due to studies that have proven their toxicity. Like many carotenoids, bixin and norbixin also present significant antioxidant properties. Both carotenoids can reduce levels of malondialdehyde (biomarker of lipid peroxidation) when induced by cyclophosphamide (immunosuppressant), as well as protect the DNA from
oxidative damage in vitro. Bixin inhibited in vitro generation of superoxide and the generation of reactive oxygen species such as hydrogen peroxide and hydroxyl radicals and with protective action against mutagenicity in human lymphocytes. Besides the antioxidant property, these carotenoids also present important metabolic actions in lipids and sugars. Bixin acts as PPAR-γ agonist (receptor activated by peroxisome proliferators range), a nuclear receptor that acts in the metabolism of lipids and carbohydrates and has anti-inflammatory, immunomodulatory and anti-atherosclerotic action. This interaction of BIX and the PPAR gamma receptor may increase the sensitivity to insulin in adipocytes so that there is a greater glucose uptake. Furthermore, the interaction with the receptor regulates lipid metabolism improving metabolic syndrome present in diabetic patients.
Carotenoids: Food Sources, Production and Health Benefits, 1 edited by Masayoshi Yamaguchi, 07/2013: chapter Chapter 13 - Bixin and Norbixin: Chemistry, Production and Health Benefits: pages 261-270; Nova Publishers., ISBN: 978-1-62808-622-5
[Show abstract][Hide abstract] ABSTRACT: Low molecular weight (LMW) polyphenolics containing a polyhydroxylated benzyl moiety are abundant in medicinal plants. In the present study, we report on the activities of seven LMW polyphenolics isolated from Inonotus obliquus, a medicinal mushroom. The isolated compounds included caffeic acid (CA), 3,4-dihydroxybenzalacetone (DBL), gallic acid, syringic acid, protocatechuic acid, 3,4-dihydroxybenzaldehyde and 2,5-dihydroxyterephthalic acid. We analyzed their inhibitory effects on DNA polymerase (pol) and DNA topoisomerase (topo), and their effects on human cancer cell growth. All isolated compounds inhibited human topo II activity; the most potent were DBL and CA, which contain a catechol propanoid moiety. CA and DBL inhibited the activity of human topo I, whereas other compounds had no effect. No compound modulated the activities of 11 mammalian pol species or other DNA metabolic enzymes, including T7 RNA polymerase, mouse IMP dehydrogenase (type II), T4 polynucleotide kinase and bovine deoxyribonuclease I. CA and DBL markedly suppressed the proliferation of human colon HCT116 carcinoma cells with an LD50 of 70.0 and 49.4 µM, respectively, and halted the cell cycle in the G2/M phase. The suppressive effect of these compounds on cancer cell growth correlated with their ability to inhibit topo II. These results suggest that CA- and DBL-dependent decreases in cell proliferation are due to the inhibition of cellular topo II. The mechanism of action of these catechol propanoid compounds and the implication for their use as anticancer agents are discussed.
Molecular Medicine Reports 06/2013; 8(2). DOI:10.3892/mmr.2013.1547 · 1.55 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Endogenous tocopherols in extracted lipids from Jack beans (Canavalia gladiata DC.) were determined by high-performance liquid chromatography (HPLC), and were investigated in relation to the fatty acids (FA) distribution of triacylgycerols (TAG) and phospholipids (PL). The dominant tocopherols were (δ)-tocopherol (78.9-96.5mg%) and (γ)-tocopherol (42.1-56.1mg%) with much smaller amounts of (α)-tocopherol (1.1-1.3mg%). The lipids of Jack beans comprised mainly TAG (34.6-38.6wt.%) and PL (54.8-57.4wt.%), and other components were also detected in minor proportions (0.3-3.8wt.%). The PL components included phosphatidyl choline (46.2-48.7wt.%), phosphatidyl inositol (23.4-29.6wt.%) and phosphatidyl ethanolamine (18.5-21.2wt.%). Comparison of these different beans showed, with a few exceptions, no significant differences (P>0.05) in FA distribution. The FA distribution of TAG among the five beans was evident in the Jack beans: unsaturated FA (93.3-95.3wt.%) were predominantly concentrated at the sn-2 position and saturated FA (33.6-34.4wt.%) primarily occupying the sn-1 position or sn-3 position. The results obtained from this work would provide useful information to both producers and consumers for manufacturing functional foods or beverages in Japan and elsewhere.
[Show abstract][Hide abstract] ABSTRACT: Vitamin Ks (VKs) are fat-soluble quinone compounds known to have various bioactivities. This review describes the inflammatory effects of VKs and their related quinone derivatives based on DNA polymerase (pol) inhibition. VK3, but not VK1 or VK2 (=MK-4), inhibited the activity of human pol γ, which is the DNA replicative pol in mitochondria. Of the intermediate compounds between VK2 and VK3 (namely MK-3, MK-2 and MK-1), MK-2 was the strongest inhibitor of mammalian pols α, κ and λ, which belong to the B-, Y- and X-families of pols, respectively. Among the VK3 based quinone derivatives, such as 1,4-naphthoquinone (NQ), 2-dimethyl-1,4-naphthoquinone (1,2-dimethyl-NQ), 1,4-benzoquinone (BQ), 9,10-anthraquinone (AQ) and 5,12-naphthacenequinone (NCQ), NQ was the strongest inhibitor of mammalian pols α and λ, in particular, DNA repair-related pol λ. Among the all compounds tested, NQ displayed the strongest suppression of tumor necrosis factor (TNF)-α production induced by lipopolysaccharide (LPS) in a cell culture system using RAW264.7 mouse macrophages. NQ also suppressed the expression of pol λ protein in these cells, after LPS-treated RAW264.7 cells were stimulated to induce pol λ expression. In an in vivo mouse model of LPS-evoked acute inflammation, intraperitoneal injection of NQ into mice suppressed TNF-α production in peritoneal macrophages and serum. In an in vivo colitis mouse model induced using dextran sulfate sodium (DSS), NQ markedly suppressed DSS-evoked colitis. The promising anti-inflammatory candidates based on the inhibition of DNA repair-related pols, such as pol λ, by VKs quinone derivatives, such as NQ, are discussed.
International Journal of Oncology 01/2013; 42(3). DOI:10.3892/ijo.2013.1771 · 3.03 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Three fractions from freeze-dried fruits and jams of strawberries and blueberries were prepared : (1) ethanolinsoluble extracts, (2) diethyl ether-insoluble extracts, and (3) diethyl ether-soluble extracts. The inhibitory effects of fruit fractions (1).(3) on the activity of calf DNA polymerase α (pol α), which is involved in DNA replication, were stronger than those of the corresponding jam fractions. Among the 12 fractions prepared, strawberry jam fraction (3) was the strongest inhibitor of human pol λ, which is involved in DNA repair/recombination. Furthermore, strawberry jam fraction (3) exhibited the greatest anti-inflammatory activity in a TPAinduced (12-O-tetradecanoylphorbol-13-acetate) mouse ear model. These results suggest that the hydrophobic fraction (3) from strawberry jam can be used as an anti-inflammatory additive for foods and cosmetics.
[Show abstract][Hide abstract] ABSTRACT: Previously, we observed that purified monogalactosyl diacylglycerol (MGDG), a major glycoglycerolipid from spinach, selectively inhibits the activities of mammalian replicative DNA polymerases (α, δ and ε). However, the function of MGDG following ingestion is not well-known. In the present study, spinach MGDG suppressed the proliferation of Colon26 mouse colon cancer cells with an LD(50) of 24 μg/ml in vitro. γ-cyclodextrin (CD)-MGDG complex was prepared and administered orally following Colon26 mouse tumor adhesion for 26 days. It was observed that 20 mg/kg equivalent (eq.) of the CD-MGDG complex reduced tumor volume by ∼60% compared with that of the vehicle-treated controls. In immunohistochemical analysis, the CD-MGDG complex group showed a decreased number of proliferating cell nuclear antigen (PCNA)-positive cells and reduction of mitosis in the tumor cells compared with the control group. In addition, the CD-MGDG complex increased the number of terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL)-positive apoptotic cells and inhibited CD31-positive tumor blood vessel growth significantly. These results suggest that MGDG has the potential for cancer prevention and health promotion.
Experimental and therapeutic medicine 01/2013; 5(1):17-22. DOI:10.3892/etm.2012.792 · 1.27 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The present study was designed to investigate the anticancer activity of novel nine small peptides (compounds 1-9) derived from TT-232, a somatostatin structural analogue, by analyzing the inhibition of mammalian DNA polymerase (pol) and human cancer cell growth. Among the compounds tested, compounds 3 [tert-butyloxycarbonyl (Boc)-Tyr-Phe-1-naphthylamide], 4 (Boc-Tyr-Ile-1-naphthylamide), 5 (Boc-Tyr-Leu-1-naphthylamide) and 6 (Boc-Tyr-Val-1-naphthylamide) containing tyrosine (Tyr) but no carboxyl groups, selectively inhibited the activity of rat pol β, which is a DNA repair-related pol. Compounds 3-6 strongly inhibited the growth of human colon carcinoma HCT116 p53(+/+) cells. The influence of compounds 1-9 on HCT116 p53(-/-) cell growth was similar to that observed for HCT116 p53(+/+) cells. These results suggest that the cancer cell growth suppression induced by these compounds might be related to their inhibition of pol. Compound 4 was the strongest inhibitor of pol β and cancer cell growth among the nine compounds tested. This compound specifically inhibited rat pol β activity, but had no effect on the other 10 mammalian pols investigated. Compound 4 combined with methyl methane sulfonate (MMS) treatment synergistically suppressed HCT116 p53(-/-) cell growth compared with MMS alone. This compound also induced apoptosis in HCT116 cells with or without p53. From these results, the influence of compound 4, a specific pol β inhibitor, on the relationship between DNA repair and cancer cell growth is discussed.
[Show abstract][Hide abstract] ABSTRACT: BACKGROUND: Gemcitabine (GEM) is used to treat various carcinomas and represents an advance in pancreatic cancer treatment. In the screening for DNA polymerase (pol) inhibitors, a glycoglycerolipid, monogalactosyl diacylglycerol (MGDG), was isolated from spinach. METHODS: Phosphorylated GEM derivatives were chemically synthesized. In vitro pol assay was performed according to our established methods. Cell viability was measured using MTT assay. RESULTS: Phosphorylated GEMs inhibition of mammalian pol activities assessed, with the order of their effect ranked as: GEM-5'-triphosphate (GEM-TP)>GEM-5'-diphosphate>GEM-5'-monophosphate>GEM. GEM suppressed growth in the human pancreatic cancer cell lines BxPC-3, MIAPaCa2 and PANC-1 although phosphorylated GEMs showed no effect. MGDG suppressed growth in these cell lines based on its selective inhibition of replicative pol species. Kinetic analysis showed that GEM-TP was a competitive inhibitor of pol α activity with nucleotide substrates, and MGDG was a noncompetitive inhibitor with nucleotide substrates. GEM combined with MGDG treatments revealed synergistic effects on the inhibition of DNA replicative pols α and γ activities compared with GEM or MGDG alone. In cell growth suppression by GEM, pre-addition of MGDG significantly enhanced cell proliferation suppression, and the combination of these compounds was found to induce apoptosis. In contrast, GEM-treated cells followed by MGDG addition did not influence cell growth. CONCLUSIONS: GEM/MGDG enhanced the growth suppression of cells based on the inhibition of pol activities. GENERAL SIGNIFICANCE: Spinach MGDG has great potential for development as an anticancer food compound and could be an effective clinical anticancer chemotherapy in combination with GEM.
[Show abstract][Hide abstract] ABSTRACT: In this study, the inhibitory activities against DNA polymerases (pols) and DNA topoisomerases (topos) by eight major green tea catechin derivatives (flavan-3-ols) were investigated. Some catechins inhibited mammalian pols (α and β) and human topos (I and II), with (-)-epigallocatechin gallate (EGCg) the strongest inhibitor of both enzyme types, showing IC(50) values of 3.8-21.5 and 2.0-20.0 μM, respectively. EGCg did not affect the activities of plant (cauliflower) pol α or prokaryotic pols and showed no effect on the activities of other DNA metabolic enzymes tested. Next, a method was established for assay of mouse one-cell zygote development inhibition, the catechin derivatives screened for bioactivity, and the inhibition was assessed and their effects ranked as: EGCg > GCg > Cg > others. In the mouse one-cell zygote assay, EGCg at 50 μM increased abnormal cells and 75 μM of EGCg-induced apoptosis. The observed ranking of catechin derivative inhibition effects against mouse one-cell zygote development in vivo was similar to their ranking by topo inhibition in vitro rather than by pol inhibition; therefore, topo inhibition might have been effecting zygote development inhibition. These results suggested that catechin derivatives indeed reached the nuclear DNA where topo inhibition can occur, thus causing the observed cellular effects. From these findings, this zygote development inhibition assay will be useful as an anti-pregnant agent screening.
Journal of Bioscience and Bioengineering 10/2012; 115(3). DOI:10.1016/j.jbiosc.2012.10.001 · 1.88 Impact Factor