Biomedical subjects

Yoshiyuki Mizushina

Publications and source records attributed to Yoshiyuki Mizushina.

At least 19 recordsLinked to original sources

PubMed2007

Structure-activity relationship of a glycolipid, sulfoquinovosyl diacylglycerol, with the DNA binding activity of p53.

The in vitro relationship between the human p53 DNA binding domain (p53 DBD) and glycolipids was investigated. We isolated the glycolipid fraction from spinach (Spinacia oleracea L.) and found that the fraction inhibited the double-stranded DNA (dsDNA) binding activity of p53 DBD. Since the fraction contained mainly three glycolipids, monogalactosyl diacylglycerol (MGDG), digalactosyl diacylglycerol (DGDG) and sulfoquinovosyl diacylglycerol (SQDG), and each glycolipid was purified using silica gel column chromatography. Purified SQDG inhibited the activity, however, purified MGDG and DGDG had no influence. In this study, we demonstrated the structure-function relationship between chemically synthetic SQDG and p53 DBD. The major action is probably dependent on the fatty acid effect, although SQDG was a much stronger inhibitor than the fatty acid alone present in SQDG. The inhibitory activity of SQDG was weakened by the R248A mutant of p53 DBD, suggesting that R248 in the dsDNA binding site of p53 must be important for the inhibitory activity of SQDG. SQDG binding to p53 DBD could be reversed with a non-ionic detergent, Nonidet P-40. This is the first study of a glycolipid, SQDG, acting as a dsDNA binding inhibitor of p53, and it could be considered that a SQDG-containing thylakoid membrane in plant chloroplasts might regulate the activity of p53 for cell division, cell cycle checkpoint and tumor suppression.

Computer Simulation↗

PubMed2006

Anti-tumor effects of dehydroaltenusin, a specific inhibitor of mammalian DNA polymerase alpha.

In the screening of selective inhibitors of eukaryotic DNA polymerases (pols), dehydroaltenusin was found to be an inhibitor of pol alpha from a fungus (Alternaria tennuis). We succeeded in chemically synthesizing dehydroaltenusin, and the compound inhibited only mammalian pol alpha with IC50 value of 0.5 microM, and did not influence the activities of other replicative pols such as pols delta and epsilon, but also showed no effect on pol alpha activity from another vertebrate, fish, or from a plant species. Dehydroaltenusin also had no influence on the other pols and DNA metabolic enzymes tested. The compound also inhibited the proliferation of human cancer cells with LD50 values of 38.0-44.4 microM. In an in vivo anti-tumor assay on nude mice bearing solid tumors of HeLa cells, dehydroaltenusin was shown to be a promising suppressor of solid tumors. Histopathological examination revealed that increased tumor necrosis and decreased mitotic index were apparently detected by the compound in vivo. Therefore, dehydroaltenusin could be of interest as not only a mammalian pol alpha-specific inhibitor, but also as a candidate drug for anti-cancer treatment.

Animals↗

PubMed2006

Site-directed mutational analysis of structural interactions of low molecule compounds binding to the N-terminal 8 kDa domain of DNA polymerase beta.

We previously reported the mode of inhibition of DNA polymerase beta (pol. beta) by long chain fatty acids and a bile acid, involving binding analyses to the N-terminal 8-kDa DNA binding domain. Here we describe a site-directed mutational analysis in which the key amino acids (L11, K35, H51, K60, L77, and T79), which are direct interaction sites in the domain, were substituted with K, A, A, A, K, and A, respectively. And their pol. beta interactions with a C24-long chain fatty acid, nervonic acid (NA), and a bile acid, lithocholic acid (LCA), were investigated by gel mobility shift assay and NMR spectroscopy. In the case of K35A, there was complete loss of DNA binding activity while K60A hardly has any activity. In contrast the other mutations had no appreciable effects. Thus, K35 and K60 are key amino acid sites for binding to template DNA. The DNA binding activities of L11K, H51A, and T79A as well as the wild type were inhibited by NA to the same extent. T79A demonstrated a disturbed interaction with LCA. 1H-15N HSQC NMR analysis indicated that despite their many similarities, the wild-type and the mutant proteins displayed some significant chemical shift differences. Not only were the substituted amino acid residues three-dimensionally shifted, but some amino acids which are positioned far distant from the key amino acids showed a shift. These results suggest that the interaction surface was significantly distorted with the result that LCA could not bind to the domain. These findings confirm our previous biochemical and 3D structural proposals concerning inhibition by NA and LCA.

Amino Acids↗

PubMed2006

Beta-sitosterol-3-O-beta-D-glucopyranoside: a eukaryotic DNA polymerase lambda inhibitor.

Beta-sitosterol-3-O-beta-D-glucopyranoside (compound 1), a steroidal glycoside isolated from onion (Allium cepa L.) selectively inhibited the activity of mammalian DNA polymerase lambda (pol lambda) in vitro. The compound did not influence the activities of replicative DNA polymerases such as alpha, delta and epsilon, but also showed no effect even on the activity of pol beta which is thought to have a very similar three-dimensional structure to the pol beta-like region of pol lambda. Since parts of compound 1 such as beta-sitosterol (compound 2) and D-glucose (compound 3) did not influence the activities of any enzymes tested, the converted structure of compounds 2 and 3 might be important for pol lambda inhibition. The inhibitory effect of compound 1 on both intact pol lambda (i.e. residues 1-575) and a truncated pol lambda lacking the N-terminal BRCA1 C-terminus (BRCT) domain (133-575, del-1 pol lambda) was dose-dependent, and 50% inhibition was observed at a concentration of 9.1 and 5.4 microM, respectively. The compound 1-induced inhibition of del-1 pol lambda activity was non-competitive with respect to both the DNA template-primer and the dNTP substrate. On the basis of these results, the pol lambda inhibitory mechanism of compound 1 is discussed.

Animals↗

PubMed2006

Inhibitory effect of monogalactosyldiacylglycerol, extracted from spinach using supercritical CO2, on mammalian DNA polymerase activity.

We investigated the effective extraction of monogalactosyldiacylglycerol (MGDG) from dried spinach (Spinacia oleracea) using supercritical fluid carbon dioxide (SC-CO(2)) with a modifier/entrainer. The yield of MGDG in the SC-CO(2) extract was not influenced by increasing temperature at a constant pressure, although the total extract yield was decreased. The total extract yield and MGDG yield in the extract from commercially purchased spinach (unknown subspecies), were greatly influenced by lower pressure. In a modifier (i.e., ethanol) concentration range of 2.5-20%, both the extract and MGDG yield increased as the ethanol concentration rose. The highest total extract yield (69.5 mg/g of spinach) and a good MGDG yield (16.3 mg/g of spinach) were obtained at 80 degrees C, 25 MPa, and 20% ethanol. The highest MGDG concentration (76.0% in the extract) was obtained at 80 degrees C, 25 MPa, and 2.5% ethanol, although the total extract yield under these conditions was low (5.2 mg/g of spinach). The optimal conditions for the extraction of MGDG were 80 degrees C, 20 MPa, and 10% ethanol. Of the 11 subspecies of spinach tested under these conditions, "Ujyou" had the highest concentration of MGDG. The total extract yield and MGDG concentration of Ujyou were 20.4 mg of the extract/g of spinach and 70.5%, respectively. The concentration of MGDG was higher in the SC-CO(2) extract than in the extract obtained using solvents such as methanol and n-hexane. The extract of Ujyou, which was the optimal subspecies for the extraction of MGDG, inhibited the activity of calf DNA polymerase alpha with IC(50) values of 145 microg/mL but was not effective against DNA polymerase beta.

Animals↗

PubMed2006

The inhibitory action of long-chain fatty acids on the DNA binding activity of p53.

The in vitro relationship between human p53 DNA binding domain (p53 DBD) and FA was investigated. We found that saturated and monounsaturated long-chain FA inhibited the double-stranded DNA (dsDNA) binding activity of p53 DBD. The strongest inhibitors of saturated and unsaturated FA were docosanoic acid (22:0) and cis-12-heneicosenoic acid (21:1n-9), respectively. n-Octadecane, trans-unsaturated FA, and FAME had no influence on the binding activity of p53 DBD, showing that the FA structures such as one or no double bond of cis configuration, hydrocarbon chain of length C20 to C22, and free carboxyl groups are important for the inhibition. The inhibitory effect of the R248A mutant of p53 DBD by saturated FA was as strong as that for wild-type p53 DBD. On the other hand, the inhibition of dsDNA binding activity of the same mutant by the cis-configuration of monounsaturated FA was weaker than that for the wild type. These results suggest that R248 in p53 DBD is important for binding to monounsaturated FA. This is the first report that long-chain FA act as a dsDNA binding inhibitor of p53, and it could be considered that FA in the cell membrane might regulate the activity of p53 for cell division, cell-cycle checkpoint, and tumor suppression.

Computer Simulation↗

PubMed2006

Catechin conjugated with fatty acid inhibits DNA polymerase and angiogenesis.

Catechins in green tea have anticancer and antiangiogenesis activities, with epigallocatechin-3-gallate (EGCG) being the most potent antiangiogenic tea catechin. This study examined whether chemical modification of catechin enhanced anticancer and antiangiogenic effects. Catechin, conjugated with fatty acid (acyl-catechin), strongly inhibited DNA polymerase, HL-60 cancer cell growth, and angiogenesis. Catechin conjugated with stearic acid [(2R,3S)-3',4',5,7-tetrahydroxyflavan-3-yl octadecanoate; catechin-C18] was the strongest inhibitor in DNA polymerase alpha and beta and angiogenesis assays. Catechin-C18 also suppressed human endothelial cell (HUVEC) tube formation on the reconstituted basement membrane, suggesting that it affected not only DNA polymerases but also signal transduction pathways in HUVECs. These data indicate that acyl-catechins target both DNA polymerases and angiogenesis as anticancer agents. These results suggest that acylation of catechin is an effective chemical modification to improve the anticancer activity of catechin.

Acylation↗

PubMed2006

Inhibitory effect of coenzyme Q on eukaryotic DNA polymerase gamma and DNA topoisomerase II activities on the growth of a human cancer cell line.

Coenzyme Q (CoQ) is an isoprenoid quinine that functions as an electron carrier in the mitochondrial respiratory chain in eukaryotes. CoQ having shorter isoprenoid chains, especially CoQ1 and CoQ2, selectively inhibited the in vitro activity of eukaryotic DNA polymerase (pol) gamma, which is a mitochondrial pol. These compounds did not influence the activities of nuclear DNA replicative pols such as alpha, delta and epsilon, and nuclear DNA repair-related pols such as beta, eta, iota, kappa and lambda. CoQ also inhibited DNA topoisomerase II (topo II) activity, although the enzymatic characteristics, including modes of action, amino acid sequences and three-dimensional structures, were markedly different from those of pol gamma. These compounds did not inhibit the activities of procaryotic pols such as Escherichia coli pol I, and other DNA metabolic enzymes such as human immunodeficiency virus reverse transcriptase, T7 RNA polymerase and bovine deoxyribonuclease I. CoQ1, which has the shortest isoprenoid chains, had the strongest inhibitory effect on pol gamma and topo II activities among CoQ1-CoQ10, with 50% inhibitory concentration (IC50) values of 12.2 and 15.5 microM, respectively. CoQ1 could prevent the growth of human promyelocytic leukemia cells, HL-60, and the 50% lethal dose (LD50) value was 14.0 microM. The cells were halted at S phase and G1 phase in the cell cycle, and suppressed mitochondrial proliferation. From these results, the relationship between the inhibition of pol gamma/topo II and cancer cell growth by CoQ is discussed.

Apoptosis↗

PubMed2006

Structural relationship of curcumin derivatives binding to the BRCT domain of human DNA polymerase lambda.

We previously reported that phenolic compounds, petasiphenol and curcumin (diferuloylmethane), were a selective inhibitor of DNA polymerase lambda (pol lambda) in vitro. The purpose of this study was to investigate the molecular structural relationship of curcumin and 13 chemically synthesized derivatives of curcumin. The inhibitory effect on pol lambda (full-length, i.e. intact pol lambda including the BRCA1 C- terminal [BRCT] domain) by some derivatives was stronger than that by curcumin, and monoacetylcurcumin (compound 13) was the strongest pol lambda inhibitor of all the compounds tested, achieving 50% inhibition at a concentration of 3.9 microm. The compound did not influence the activities of replicative pols such as alpha, delta, and epsilon. It had no effect on pol beta activity either, although the three-dimensional structure of pol beta is thought to be highly similar to that of pol lambda. Compound 13 did not inhibit the activity of the C-terminal catalytic domain of pol lambda including the pol beta-like core, in which the BRCT motif was deleted from its N-terminal region. MALDI-TOF MS analysis demonstrated that compound 13 bound selectively to the N-terminal domain of pol lambda, but did not bind to the C-terminal region. Based on these results, the pol lambda-inhibitory mechanism of compound 13 is discussed.

Amino Acid Motifs↗

PubMed2006

Inhibitory action of C22-fatty acids on DNA polymerases and DNA topoisomerases.

We reported previously that unsaturated linear-chain fatty acids of the cis-configuration with a C18-hydrocarbon chain such as linoleic acid (cis-9, 12-octadecadienoic acid, C18:2) could potently inhibit the activity of mammalian DNA polymerases (Biochim Biophys Acta 1308: 256-262, 1996). In this study, we investigated the inhibitory effects of cis-type C22-fatty acids including cis-7,10,13,16,19-docosapentaenoic acid (DPA, C22:5) and cis-4,7,10,13,16,19-docosahexaenoic acid (DHA, C22:6) on mammalian DNA polymerases and human DNA topoisomerases. Cis-13,16-docosadienoic acid (C22:2) was the strongest inhibitor of both DNA polymerases and topoisomerases of all C22-fatty acids tested. The inhibitory tendency by the fatty acids on DNA polymerases was the same as that of DNA topoisomerases, and the second strongest inhibitor was cis-13,16,19-docosatrienoic acid (C22:3). The energy-minimized three-dimensional structures of the fatty acids were calculated and it was found that a length of 19-21 Angstrom and width of more than 7 Angstrom in C22-fatty acid structure were important for enzyme inhibition. The three-dimensional structure of the active site of both DNA polymerases and topoisomerases must have a pocket to join C22:2, and this pocket was 19.41 Angstrom long and 9.58 Angstrom wide.

Animals↗

PubMed2005

5-(Hydroxymethyl)-2-furfural: a selective inhibitor of DNA polymerase lambda and terminal deoxynucleotidyltransferase.

5-(Hydroxymethyl)-2-furfural (HMF), a pyrolysate of carbohydrate isolated from instant coffee (Coffea arabica L.), selectively inhibits the activities of mammalian DNA polymerase lambda (pol lambda) and terminal deoxynucleotidyltransferase (TdT) which are family X pols, in vitro. The compound influenced neither the activities of replicative DNA polymerases such as alpha, delta, and epsilon, nor even the activity of pol beta which is from the same family and thought to have a very similar three-dimensional structure to the pol beta-like region of pol lambda. Since parts of HMF such as furan, furfuryl alcohol, and 2-furaldehyde did not influence the activities of any enzymes tested, the substituted form of furan with a hyroxymethyl group and a formyl group might be important for the inhibition of pol lambda and TdT. The inhibitory effect of HMF on intact pol lambda (i.e., residues 1-575), a truncated pol lambda lacking the N-terminal BRCA1 C-terminus domain (133-575, del-1 pol lambda) and another truncated pol lambda lacking the N-terminal proline-rich region (245-575, del-2 pol lambda) was dose-dependent, and 50% inhibition was observed at a concentration of 26.1, 10.3, and 4.6 microM, respectively. The IC(50) value of HMF for TdT was the same as that for del-2 pol lambda (5.5 microM). The HMF-induced inhibition of both pol lambda and TdT activities was competitive with respect to both the DNA template-primer and the dNTP substrate. On the basis of these results, HMF was suggested to bind to the pol beta-like region of pol lambda and TdT.

Animals↗

PubMed2005

Inhibitory effect of tocotrienol on eukaryotic DNA polymerase lambda and angiogenesis.

Tocotrienols, vitamin E compounds that have an unsaturated side chain with three double bonds, selectively inhibited the activity of mammalian DNA polymerase lambda (pol lambda) in vitro. These compounds did not influence the activities of replicative pols such as alpha, delta, and epsilon, or even the activity of pol beta which is thought to have a very similar three-dimensional structure to the pol beta-like region of pol lambda. Since delta-tocotrienol had the strongest inhibitory effect among the four (alpha- to delta-) tocotrienols, the isomer's structure might be an important factor in the inhibition of pol lambda. The inhibitory effect of delta-tocotrienol on both intact pol lambda (residues 1-575) and a truncated pol lambda lacking the N-terminal BRCA1 C-terminus (BRCT) domain (residues 133-575, del-1 pol lambda) was dose-dependent, with 50% inhibition observed at a concentration of 18.4 and 90.1microM, respectively. However, del-2 pol lambda (residues 245-575) containing the C-terminal pol beta-like region was unaffected. Tocotrienols also inhibited the proliferation of and formation of tubes by bovine aortic endothelial cells, with delta-tocotrienol having the greatest effect. These results indicated that tocotrienols targeted both pol lambda and angiogenesis as anti-cancer agents. The relationship between the inhibition of pol lambda and anti-angiogenesis by delta-tocotrienol was discussed.

Animals↗

PubMed2005

Apoptosis-inducing effect of epolactaene derivatives on BALL-1 cells.

Epolactaene, a neuritogenic compound in human neuroblastoma SH-SY5Y, induces apoptosis in a human leukemia B-cell line, BALL-1. The apoptosis-inducing activities of 34 epolactaene derivatives, including those of the newly synthesized alpha-alkyl-alpha,beta-epoxy-gamma-lactam derivative and cyclopropane derivatives, were also tested. The structure-activity relationships of the epolactaene derivatives as an inducer of apoptosis are described. The alpha-acyl-alpha,beta-epoxy-gamma-lactam moiety as well as the hydrophobicity derived from the long alkyl side chain are both important for activity. Compound 1e displayed the strongest activity among all the synthesized compounds with an IC50 value of 0.70 microM.

Apoptosis↗

PubMed2005

Monoacetylcurcumin: a new inhibitor of eukaryotic DNA polymerase lambda and a new ligand for inhibitor-affinity chromatography.

We previously reported that a phenolic compound, curcumin (diferuloylmethane), was a selective inhibitor of DNA polymerase lambda (pol lambda) in vitro [Y. Mizushina, M. Hirota, C. Murakami, T. Ishidoh, S. Kamisuki, N. Shimazaki, M. Takemura, M. Perpelescu, M. Suzuki, H. Yoshida, F. Sugawara, O. Koiwai, K. Sakaguchi, Some anti-chronic inflammatory compounds are DNA polymerase lambda-specific inhibitors, Biochem. Pharmacol. 66 (2003) 1935-1944.]. We also found that monoacetylcurcumin ([1E,4Z,6E]-7-(4''-acetoxy-3''-methoxyphenyl)-5-hydroxy-1-(4'-hydroxy-3'-methoxyphenyl)hepta-1,4,6-trien-3-on), a chemically synthesized derivative of curcumin, was a stronger pol lambda inhibitor than curcumin, achieving 50% inhibition at a concentration of 3.9microM. Monoacetylcurcumin did not influence the activities of replicative pols such as alpha, delta, and epsilon, and showed no effect even on the activity of pol beta, the three-dimensional structure of which is thought to be highly similar to that of pol lambda. The compound-induced inhibition of pol lambda activity was non-competitive with respect to both the DNA template-primer and the dNTP substrate. Monoacetylcurcumin did not inhibit the activity of the C-terminal catalytic domain of pol lambda including the pol beta-like core, in which the BRCT motif was deleted. The compound did not influence the activities of prokaryotic pols or other mammalian DNA metabolizing enzymes such as calf primase of pol alpha, calf terminal deoxynucleotidyl transferase, human telomerase, human immunodeficiency virus type-1 reverse transcriptase, T7 RNA polymerase, T4 polynucleotide kinase, and bovine deoxyribonuclease I. Therefore, we concluded that monoacetylcurcumin is a selective inhibitor of pol lambda and could be used as a chromatographic ligand to purify pol lambda. We then made a monoacetylcurcumin-conjugated column with epoxy-activated Sepharose 6B. In the column, pol lambda of full length was selectively adsorbed and eluted.

Animals↗

PubMed2005

Structural analysis of isosteviol and related compounds as DNA polymerase and DNA topoisomerase inhibitors.

Isosteviol (ent-16-ketobeyeran-19-oic acid) is a hydrolysis product of stevioside, which is a natural sweetener produced in the leaves of Stevia rebaudiana (Bertoni) Bertoni. In this report, we prepared isosteviol and related compounds from stevioside by microbial transformation and chemical conversion and assayed the inhibitory activities toward DNA metabolic enzymes and human cancer cell growth. Among twelve compounds obtained, only isosteviol (compound 3) potently inhibited both mammalian DNA polymerases (pols) and human DNA topoisomerase II (topo II), and IC50 value for pol alpha was 64.0 microM. This compound had no inhibitory effect on higher plant (cauliflower) pols, prokaryotic pols, human topo I, and DNA metabolic enzymes such as human telomerase, T7 RNA polymerase, and bovine deoxyribonuclease I. With pol alpha, isosteviol acted non-competitively with the DNA template-primer and nucleotide substrate. Isosteviol prevented the growth of human cancer cells, with LD50 values of 84-167 microM, and 500 microg of the compound caused a marked reduction in TPA (12-O-tetradecanoylphorbol-13-acetate)-induced inflammation (inhibitory effect, 53.0%). The relationship between the structure of stevioside-based compounds and these activities were discussed.

Animals↗

PubMed2005

Inhibitory effect of conjugated eicosapentaenoic acid on mammalian DNA polymerase and topoisomerase activities and human cancer cell proliferation.

Conjugated eicosapentaenoic acid (cEPA) selectively inhibited the activities of mammalian DNA polymerases (pols) and human DNA topoisomerases (topos) [Yonezawa Y, Tsuzuki T, Eitsuka T, Miyazawa T, Hada T, Uryu K, et al. Inhibitory effect of conjugated eicosapentaenoic acid on human DNA topoisomerases I and II. Arch Biochem Biophys 2005;435:197-206]. In this report, we investigated the inhibitory effect of cEPA on a human promyelocytic leukemia cell line, HL-60, to determine which enzymes influence cell proliferation. cEPA inhibited the proliferation of HL-60 cells (LD(50)=20.0 microM), and the inhibitory effect was stronger than that of non-conjugated EPA. cEPA arrested the cells at G1/S-phase, increased cyclin A and E protein levels, and prevented the incorporation of thymidine into the cells, indicating that it blocks the primary step of in vivo DNA replication by inhibiting the activity of replicative pols rather than topos. This compound also induced apoptosis of the cells. These results suggested the therapeutic potential of cEPA as a leading anti-cancer compound that poisons pols.

Antineoplastic Agents↗

PubMed2005

Structural analysis of catechin derivatives as mammalian DNA polymerase inhibitors.

The inhibitory activities against DNA polymerases (pols) of catechin derivatives (i.e., flavan-3-ols) such as (+)-catechin, (-)-epicatechin, (-)-gallocatechin, (-)-epigallocatechin, (+)-catechin gallate, (-)-epicatechin gallate, (-)-gallocatechin gallate, and (-)-epigallocatechin gallate (EGCg) were investigated. Among the eight catechins, some catechins inhibited mammalian pols, with EGCg being the strongest inhibitor of pol alpha and lambda with IC(50) values of 5.1 and 3.8 microM, respectively. EGCg did not influence the activities of plant (cauliflower) pol alpha and beta or prokaryotic pols, and further had no effect on the activities of DNA metabolic enzymes such as calf terminal deoxynucleotidyl transferase, T7 RNA polymerase, and bovine deoxyribonuclease I. EGCg-induced inhibition of pol alpha and lambda was competitive with respect to the DNA template-primer and non-competitive with respect to the dNTP (2'-deoxyribonucleotide 5'-triphosphate) substrate. Tea catechins also suppressed TPA (12-O-tetradecanoylphorbol-13-acetate)-induced inflammation, and the tendency of the pol inhibitory activity was the same as that of anti-inflammation. EGCg at 250 microg was the strongest suppressor of inflammation (65.6% inhibition) among the compounds tested. The relationship between the structure of tea catechins and the inhibition of mammalian pols and inflammation was discussed.

Animals↗

PubMed2005

Systematic synthesis of galloyl-substituted procyanidin B1 and B2, and their ability of DPPH radical scavenging activity and inhibitory activity of DNA polymerases.

Six galloyl-substituted procyanidin B1 and B2, 3-O-gallate, 3''-O-gallate, and 3,3''-di-O-gallate, were systematically synthesized with the condensation method using TMSOTf as a catalyst. Their ability of DPPH radical scavenging activity and DNA polymerase inhibitory activity were also investigated. The results indicated that the galloyl group of these compounds is very important for both activities. 3,3''-Di-O-gallate dimers acted as strong inhibitor against DNA polymerase alpha and beta, whereas the desgalloyl and monogalloyl compounds did not exhibit any appreciable inhibitory activity against the DNA polymerase beta.

Animals↗