Open Access

Isolation and characterization of antimutagenic components of Glycyrrhiza aspera against N-methyl-N-nitrosourea

  • Keiko Inami1Email author,
  • Yusuke Mine1,
  • Jin Tatsuzaki2,
  • Chihiro Mori2 and
  • Masataka Mochizuki1
Genes and Environment201739:5

https://doi.org/10.1186/s41021-016-0068-2

Received: 12 May 2016

Accepted: 8 December 2016

Published: 6 January 2017

Abstract

Background

A powdered ethanolic extract of Glycyrrhiza aspera root exhibits antimutagenic activity against N-methyl-N-nitrosourea (MNU) based on the Ames assay with Salmonella typhimurium TA1535. The aim of this study was to identify the antimutagenic components of the powdered ethanolic extract of G. aspera root.

Results

The powdered ethanolic extract of G. aspera root was sequentially suspended in n-hexane, carbon tetrachloride, dichloromethane, ethyl acetate, and ethanol, and each solvent soluble fraction and the residue were assayed for antimutagenic activity against MNU in S. typhimurium TA1535. The dichloromethane soluble fraction exhibited the highest antimutagenicity and was fractionated several times by silica gel chromatography. The fraction with the highest antimutagenic activity was further purified using HPLC, and the fractions were assayed for antimutagenicity against MNU in S. typhimurium TA1535. Finally, five components with antimutagenic activity against MNU were identified as glyurallin A, glyasperin B, licoricidin, 1-methoxyphaseollin, and licoisoflavone B.

Conclusions

The five components were demonstrated to possess an antigenotoxic effect against carcinogenic MNU for the first time. It is important to prevent DNA damage by N-nitrosamines for cancer chemoprevention.

Keywords

Glyurallin AGlyasperin BLicoricidin1-MethoxyphaseollinLicoisoflavone B

Background

Humans are exposed to endogenous and exogenous N-nitroso compounds [1]. Approximately 45–75% of the total human exposure to N-nitroso compounds is estimated to be due to in vivo synthesis [2]. Almost all tested N-nitroso compounds have carcinogenic activity in experimental animals [1]. Therefore, exposure to N-nitroso compounds is suspected to induce human cancer. Several epidemiological studies have demonstrated that the endogenous formation of N-nitroso compounds is correlated with the cancer incidence in humans [39]. Recently, the International Agency for Research on Cancer (IARC) has reported that the consumption of red meat and processed meat is carcinogenic, and this may be caused by N-nitroso compounds that form during meat processing or cooking [10].

N-Methyl-N-nitrosourea (MNU) is a DNA alkylating carcinogen that induces cancer in various organs, particularly the forestomach, brain and nervous system, in rodents [11]. MNU is produced by the nitrosation of creatinine or fermented foods at the gastric pH [1215]. Additionally, MNU is formed by the nitrosation of methylurea with nitrite in guinea pig stomachs [16]. Therefore, for cancer chemoprevention, it is important to identify compounds that can inhibit mutagenicity induced by MNU.

Short-term bacterial mutation assays, such as the Ames assay, are an effective screening tool for the identification of various mutagenic or antimutagenic compounds in complex materials [17]. The assay has advantages as an inexpensive and flexible screening method that provides preliminary information related to antimutagenesis. There are many reports about the antimutagenicity of edible plants; however, the inhibitory effects against MNU mutagenesis are less well studied [18, 19].

Glycyrrhiza root has long been used worldwide as an herbal medicine and natural sweetener [2022]. The genus Glycyrrhiza (Leguminosae) consists of about 30 species including G. glabra, G. uralensis, G. inflata, G. aspera, G. korshinskyi and G. eurycarpa [23]. In Japanese pharmacopeia, only G. glabra and G. uralensis are permitted to be used as licorice and licorice powder, and the other Glycyrrhiza species can be used as raw materials of licorice extract [23]. Glycyrrhiza has a reported chemopreventive effect based on its anticarcinogenesis and antimutagenesis toward both indirect-acting and direct-acting mutagens [2429]; however, the inhibitory effects against MNU mutagenesis have not been studied in detail.

In our previous study, a powdered ethanolic extract of G. aspera root decreased MNU-induced mutagenicity in a preliminary antimutagenic screen using the Ames assay [30]. The aim of this study was to identify the antimutagenic components of the powdered ethanolic extract of G. aspera root.

Methods

General experimental procedures

The reaction progress was monitored using thin-layer chromatography (TLC) on silica gel 60 F254 (0.25 mm, Merck, Darmstadt, Germany). Column chromatography was performed using silica gel 60 (0.04–0.063 mm, Merck). Melting points were determined using a Yanaco (Tokyo, Japan) micro-melting-point apparatus without correction. HPLC was performed using an EYELA Preparative LC system [VSP-3050 pump, UV-9000 spectrometric detector, LiChrosorb RP-18 column (10 μm, 25 mm × 300 mm)] (Tokyo Rikakikai Co. Ltd., Tokyo, Japan) and a Shimadzu LC system [LC-6 AD pump, SPD-20A UV spectrometric detector, Mightysil RP-18 column (5 μm, 20 mm × 250 mm)] (Kyoto, Japan). The NMR spectra were recorded with a JEOL JNM-LA400 spectrometer (Tokyo, Japan). The chemical shifts were expressed in ppm, downfield from TMS. The mass spectra were collected using a JEOL JMS-SX102A mass spectrometer (Tokyo, Japan).

Reagents

Sodium ammonium hydrogen phosphate tetrahydrate was purchased from Merck (Darmstadt, Germany). Bacto agar and Bacto nutrient broth were obtained from Becton Dickinson Microbiology Systems (Sparks, USA). MNU were obtained from Toshin Gousei (Tokyo, Japan). Other reagents were purchased from Wako Pure Chemical Industries (Osaka, Japan). A powdered ethanolic extract of G. aspera (China) root was kindly provided by Tokiwa Phytochemical Co. Ltd. (Chiba, Japan).

Preparation of a powdered ethanolic extracts of Glycyrrhiza aspera root

A root of G. aspera (100 g) was refluxed with 95% ethanolic aqueous solution (1000 mL) for 1 h, and the mixture was filtered with suction. The residue was refluxed again with 95% ethanolic aqueous solution (1000 mL) for 1 h, and the mixture was filtered with suction. The combined filtrates were concentrated under reduced pressure and vacuum dried to a constant weight, and finally a brown powder was obtained.

Fractionation of the powdered ethanolic extract of Glycyrrhiza aspera root based on solubility in organic solvents

The powered ethanolic extract of G. aspera root (10 g) was added to hexane (100 mL) and stirred for 10 min. The supernatant was filtered with suction. The stirring and filtration of the residue was repeated twice. Sequentially, the residue was suspended in carbon tetrachloride (100 mL × 3), dichloromethane (100 mL × 3), ethyl acetate (100 mL × 3), and ethanol (100 mL × 3) following the same procedure. The organic solvent portions were removed organic solvent by rotary evaporator and the residue was dried in vacuo. The whole extraction procedure was repeated twice; the organic portions and residue were combined. Finally, hexane soluble fraction (62 mg), carbon tetrachloride soluble fraction (880 mg), dichloromethane soluble fraction (15.6 g), ethyl acetate soluble fraction (11.4 g), ethanol soluble fraction (700 mg) and the residue (1.7 g) were obtained from the powdered ethanolic extract of G. aspera root (30 g). Recovery of the weight was 101%.

Isolation of antimutagenic compounds from the dichloromethane soluble fraction

The dichloromethane soluble fraction was chromatographed on a silica gel, eluted with 5% methanol-CH2Cl2, 3% methanol-CH2Cl2, 1% methanol-CH2Cl2, 10% ethyl acetate-CH2Cl2, and later separated on an RP-18 column by preparative HPLC and eluted with 80% methanol in water (see the Additional file 1). Five peaks representing active components were purified using HPLC and characterized by comparing their spectroscopic (NMR and MS) properties with literature values.

Bacterial mutation assay

The antimutagenic effect of each plant extract was assayed according to the Ames method using the plate-incorporation protocol [31, 32]. Dr. T. Nohmi (National Institute of Health Sciences, Tokyo, Japan) kindly provided the S. typhimurium TA1535.

A solution of MNU (1.5 μmol/50 μL DMSO) was added to a test tube and supplemented with 0.1 M sodium phosphate buffer (pH 7.4, 0.5 mL), a solution (50 μL) with various concentrations of fraction, and a culture of the S. typhimurium TA1535 (0.1 mL), and the solution was thoroughly mixed. Then, Top Agar (2 mL) was added, and the mixture was poured onto a minimal-glucose agar plate. The revertant colonies were counted after incubation at 37 °C for 44 h. Each sample was assayed using duplicate plates. The results are expressed as the mean number of revertant colonies per plate. Plates with neither MNU nor plant extract were considered negative controls. MNU (1.5 μmol/50 μL) resulted in 1470 ± 70 colonies. All of the tested plates were microscopically examined for thinning or the absence of a background lawn and/or presence of microcolonies, which are considered indicators of toxicity induced by the test material. Neither MNU nor plant extracts displayed toxicity to S. typhimurium TA1535 under the conditions of the antimutagenicity test.

Mutagenic activity in the presence of extracts is expressed as the percentage of mutagenicity (% = Rs/R × 100), where Rs is the number of his+ revertants/plate for plates exposed to MNU and plants extracts, and R is the number of his+ revertants/plate of MNU. The number of spontaneous revertants was subtracted beforehand to give Rs and R. Thus, the mutagenicity of MNU in the absence of plant extracts was defined as 100% MNU mutagenicity.

Cytotoxicity test

Toxicity assays under the same conditions as those used for the Ames test were performed to determine the maximum concentrations of plant extracts that could be added without exerting toxic effects on the bacteria used in the Ames test. A solution of MNU (1.5 μmol/50 μL DMSO) was added to a test tube, and supplemented with 0.1 M sodium phosphate buffer (pH 7.4, 0.5 mL), each solution of plant extract (50 μL), and a culture of S. typhimurium TA1535 (0.1 mL). A portion of the mixture was diluted 105 times in 1/15 M PB. The diluted solution (200 μL) was supplemented with histidine-free Top Agar (2 mL) and poured on a Nutrient Broth agar plate. The colonies were counted after incubation at 37 °C for 20 h. Each sample was assayed using duplicate plates. A substance was considered cytotoxic when the bacterial survival was less than 80% of that observed in the negative control. The mutation frequency was estimated as the number of mutants per 107 surviving bacterial cells [31, 32].

Results and discussion

Identification of antimutagenic components from a powdered ethanolic extract of Glycyrrhiza aspera root

A powdered ethanolic extract of G. aspera root was sequentially suspended in n-hexane, carbon tetrachloride, dichloromethane, ethyl acetate, and ethanol. Each soluble fraction and the residue were assayed for inhibitory effects against MNU mutagenesis in Salmonella typhimurium TA1535 (Fig. 1).
Fig. 1

Effect of each soluble fraction on MNU-induced mutagenicity in S. typhimurium TA1535

The dichloromethane soluble fraction showed the highest antimutagenic activity, and was fractionated using a silica gel column and preparative high-performance liquid chromatography (HPLC), and its antimutagenic components were identified. The fractionation and mutagenicity assay were conducted repeatedly (Fig. 2 and the Additional file 1). In each fractionation step, the recoveries of weights were more than 89%.
Fig. 2

Diagram of the separation procedure for the dichloromethane soluble fraction

Finally, the fraction (Fr.3-2-2-3-2) with the highest antimutagenic activity was separated into fractions 1–9 using HPLC (Fig. 3a). Those fractions were tested for mutagenicity against MNU, and the compounds from peaks 4–8 each inhibited MNU-induced mutagenicity (Fig. 3b)
Fig. 3

a HPLC diagram of Fr. 3-2-2-3-2; b Effect of each fraction from Fr.3-2-2-3-2 on MNU-induced mutagenicity in S. typhimurium TA1535

The compounds from fractions 4–8 were each analysed using mass spectrometry and 1H nuclear magnetic resonance spectroscopy, and five antimutagenic compounds were identified, i.e., glyurallin A [33], glyasperin B [34], licoricidin [35, 36], 1-methoxyphaseollin [37], and licoisoflavone B [38], by comparing their spectroscopic properties with literature values (Fig. 4).
Fig. 4

Structures of antimutagenic agents from the powdered ethanolic extract of Glycyrrhiza aspera root

Glyurallin A was a pterocarpene and 1-methoxyphaseollin was a pterocarpan. Glyasperin B, licoricidin, and licoisoflavone B were an isoflavanone, an isoflavan, and an isoflavone, respectively. A phenolic hydroxyl group is a common in five isolated compounds with antimutagenicity.

Flavonoids are well-known antimutagens based on the results of Ames assays [39, 40], whereas pterocarpenes and pterocarpans are not well-known for their antimutagenicity.

Inhibitory effect of licoricidin from the powdered ethanolic extract of Glycyrrhiza aspera root on MNU-induced mutagenicity

Licoricidin (peak 6) did not show any revertant colonies by cytotoxicity (Fig. 3b). For the antimutagenicity assay, it was necessary to determine the concentration at which the viability of the tester strain did not decrease. Licoricidin reduced revertant colonies induced by MNU in S. typhimurium TA1535 (Fig. 5a) without cytotoxicity at the maximum concentration of
Fig. 5

Mutagenicity (a), survival rate (b), and mutation frequency (c) of licoricidin on MNU-induced mutagenicity in S. typhimurium TA1535

100 μg/plate (Fig. 5b). To assess the precise antimutagenic potency of licoricidin, mutation frequency was calculated by dividing the number of mutants with the surviving fraction of bacteria (Fig. 5c). These data clearly showed that licoricidin possessed antimutagenic activity against MNU in S. typhimurium TA1535.

The antimutagenic activity of the G. glabra extract against ethyl methanesulfonate (EMS) is reportedly attributed to glabrene [41]. In our study, glabrene was not isolated from the fraction with the highest mutagenic activity. The difference between the isolated compounds in antimutagenic activity for the powdered ethanolic extract of G. aspera root probably reflects differences in the mechanism of action between MNU and EMS. MNU reacts mainly via an SN1 mechanism and efficiently alkylated both nitrogens and oxygens in DNA. EMS, which reacts predominantly via an SN2 mechanism, alkylates the nitrogens at the DNA bases and produced little alkylation of the oxygens in DNA bases [42, 43]. Thus, the MNU is far more mutagenic than EMS. Additionally, the main bioactive components were different between G. glabra and G. aspera [23].

In vitro, N-nitrosamine formation is inhibited by phenolic compounds, ascorbic acid, thiols, and metals [18, 19]. Mutagenesis by direct-acting mutagens can be reduced or prevented in several ways; MNU can be decomposed to non-mutagenic products via antimutagens, or reactive mutagenic products from MNU can react with antimutagens before reaching DNA. It is also possible to induce repair enzymes in the Salmonella strain [44].

A number of known flavonoids (such as genistein etc) possess significant antimutagenic activity [40, 45, 46]; however, the detailed mechanism for the antimutagenicity has not been completely established. The inhibitory effect on the mutagenicity of direct-acting mutagens is probably caused by a chemical reaction between the mutagen and antimutagen. The inhibitory effect of phenolic acid results from the scavenging action on an electrophilic decomposition product of MNU [47]. Hung et al have reported that hydroxylated flavonoids showed antimutagenic activity toward benzo[a]pyrene 7,8-diol-9,10-epoxide by direct interaction with the 7,8-diol-9,10-epoxide [48]. Therefore, we assumed that the antimutagenic mechanisms of the isolated compounds were similar to that of phenolic acid or hydroxylated flavonoids. Furthermore, MNU treatments are reported to induce not only DNA alkylation but also increase intracellular ROS level [4951], and then the antimutagenicity was partly attributed to its radical scavenging potency of flavonoids [5254]. We are working to elucidate the antimutagenic mechanisms for the isolated compounds against MNU.

Antimutagens and anticarcinogens in the diet are suggested to be highly effective for cancer prevention [44, 55, 56]. The intake of medicinal and edible plants that include antimutagens may play a role in improving human health.

Conclusions

It is important to prevent DNA damage by N-nitrosamines for cancer chemoprevention. In this study, five components with antimutagenic activity against MNU from a powdered ethanolic extract of G. aspera root were identified as glyurallin A, glyasperin B, licoricidin, 1-methoxyphaseollin, and licoisoflavone B. To the best of our knowledge, this report describes the first demonstration of the antigenotoxic effects of these components against carcinogenic MNU.

Abbreviation

MNU: 

N-Methyl-N-nitrosourea

Declarations

Acknowledgements

This work was supported in part by a Grant-in-Aid from the Ministry of Education, Culture, Sports, Science and Technology of Japan and by a Grant-in-Aid for the Science Research Promotion Fund from the Japan Private School Promotion Foundation.

Authors’ contributions

KI coordinated the study, the data analysis, the statistical analysis, and the writing the manuscript. YM, JT and CM performed the experiment and the data analysis. MM conceived of the study, participated in designing the study, and helped to draft the manuscript. All authors read and approved the final manuscript.

Competing interests

The authors declare that they have no competing interests.

Ethics approval and consent to participate

Not applicable.

Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

Authors’ Affiliations

(1)
Faculty of Pharmaceutical Sciences, Tokyo University of Science
(2)
Tokiwa Phytochemical Co. Ltd

References

  1. Lijinsky W. Chemistry and biology of N-nitroso compounds. Cambridge Monographs on Cancer Research. Cambridge: Cambridge University Press; 1992.Google Scholar
  2. Tricker AR. N-Nitroso compounds and man: sources of exposure, endogenous formation and occurrence in body fluids. Eur J Cancer Prev. 1997;6:226–68.View ArticlePubMedGoogle Scholar
  3. Keszei AP, Goldbohm RA, Schouten LJ, Jakszyn P, van den Brandt PA. Dietary N-nitroso compounds, endogenous nitrosation, and the risk of esophageal and gastric cancer subtypes in the Netherlands cohort study. Am J Clin Nutr. 2013;97:135–46.Google Scholar
  4. Catsburg CE, Gago-Dominguez M, Yuan JM, Castelao JE, Cortessis VK, Pike MC, Stern MC. Dietary sources of N-nitroso compounds and bladder cancer risk: findings from the Los Angeles bladder cancer study. Int J Cancer. 2014;134:125–35.View ArticlePubMedGoogle Scholar
  5. DellaValle CT, Daniel CR, Aschebrook-Kilfoy B, Hollenbeck AR, Cross AJ, Sinha R, Ward MH. Dietary intake of nitrate and nitrite and risk of renal cell carcinoma in the NIH-AARP diet and health study. Br J Cancer. 2013;108:205–12.Google Scholar
  6. Loh YH, Jakszyn P, Luben RN, Mulligan AA, Mitrou PN, Khaw KT. N-Nitroso compounds and cancer incidence: the European prospective investigation into cancer and nutrition (EPIC)-Norfolk study. Am J Clin Nutr. 2011;93:1053–61.View ArticlePubMedGoogle Scholar
  7. Kamangar F, Chow WH, Abnet CC, Dawsey SM. Environmental causes of esophageal cancer. Gastroenterol Clin North Am. 2009;38:27–57.View ArticlePubMedPubMed CentralGoogle Scholar
  8. Santarelli RL, Pierre F, Corpet DE. Processed meat and colorectal cancer: a review of epidemiologic and experimental evidence. Nutr Cancer. 2008;60:131–44.View ArticlePubMedPubMed CentralGoogle Scholar
  9. Jakszyn P, Gonzalez CA. Nitrosamine and related food intake and gastric and oesophageal cancer risk: a systematic review of the epidemiological evidence. World J Gastroenterol. 2006;12:4296–303.View ArticlePubMedPubMed CentralGoogle Scholar
  10. International agency for research on cancer (IARC). Evaluate consumption of red meat and processed meat. 2015. https://www.iarc.fr/en/media-centre/pr/2015/pdfs/pr240_E.pdf. Accessed 16 Dec 2016.
  11. Preussmann R, Eisenbrand G. N-Nitroso carcinogens in the environment. In: Searle CE, editor. Chemical carcinogens, ACS Monograph No. 182. Washington DC: American Chemical Society; 1984. p. 829–68.Google Scholar
  12. Sen NP, Seaman SW, Burgess C, Baddoo PA, Weber D. Investigation on the possible formation of N-nitroso-N-methylurea by nitrosation of creatinine in model systems and in cured meats at gastric pH. J Agric Food Chem. 2000;48:5088–96.View ArticlePubMedGoogle Scholar
  13. Sen NP, Seaman SW, Baddoo PA, Burgess C, Weber D. Formation of N-nitroso-N-methylurea in various samples of smoked/dried fish, fish sauce, seafoods, and ethnic fermented/pickled vegetables following incubation with nitrite under acidic conditions. J Agric Food Chem. 2001;49:2096–103.View ArticlePubMedGoogle Scholar
  14. Deng D, Li T, Ma H, Wang R, Gu L, Zhou J. Characterization of N-(nitrosomethyl)urea in nitrosated fermented fish products. J Agric Food Chem. 1998;46:202–5.View ArticlePubMedGoogle Scholar
  15. Haorah J, Zhou L, Wang X, Xu G, Mirvish SS. Determination of total N-nitroso compounds and their precursors in frankfurters, fresh meat, dried salted fish, sauces, tobacco, and tobacco smoke particulates. J Agric Food Chem. 2001;49:6068–78.View ArticlePubMedGoogle Scholar
  16. Engemann A, Focke C, Humpf HU. Intestinal formation of N-nitroso compounds in the pig cecum model. J Agric Food Chem. 2013;61:998–1005.View ArticlePubMedGoogle Scholar
  17. Nersesyan A, Mišík M, Knasmüller S. Methods used for detection of antimutagens: an overview. In: Knasmüller S, DeMarini DM, Johnson I, Gerhäuser C, editors. Chemoprevention of cancer and DNA damage by dietary factors. Weinhim: Wiley-VCH; 2009. p. 211–27.Google Scholar
  18. Gichner T, Velemínský J. Inhibitors of N-nitroso compounds-induced mutagenicity. Mutat Res. 1988;195:21–43.View ArticlePubMedGoogle Scholar
  19. Gichner T, Veleminsky J. Mechanisms of inhibition of N-nitroso compounds-induced mutagenicity. Mutat Res. 1988;202:325–34.View ArticlePubMedGoogle Scholar
  20. Asl MN, Hosseinzadeh H. Review of pharmacological effects of Glycyrrhiza sp. and its bioactive compounds. Phytother Res. 2008;22:709–24.View ArticlePubMedGoogle Scholar
  21. Shibata S. A drug over the millennia: pharmacognosy, chemistry, and pharmacology of licorice. Yakugaku Zasshi. 2000;120:849–62.PubMedGoogle Scholar
  22. Kao TC, Wu CH, Yen GC. Bioactivity and potential health benefits of licorice. J Agric Food Chem. 2014;62:542–53.View ArticlePubMedGoogle Scholar
  23. Nomura T, Fukai T, Akiyama T. Chemistry of phenolic compounds of licorice (Glycyrrhiza species) and their estrogenic and cytotoxic activities. Pure Appl Chem. 2002;7:1199–206.Google Scholar
  24. Wang ZY, Nixon DW. Licorice and cancer. Nutr Cancer. 2001;39:1–11.View ArticlePubMedGoogle Scholar
  25. Nishino H, Tokuda H, Satomi Y, Masuda M, Onozuka M, Yamaguchi S, Takayasu J, Tsuruta J, Takemura M, Ii T, Ichiishi E, Kuchide S, Okuda M, Murakoshi M. Cancer chemoprevention by phytochemicals and their related compounds. Asian Pac J Cancer Prev. 2000;1:49–55.PubMedGoogle Scholar
  26. Wall ME. Antimutgenic agents from natural products. J Nat Prod. 1992;55:1561–8.View ArticlePubMedGoogle Scholar
  27. Ngo HN, Teel RW, Lau BHS. Modulation of mutagenesis, DNA-binding, and metabolism of aflatoxin B1 by licorice compounds. Nutr Res. 1992;12:247–57.View ArticleGoogle Scholar
  28. Agabeili RA. Genetic effects of root extracts of Glycyrrhiza glabra L. in different test systems. Cytol Genet. 2012;46:297–301.View ArticleGoogle Scholar
  29. Zani F, Cuzzoni MT, Daglia M, Benvenuti S, Vampa G, Mazza P. Inhibition of mutagenicity in Salmonella typhimurium by Glycyrrhiza glabra extract, glycyrrhizinic acid, 18α- and 18β-glycyrrhetinic acids. Planta Med. 1993;59:502–7.View ArticlePubMedGoogle Scholar
  30. Tatsuzaki J, Jinwei Y, Kojo Y, Mine Y, Ishikawa S, Mochizuki M, Inami K. Antimutagenicity screening of extracts from medicinal and edible plants against N-methyl-N-nitrosourea by the Ames assay. Genes Environ. 2014;6:39–46.View ArticleGoogle Scholar
  31. Maron DM, Ames BN. Revised methods for the Salmonella mutagenicity test. Mutat Res. 1983;113:173–215.View ArticlePubMedGoogle Scholar
  32. Mortelmans K, Zeiger E. The Ames Salmonella/microsome mutagenicity assay. Mutat Res. 2000;455:29–60.View ArticlePubMedGoogle Scholar
  33. Shibano M, Henmi A, Matsumoto Y, Kusano G, Miyase T, Hatakeyama Y. Pharmaceutical botanical studies on some Glycyrrhiza species. Heterocycles. 1997;45:2053–60.View ArticleGoogle Scholar
  34. Zeng L, Fukai T, Nomura T, Zhang RY, Lou ZC. Four new prenylated flavonoids, Glyasperins A, B, C, and D from the roots of Glycyrrhiza aspera. Heterocycles. 1992;34:575–87.View ArticleGoogle Scholar
  35. Fukai T, Toyono M, Nomura T. On the structure of licoricidin. Heterocycles. 1988;27:2309–13.View ArticleGoogle Scholar
  36. Park SY, Lim SS, Kim JK, Kang IJ, Kim JS, Lee C, Kim J, Park JH. Hexane-ethanol extract of Glycyrrhiza uralensis containing licoricidin inhibits the metastatic capacity of DU145 human prostate cancer cells. Br J Nutr. 2010;104:1272–82.View ArticlePubMedGoogle Scholar
  37. Kitagawa I, Chen WZ, Hori K, Harada E, Yasuda N, Yoshikawa M, Ren J. Chemical studies of Chinese licorice-roots. I. Elucidation of five new flavonoid constituents from the roots of Glycyrrhiza glabra L. collected in Xinjiang. Chem Pharm Bull. 1994;42:1056–62.View ArticlePubMedGoogle Scholar
  38. Teng SC, Tsai HJ, Tsai MG, Lee WM, Chen IC, Lin CC. Using both chemical and biological fingerprints for the quality study of estrogenic licorice (Glycyrrhiza uralensis). J Food Science. 2003;68:2372–7.View ArticleGoogle Scholar
  39. Birt DF, Hendrich S, Wang W. Dietary agents in cancer prevention: flavonoids and isoflavonoids. Pharmacol Ther. 2001;90:157–77.View ArticlePubMedGoogle Scholar
  40. Resende FA, da Silva Almeida CP, Vilegas W, Varanda EA. Differences in the hydroxylation pattern of flavonoids alter their chemoprotective effect against direct- and indirect-acting mutagens. Food Chem. 2014;155:251–5.View ArticlePubMedGoogle Scholar
  41. Mitscher LA, Drake S, Gollapudi SR, Harris JA, Shankel DM. Isolation and identification of higher plant agents active in antimutagenic assay systems: Glycyrrhiza Glabra. In: Shankel DM, Hartman PE, Kada T, editors. Antimutagenesis and anticarcinogenesis mechanisms. New York: Springer; 2013. p. 153–65.Google Scholar
  42. Singer B. Sites in nucleic acids reacting with alkylating agents of differing carcinogenicity or mutagenicity. J Toxicol Environ Health. 1977;2:1279–95.View ArticlePubMedGoogle Scholar
  43. Eder E, Wiedenmann M, Deininger C, Kütt W. The relationship between mutagenicity in His G46 Salmonella and the O 6 -guanine alkylation in bacterial DNA by monofunctional methanesulphonates. Toxicol in Vitro. 1990;4(3):167–74.View ArticlePubMedGoogle Scholar
  44. Bhattacharya S. Natural Antimutagens. Res J Med Plant. 2011;5:116–26.View ArticleGoogle Scholar
  45. Cassady JM, Baird WM, Chang CJ. Natural products as a source of potential cancer chemotherapeutic and chemopreventive agents. J Nat Prod. 1990;53:23–41.View ArticlePubMedGoogle Scholar
  46. Choi JS, Park KY, Moon SH, Rhee SH, Young HS. Antimutagenic effect of plant flavonoids in the Salmonella assay system. Arch Pharm Res. 1994;17:71–5.View ArticlePubMedGoogle Scholar
  47. Gichner T, Pospísil F, Velemínský J, Volkeová V, Volke J. Two types of antimutagenic effects of gallic and tannic acids towards N-nitroso-compounds-induced mutagenicity in the Ames Salmonella assay. Folia Microbiol (Praha). 1987;32:55–62.View ArticleGoogle Scholar
  48. Huang MT, Chang RL, Wood AW, Newmark HL, Sayer JM, Yagi H, Jerina DM, Conney AH. Inhibition of the mutagenicity of bay-region diol-epoxides of polycyclic aromatic hydrocarbons by tannic acid, hydroxylated anthraquinones and hydroxylated cinnamic acid derivatives. Carcinogenesis. 1985;6(2):237–42.View ArticlePubMedGoogle Scholar
  49. Hebels DG, Briedé JJ, Khampang R, Kleinjans JC, de Kok TM. Radical mechanisms in nitrosamine- and nitrosamide-induced whole-genome gene expression modulations in Caco-2 cells. Toxicol Sci. 2010;116:194–205.View ArticlePubMedGoogle Scholar
  50. Tsuruma K, Yamauchi M, Inokuchi Y, Sugitani S, Shimazawa M, Hara H. Role of oxidative stress in retinal photoreceptor cell death in N-methyl-N-nitrosourea-treated mice. J Pharmacol Sci. 2012;118:351–62.View ArticlePubMedGoogle Scholar
  51. Wang J, Chen X, Wang F, Zhang J, Li P, Li Z, Xu J, Gao F, Jin C, Tian H, Zhang J, Li W, Lu L, Xu GT. OFD1, as a ciliary protein, exhibits neuroprotective function in photoreceptor degeneration models. PLoS One. 2016;11:e0155860.View ArticlePubMedPubMed CentralGoogle Scholar
  52. Toda S, Shirataki Y. Inhibitory effects of licoisoflavones A and B and sophoraisoflavone A of Sophra mooracroftiana Beth ex Baker on copper-ion-induced protein oxidative modification of mice brain homogenate, in vitro. Biol Trace Elem Res. 2001;81:169–75.View ArticlePubMedGoogle Scholar
  53. Fu Y, Chen J, Li YJ, Zheng YF, Li P. Antioxidant and anti-inflammatory activities of six flavonoids separated from licorice. Food Chem. 2013;141:1063–71.View ArticlePubMedGoogle Scholar
  54. Ramos AA, Pedro D, Collins AR, Pereira-Wilson C. Protection by Salvia extracts against oxidative and alkylation damage to DNA in human HCT15 and CO115 cells. J Toxicol Environ Health A. 2012;75:765–75.View ArticlePubMedGoogle Scholar
  55. Ferguson LR. Antimutagens as cancer chemopreventive agents in the diet. Mutat Res. 1994;307:395–410.View ArticlePubMedGoogle Scholar
  56. DeMarini DM. Dietary interventions of human carcinogenesis. Mutat Res. 1998;400:457–65.View ArticlePubMedGoogle Scholar

Copyright

© The Author(s) 2017

Advertisement