Inhibition of N-nitrosation of secondary amines in vitro by tea extracts and catechins

Tanaka, Kosaku; Hayatsu, Toshiko; Negishi, Tomoe; Hayatsu, Hikoya

doi:10.1016/s1383-5718(97)00178-2

Cited by 67 publications

(37 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In this case, AEP may deactivate DXR or the free radicals that are produced during its transformation. This deactivation could be related to the antioxidant activity of phenolic compounds, such as tannin and ursolic acid in AEP, as observed by several authors who have attributed this fact to the antigenotoxic action of these phenolics (Tanaka et al, 1998;Dhawan et al, 2002;Maurich et al, 2004;Pellegrina et al, 2005).…”

Section: Resultsmentioning

confidence: 66%

Modulatory effect of Palicourea coriacea (Rubiaceae) against damage induced by doxorubicin in somatic cells of Drosophila melanogaster

Passos¹,

Ferreira²,

Vieira³

et al. 2010

Genet. Mol. Res.

View full text Add to dashboard Cite

ABSTRACT. Palicourea coriacea, popularly known as "douradinha", is a medicinal plant from the Brazilian Cerrado region used in folk medicine to treat kidney and urethral stones and kidney inflammation. We evaluated the cytotoxic, genotoxic, and possible antigenotoxic activities of an aqueous extract of P. coriacea on somatic cells of Drosophila melanogaster, using the somatic mutation and recombination test. We used third-stage larvae of D. melanogaster from a standard cross and a high bioactivation cross and tested 10 different doses of P. coriacea aqueous extract (5, 15, 25, 35, 50, 65, 80, 95, 110, and 125 mg/mL). Doxorubicin (0.125 mg/mL) was used as a positive control and distilled water as a negative control. None of the doses was lethal to the larvae. There was no genotoxic effect at 5, 10, or 15 mg extract/mL. However, a significant decrease in the frequency of spots induced by doxorubicin was observed when administered with P. coriacea aqueous extract at these same doses. We conclude that P. coriacea aqueous extract is not cytotoxic or genotoxic at these doses, but it does protect against the genotoxic action of doxorubicin.

show abstract

Section: Resultsmentioning

confidence: 66%

Modulatory effect of Palicourea coriacea (Rubiaceae) against damage induced by doxorubicin in somatic cells of Drosophila melanogaster

Passos¹,

Ferreira²,

Vieira³

et al. 2010

Genet. Mol. Res.

View full text Add to dashboard Cite

show abstract

“…Then, the scavenging of toxic quinones and/or charge-transfer complexes produced in the stomach increases with the increase in the concentration of thiocyanic acid in saliva. In addition, Figure 4 suggests that i) if the gastric concentration of nitrous acid is lower than that of ascorbic acid, the oxidation of phenolic compounds does not proceed resulting in the increase in the efficiency of the transport of phenolic compounds to the intestine, and that ii) the reactions of phenolic compounds with nitrous acid may result in the suppression of carcinogenic nitrosoamine formation in the stomach as has been discussed previously [66,75,76]. Further studies, however, on the nitrous acid-induced oxidation of phenolic compounds in ingested foods are necessary under simulated stomach conditions to discuss their beneficial and unbeneficial effects of their products.…”

Section: Summarization Of the Reactions In Nitrous Acid-flavonoid Sysmentioning

confidence: 77%

Possible Reactions of Dietary Phenolic Compounds with Salivary Nitrite and Thiocyanate in the Stomach

Takahama

Hirota

2017

Preprint

View full text Add to dashboard Cite

Foods are mixed with saliva in the oral cavity and swallowed. During staying in the stomach, saliva is contentiously provided to mix with the ingested foods. Because a salivary component nitrite is protonated to produce active nitrous acid at acidic pH, the redox reactions of nitrous acid with phenolic compounds in foods become possible in the stomach. In the reactions, nitrous acid is reduced to nitric oxide ( • NO), producing various products from phenolic compounds. In the products, stable hydroxybezoyl benzofuranone derivatives, which are produced from quercetin and its 7-O-glucoside, are included. Caffeic acid, chlorogenic acid, and rutin are oxidized to quinones and the quinones can react with thiocyanic acid derived from saliva producing stable oxathiolone derivatives. 6,8-Dinitrosocatechis are produced from catechins by the redox reaction, and the dinitrocatechins are oxidized further by nitrous acid producing the quinones, which can make charge transfer complexes with the dinitrosocatechin and can react with thiocyanic acid producing the stable thiocyanate conjugates. In this way, various products can be produced by the reactions of salivary nitrite with dietary phenolic compounds, and reactive and toxic quinones formed by the reactions are postulated to be removed in the stomach by thiocyanic acid derived from saliva.

show abstract

“…Besides, antimutagenic activity was also claimed mainly due to the tannin content which was a phenolic compound that could affect the mutagenic activities Tanaka et al, 1998). Previous study done by (Imanishi et al, 1991) had reported that in the presence of metabolic activation system S9, tannin showed effective antimutagenic activity at low concentration thus enhance the activity of DNA excision repair by activating the repair enzyme (Shimoi et al, 1985).…”

Section: Discussmentioning

confidence: 99%

The Mutagenicity and Antimutagenicity of Canarium odontophyllum (Dabai) Acetone Leaves Extracts

Ghazali¹,

Khairuddin²,

Nagapan³

et al. 2017

JAS

View full text Add to dashboard Cite

Canarium odontophyllum or locally known as Dabai in Sarawak is a fruit largely consumed by the locals. Based on previous studies, the plant possessed various biological activities, such as antimicrobial, antioxidant, antifungal and anticancer. Our aim was to investigate the mutagenicity and antimutagenicity of C. odontophyllum acetone leaves extracts by using the Ames test (Salmonella reverse mutagenicity assay).The Ames test also involved the pre-incubation method against Salmonella typhimurium TA98 and TA100 bacterial strains in the absence and presence of metabolic activator S9 system. C. odontophyllum crude acetone extracts were diluted with 10% DMSO to obtain three different concentrations of 3.125, 12.5 and 50 mg/ml. To determine the mutagenicity effects of the extracts, each concentration of the extract was evaluated based on the two-fold value of the number of revertant's colony in negative control plate as the cut-of point. No mutagenic activity was observed for the frameshift mutation (TA98) and base-pair substitution mutation (TA100) in all concentrations of C. odontophyllum in the presence and absence of metabolic activator S9 system. Antimutagenicity test was carried out to determine the potential of C. odontophyllum extracts to inhibit the mutation induced by specific mutagens. The highest antimutagenic activity was seen in the presence of metabolic activator S9 system with inhibition percentage greater than 50% in both bacteria strains TA98 (62.38%) and TA100 (58.24%). In conclusion, C. odontophyllum acetone leaves extract was not mutagenic and had significant inhibitory effects on mutagenicity in both bacterial strains with and without the metabolic activator S9 system. Our results could contribute to the safe use of C. odontophyllum. In addition, based on the significant antimutagenic activity demonstrated by the C. odontophyllum acetone leaves extracts, the extract could also be developed as a chemopreventive agent.

show abstract

Inhibition of N-nitrosation of secondary amines in vitro by tea extracts and catechins

Cited by 67 publications

References 13 publications

Modulatory effect of Palicourea coriacea (Rubiaceae) against damage induced by doxorubicin in somatic cells of Drosophila melanogaster

Modulatory effect of Palicourea coriacea (Rubiaceae) against damage induced by doxorubicin in somatic cells of Drosophila melanogaster

Possible Reactions of Dietary Phenolic Compounds with Salivary Nitrite and Thiocyanate in the Stomach

The Mutagenicity and Antimutagenicity of Canarium odontophyllum (Dabai) Acetone Leaves Extracts

Contact Info

Product

Resources

About