• The Korean Journal of Mycology
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• 제42권3호
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• pp.191-200
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• 2014

Nuruk samples collected from various regions in Korea were investigated in terms of fungal contents and diversity. In measurement of colony forming unit (CFU) in Nuruk suspensions on DRBC agar, Nuruk samples MS4, MS8, and MS10 were among the highest fungal density, with $1,278.9{\pm}21.6$ (${\times}10^4$), $1,868.0{\pm}27.7$ (${\times}10^4$), and $775.1{\pm}19.2$ (${\times}10^4$) were among the samples showing the highest fungal density. CFU per 20 mg Nuruk, respectively. The majority of fungal components were yeasts, including Pichia anomala, P. kudriavzevii, Kluyveromyces marxianus, and Saccharomycopsis fibuligera, whereas Aspergillus oryzae and Rhizopus oryzae, the representative Nuruk fungi, were predominant only in the low fungal density Nuruks (MS2, MS5, and MS11). Saccharification capability of the fungal isolates was assessed by measurement of amylase activity in the culture broth. The highest amylase activity was found in A. niger and A. luchuensis, followed by S. fibuligera. A. oryzae and R. oryzae showed fair amylase activity but significantly lower than those of the three fungal species. R. oryzae was suggested to play an additional role in degradation of ${\beta}$-glucan in crop component of Nuruk since R. oryzae was the only fungus that showed ${\beta}$-glucanase activity among the fungal isolates. To confirm the safety of Nuruk, aflatoxigenicity of the isolated Aspergillus was estimated using the DNA markers norB-cypA, aflR, and omtA. All of the isolates turned out to be non-aflatoxigenic as evidenced by the deletion of gene markers, norB-cypA and aflR, and the absence of aflatoxin in the culture supernatants shown by TLC analysis.

• Journal of Food Hygiene and Safety
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• 제10권3호
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• pp.133-138
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• 1995

In vitro antimutagenic activity of methanol extract from brrwn rice and its physico-chemical characteristics were investigated using Salmonella typhimurium reversion assay and SOS chromotest. Methanol extracts of brown rice were not mutagenic compared with direct and indirect, mutagenicities of 4NQO (4-nitroquinoline oxide), 2NF(2-nitrofluorene), Trp-p-1(3-Amino-1,4-dimethyl-5H-pyrido-[4,3-b]indole), and Trp-p-2(3-Amino-1-methy-5H-pyrido-[4,3-b]indole). Antimutagenic activity against the indirect mutagenicties induced by Trp-p-1, Trp-p-2 and AFB1 (aflatoxin B1) was found in methanol extract. Even though antimutagenic activity showed dose-dependent, it remained constant at inhibition rate ranging 60~90% when the concentration was abov 3mg/plate in the S. typhimurium reversion assay and 0.2~0.6 mg/assay in the SOS chromotest. The antimutagenic activity of the methanol extracts was stable at various pH (2, 7 and 10), temperatures (60, 80 and 10$0^{\circ}C$)and heation times (2, 4, 6, 8, 10 min at 10$0^{\circ}C$).

• The Korean Journal of Mycology
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• 제49권3호
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• pp.303-313
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• 2021

Peanuts in storage were estimated for mycotoxigenic fungi and mycotoxins. Peanut samples collected from storages in Gochang were mainly contaminated with Fusarium (17.2±28.0%), Penicillium (12.4±28.0%), and Aspergillus (8.0±7.6%). Other genera, including Talaromyces, Rhizopus, Rhizoctonia, Trichocladium, Clonostachys, Mucor, Chaetomium, Trametes, Epicoccum, and Humicola, were also found. Although aflatoxins were not detected in the peanut samples, 29 strains of Aspergillus flavus were identified using molecular marker genes. Among them, 17 selected isolates produced aflatoxins in solid culture media ranging from 0.61-187.82 ㎍/kg. All of them could produce both aflatoxin B₁ and B₂ and some (n=5) produced additional G₁, G₂, or both. This study is the first report that A. flavus stains obtained from Korean stored peanut are aflatoxigenic.

• Journal of the Korean Society of Food Science and Nutrition
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• 제28권2호
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• pp.452-457
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• 1999

The inhibitory effect of Coprinus comatus on the mutagenicity in Salmonella assay system and SOS chromotest were studied. In Ames test, the ethanol and water extracts and the cultured mycelia fractions of Coprinus comatus did not show any mutagenicity, but the Coprinus comatus ethanol extracts showed inhibitory effects of 8 0∼90% on the mutagenicity induced by indirect mutagen of benzo(a)pyrene(B(a)P) and aflatoxin B1(AFB1) in Salmonella typhimurium TA98 and TA100. The antimutagenic effect increased with increasing concentration of the ethanol extract toward N methyl N' nitro N nitrosoguanidine(MNNG). However, the water extracts inhibited about 40∼50% against direct and indirect mutagen. The cultured mycelial filtrate of Coprinus comatus, the fractionⅡ, showed antimutagenic effect of 90% on MNNG and 25∼50% on B(a)P and AFB1. In SOS chromotest, the ethanol extracts of Coprinus comatus showed antimutagenic effect of 65∼81% on SOS function induced by 4 NQO, and the cultured mycelia fractionⅡ showed low inhibitory effect of 20∼50%.

• Preventive Nutrition and Food Science
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• 제1권2호
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• pp.203-207
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• 1996

Methanol extract of dried persimmon leaves was refractionated using hexane, chloroform, ethylacetate, n-butanol aqueous fractions. Among these chloroform fraction showed the highest inhibition rate on the mutagenicities of aflatoxin B₁(AFB₁) and 3,2' -dimethyl-4-amino-bipheny1(DMAB) in Salmonella typhimurium TA 100. Chloroform fraction was further fractionated into eight fractions by silica gel column chromatography and thin layer chromatography(TLC). The fraction 5 on TLC exhibited the highest antimutagenic activities in AFB₁and DMAB. 2,4-Decadienal, dihydro-4-methyl-2(3H)-furanone, hexanoic acid 1,4-bis(1-methy1 ethy1)benzene, heptanoic acid, phenol, octanoic acid, nonanoic acid and benzoic acid were tentatively identified from this antimutagenic fraction by GC-MS.

• The Korean Journal of Community Living Science
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• 제15권1호
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• pp.49-55
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• 2004

The purpose of this study is to research the antimutagenic and antioxidative effects of water dropwort and small water dropwort by Ames test and by measuring malondialdehyde(MDA) production. Water dropwort and small water dropwort were extracted with methanol and then further fractionated to hexane, chloroform, ethyl acetate, butanol and water, stepwise. The methanol extracts from both samples reduced the mutagenicities by aflatoxin $B_1(AFB_1)$ in Salmonella typhimurium TA 98. The production of MDA also decreased when the methanol extracts were added to the system. The hexane, chloroform and ethyl acetate fractions revealed higher antimutagenic activities against $AFB_1$ than the butanol and water fractions. Among the five fractions, the ethyl acetate fraction showed the highest level of antioxidant activity. From the results of the experiment, water dropwort and small water dropwort seem to be good antimutagenic and antioxidative sources of food.

• Asian Pacific Journal of Cancer Prevention
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• 제16권14호
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• pp.5987-5991
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• 2015

Our previous study detected aflatoxins in red chili peppers from Chile, Bolivia, and Peru, each of which have a high incidence of gallbladder cancer (GBC). Since the aflatoxin B1 concentration was not so high in these peppers, it is important to clarify the presence of other mycotoxins. Here we attempted to determine any associations between the concentrations of aflatoxins and ochratoxin A (OTA) in red chili peppers, and the corresponding GBC incidences. We collected red chili peppers from three areas in Peru: Trujillo (a high GBC incidence area), Cusco (an intermediate GBC incidence area), and Lima (a low GBC incidence rate), and from Chile and Bolivia. Aflatoxins and OTA were extracted with organic solvents. The concentrations of aflatoxins B1, B2, G1, and G2, and OTA were measured by high-performance liquid chromatography. The values obtained were compared with the incidence of GBC in each area or country. All of the red chili peppers from the three areas showed contamination with aflatoxins below the Commission of the European Communities (EC) recommended limits ($5{\mu}g/kg$), but the OTA contamination of two samples was above the EC recommended limit ($15{\mu}g/kg$). The mean concentrations of OTA in the peppers from Chile (mean $355{\mu}g/kg$, range < $5-1,059{\mu}g/kg$) and Bolivia (mean $207{\mu}g/kg$, range $0.8-628{\mu}g/kg$), which has a high incidence of GBC, were higher than that in Peru ($14{\mu}g/kg$, range < $5-47{\mu}g/kg$), which has an intermediate GBC incidence. The OTA contamination in the red chili peppers from Chile, Bolivia, and Peru was stronger than that of aflatoxins. Our data suggest that OTA in red chili peppers may be associated with the development of GBC.

• Preventive Nutrition and Food Science
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• 제1권2호
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• pp.151-158
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• 1996

Antimutagenic effect of Doenjang (Korean soy paste) on various carcinogens in Salmonella typhimurium strains of TA98 and TA100 were studied. By the addition of methanol extract of Doenjang to aflatoxin B₁(AFB₁)in the experimental system, the mutagenicity of AFB₁ on the strains of TA98 and TA100 was com-pletely inhibited. The methenol extract of the Doenjang also inhibited the mutagencities induced by direct mutagens such as N-methy1-N'-nitro-N-nitroguanidine(MNNG)and 4-nitroquinoline-1-oxide(4-NQO), and another indirect mutagens of benzo(a) pyrene(BaP) and dimethylnitrosamine(DMN). From the solvents and thin layer chromatographic(TLC) fractionations, free fatty acid(s), especially linoleic acid in Doenjang seemed to be one of the active antimutagenic compounds.

• Korean Journal of Pharmacognosy
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• 제27권2호
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• pp.96-100
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• 1996

The extracts of aerial parts of Artemisia princeps var. orientalis, A. argyi, A. capillaris, A. rubripes and A. laciniata were investigated on the antimutagenic effect againt aflatoxin $B_1$ $(AFB_1)$. The methanolic extracts of 5 Artemisia species reduced the mutagenicity of $AFB_1$. And also 4,5-O-dicaffeoylquinic acid isolated from A. princeps var. orientalis revealed the antimutagenic activity.

• Preventive Nutrition and Food Science
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• 제2권1호
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• pp.29-34
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• 1997

In order to determine the effectiveness of linoleic acid(LA) to inhibit carcinogens/mutagens-induced mu-tagenesis, Ames test using Salmonella typhimurium TA100 and the SOS chromotest using E. Coli PQ37, were carried out. The inhibitory effect of LA(1%) on the Ames mutagenicity test were 98%, 78%and 69% mediated by aflatoxin B₁(AFB₁), N-methyl-N'-nitro-N-nitrosoguanidine(MNNG) and 4-nitroquinoline-1-oxide(4-NQO), respectively. LA exhibited a strong antimutagenic activity aganist indirect mutagen, AFB₁whereas exhibited the same concentration of LA showed weaker inhibitory effects on direct mutagens of MNNG and 4-NQO than that AFB₁. LA also reduced the SOS responses induced by MNNG and 4-NQO significantly. This result showed a possibility that LA can be a protective agent in early step of cancinogenesis.