• The Korean Journal of Mycology
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• v.51 no.3
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• pp.219-227
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• 2023

This study was conducted to analyze the distribution and characteristics of fungal species in meju using the traditional method. Fungal distribution in meju was investigated using metagenomic and morphological analyses, based on which Aspergillus flavus/oryzae strains were identified as the dominant fungi in all meju samples, followed by Pichia, Rhizopus and Lichtheimia spp. As A. flavus/oryzae was dominant, we further evaluated the aflatoxin production ability and enzymatic activity of the isolates. Thin-layer chromatography and polymerase chain reaction revealed that the A. flavus/oryzae strains isolated from meju are non-aflatoxigenic fungi. Based on the analyses of amylase and protease activities, strains with high activities of amylase or protease were identified, which are proposed to be used as starters for meju fermentation.

• Proceedings of the Ginseng society Conference
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• 1980.09a
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• pp.87-113
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• 1980

This experiment was carried out to evaluate the effects of Korean ginseng extract on carcinogenesis induced by various chemical carcinogens. Red ginseng extract was used for this study and was administered orally to the experimental animals. Carcinogens that were injected in subscapsular region of ICR newborn mice within 24 hours after birth were 9,10-dimethyl-1,2-benzan-thracene (DMBA), urethane, N-2-fluorenylacetamide(AAF), aflatoxin $B_1$ and tobacco smoke condensate. N -methyl-N -nitroso-N'-nitroguani-dine(MNNG) was injected subcutaneously at the back of wistar rats. Experimental animals were autopsied in immediately after being sacrificed. All major organs were examined grossly and weighted. After fixation histopathological preparations were made for microscopical study. Following results were obtained. In DMBA group sacrificed at the 26th week after the treatment with DMBA, the incidence of lung adenoma was $77\%$ and the average number of the tumor was 17. However, in DMBA combined with red ginseng group, the incidence was $78\%$ and the average number of lung adenoma was 14.1. This indicates that ginseng extract had no effect on the incidence of lung adenoma but decreased the average number of lung adenoma by $17\%.$ In DMBA group sacrificed at the 48th week after the injection of DMBA, the lung adenoma incidence was $88\%.$ The average diameter of the largest lung adenoma was 3.5 cm, the incidence of diffuse pulmonary infiltration was $18\%$ and the average lung weight of male experimental mice was $528.2{\pm}469.1\;gm.$ On the other hand, in DMBA combined with red ginseng group sacrificed at the 48th week, the incidence of lung adenoma was $96\%.$ The average diameter of the largest adenoma was 2.7 cm, the incidence of diffuse pulmonary infiltration was $7\%$ and the average lung weight of male mice was $418.0{\pm}520\;gm.$ These observations show that ginseng extract did not have any inhibitory effect on the incidence of lung adenoma but decreased the average diameter of the largest lung adenoma by $23\%,$ the incidence of duffuse pulmonary infiltration by $63\%$ and the average lung weight of male experimental mice by $21\%.$ From these results we have found that the prolonged administration with ginseng extract showed no inhibitory effect on the incidence of adenoma but it had the inhibitory effect on the proliferation of lung adenomas induced by DMBA. In urethane group sacrificed at the 28th week after the injection of urethane, the incidence of lung adenoma was $94\%$ and the average number of lung adenoma was 8.6. In urethane combined with red ginseng group, the. incidence of lung adenoma was $73\%$ and the average number of adenoma was 6.0. These results indicate that there were $22\%$ decrease of the lung adenoma incidence and $31\%$ decrease of the average number of adenoma in urethane combined with red ginseng group. And in urethane group sacrificed at the 50th week, the incidence of lung adenoma was $98\%$ and the incidence of diffuse pulmonary infiltration was $14\%$. In urethane combined with ginseng group the incidence of lung adenoma was $85\%$ and the incidence of diffuse pulmonary infiltration was $12\%$. Therefore the ginseng administration resulted in $15\%$ decrease of the lung adenoma incidence and $14\%$ decrease of the diffuse pulmonary infiltration incidence. From these results we knew that the prolonged administration with ginseng extract inhibited the incidence and also the proliferation of the lung adenoma induced by urethane. Lung adenoma and hepatoma were induced in the experimental mice sacrificed at the 68th week but not in the experimental mice sacrificed at the 28th week after the injection of AAF. In AAF group sacrificed at the 68th week after the injection of AAF the incidence of lung adenoma was $18\%$ and the incidence of hepatoma was $27\%$. And in AAF combined with ginseng group the lung adenoma incidence was $12\%$ and the hepatoma incidence was $37\%$. So the ginseng seemed to decrease the lung adenoma incidence by AAF, but we were unable to conclude the significant inhibitory effect of the ginseng extract on the incidence of lung adenoma by AAF because the above incidence of lung adenoma were similar to that of control group which was $11\%$. And these experimental data revealed that ginseng extract didn't have any inhibitory effect on the incidence of hepatoma induced by AAF. In aflatoxin $B_1$ group sacrificed at the 56th week, the incidence of lung adenoma was $24\%$ and hepatoma was $11\%$. However in aflatoxin $B_1$ combined with ginseng group the incidence of lung adenoma was $17\%$ and hepatoma was $3\%$ These results indicate that there were $29\%$ decrease of the lung adenoma incidence and $75\%$ decrease of the hepatoma incidence in aflatoxin $B_1$ combined with ginseng group. In tobacco smoke condensate experimental group sacrificed at 67th week, no tumors were induced except just a few lung adenoma. The lung adenoma incidence both in tobacco smoke condensate group and in tobacco smoke condensate combined with ginseng group was $8\%$. And this incidence rate was similar to that of control group. These results indicate that the injection of 320 ug tobacco smoke condensate per ICR newborn mouse was unable to induce lung adenoma in our experiments. In MNNG group sacrificed at the 27th week the tumor incidence was $38.5\%$ and in MNNG combined with ginseng extract group was $37\%$. In MNNG group for investigation of the life span of tumor bearing rats the tumor incidence was $93\%$ and the average life span of tumor bearing rats was 318 days. And in MNNG combined with ginseng extract group the tumor incidence was $96\%$ and the average life span was 337 days. Tumor induced by MNNG was almost sarcoma. This indicates that there was no inhibitory effect of ginseng extract on the tumor incidence, but the extract prolonged the average life span of tumor bearing rats by approximately 19 days.

• Applied Biological Chemistry
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• v.13 no.1
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• pp.35-42
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• 1970

Five samples of Korean native Maeju(fermented soy-bean mash) loaves which were collected each from Kyunggi, Chungchung, Kangwon, Cholla and Kyungsang-Do were examined for their fermenting microorganisms. The results of taxonomic and ecological studies of fermentation microorganisms in these Maeju loaves were as the fellows. (1) The fungus flora grew only is the outer layer of Maeju loaves. Miscellaneous molds, 3 species of Mucor, 2 species of Pericallium., one species each of Scopulariopsis and Aspergillus, were isolated. None of them seemed exclusively predominant to be able to designate as the ecologically significant. (2) The bacterial flora which consisted of two species, Bacillus subtilis and Bacillus pumilus were distributed uniformly in th a entire Maeju loaves. The inner parts of Maeju loaves were especially inhabited solely by these bacterial flora. Probably the Korean native Maeju fermentation could be characterized by these bacterial flora. A Staphylococcus species was also isolated probably as a casual contaminant. (3) The yeasts, Rhodotorula flava and Torulopsis dattila, were isolated from Maeju loaves though their ecological significance was not clear. (4) The ecological aspects of fermentation microbes in the outer and inner parts of Maeju loaves were apparently different, consequently different fermentation processes might have occurred in these two parts and it brought quite different final outlooks in the final matured Maeju loaves. The outer part, rather rigid and dry, retained the light brown color of boiled soy-bean; whereas the inner part, soft and sticky, showed dark brown color indicating severe chemical changes. (5) The aflatoxin producing mold, Aspergillus oryzae was isolated from one sample among 5 of Maeju loaves. In addition to the low probability of isolability from Maeju loaves samples, since this mold grew only in the outer layer of Maeju loaves with such a low population density, about $10^4/g$, perhaps the aflatoxin problem in Korean native soysauce may not be critical.

• Journal of Food Hygiene and Safety
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• v.36 no.1
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• pp.24-33
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• 2021

For this study, we surveyed concentrations of 8 mycotoxins (aflatoxin B1, B2, G1, G2, ochratoxin A, fumonisin B1, B2 and zearalenone) in agricultural products used for food and medicine by liquid chromatography-tandem mass spectrometry and conducted a risk assessment. Samples were collected at the Yangnyeong Market in Seoul, Korea, between January and November 2019. Mycotoxins were extracted from these samples by adding 0.1% formic acid in 50% acetonitrile and cleaned up by using an ISOLUTE Myco cartridge. The method was validated by assessing its matrix effects, linearity, limit of detection (LOD), limit of quantification (LOQ), recovery and precision using four representative matrices. Matrix-matched standard calibration was used for quantification and the calibration curves of all analytes showed good linearity (r2>0.9999). LODs and LOQs were in the range of 0.02-0.11 ㎍/kg and 0.06-0.26 ㎍/kg, respectively. Sample recoveries were from 81.2 to 118.7% and relative standard deviations lower than 8.90%. The method developed in this study was applied to analyze a total of 187 samples, and aflatoxin B1 was detected at the range of 1.18-7.29 ㎍/kg (below the maximum allowable limit set by the Ministry of Food and Drug Safety, MFDS), whereas aflatoxin B2, G1 and G2 were not detected. Mycotoxins that are not regulated presently in Korea were also detected: fumonisin (0.84-14.25 ㎍/kg), ochratoxin A (0.76-17.42 ㎍/kg), and zearalenone (1.73-15.96 ㎍/kg). Risk assessment was evaluated by using estimated daily intake (EDI) and specific guideline values. These results indicate that the overall exposure level of Koreans to mycotoxins due to the intake of agricultural products used for food and medicine is unlikely to be a major risk factor for their health.

• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.3
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• pp.307-312
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• 1993

Methanol extract of dried persimmon leaves was fractionated to hexane, chloroform, ethyl acetate, butanol, and aqueous tractions. Hexane, butanol, and aqueous fractions had high yields of extracts. Hexane fraction among these fractions showed the highest inhibition rate on the mutagenicities of aflatoxin (AFB$_1$), dimethyl-amino-bi-phenyl (DMAB), N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), and 4-nitroquinoline-1-oxide (4-NQO) in Salmonella typhimurium TA100. Hexane fraction was further fractionated into eight fractions by silica gel column c-hromatography and thin layer chromatography (TLC). The fraction 5 on TLC exhibited the highest antimutagenic activity on AFB$_1$, DMAB, and MNNC. 1'-oxocannabinol, 3B-acetoxy-17-methyl-5a-18 (13-17) abeoardrost-13-one, 4-methoxy-2'6'-dinitro-3, 5-di-t-butylbiphenyl, 8, 9-dihydro-5, 6-dimethoxy-dibenz ［c, h］isoquino ［2, 1, 8-1 ma］carbazole-11, 16-dione were tentatively identified from this antimutagenic fraction by GC-MS.

• KSBB Journal
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• v.15 no.4
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• pp.331-336
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• 2000

The antimutagenic activity of the extract of Artemisia capillaris THUNB on the mutagenicity induced by benzo(a)pyrene [B(a)P] in the presense of S9 mixture was studied using bacterial mutagenic assay system. Samples harvested in summer and autumn were extracted using ethanol and hot water. Among these extracts the water extract of summer sample had the strongest inhibitory effect against the mutagenenicity of B(a)P, The water extract of Artemisia capillaris THUNB was separated again into ethanol soluble and insoluble parts. The ethanol insoluble part(El) of water extract exhibited higher inhibition effects than the ethanol soluble part against the mutagenic activity of B(a)P. El showed dose-dependent activity on the mutagenicity of B(a)P in SOS Chromotest and Ames test. The 50% inbibition concentraction $(IC_{50}$ of El were $200{\mu}g/assay$ $600{\mu}g/plate$ and $800{\mu}b/plate$ in E. coil PQ37 S. typhimurium TA100 and TA98 respectively. El were showed desmutagenic effect but had no effect on the DNA repair system for B(a)P-induced mutagenesis. HPLC analysis showed that the formation of aflatoxin M1 by cytochrome P-450 1A1 known as playing an impotant role on B(a) P-induced mutagenicity was highly inhibited by El. Therefore we encluded that B(a)P-induced mutagencity can be reduced possible due to the interference of el with cytochrome P-450 1A1-dependent bioactivation.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.9
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• pp.1439-1444
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• 2004

Antitumor activities of onion methanol extract (OME) and onion Kimchi methanol extract (OKME) were investigated by using aflatoxin $B_1$-mediated Salmonella typhimurium mutagenicity and the model of cytotoxicity on the cancer cell lines. Their immune activities were also investigated by using mouse spleen cells and macrophage cell lines, respectively. OME and OKME showed the enhanced antimutagenicity in a dose-dependent manner in particular, the activity of OKME was higher than that of OME. OME and OKME decreased over 20% of the proliferation of the A549 (lung cancer cell) and MCF-7 (breast cancer cell) cell lines when compared with the control at 1,000 ${\mu}$g/mL. The proliferation of mouse spleen cells and the NO production in marcrophage cell lines treated OME and OKME were increased in a dose-dependent manner compared with untreated control cells, and their activities of OKME were higher than those of OME.

• Journal of the Korean Society of Food Science and Nutrition
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• v.16 no.4
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• pp.278-286
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• 1987

The results in vestigated produced fluorescence compounds and mycotoxins, studied stability and toxicity of these compounds which were isolated from varicous moistured rice culture extacts inoculated Aspergillus versicolor IFO 30338, 10 kinds of fluorescence compounds were isolated. Sterigmatocystin was produced $38{\mu}g/kg$ in 16%, $329{\mu}g/kg$ in 25% and $380{\mu}g/kg$ in 35% moistured rice 20 days culture respectively. Aflatoxin $B_1$ was produced $3{\mu}g/kg$ in 25% and $12.6{\mu}g/kg$ in 35% moistured rice 20 days culture. In embryo test of isolated fraction 2, 4 and 6 by T.L.C., $LD_{50}$ of fraction 2 was $40{\mu}g/egg$ and fraction 4,6 was $60{\mu}g/egg$, and these compounds were mostly decomposed and fraction 4 and 6 were partly changed into fraction 2 below pH 2 and above pH 10. fraction 2,4 and 6 were all stable when treated 60 min, at $100^{\circ}C$, but were decomposed $60{\sim}65%$ when treated 60 min at $150^{\circ}C$, $95{\sim}100%$ when treated 10 min at $200^{\circ}C$.

• Korean Journal of Food Science and Technology
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• v.2 no.1
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• pp.88-92
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• 1970

1. Aflatoxin free and highly active new type kokja was made with strong two strains of yeast (Y-16, Y-21) and two strains of highly saccharifying active Aspergillus (A-32, A-11). And they were isolated from many kinds of kokja (over hundred) collected from all over Korea. 2. Activities of new type kokja was compared with old type kokja, and results were as following. (i) Saccharifying activity; New type kokja B, C and D were excellent (over 8. 0%), and home made old type kokja were poor quality. (ii) Alcohol fermentation; New type kokja C and D were over 12% and the old type K-12 and K-161 were low activity (less than 10%). (iii) Acid fermentation; Old type kokja K-2o and K-156 (industrial use) were better than the new type C and D. (iv) Fusel oil fermentation; Old type kokja K-23, K-26 (industrial use) and K-12 (home made) fermented high fusel oil (0.07%) and new type kokja C, D and B were the lowest (0.04%). 3. Adding food preservatives (AF-2, D.E.P.C.) and heat sterilizing of wheat bran for kokja had little concerning with the activity of new type kokja. 4. In brewing test, takju made from kokja C and D were more excellent in alcohol and fusel oil concentration than those from old type kokja K-1 and K-23. Taste and odour of takju from new type kokja was good enough to drink.

• Korean Journal of Food Science and Technology
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• v.30 no.2
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• pp.439-445
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• 1998

The antimutagenic activity of the water extract of Rehmannia glutinosa Liboschitz (RG) on the mutagenicity induced by 4-nitroquinoline 1-oxide (4-NQO), N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), mitomycin C (MMC), $aflatoxin\;B_1\;(AFB_1)$ and benzo(a)pyrene [B(a)P] were studied using the SOS Chromotest with Escherichia coli PQ37. The water extract of RG was separated into methanol soluble and methanol insoluble parts. The methanol soluble part exhibited higher inhibition effects than the methanol insoluble part against the mutagenic activities of five mutagens. Step-wise fractionation of methanol soluble part was done using methanol, ethyl acetate and water. Among these fractions, water fraction had the strongest inhibitory effects against the mutagenenicity of five model mutagens, showing $4.5{\sim}29.5%$ inhibition, but the $AFB_1$ mutagenic potency was increased slightly by ethyl acetate fraction. The water fraction was further partitioned by sephadex LH-20 column chromtography, and 9 subfractions were obtained. The fraction III showed the strongest inhibitory effects with dose response against the mutagenic activities induced by all the tested chemical mutagens. The inhibition rates of fraction III at concentration of $400\;{\mu}g/assay$ were 29%, 35%, 38%, 25% and 24% against 4-NQO, MNNG, MMC, AFBl and B(a)P, respectively. The fraction III also exhibited a strong bio-an-timutagenicity against 4-NQO and $AFB_1$ by showing more than 40% inhibition.