• Journal of the Korean Applied Science and Technology
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• v.40 no.5
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• pp.1163-1175
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• 2023

Cholesterol is prone to oxidation, which results in the formation of cholesterol oxidation products (COPs). This occurs because it is a monounsaturated lipid with a double bond on C-5 position. Cholesterol in foods is mostly non-enzymatically oxidized by reactive oxygen species (ROS)-mediated auto-oxidative reaction. The COPs are found in many common foods of animal-origin and are formed during their manufacture process. The formation of COPs is mainly related to the temperature and the heating time the food is processed, storage condition, light exposure and level of activator present such as free radical. The level of COPs in processed foods could reach up to 1-10 % of the total cholesterol depending on the foods. The most predominant COPs in foods including meat, eggs, dairy products as well as other foods of animal origin were 7-ketocholesterol, 7 α-hydroxycholesterol (7α-OH), 7β-hydroxycholesterol (7β-OH), 5,6α-epoxycholesterol (5,6α-EP), 5,6β-epoxycholesterol (5,6β-EP), 25-hydoxycholesterol (25-OH), 20-hydroxycholesterol (20-OH) and cholestanetriol (triol). They are mainly formed non-enzymatically by cholesterol autoxidation. The COPs are known to be potentially more hazardous to human health than pure cholesterol. The procedure to block cholesterol oxidation in foods should be similar to that of lipid oxidation inhibition since both cholesterol and lipid oxidation go through the same free radical mechanism. The formation of COPs in foods can be stopped by decreasing heating time and temperature, controlling storage condition as well as adding antioxidants into food products. This review aims to present, discuss and respond to articles and studies published on the topics of the formation and inhibition of COPs in foods and key factors that might affect cholesterol oxidation. This review may be used as a basic guide to control the formation of COPs in the food industry.

• Preventive Nutrition and Food Science
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• v.9 no.2
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• pp.167-173
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• 2004

The aim of this study was to investigate the antioxidant effect of medicinal plants used by diabetic patients. Fourteen medicinal plants were selected and antioxidant activity such as 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, inhibition effect of linoleic acid autoxidation and low density lipoprotein (LDL) oxidation, thiobarbituric acid (TBA) value were measured. The Cornus officinalis had DPPH radical scavenging activity of 84.79%, which was higher than the 78.79% for $\alpha$-tocopherol. Rosa rugosa Thunberg, Pueraria thundergiana Bentham, Artemisia princeps var. orientalis and Sasamorpha purpurascens Nakai also had high values. Extracts with higher DPPH radical scavenging activities had higher total phenol concentrations, and positive correlations between these parameters were found. Inhibitory activities of linoleic acid autoxidation, LDL oxidation and TBA value, used as indices of oxidative stress, were observed in most of the selected medicinal plants. The highest inhibitory activity for TBA value was observed in the extract of Pueraria thundergiana Bentham. Rosa rugosa Thunberg (75.50 %), Sasamorpha purpurascens Nakai (74.00 %), and Cornus officinalis (73.00 %) all had high antioxidant activity against linoleic acid autoxidation, similar to that of $\alpha$-tocopherol. The same 3 plants also had high in inhibitory activity against LDL oxidation. Therefore, we demonstrated that medicinal plants used as folk remedy by diabetic patients had antioxidant activity. Especially, Rosa rugosa Thunberg, Cornus officinalis, Pueraria thundergiana Bentham, Arlemisia princeps var. orientalis, and Sasamorpha purpurascens Nakai had high phenol concentrations which resulted in high values for DPPH radical scavenging. These same plants exhibited high values for inhibitory activities for TBA value, linoleic acid autoxidation and LDL oxidation, indices associated with lipid peroxidation.

• Applied Biological Chemistry
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• v.46 no.1
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• pp.32-38
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• 2003

Seventy percent ethanolic extracts from commercially available 13 legumes were made to investigated their antioxidative activities by determining the reducing power, inhibitory effect on lipid peroxidation, scavenging activity against both superoxide radical and hydroxyl radical, together with inhibitory activity toward mitomycin C-induced oxidative damage of DNA. High level of reducing powers were detected in Yepat, Sokpiri, Yuweol-bean and Jeokdu. Inhibitory effects on lipid peroxidation were found ubiquitously in all extracts examined when employing the linoleic acid autoxidation system, whereas, only 3 legumes, Yepat, Namul-bean and Jeenuni-bean, were revealed marked inhibition in rabbit erythrocyte-ghost membrane lipid peroxidation system. Yepat, Namul-bean, Jeokdu and Jeenuni-bean showed great scavenging activities on superoxide radical, on the other hand, high level of hydroxyl radical scavenging activities were demonstrated in Sokpiri, Chungtae, Yepat and Jebi-bean. Ubiquitous inhibitory effects on mitomycin C-induced oxidative damage on DNA were found in all extracts tested, Among them, however, Yepat, Jeenuni-bean, Namul-bean, Nokdu and Jeokdu showed the higher level of inhibition. Taken together, we could assign Yepat, Jeokdu, Jeenuni-bean and Sokpiri, for the legume species highly functional on overall antioxidative activity.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.6
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• pp.937-941
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• 2003

Red mustard leaf (RML) kimchi was prepared with native Brassica juncea czerniak et coss as a major raw material and antioxidative characteristics of crude anthocyanin (CA)/refined anthocyanin (RA) isolated from RML kimchi were studied. Among crude pigment fractions, CA fraction showed a higher inhibition rate of peroxide formation in linoleic acid autoxidation system. These effects seemed to be increased with the increase of CA concentration. CA also was considered to have a role of electron donor by the experiments using DPPH ($\alpha$, $\alpha$＇-diphenyl-$\beta$-picrylhydrazyl) reaction. Furthermore, various RA fractions had a higher antioxidative activity and especially RA-fraction 3 demonstrated the highest score of the antioxidative characteristics in terms of the prevention of lipid peroxidation and scavenging of free radicals.

• Applied Biological Chemistry
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• v.47 no.1
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• pp.61-66
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• 2004

70% ethanolic extracts were prepared from the three mutant rice cultivars with giant embryo termed Shinsunchal-giant embryonic rice, Whachung-giant embryonic rice and Nampung-giant embryonic rice, and its antioxidative and antimutagenic properties were evaluated and compared. For analysing antioxidativity, various antioxidative indices, such as electron donating ability to DPPH radical, scavenging capacity to hydroxyl radicals generated by Fenton reaction, scavenging capacity to superoxide radicals generated by HPX/XOD system, inhibitory effect on autoxidation of linoleic acid and inhibitory effect on membrane lipid peroxidation derived from rabbit erythrocyte ghost, were determined. For analysing antimutagenicity, suppressive effects on mutagenesis induced by the chemical mutagen, mitomycin C, were measured using E. coli PQ 37 as a indicator cell. The results showed that for both antioxidativity and antimutagenicity the giant embryonic rices were more effective compared to the general cooking rice, Among the giant embryonic rice cultivars, Nampung-giant embryonic rice tended to be most effective, showing its scavenging activity to DPPH radical, superoxide radical and hydroxyl radical, and inhibitory activity to lipid peroxidation was 2,3-, 3,3-, 1.7-, and 2.5-fold greater than those of normal rice, respectively.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.23 no.3
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• pp.101-107
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• 1997

Phellinus linteus was artificially cultivated in kangwon province in Korea. The air-dried phellinus linteus was frozen in liquid nitrogen tank and powdered in jar. 10g of the powder was extracted with each 200g of ethanol, methanol, distilled water and 1,3-butylene glycol/distilled water 4 hours under refluxing and then the liquidextract was concentrated under reduced pressure. As a result of analysis by high performance liquid chromatography and thin layer chromarography, many kinds of sugar and flavonoids were detected. Also we knew that phellinus linteus' extract had a strong UV-ray absorption. In the efficacy test for applying to cosmetics, free radical scavenging effect was confirmed. As a result, 2% of sample was the most potent inhibitory effect and the free radical savenging activity, was 0.31%. This is more effective than any other meterial. In the test of antioxidative activity against lipid autoxidation, phellinus linteus' extract had a good effect by 46% while vitamine E was 42.3%. The immunological activity of phellinus linteus was showed through the activation of macrophage cell. Actually, phellinus linteus activated macrophage function of 1.1-1.8 times including nitrite production compared to control. The whitening effect of phellinus linteus was showed through the inhibition of tyrosinase activity, melanin biosynthesis of S. bikiniensis and B-16 melanoma cells. Phellinus linteus' extract was showed strong mushroom tyrosinase inhibitory activity with IC50 value of 0.5% and inhibited melanin biosynthesis with 28mm inhibition zone at 0.005%/paper disc in S. bikinniensis, a bacterium used as an indicator organism in this work. Also it inhibited melanin biosynthesis in B-16 melanoma cells with a minimum inhibitory concentration of 0.134%.

• The Korean Journal of Food And Nutrition
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• v.22 no.3
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• pp.367-376
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• 2009

This study aimed to determine the antioxidant and antibacterial effects of solvent extracts from Scutellaria baicalensis. The S. baicalensis was successively extracted with 5 kinds of solvents. The obtained samples were as follows; hexan fraction (IPK-1), chloroform fraction(IPK-2), ethyl acetate fraction(IPK-3), butanol fraction(IPK-4), and water fraction(IPK-5). These extracts were determined to process antibacterial effects using a paper disc method against 18 species of human pathogenic bacteria, antioxidant activity using 1,1-diphenyl-2-picrylhydrazyl(DPPH) method and inhibiting ability of linoleic acid autoxidation. Extracts of S. baicalensis has shown selective antibacterial effects on various strains of bacteria. Ethyl acetate fraction(IPK-3) showed the highest antimicrobial activity against selective bacteria, such as Staphylococcus aureus 285, S. aureus 503. In antioxidant activity test, free radical scavenger activity of IPK-3 fraction was 92% compared with BHA at the same concentration, while lipid peroxidation inhibition was 48%. These results suggest that IPK-3 fraction of S. baicalensis could be suitable in development of antimicrobial and antioxidant agents.

• Journal of Applied Biological Chemistry
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• v.52 no.4
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• pp.174-179
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• 2009

Biological functionality of nineteen commercially available carbonated vinegar liquors including wood vinegar liquor (WVL), bamboo vinegar liquor (BVL) and chaff vinegar liquor (CVL) were evaluated, focusing mainly on electron donating ability to DPPH radical, reducing power against ferricyanide ($Fe^{3+}$), blockading ability to linoleic acid autoxidation and NO production from LPS-stimulated RAW264.7 cells plus cytotoxicity to RAW264.7 cells. The results showed that crude carbonated vinegar liquors, regardless of their source materials, have high capacity of antioxidation such as electron donating ability, reducing power, blockading ability to lipid peroxidation and NO production, as well as cell cytotoxicity. Refined carbonated vinegar liquors for skin care or bath showed significantly low cell cytotoxicity, however, overall antioxidant potencies were also low. Especially, these carbonated vinegar liquors revealed low levels of inhibition for NO production deeply involved in inflammation. Among nineteen carbonated vinegar liquors examined, chaff vinegar liquor was observed to be the most potent carbonated vinegar liquor with high antioxidant activities together with low cytotoxicity to mammalian cells.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.2
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• pp.249-254
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• 2004

Effect of mulberry tree powders on the antioxidant activity of submerged -liquid culture of mushrooms was investigated. Agaricus blazei (AB), Hericicum erinacium (HE), Pleurotus ostreatus (PO), Phellinus linteu (PL) and Paecilomyces japonicus (PJ) were cultured in a shaking incubator (200 rpm, $25^{\circ}C$) for 7 days in culture media: 1) basal medium (BM) and 2) BM+1% mulberry tree powders (BMM). Hot water extracts from the submerged-liquid cultures of mushrooms and BMM were freeze-dried for the measurement of antioxidant activity, of which reaction mixture (25 mL: 10 mL of 0.2 M sodium phosphate buffer, pH 8.0; 4.5 mL distilled water; and 10.5 mL ethanol) contained 275 $\mu$mol linoleic acid and one mg test sample. The reaction mixture was incubated in a shaking incubator (200 rpm, 4$0^{\circ}C$) for 16 days. Peroxide value (POV) was measured for a period of over 16 days, and malonaldehyde (MA) was determined only for samples from the day 16 of incubation. Mycelial weight of mushroom strains cultured in BMM was greater than BM. The antioxidant activities of AB-cultured in BW (AB-BMM) and HE-cultured in BMM (HE-BMM) were superior to those of other mushroom strains-cultured in BMM or BM and of BMM. These results suggest that mulberry tree powders enhance the antioxidant activity of submerged-liquid culture of mushroom strains. The AB-BMM and HE-BMM were the most active cultures.