• Journal of the Korean Society of Food Science and Nutrition
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• v.20 no.4
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• pp.401-407
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• 1991

Anticarcinogenic conjugated dienoic derivatives of linoleic acid (CLA) is present in grilled beef, cheese, and related foods, CLA is generated via isomerization of linoleic acid in the cow's rumen by anaerobic bacteria and food proceessing as well. Another source of CLA is its endogenous generation via the carbon centered free radical oxdation of linoleic acid. We propose that the formation and generation of CLA in vivo represents a previously unrecognized in situ "defense mechanism" against membrane attack by oxygen free radicals. The cis, 9-trans, 11 CLS isomer is selectively incorporated into cellular phospholipid, which exhibits a potent antioxidant, reduces the activation of 2-amino-3-methylimidazo, [4,5-f] quinoline (IQ) for baxterial mutagenesis, and inhibits ornithine decarboxylase(ODC) activity induced by 12-0-tetradecanoylphorbol-13-acetate (TPA). We believe that at least these biological activities of CLA explain the anticarcinogenic activity of CLA.

• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.5
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• pp.565-569
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• 1993

Antioxidative activity of browning product(BP) fractionated from fermented soybean sauce(SS) was studied during the oxidation process of linoleic acid mixture system. SSBP was a powder type product prepared from fermented soybean sauce by the fractionation through the Sephadex G-10 column and freeze drying of collected fraction. The aqueous model systems were used for the evaluation of antioxidative activity of SSBP during the oxidative reaction at $50^{\circ}C$ by the determination of peroxider and conjugated dienoic acid compounds. The linoleic acid mixture for the aqueous model systems was consisted of linoleic acid(64.6%), oleic acid(27.4%), and other acids in ethanolic phosphate buffer solution(pH 7.0). SSBP had a considerable antioxidative activity with the inhibition of formation of peroxides and conjugated dienoic acids during the autoxidation of linoleic acid mixtures in aqueous model systems. Antioxidative activity of SSBP was relatively higher than SS, however, lower than ${\alpha}-tocopherol$ and butylated hydroxyanisol. The antioxidative effect of SSBP was increased by the its concentrations from 0.05% to 0.5% in the oxidation reactions of aqueous model systems. Therefore, SSBP was considered as one of the potential natural antioxidants for the use of food products.

• Preventive Nutrition and Food Science
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• v.4 no.3
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• pp.203-208
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• 1999

The effect of the polyunsaterated fatty acids, linoleic acid(LA), arachidonic acid(AA) and conjugated dienoic linoleic acid(CLA) on IEC-6 cells (rat intestinal cell)proliferation and cell transduction have been determined in vitro. IEC-6 cells proliferation was assessed by cell growth and [3H]-thymidine incroporation analysis. At 10 μM concentration , the proliferationof cells supplemented with AA or LA was significantly higher than that of CLA. [3H]-thymidine uptake showed the same results. LA and AA increased [3H]-thymidine uptake more than CLA. The stimulatory effect of LA or AA was even more pronounced in the presence of IGF. Both cell number analysis and [3H]-thymidine incorporation revealed that IEC-6 cell proliferation was influenced differently by exogenous free fatty acids, in which AA or LA stimulated IEC-6 cell proliferation and CLA inhibited it. Tyorosine phosphorylation provides a key switch to regulate celluar acitivity in response to extracellular stimuli. At 20 μM and 10μM, AA with IGF-1 stimulated protein tyrosine phophorylation in IEC-6 cells, but LA's impact was less than that of AA. CLA and CLA with IGF-1 inhibited protein tyrosine phosphorylation in IEC-6 cells. These results suggest there is a possible correlation between cell proliferation and IGF receptor tyrosine knase activity driven by AA.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.5
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• pp.972-977
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• 1997

Conjugated dienoic derivatives of linoleic acid(CLA) are a series of positional and gemotric isomers of linoleic acid which are found naturally in food, mainly dietary products and breef. We studied the effects of CLA on the growth of tumor cells and the production of interleukin-1(IL-1) and interleukin-2(IL-2). CLA treatment markedly inhibited the growth of Yac-1 cells and sarcoma-180 cells by 99 and 82% to that of control, respectively, after four days of incubation at 37$^{\circ}C$. To elucidate the immunological mechanism of antitumor activity of CLA, spleen cells of Balb/c mouse were exposed to 31, 63, 125, 250 $\mu\textrm{g}$ of CLA per ml for 24 hrs at 37$^{\circ}C$. The culture supernatants of CLA-exposed spleen cells reduced the production of IL-1 and IL-2 in all of the test conditions. These results indicate that the anticarcino-genic effect of CLA was mediated by the other actions rather than the production of the Il-1 or IL-2. We suggest that CLA might have an antiinflammatory effect in part due to its inhibitory action on the production of IL-1.

• Journal of Nutrition and Health
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• v.30 no.4
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• pp.442-450
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• 1997

Conjugated dienoic derivatives of linoleic acid(CLA) are a mixture of positional and geometric isomers of linoleic acid(LA). We previously found that CLA changes the fatty acid profile in chicken eggs and serum by decreasing monounsaturated fatty acids. Studies were conducted to explore the effects of CLA on fatty acid composition. Rabbits were fed a semisynthetic diet with or without CLA(0.5g CLA/rabbit/day) for 22 weeks. Compared to the control, rabbits fed CLA had significantly lower monounsaturated fatty acid levels(palmitoleic acid Cl6 : 1 by 50% and oleic acid Cl8 : 1, by 20%) in plasma lipids. We found similar differences in fatty acid composition in the liver and the aorta. The inhibitory effect of CLA on $\Delta$9 desaturation was confirmed in a human hepatoma cell line, Hep G2. CLA significantly decreased $\Delta$9 desaturation in 4-5 hours as shown by an increase in the ratio of Cl6 : 0 to C 16 1, This is apparently due to a decrease in $\Delta$9 desaturase(stearoyl-CoA desaturase, SCD) activity ; it was decreased more than 50%. These results, along with our previous findings, indicate that CLA is an inhibitor of $\Delta$9 desaturase in the liver.

• Preventive Nutrition and Food Science
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• v.8 no.3
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• pp.253-259
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• 2003

Conjugated linoleic acid (CLA) is a class of positional, geometric conjugated dienoic isomers of linoleic acid (LA). CLA activates the immune system, protects against tumorigenesis, and reduces the incidence of atherosclerosis. Trans-10, cis-12 CLA has specific effects on lipid metabolism, it has been shown to reduce body fat gain and regulates some adipocyte secreted proteins in vivo and in vitro. Here we report that a CLA mixture affects cytokine secretion from rat primary adipocytes. Rat primary adipocytes were treated with 1 mM, 100 $\mu$M, 1 $\mu$M or 100 nM CLA mixture doses; and leptin, tumor necrosis factor alpha (TNF a ), interleukin-6 (IL-6) and glycerol levels in the medium were measured. Leptin secretion was lower, TNF $\alpha$ secretion higher and IL-6 secretion did not change in response to the CLA mixture. Leptin and TNF $\alpha$ secretions did not change with CLA mixture treatment in a dose-dependent manner. In addition, the CLA mixture did not appear to enhance lipolysis in rat primary adipocytes. In conclusion, our study demonstrates that the decrease in leptin and increase in TNF $\alpha$ secretion in adipocytes treated with CLA mixture may be due to the apoptotic effect and to a reduction in peroxisome proliferator-activated receptor gamma (PPAR ${\gamma}$ ) ligands.

• Food Science of Animal Resources
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• v.36 no.2
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• pp.170-177
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• 2016

Conjugated linoleic acid (CLA) is a group of positional and geometric isomers of conjugated dienoic derivatives of linoleic acid. CLA has been reported to be able to reduce body fat. In this study, we investigated the antidiabetic effect of fermented milk (FM) containing CLA on type II diabetes db/db mice. Mice were treated with 0.2% low FM, 0.6% high FM, or Glimepiride (GLM) for 6 wk. Our results revealed that the body weight and the levels of fasting blood glucose, serum insulin, and leptin were significantly decreased in FM fed mice compared to db/db mice. Oral glucose tolerance and insulin tolerance were significantly ameliorated in FM fed mice compared to db/db mice. Consistent with these results, the concentrations of serum total cholesterol, triglycerides, and LDL cholesterol were also significantly decreased in FM fed mice compared to db/db mice. However, the concentration of HDL cholesterol was significantly higher in FM fed mice compared to db/db mice. These results were similar to those of GLM, a commercial anti-diabetic drug. Therefore, our results suggest that FM has anti-diabetic effect as a functional food to treat type II diabetes mellitus.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.3
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• pp.377-381
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• 2001

Chlorophyll a and b, pheophytin a and b and $\beta$-carotene, crude chlorophylls and carotenoids (CCC) extracts of mustard leaf kimchi were isolated by DEAE-sepharose CL-6B and Sepharose CL-6B colume and TLC. The effects of chlorophyll a and b, pheophytin a and b and $\beta$-carotene on linoleic acid autoxidation were examined by the determination of peroxide value and conjugated dienoic acid content. Among them, chlorophyll a showed greater antioxidative activity than others, followed by chlorophyll b, pheophytin a, pheophytin b and $\beta$-carotene. Degradation of pheophytin b was observed to be slower than others and $\beta$-carotene showed highest degradation level during the autoxidation reaction of linoleic acid.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.6
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• pp.1126-1133
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• 2002

Conjugated linoleic acid (CLA) is a collective term for a class of positional and geometric conjugated dienoic isomers of linoleic acid (LA) and has anti-cancer activity in experimental animals. We have previously observed that an isomeric mixture of CLA and trans-10,cis-12 (t10c12) inhibited cell growth in a dose-dependent manner whereas LA and cis-9,trans-11 (c9t11) had no effect. The present study examined whether the CLA mixture and t10c12 induce apoptotic cell death. TSU-Prl cells were incubated for three days in serum-free medium in the absence or presence of individual fatty acids, and the DNA fragmentation assay was performed. Cells treated with the CLA mixture or t10c12 produced a distinct oligonucleosomal ladder with different sizes of DNA fragments, a typical characteristic of cells undergoing apoptosis. By contrast, LA and c9t11 had no effect. Western immunoblot analysis of total lysates revealed that t10c12 reduced anti-apoptotic, 26 kDa, Bcl-2 protein levels by 49$\pm$8% compared with controls, whereas this CLA isomer did not alter pro-apoptotic,21 kDa, Bax protein levels. These results suggest that growth inhibitory effect of the t10c12 CLA isomer may, at least in part, be attributed to Increased apoptotic death in TSU-Prl cells.

• Food Science and Preservation
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• v.16 no.6
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• pp.884-892
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• 2009

We determined the chemical changes occurring in oil after exposure to high temperatures for various periods of time. Alterations in the chemical parameters of oil after heating for 30, 60, 90, and 120 min at 120C were investigated. The study involved cold-pressed perilla oil (CPPO), virgin perilla oil (VPO), and commercial heat press-extracted perilla oil (CHPEPO), and we assessed quality properties such as Hunter's color values, browning color intensity, acid value, conjugated dienoic acid level, peroxide value, total phenolic content, electron-donating ability, and fatty acid concentration. Hunter L values were higher for CPPO than for VPO or CHPEPO, whereas browning color intensity was greatest for CHPEPO. Peroxide value data showed higher levels of oxidation products in CPPO than in VPO or CHPEPO, whereas conjugated dienoic acid level was most increased in CHPEPO. The content of total phenolics and electron-donating ability were higher in CHPEPO than in CPPO or VPO. After thermal treatment, fatty acid content was most altered in CPPO; in particular, the level of polyunsaturated fatty acids dropped significantly. Hunter L value, acid value, conjugated dienoic acid level, and peroxide concentration also increased whereas Hunter a and b values, browning color intensity, and total phenolic content were decreased in perilla seed oils after thermal oxidation treatment.