• Journal of Nutrition and Health
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• 제36권7호
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• pp.661-666
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• 2003

The study was designed to compare the anti-carcinogenic effect of conjugated linoleic acid (CLA) isomers on colon carcinogenesis in 1,2-dimethylhydrazine (DMH)-treated rats by determining the levels of apoptosis, cell proliferation, eicosanoids and 1,2-diacylglycerol (DAG) in colonic mucosa. Sixty male Sprague Dawley rats were randomly divided into 3 groups depending on the types of CLA isomers, i.e. BT group (no CLA contained), CLA-C group (cis-9, trans11 isomer contained), and CLA- T group (trans-10, cis-12 isomer contained). The experimental diet was composed of protein at 20%, carbohydrate at 56.2%, and fat at 14.5% including 0.8% CLA isomers by weight. The experimental diet was fed for 14 weeks with the initiation of intramuscular injection of DMH, which was injected twice a week for 6 weeks to give total dose of l80mg per kg body weight. Two CLA isomers (c9t11 and t10c12) significantly increased the relative percentage of apoptosis but reduced cell proliferation in mucosal cell and also the levels of PGE$_2$, TXB$_2$, and DAG in colonic mucosa. However, there was no significant differences in anti-carcinogenic effect between c9t11 isomer and t10c12 isomer. Overall, colon carcinogenesis could be significantly inhibited by CLA isomers by increasing apoptosis and reducing cell proliferation, the levels of eicosanoids and DAG in colonic mucosa.

• 한국축산식품학회지
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• 제30권6호
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• pp.879-885
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• 2010

Conjugated linoleic acid (CLA) isomers are found naturally in foods, such as milk, milk products, beef and others, from biohydrogenation of vegetable oils. They are heterogenous group of isomers of linoleic acid in the family of polyunsaturated fatty acids. Among the isomers of linoleic acid cis9, trans11- CLA (c9, t11-CLA) and trans10, cis12- CLA (t10, c12-CLA) are found to be biologically active isomers. These biologically active isomers either individual or combined found to be health beneficial in various diseases, such as cancer, diabetes, obesity, and atherosclerosis, conclusive participation in physiological processes are necessary. This review focused on the current study of CLA in prevention of disease, such as cancer, diabetes and atherosclerosis, and their effective function in body fat reduction, improvement of bone and muscle mass at a cellular, clinical and systematic level.

• Preventive Nutrition and Food Science
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• 제5권2호
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• pp.86-92
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• 2000

Conjugated linoleic acid(CLA) refers to a collective term of positional and geometric isomers of linoleic acid, which are different in their biological activities. The predominant isomer of CLA in animal tissues is cis-9, trans-11; smaller amounts of trans-10, cis-12 CLA isomers, CLA methyl ester (CLA-ME) was chemically syn-thesized from linoleic acid by the alkaline isomerization method. The synthetic CLA-ME, mainly composed of cis-9, trans-11 CLA and trans-10, cis-12 CLA, was dissolved in acetone, stored at 68$^{\circ}C$ for 1 day, and the supernatant(cis-9, trans-11 CLA-Me) was separated from the precipitate (trans-10, cis-12 CLA-Me). After the processes were repeated three times at -68$^{\circ}C$, the whole processes were repeated three times at -71$^{\circ}C$ in order to increase the purity of these two isomers. The cis-9, trans-11 CLA-Me and trans-10, cis-12 CLA isomers were further purified by the urea adduct. Purities of the cis-9, trans-11 CLA-Me and trans-10, cis-12 CLA-Me were 90.3 and 99.9%, respec-tively. This method could be employed for the preparation of a large quantity of highly purified cis-9, trans-11 CLA-Me or trans-10, cis-12 CLA-Me from synthetic CLA-Me.

• 생명과학회지
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• 제27권8호
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• pp.965-973
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• 2017

CLA는 탄소가 18개(C18)인 linoleic acid의 이중결합이 C9,C11; C10,C12 위치로 이동됨으로 생성되는 입체이성(c,c; c,t; t,c; t,t)체를 총괄적으로 일컷는 말이다. 이론적으로 가능한 이성체 중에서 c9,t11-CLA가 rumen bacteria, lactic bacteria, 버섯균 등의 linoleate isomerase에 의해 linoleic acid로부터 생합성된다. 그러나 linoleic acid를 알카리 이성화로 합성한 CLA에는 이론적으로 가능한 모든 CLA 이성체가 존재한다. 그 중 c9,t11-CLA와 t10,c12-CLA가 약 45%씩 동일량 존재한다. CLA가 1939 년 linoleic acid의 elaidinization 반응에서 처음으로 소개되었으나 그 이후에는 과학적인 이용가치가 없어 과학자들의 관심의 대상이 되지 않았다. 그러나 1987년에 CLA가 7,12-dimethylbenz[a]anthracene (DMBA)으로 유도한 mouse skin carcinogenesis에서 항암성이 있다는 보고 이후 CLA에 관한 연구는 급속도로 증가하여 현재까지 약 6,100 연구논문이 발표되었다. CLA와 c9,t11-CLA 및 t10,c12-CLA 이성체는 in vitro와 in vivo에서 항암성, 항당뇨성, 항혈압성, 항동맥경화성, 면역증강성, 항산화성, 체지방감소성, testosterone 생산성 등의 생물학적 기능이 갖는다고 밝혀졌다. 이들 생리활성에 c9,t11-CLA와 t10,c12-CLA가 in vitro와 in vivo에서 다른 활성을 보이고 있다. 특히, 합성 CLA에 소량 혼합되어 있는 t,t-CLA가 carcinogen으로 유도한 동물모델이나 암세포에서 다른 이성체 보다 강한 항암성을 보이는 결과는 앞으로 더 많은 연구의 대상이 될 것이다. 본 총설에서는 CLA 관련 연구가 시작된 1939년부터 현재까지의 CLA 연구 트렌드를 살펴보고 밝혀진 주요 기능성을 보고한다.

• Journal of Nutrition and Health
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• 제37권7호
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• pp.533-539
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• 2004

It has been reported that CLA decreases fat deposition in vivo and in vitro experiments. Among CLA isomers, c9t11 and t10c12 have been shown to exert active biological activities. For example, t10c12 reduces body weight and increases lean body mass, whereas, c9t11 has little effect on body fattness. However, the underlying molecular mechanism for the anti-obesity action of CLA isomers are not well understood. The purpose of this study was to examine the effects of t10c12 and c9t11 on lipid accumulation, cell proliferation, cell death and the expression levels of Ucp genes which are proposed as targets for anti-obesity in 3T3-L1 preadipocytes. Isomers of CLA at 50$\mu$M were added into preadipocyte differentiation medium for 3, 6 and 9days. Control cells received only the vehicle in the differentiation medium. Cytochemical analyses for lipid accumulation, cell proliferation and apotosis were carried out to compare lipidogenesis and cellular activity. RT-PCR analysis of GAPDH, Ucp 2,3 and 4 were also performed to find any modulatory effects of CLA isomers on the metabolic genes. Lipid accumulation indicated by Oil Red-O staining was inhibited in CLA isomers as compared to the control. T10c12 isomer showed less lipidogenesis than c9t11 did. A decrease occurred in CLA isomers as shown by BrdU incorporation. Apotosis has occured at higher level in t10c12 when compared to that of t9c11. Ucp 2, 3 and 4 genes were also upregulated in CLA isomers. T10c12 showed higher level of Ucp gene expressions than the c9t11 did. The biological activities of CLA isomers were also found to be different during differentiation of 3T3-L1 preadipocytes, suggesting that different isomers may be active in certain stage of lipidogenesis. The results indicate that both c9t11 and t10c12 CLA isomers decrease lipidogenesis, inhibit cell proliferation, increase cell death and upregulate in Ucp gene expressions during 3T3-L1 preadipocyte differentiation. T10c12 isomer was more effective than c9t11 in overall anti-obesity activity.

• Nutrition Research and Practice
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• 제2권4호
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• pp.326-330
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• 2008

Conjugated linoleic acids (CLA) were identified in 1980's, since then it has been intensively studied due to its various beneficial health effects such as anti-inflammatory, anti-atherogenic, anti-carcinogenic and anti-diabetic/obesity effects. Isomer specificity of a number of CLA isomers, especially predominant isomer 9Z,11E- and 10E,12Z-CLA, is now recognized. However, the less prevalent CLA isomers have not been well characterized. Recently, studies have reported the distinctively different effects of 9E, 11E-CLA in colon cancer cells, endothelial cells, and macrophage cells compared to the rest of CLA isomers. In this review, various effects of CLAs, especially anti-inflammatory and anti-atherogenic effects, will be discussed with focusing on the isomer-specific effects and potential mechanism of action of CLA. At last, recent studies about 9E,11E-CLA in in vitro and animal models will be discussed.

• Asian-Australasian Journal of Animal Sciences
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• 제22권3호
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• pp.448-458
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• 2009

It has been well documented from animal and human studies that conjugated linoleic acid (CLA) has numerous beneficial effects on health. In chickens, CLA exerts many effects on performance ranging from egg quality and yolk lipids to meat quality. Although there are several CLA isomers available, not all CLA isomers have the same incorporation rates into egg yolk: cis-9,trans-11 and trans-10,cis-12 CLA isomers are more favorably deposited into egg yolk than other isomers investigated, but of the two isomers, the former has a higher incorporation rate than the latter. CLA alters the amounts and profiles of lipids in plasma, muscles and liver. Furthermore, increased liver weight was reported in chickens fed dietary CLA. As observed in egg yolk, marked reduction in intramuscular lipids as well as increased protein content was observed in different studies, leading to elevation in protein-to-fat ratio. Inconsistency exists for parameters such as body weight gain, feed intake, feed conversion ratio, egg production rate and mortality, depending upon experimental conditions. One setback is that hard-cooked yolks from CLA-consuming hens have higher firmness as refrigeration time and CLA are increased, perhaps owing to alterations in physico-chemistry of yolk. Another is that CLA can be detrimental to hatchability when provided to breeders: eggs from these breeders have impaired development in embryonic and neonatal stages, and have increased and decreased amounts of saturated fatty acids and monounsaturated fatty acids (MUFAs), respectively. Thus, both problems can be fully resolved if dietary sources rich in MUFAs are provided together with CLA. Emerging evidence suggests that CLA exerts a critical impact on stress and immune functions as it can completely nullify some of the adverse effects produced by immune challenges and reduce mortality in a dose-dependent manner. Finally, CLA is a key regulator of genes that may be responsible for lipid metabolism in chickens. CLA down-regulates both expression of the gene encoding stearoyl-CoA desaturase-1 and its protein activity in the chicken liver while up-regulating mRNA of sterol regulatory element-binding protein-l.

• Journal of Nutrition and Health
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• 제37권9호
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• pp.763-770
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• 2004

This study was designed to compare the anti-carcinogenic effect of conjugated linoleic acid isomers on tumor incidence, cell proliferation and the levels of thromboxane (TX) B$_2$, prostaglandin (PG) E$_2$ and 1,2-diacylglycerol (DAG), and the related enzyme expression of cyclooxygenase (COX)-2 and protein kinase C (PKC) in colonic mucosa of 1,2-dimethy- lhydrazine (DMH) -treated rats. One hundred eight male Sprague Dawley rats were randomly divided into 3 groups depending on the types of CLA isomers, i.e. control group (no CLA contained), c9t11 group (cis-9, trans-11 CLA contained), and t10c12 group (trans-10, cis-12 CLA contained). The experimental diet was composed of protein at 20%, carbohydrate at 56.2%, and fat at 14.5% including 1.0% CLA isomers by weight. The experimental diet was fed for 30 weeks with the initiation of intramuscular injection of DMH, which was injected twice a week for 6 weeks to give total dose of 180 mg per kg body weight. Two CLA isomers (c9, t11, t10, c12) significantly reduced tumor incidence and cell proliferation by reducing the protein expression of COX-2 and PKC, and the level of TXB$_2$, PGE$_2$, and DAG in colonic mucosa. However, there was no significant difference in anti-carcinogenic effect between c9t11-CLA and t10c12-CLA.

• 한국임상수의학회지
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• 제21권4호
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• pp.336-342
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• 2004

돼지 말초혈액 탐식세포(PMN 및 monocyte)의 탐식성에 있어서 CLA 이성체의 탐식증강 효과를 검토하였다. 탐식세포의 탐식석은 fowl cytomery로 분석하였으며 결과는 다음과 같다. 1. CLA 이성체(CLA mixture, 10t-12c CLA, 9c-11t CLA, 9c-11c CLA, 9t-11t CLA)를 직접 첨가하여 배양한 PMN과 PBMC 및 fowl cytometry cytograpy에서 세포크기에 의해 분획한 monocyte-rich fractiondpsms 탐식증강 효과가 없었다. 2. 각각의 CLA 이성체로 배양한 PBMN 배양상층액으로 PBMC의 탐식활성을 측정한 결과 증강효과는 관찰되지 않았다. 3. CLA 이성체로 배양한 PBMC 배양상층액 중 CLA mixture, 10t-12c CLA, 9c-11c CLA 처리군에서는 PMN과 monocyte-rich fraction의 탐식활성에 있어서 현저한 증강효과가 관찰되었다. 그러나, 말초혈액 탐식세포들은 9c-11c CLA와 9t-11t CLA로 배양한 PBMC 배양상층액에 의해서는 증강효과가 나타나지 않았다. 4. CLA 이성체로 배양한 PMN 배양상층액에 있어서는 PMN과 monocyte-rich fraction의 탐식성을 측정한 결과, 어느 경우에도 증강효과는 나타나지 않았다. 이상의 결과로부터 CLA 중 CLA mixture, 10t-12c CLA. 9c-11t CLA가 돼지 말초혈액 탐식세포에 대하여 탐식증강효과를 가지고 있으며 이러한 증강효과는 직접적이라기보다는 CLA에 의해 활성화된 단핵구세포에서 분비되는 탐식촉진인자를 함유한 가용성 물질에 의해 autocrine 또는 paracrine 양상으로 탐식세포에 작용하는 것으로 생각되었다.

• Journal of Animal Science and Technology
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• 제46권6호
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• pp.967-974
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• 2004

본 연구는 여 러 conjugated linoleic acid(CLA) 이성체가 돼지 지방전구세포의 분화에 미치는 영향을 구영하기 위해 수행하였다. 돼지 지방전구세포는 갓난 돼지의 등 지방에서 분리해서 성숙지방세포로 분화될 때 까지 배양했다. 여러 CLA 이성체를 배양중의 세포에 처리했다. 세포분화는 세포배양이 끝난 후 세포의 glycerol-3-phosphate의 활성도를 측정함으로써 구명했다. 20$\mu$M과 50$\mu$M의 transto-cis12 CLA 이성체는 돼지 지방천구세포의 분화를 억제했고，한펀 cis9-cisl1 이성체는 세포분화를 촉진했다. cis9-trans 11 과 trans9-trans11 이생체는 세포분화에 아무런 영향을 마치지 않았다. CLA의 세포분화에 미치는 작용은 배양후기 (day8${\sim}$14) 보다 배양전기(day 0${\sim}$ 8)에 더 두드러지게 나타냈다. 위의 결과는 여러 CLA 이성체는 돼지 지방천구세포 분화에 각각 다른 작용을 가짐을 나타낸다.