• Nutritional Sciences
• /
• 제5권3호
• /
• pp.117-122
• /
• 2002

This study was designed to observe the effect of conjugated linoleic acid (CLA) supplementation on body fatness, fat cell sizes and leptin levels in male Sprague Dawley rats. Following weaning, forty rats were divided into 4 groups beef tallow (BT), fish oil (FO). beef tallow with CLA supplementation (BTC), and fish oil with CLA supplementation (FOC) group. For four weeks, all rats were fed experimental diets containing 12％ of total dietary fat (w/w) with or without 1％ CLA. After 4 weeks, the animals were sacrificed; the total carcass fat, plasma leptin levels, epididymal fat pad weights and fat cell sizes in adipose tissue were measured. CLA supplementation did not significantly affect the rat's body weights, total body fat, epididymal fat pad weights, and fat cell sizes. CLA also did not have a significant effect on plasma leptin levels. These results suggest that CLA supplement was not an effective way to reduce the body weights of male Sprague Dawley rats.

• Journal of Nutrition and Health
• /
• 제35권5호
• /
• pp.505-511
• /
• 2002

The study was designed to compare the anti-carcinogenic effect of different level of conjugated linoleic acid (CLA) in 1,2-dimethylhydrazine (DMH)-treated rats by determining biomarkers (apoptosis, cell proliferation, eicosanoids, 1,2-diacylglycerol) and phospholipid fatty acid profile in colonic mucosa. Eighty male Sprague Dawley rats weighing 180-220g were randomly divided into 4 groups depending on the content of CLA, i.e. 0.0% CLA, 0.5% CLA, 1.0% CLA, 1.5% CLA. The experimental diet contained protein 21.6%, carbohydrate 54.6%, and fat 14.5% including CLA mixture at different level 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 amount of 180 mg/kg body weight. Regardless of the amount of CLA supplemented to diet, CLA significantly increased the apoptotic index but did not have significant effect on cell proliferation in colonic mucosa. CLA was undetected in colonic mucosal phospholipid of rats fed the 0% CLA diet and increased to 5.9mg/g phospholipid in rats fed the 0.5% diet. The apoptotic index was increased by 251% and the 1,2-DAG content was decreased by 57% in rats fed 0.5% CLA. No further changes in these variables were observed when CLA in the diet was raised to 1.0% or 1.5%. However, dietary CLA decreased mucosal levels of prostaglandin (PG)E$_2$, thromboxane (TX)B$_2$, and arachidonic acid in dose-dependent manner. The present data indicate that dietary CLA can inhibit DMH-induced colon carcinogenesis by mechanism probably involving increased apoptosis.

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

• 한국식품과학회지
• /
• 제32권1호
• /
• pp.62-68
• /
• 2000

본 연구는 CLA를 이용한 다기능성 육제품의 제조 가능성을 알아보고자 첨가하는 지방의 일부를 CLA로 대체하여 돈육 patty를 제조하여 실험하였다. 제조된 patty를 $4^{\circ}C$의 냉장온도에서 11일 동안 저장하면서 이화학적 성질, 지방산 조성, 콜레스테롤 및 CLA 함량을 조사하였다. 조단백, 조지방은 유의적인 차이를 나타내지 않았지만, 조회분과 함유수분을 CLA 첨가 수준이 증가할수록 유의적으로 낮아지는 경향을 보였다. TBARS는 대조구에 비하여 CLA 첨가구가 유의적으로 낮은 결과를 보였으며, 저장기간이 경과함에 따라 모든 처리구가 유의적으로 증가하였다. Nitrite 함량은 CLA 첨가량이 증가할수록 유의적으로 감소하였으며, 콜레스테롤 함량은 CLA 첨가수준이 증가할수록 유의적으로 감소하는 경향을 나타내었고, CLA 첨가량이 증가할수록 CLA 축적량은 증가하였다. 이상의 결과 patty 제조시 CLA 첨가는 제품특성에 영향을 미치지 않으면서 제품의 저장기간의 연장, 콜레스테롤 함량 감소, nitrite 함량의 감소효과를 나타내어 고급 patty생산이 가능하리라 사료된다.

• Journal of Microbiology and Biotechnology
• /
• 제13권1호
• /
• pp.22-28
• /
• 2003

Increasing conjugated linoleic acid (CLA) content in dairy products has been a research Interest due to the potential health benefits resulted from consuming CLA. Attempts were made to obtain high level natural CLA containing fatty acid fractions from milk fat through bovine feeding of sunflower oil (SO) and urea fractionation. SO feeding changed the fatty acid profile of milk fat. increasing the CLA content five-fold at eight weeks of trial. Milk fat obtained from S0-fed cows was hydrolyzed to free fatty acids, which were then fractionated with urea at various ratios. The profiles of fatty acids were also greatly influenced by urea fractionation. Long-chain unsaturated fatty acids, Including CLA, were concentrated in milk fat after the fractionation, whereas saturated long-chain counterparts were eliminated. The highest level of CLA was achieved by the fractionation at 2:1 urea/fatty acid ratio (UFR2). CLA level was elevated 2.5-fold, and the Cl8:1/C18:0 fatty acid ratio was increased 120 times after the fractionation. The level of CLA in high CLA-milk fat (24mg/g fat) obtained from the feeding study was further increased through urea fractionation up to 52mg/g fat, 10 folds as high as CLA in the control milk fat (5mg/g fat).

• 한국축산식품학회지
• /
• 제31권3호
• /
• pp.381-388
• /
• 2011

Dietary conjugated linoleic acid (CLA) play key roles in lipid metabolism. Here, we investigated the effect of CLA on the transcriptional activity of TR4, an orphan nuclear receptor that plays an important role in lipid homeostasis. CLA increased TR4 gene mRNA level in 3T3-L1 adipocytes, but inhibited TR4 transcriptional activity in a dose-dependent manner. TR4 induced perilipin expression in 3T3-L1 adipocytes by activating perilipin promoter activity. In a gel shift assay, TR4 bound direct to the putative TR4 response element in the perilipin promoter. Interestingly, CLA reduced the interaction between TR4 and consensus DR1, a well-known TR4 binding site. Additionally, CLA inhibited TR4-induced perilipin promoter activity in a dose-dependent manner. Together, our results suggest that CLA may play a role in lipid homeostasis in adipocytes by functionally regulating TR4.

• 한국축산식품학회지
• /
• 제28권5호
• /
• pp.580-586
• /
• 2008

본 연구는 모유를 섭취하고 있는 생후 7일 이내의 신생아로부터 분리 및 선발된 L. acidophilus를 이용하여 다양한 생리활성을 가진 CLA를 천연적으로 생산하는 젖산균을 Screening하고 선정된 L. acidophilus에 의한 CLA의 최적 생성조건을 설정하기 위하여 실시하였다. 9종의 L. acidophilus를 LA가 $200{\mu}g/mL$의 수준으로 각각 첨가된 MRS 액체배지에 접종하여 48시간 배양한 후 L. acidophilus의 균체 세포막 내에서 형성된 cis-9, trans-11 CLA 함량과 배지 내 유리화된 cis-9, trans-11 CLA 함량을 측정한 결과, 생균수는 대부분 $10^8\;CFU/mL$ 수준이었으며 균체 내로 전환된 cis-9, trans-11 CLA는 검출되지 않거나 매우 미량 존재하였다. MRS 배지 내 유리화된 cis-9, trans-11 CLA는 전 시험 균주를 통해 생성되었으며 상대적으로 균체 내 생성량 보다 높게 나타났고, L. acidophilus NB 203과 NB 209의 생성량이 $26-27{\mu}g/mL$으로 가장 높게 나타났다. 동일한 조건으로 8% 탈지유 배지에 실험한 결과 배양 24시간째의 생균수는 $10^8\;CFU/mL$ 수준이었고, MRS 액체 배지에서의 결과와 유사하게 균체 세포막 내로 incorporation된 cis-9, trans-11 CLA는 대부분의 처리구에서 검출되지 않거나 매우 미량 존재하였으며, 반면 탈지유 배지 내 유리 cis-9, trans-11 CLA는 전 시험 균주를 통해 생성되었고 상대적으로 MRS 액체 배지에서의 생성량 보다 높았으며, 그 중 L. acidophilus NB 203 및 NB 209의 배양액 내 cis-9, trans-11 CLA 생성량이 가장 높게 나타났다. 시험 균주 중 cis-9, trans-11 CLA 생성능이 다른 균주에 비해 높은 것으로 나타난 L. acidophilus NB 203 및 NB 209를 8% 탈지유 배지에 LA 첨가량 및 배양시간을 달리하여 최적 조건을 설정하였으며, 두 시험 균주 모두 LA 첨가에 의한 증식억제 현상은 배양 48시간까지 $1.000{\mu}g/mL$ 첨가 수준에서는 전혀 나타나지 않았으며, $3,000{\mu}g/mL$ 첨가 시 미약하게 나타났다. 배양시간대 별 cis-9, trans-11 CLA 생성량은 두 시험 균주 모두 배양 24시간 이전의 대수증식 기에서 주로 증가하였으며, 배양 24시간 이후부터 생성량이 유지되거나 미량 감소하는 것으로 나타났다. LA의 첨가농도 별 cis-9, trans-11 CLA 생성에 있어 두 시험 균주 모두에서 LA 첨가량이 $1,000{\mu}g/mL$ 수준일 때 cis-9, trans-11 CLA 생성량이 가장 높았으나 $500{\mu}g/mL$ 첨가구와 큰 차이를 나타내지 않았으며, 특히 첨가량을 $3,000{\mu}g/mL$ 수준으로 높여도 $1,000{\mu}g/mL$ 수준일 때와 유사하거나 오히려 감소하는 경향을 보였다. 따라서 이 실험 균주의 최적 LA 생성조건은 탈지유 배지에 LA를 $500{\mu}g/mL$ 수준으로 첨가하여 $37^{\circ}C$에서 24시간 배양시로 나타났다.

• 한국축산식품학회:학술대회논문집
• /
• 한국축산식품학회 1998년도 정기총회 및 제21차 춘계학술발표회
• /
• pp.127-133
• /
• 1998

Ground beef에서 처음으로 분리된 conjugated linoleic acid (CLA)는 mouse epidermal carcinogenesis, mouse forestomach tumor, rat mammry carchnogenesis 및 colon carcinogenesis를 억제하는 항암성 효과를 지니고 있다. CLA는 항암성뿐만 아니라 anti-atherosclerosis, immune function과 항산화성 등의 생리활성 효능이 있는 것으로 밝혀졌으며, CLA의 주요 source는 반추동물에서 유래된 meat, 우유 및 유제품이며 일반 식물성유에도 미량으로 존재한다. 최근 국내외에서 CLA를 이용한 기능성 meat 및 식품을 생산하기 위한 연구가 수행되고 있다. 본 발표에서는 CLA에 관한 간단한 review와 본 연구진의 연구결과를 소개하고자 한다.

• Journal of Nutrition and Health
• /
• 제34권8호
• /
• pp.858-864
• /
• 2001

The study was designed to observe an antioxidant activities of conjugated linoleic acid(CLA) in rat liver by determining the activities of antioxidative enzymes(superoxide dismutase, glutathione peroxidase, catalase) and the levels of tocopherol and thiobarbituric acid reactive substance(TBARS). Male Sprague Dawley rats at weeks-old were divided into groups according to the types of dietary fat(beef tallow and fish oil) and then each group was subdivided into groups depending on CLA supplement. All rats were fed experimental diet containing 12% total fat including 1% CLA by weight for 30 weeks. CLA supplemented to beef tallow diet did not have significant effect on the level of TBARS and tocopherol. The level of TBARS was significantly increased in fish oil diet(highly unsaturated fat diet), but its level was significantly reduced by increasing SOD and GSH-Px activities when CLA was supplemented to fish oil diet so that CLA showed a sparing action of tocopherol in tissue. CLA did not have significant effect on peroxisomal catalase activities, but its activity was significantly increased when TBARS production was high in the fish oil diet. CLA could be incorporated into phospholipid of microsomal membrane, and interfered the conversions of C18 : 0 into C18 : 1 and C18 : 2 into C20 : 4 in liver. In conclusion, CLA had an antioxidant activities depending on the type of fat in diet. Therefore, it could be recommended to use CLA when highly unsaturated fat was used in meal preparation.

• Preventive Nutrition and Food Science
• /
• 제11권1호
• /
• pp.1-5
• /
• 2006

Conjugated linoleic acid (CLA) is a group of positional and geometric isomers of linoleic acid that have been used to reduce the incidence, growth and metastasis of breast, colon, prostate and gastric cancer in animals. CLA could reduce tumor growth by altering angiogenesis; a process requiring associated angiogenic factors such as vascular endothelial growth factor (VEGF). In this study, we determined whether CLA could modulate the expression of VEGF in murine mammary tumor cells and adipocytes. The c9, t11-CLA isomer reduced VEGF transcripts and protein when mammary tumor cells were stimulated with PMA. That isomer also reduced VEGF expression in un stimulated mouse 3T3-L1 adipocytes. Since VEGF can be regulated by cyclooxygenase-2 (COX-2), we determined whether CLA could alter COX-2 enzyme expression and $PGE_2$ production. The c9, t11-CLA isomer reduced not only COX-2 enzyme expression but also $PGE_2$ production. Thus, c9, t11-CLA could modulate neovascularization by alteration of VEGF expression from mammary tumor cells and adipocytes by reducing COX-2 metabolites.