• Nutritional Sciences
• /
• v.5 no.3
• /
• 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
• /
• v.35 no.5
• /
• 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
• /
• v.5 no.2
• /
• 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.

• Korean Journal of Food Science and Technology
• /
• v.32 no.1
• /
• pp.62-68
• /
• 2000

Effects of conjugated linoleic acid (CLA) on physico-chemical properties of cooked ground pork patty were investigated for 11 days at $4^{\circ}C$. Pork patties containing 0, 1, 2, and 3% CLA were cooked at $90^{\circ}C$ for 30 min. The contents of crude protein and fat did not change whereas the content of ash and water decreased as the level of CLA enhanced. Lipid oxidation as measured by thiobarbituric reactive substances of patty was inhibited by addition of CLA. CLA treatment also reduced nitrite and cholesterol content and changed fatty acid composition. Consequently, given these positive effects of CLA, it may be assumed that CLA could be used as a fat additive for value-added pork patty.

• Journal of Microbiology and Biotechnology
• /
• v.13 no.1
• /
• 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).

• Food Science of Animal Resources
• /
• v.31 no.3
• /
• 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.

• Food Science of Animal Resources
• /
• v.28 no.5
• /
• pp.580-586
• /
• 2008

Conjugated linoleic acid (CLA) is a mixture of positional and geometric isomers of linoleic acid with conjugated double bonds. These conjugated dienes were found to be responsible for many biological properties related to health. The objective of this study was to evaluate the production of cis-9, trans-11 CLA by Lactobacillus acidophilus isolated from breast-fed infants. Nine different cultures were tested for their ability to produce cis-9, trans-11 CLA from free linoleic acid in MRS broth and 8% reconstituted skim milk medium supplemented with linoleic acid at $37^{\circ}C$ for 48 hr. cis-9, trans-11 CLA was not detected or detected in very small amount when cell pellets of strains grown in MRS broth and 8% reconstituted skim milk supplemented with linoleic acid of $200{\mu}g/mL$. However, free cis-9, trans-11 CLA was produced in both media. It appeared that 8% reconstituted skim milk produced more cis-9, trans-11 CLA than MRS broth. L. acidophilus NB 203 and NB 209 produced more cis-9, trans-11 CLA than other tested cultures. The inhibitory effects of supplemented linoleic acid on the growth of L. acidophilus NB 203 and NB 209 were not detected up to $3,000{\mu}g/mL$ linoleic acid addition during the growth at $37^{\circ}C$ for 48 h. The production of cis-9, trans-11 CLA by these two L. acidophilus strains increased in the logarithmic growth phase until 24 hr incubation. Under this experimental condition, the best yield of CLA isomers for L. acidophilus NB 203 and NB 209 could be obtained from medium supplemented with $500{\mu}g/mL$ linoleic acid at $37^{\circ}C$ after 24 hr of incubation. These results indicate that the use of lactic acid bacteria producing free CLA in fermented dairy products may have potential health or nutritional benefits.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
• /
• 1998.05a
• /
• 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
• /
• v.34 no.8
• /
• 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
• /
• v.11 no.1
• /
• 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.