Dietary conjugated linolenic acid in relation to CLA differently modifies body fat mass and serum and liver lipid levels in rats

Conjugated Linolenic Acid (CLnA) vs Conjugated Linoleic Acid (CLA): A Comprehensive Review of Potential Advantages in Molecular Characteristics, Health Benefits, and Production Techniques

Conjugated linoleic acid (CLA) has been extensively characterized due to its many biological activities and health benefits, but conjugated linolenic acid (CLnA) is still not well understood. However, CLnA has shown to be more effective than CLA as a potential functional food ingredient. Current research has not thoroughly investigated the differences and advantages between CLnA and CLA. This article compares CLnA and CLA based on molecular characteristics, including structural, chemical, and metabolic characteristics. Then, the in vivo research evidence of CLnA on various health benefits is comprehensively reviewed and compared with CLA in terms of effectiveness and mechanism. Furthermore, the potential of CLnA in production technology and product protection is analyzed. In general, CLnA and CLA have similar physicochemical properties of conjugated molecules and share many similarities in regulation effects and pathways of various health benefits as well as in the production methods. However, their specific properties, regulatory capabilities, and unique mechanisms are different. The superior potential of CLnA must be specified according to the practical application patterns of isomers. Future research should focus more on the advantageous characteristics of different isomers, especially the effectiveness and safety in clinical applications in order to truly exert the potential value of CLnA.

Fatty acid isomerism: analysis and selected biological functions

The biological functions of fatty acids and the lipids in which they are esterified are determined by their chain length, double bond position and geometry and other structural motifs such as the presence of methyl branches. Unusual isomeric features in fatty acids of human foods such as conjugated double bonds or chain branching found in dairy products, some seeds and nuts, and marine foods potentially have important effects on human health. Recent advancements in identifying fatty acids with unusual double bond positions and pinpointing the position of methyl branches have empowered the study of their biological functions. We present recent advances in fatty acid structural elucidation by mass spectrometry in comparison with the more traditional methods. The double bond position can be determined by purely instrumental methods, specifically solvent-mediated covalent adduct chemical ionization (SM-CACI) and ozone induced dissociation (OzID), with charge inversion methods showing promise. Prior derivatization using the Paternò-Büchi (PB) reaction to yield stable structures that, upon collisional activation, yield the double bond position has emerged. The chemical ionization (CI) based three ion monitoring (MRM) method has been developed to simultaneously identify and quantify low-level branched chain fatty acids (BCFAs), unattainable by electron ionization (EI) based methods. Accurate identification and quantification of unusual fatty acid isomers has led to research progress in the discovery of biomarkers for cancer, diabetes, nonalcoholic fatty liver disease (NAFLD) and atherosclerosis. Modulation of eicosanoids, weight loss and the health significance of BCFAs are also presented. This review clearly shows that the improvement of analytical capacity is critical in the study of fatty acid biological functions, and stronger coupling of the methods discussed here with fatty acid mechanistic research is promising in generating more refined outcomes.

Pomegranate Seed Oil as a Source of Conjugated Linolenic Acid (CLnA) Has No Effect on Atherosclerosis Development but Improves Lipid Profile and Affects the Expression of Lipid Metabolism Genes in apoE/LDLR-/- Mice

The aim of this study was to evaluate the anti-atherosclerotic effect of pomegranate seed oil as a source of conjugated linolenic acid (CLnA) (cis-9,trans-11,cis-13; punicic acid) compared to linolenic acid (LnA) and conjugated linoleic acid (CLA) (cis-9,trans-11) in apoE/LDLR^-/- mice. In the LONG experiment, 10-week old mice were fed for the 18 weeks. In the SHORT experiment, 18-week old mice were fed for the 10 weeks. Diets were supplied with seed oils equivalent to an amount of 0.5% of studied fatty acids. In the SHORT experiment, plasma TCh and LDL+VLDL cholesterol levels were significantly decreased in animals fed CLnA and CLA compared to the Control. The expression of PPARα in liver was four-fold increased in CLnA group in the SHORT experiment, and as a consequence the expression of its target gene ACO was three-fold increased, whereas the liver's expression of SREBP-1 and FAS were decreased in CLnA mice only in the LONG experiment. Punicic acid and CLA isomers were determined in the adipose tissue and liver in animals receiving pomegranate seed oil. In both experiments, there were no effects on the area of atherosclerotic plaque in aortic roots. However, in the SHORT experiment, the area of atherosclerosis in the entire aorta in the CLA group compared to CLnA and LnA was significantly decreased. In conclusion, CLnA improved the lipid profile and affected the lipid metabolism gene expression, but did not have the impact on the development of atherosclerotic plaque in apoE/LDLR^-/- mice.

Conjugated linoleic acid regulates adipocyte fatty acid binding protein expression via peroxisome proliferator-activated receptor α signaling pathway and increases intramuscular fat content

Intramuscular fat (IMF) is correlated positively with meat tenderness, juiciness and taste that affected sensory meat quality. Conjugated linoleic acid (CLA) has been extensively researched to increase IMF content in animals, however, the regulatory mechanism remains unclear. Adipocyte fatty acid binding protein (A-FABP) gene has been proposed as candidates for IMF accretion. The purpose of this study is to explore the molecular regulatory pathways of CLA on intramuscular fat deposition. Here, our results by cell lines indicated that CLA treatment promoted the expression of A-FABP through activated the transcription factor of peroxisome proliferator-activated receptor α (PPARα). Moreover, in an animal model, we discovered that dietary supplemental with CLA significantly enhanced IMF deposition by up-regulating the mRNA and protein expression of PPARα and A-FABP in the muscle tissues of mice. In addition, our current study also demonstrated that dietary CLA increased mRNA expression of genes and enzymes involved in fatty acid synthesis and lipid metabolism the muscle tissues of mice. These findings suggest that CLA mainly increases the expression of A-FABP through PPARα signaling pathway and regulates the expression of genes and enzymes related to IMF deposition, thus increasing IMF content. These results contribute to better understanding the molecular mechanism of IMF accretion in animals for the improvement of meat quality.

Jacaranda oil administration improves serum biomarkers and bioavailability of bioactive conjugated fatty acids, and alters fatty acid profile of mice tissues

Jacaric acid, a conjugated linolenic acid (CLNA) present in jacaranda oil (JO), is considered a potent anticarcinogenic agent. Several studies have focused on its biological effects, but the metabolism once consumed is not clear yet. The aim of this work was to evaluate the effects of two different daily doses of JO on serum parameters and fatty acid (FA) profile of mice tissues after 4 weeks of feeding. No significant changes on body weight gain, food intake, or tissue weight were determined after 0.7 or 2 ml/kg of JO supplementation compared to control animals. Significantly lower blood low-density lipoproteins-cholesterol (20 mg/dl) and glucose (~147-148 mg/dl) levels were detected in both oil-treated groups compared to control (31.2 and 165 mg/dl, respectively). Moreover, jacaric acid was partially converted into cis9, trans11 conjugated linoleic acid (CLA) and thus further incorporated into tissues. Liver evidenced the highest total conjugated fatty acid content (1.1%-2.2%), followed by epididymal (0.7%-1.9%) and mesenteric (1.4%-1.8%) fat. Lower saturated and higher unsaturated fatty acid content was detected in both oil-treated groups compared to control. Our results support the safety of JO and its potential application with a functional or nutraceutical propose, by increasing human CLNA consumption and further availability of CLA.

Conjugated Fatty Acids in Muscle Food Products and Their Potential Health Benefits: A Review

Conjugated fatty acids (CFAs) are a group of positional and geometric isomers of polyunsaturated fatty acids (PUFAs) with conjugated double bonds. There are several subgroups of CFAs including conjugated linoleic acids (CLAs), conjugated linolenic acids (CLNAs), conjugated eicosapentaenoic acids (CEPAs), and conjugated docosahexaenoic acids (CDHAs). CFAs, especially CLAs, have been studied in recent years both for their health benefits and factors that affect their level in muscle food products. CFAs have been reported in numerous studies as having antitumor, antiobesity, antidiabetes, anticardiovascular disease, and modulating immune system effects. These biological activies are involved in changes of lipid peroxidation and energy expenditure, as well as inhibitory effects on the hormone receptor, lipid metabolism, lipoprotein lipase activity, and adiponectin production. A large body of studies has revealed that the diet, processing, storage conditions, slaughter season, and age are common factors that affect CFA content in muscle food products, as detailed in this review. Recommendations are made regarding animal farming and meat product processing to obtain high CFA content meat products and to optimize the benefits of CFA for health promotion.

Punica granatum L.-derived omega-5 nanoemulsion improves hepatic steatosis in mice fed a high fat diet by increasing fatty acid utilization in hepatocytes

Pomegranate seed oil (PSO) is mainly composed of punicic acid (PA), a polyunsaturated fatty acid also known as omega-5 (ω-5), a potent antioxidant associated with a variety of metabolic and cellular beneficial effects. However, the potential benefits of a nanoemulsified version of ω-5 (PSOn) have not been evaluated in a pathological liver condition. Here, we examined whether PSOn had beneficial effects on C57BL/6N mice fed a high-fat diet (HFD), specifically on hepatic steatosis. We observed that PSOn supplementation decreased body weight and body fat mass in control mice, whereas glucose intolerance, insulin resistance, energy expenditure, and hepatic steatosis were improved in both control mice and in mice fed a HFD. Interestingly, PSOn increased fatty acid oxidation in primary hepatocytes and antioxidant gene expression. Altogether, our data indicate that PSOn effectively reduces some of the HFD-derived metabolic syndrome indicators by means of an increase in fatty acid oxidation within hepatocytes.

Thladiantha Seed Oils - New Source of Conjugated Fatty Acids: Characterization of Triacylglycerols and Fatty Acids

In this study, seed oils of Thladiantha nudiflora and Thladiantha dubia were found to contain 55.5 and 44.4% mole of conjugated octadecatrienoic fatty acids, respectively. The presence of moieties of conjugated fatty acids was confirmed by a series from physical methods: UV, IR, ¹H and ¹³C NMR. The triacylglycerols (TAGs) isolated of the seed oils were studied by RP-HPLC with diode array and mass spectrometric detections. It was shown that all 15 TAGs of Thladiantha dubia contain moieties of conjugated fatty acids - punicic, (9Z,11E,13Z)-octadeca-9,11,13-trienoic acid (35.6% mole) and 8.9% mole α-eleostearic, (9Z,11E,13E)-octadeca-9,11,13-trienoic acid. Meanwhile, 24 TAGs of Thladiantha nudiflora seed oil contain both acids in approximately equal proportions (27.4:28.2 % mole). The enrichment for polyunsaturated fatty acids of the hydrolysis product of the seed oils due to urea inclusion complex formation was discussed.

Gut microbiota-derived metabolites in obesity: a systematic review

Recent evidence suggests that gut microbiota-derived metabolites affect many biological processes of the host, including appetite control and weight management. Dysbiosis of the gut microbiome in obesity influences the metabolism and excretion of gut microbiota byproducts and consequently affects the physiology of the host. Since identification of the gut microbiota-host co-metabolites is essential for clarifying the interactions between the intestinal flora and the host, we conducted this systematic review to summarize all human studies that characterized the gut microbiota-related metabolites in overweight and obese individuals. A comprehensive search of the PubMed, Web of Science, and Scopus databases yielded 2,137 articles documented up to July 2018. After screening abstracts and full texts, 12 articles that used different biosamples and methodologies of metabolic profiling and fecal microbiota analysis were included. Amino acids and byproducts of amino acids, lipids and lipid-like metabolites, bile acids derivatives, and other metabolites derived from degradation of carnitine, choline, polyphenols, and purines are among the gut microbiota-derived metabolites which showed alterations in obesity. These metabolites play an important role in metabolic complications of obesity, including insulin resistance, hyperglycemia, and dyslipidemia. The results of this study could be useful in development of therapeutic strategies with the aim of modulating gut microbiota and consequently the metabolic profile in obesity.

Beneficial Effects of a Low-dose of Conjugated Linoleic Acid on Body Weight Gain and other Cardiometabolic Risk Factors in Cafeteria Diet-fed Rats

Conjugated linoleic acid (CLA) is a dietary supplement that has been shown to improve obesity. However, some authors have associated high doses of CLA supplementation with liver impairment and insulin resistance. The aim of this study was to assess whether the consumption of low doses of CLA maintained the beneficial effects on the main metabolic disturbances associated with metabolic syndrome (MetS) but prevented the occurrence of non-desirable outcomes associated with its consumption. Male Wistar rats, fed standard or cafeteria (CAF) diet for 12 weeks, were supplemented with three different low doses of CLA in the last three weeks. Both biochemical and H¹ NMR-based metabolomics profiles were analysed in serum and liver. The consumption of 100 mg/kg CLA, but not doses of 200 and 300 mg/kg, ameliorated the increase in body weight gain as well as the serum concentrations of glucose, insulin, cholesterol, triglyceride, diglyceride, and total phospholipid induced by a CAF diet. In turn, CLA reverted the increase in lactate, alanine, and glucose concentrations in the liver of these animals, but enhanced hepatic cholesterol accumulation without any detrimental effect on liver function. In conclusion, a low dose of CLA corrected the adverse effects associated with MetS without compromising other metabolic parameters.

Liver and serum lipids in Wistar rats fed a novel structured lipid containing conjugated linoleic acid and conjugated linolenic acid

Conjugated linoleic acid (CLA) and conjugated linolenic acid (CLnA) have been known to have several health-promoting effects. The aim of this study was to introduce a novel structured lipid (SL) including both CLA and CLnA (cis9, trans11, cis13-18:3, punicic acid) into one triacylglycerol (TAG) molecule through enzymatic interesterification and investigate its effect on body weight, liver and serum lipids in Wistar rats. CLA oil, pomegranate seed oil (as a rich source of CLnA) and soybean oil (as a negative control) were applied as other experimental oils. The rats were fed the oils at 1500 mg/kg body weight per day via oral gavage for 45 days. Gas chromatography analysis showed that SL included CLnA and CLA in roughly equal concentrations. The in vivo study revealed that SL had the greatest effect on the reduction in liver lipid weight (4.65 g/100g of liver) and liver TAG (13.28 mg/g) compared to soybean oil (8.7 g/100g and 18.8 mg/g, respectively). High density lipoprotein cholesterol (HDL-C) in the serum of rats which were fed CLA oil significantly (p < 0.05) increased (from 0.95 to 1.14 mmol/l). Pomegranate seed oil reduced low density lipoprotein cholesterol (LDL-C) and total cholesterol (about 40% and 24% reduction, respectively). A remarkable TAG reduction (p < 0.05) was observed in all treated rats.

The Human Gut Microbiome - A Potential Controller of Wellness and Disease

Interest toward the human microbiome, particularly gut microbiome has flourished in recent decades owing to the rapidly advancing sequence-based screening and humanized gnotobiotic model in interrogating the dynamic operations of commensal microbiota. Although this field is still at a very preliminary stage, whereby the functional properties of the complex gut microbiome remain less understood, several promising findings have been documented and exhibit great potential toward revolutionizing disease etiology and medical treatments. In this review, the interactions between gut microbiota and the host have been focused on, to provide an overview of the role of gut microbiota and their unique metabolites in conferring host protection against invading pathogen, regulation of diverse host physiological functions including metabolism, development and homeostasis of immunity and the nervous system. We elaborate on how gut microbial imbalance (dysbiosis) may lead to dysfunction of host machineries, thereby contributing to pathogenesis and/or progression toward a broad spectrum of diseases. Some of the most notable diseases namely Clostridium difficile infection (infectious disease), inflammatory bowel disease (intestinal immune-mediated disease), celiac disease (multisystemic autoimmune disorder), obesity (metabolic disease), colorectal cancer, and autism spectrum disorder (neuropsychiatric disorder) have been discussed and delineated along with recent findings. Novel therapies derived from microbiome studies such as fecal microbiota transplantation, probiotic and prebiotics to target associated diseases have been reviewed to introduce the idea of how certain disease symptoms can be ameliorated through dysbiosis correction, thus revealing a new scientific approach toward disease treatment. Toward the end of this review, several research gaps and limitations have been described along with suggested future studies to overcome the current research lacunae. Despite the ongoing debate on whether gut microbiome plays a role in the above-mentioned diseases, we have in this review, gathered evidence showing a potentially far more complex link beyond the unidirectional cause-and-effect relationship between them.

Pomegranate seed oil influences the fatty acids profile and reduces the activity of desaturases in livers of Sprague-Dawley rats

The aim of our study was to compare the influence of diet supplementation with pomegranate seed oil - as conjugated linolenic acids (CLnA) source, or conjugated linoleic acids (CLA) and to examine the mechanism of their activity. The content of fatty acids, levels of biomarkers of lipids' oxidation and the activity of key enzymes catalyzing lipids metabolism were measured. Obtained results revealed that conjugated fatty acids significantly decrease the activity of Δ5-desaturase (p=0.0001) and Δ6-desaturase (p=0.0008) and pomegranate seed oil reduces their activity in the most potent way. We confirmed that diet supplementation with pomegranate seed oil - a rich source of punicic acid leads to the increase of cis-9, trans-11 CLA content in livers (p=0.0003). Lack of side effects and beneficial influence on desaturases activity and fatty acids profile claim pomegranate seed oil to become interesting alternative for CLA as functional food.

The effect of pomegranate fresh juice versus pomegranate seed powder on metabolic indices, lipid profile, inflammatory biomarkers, and the histopathology of pancreatic islets of Langerhans in streptozotocin-nicotinamide induced type 2 diabetic Sprague-Dawley rats

BACKGROUND

Type 2 diabetes mellitus (T2DM) is associated with hyperglycemia, inflammatory disorders and abnormal lipid profiles. Several functional foods have therapeutic potential to treat chronic diseases including diabetes. The therapeutic potential of pomegranate has been stated by multitudinous scientists. The present study aimed to evaluate the effects of pomegranate juice and seed powder on the levels of plasma glucose and insulin, inflammatory biomarkers, lipid profiles, and health of the pancreatic islets of Langerhans in streptozotocin (STZ)-nicotinamide (NAD) induced T2DM Sprague Dawley (SD) rats.

METHODS

Forty healthy male SD rats were induced to diabetes with a single dose intra-peritoneal administration of STZ (60 mg/kg b.w.) - NAD (120 mg/kg b.w.). Diabetic rats were orally administered with 1 mL of pomegranate fresh juice (PJ) or 100 mg pomegranate seed powder in 1 mL distilled water (PS), or 5 mg/kg b.w. of glibenclamide every day for 21 days. Rats in all groups were sacrificed on day 22. The obtained data was analyzed by SPSS software (v: 22) using One-way analysis of variance (ANOVA).

RESULTS

The results showed that PJ and PS treatment had slight but non-significant reduction of plasma glucose concentration, and no impact on plasma insulin compared to diabetic control (DC) group. PJ lowered the plasma total cholesterol (TC) and triglyceride (TG) significantly, and low-density lipoproteins (LDL) non-significantly compared to DC group. In contrast, PS treatment significantly raised plasma TC, LDL, and high-density lipoproteins (HDL) levels compared to the DC rats. Moreover, the administration of PJ and PS significantly reduced the levels of plasma inflammatory biomarkers, which were actively raised in diabetic rats. Only PJ treated group showed significant repairment and restoration signs in islets of Langerhans. Besides, PJ possessed preventative impact against 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals almost 2.5 folds more than PS.

CONCLUSIONS

Our findings suggest that active constituents with high antioxidant properties present in PJ are responsible for its anti-hyperlipidemic and anti-inflammatory effects, likewise the restoration effect on the damaged islets of Langerhans in experimental rats. Hence, the pharmacological, biochemical, and histopathological profiles of PJ treated rats obviously indicated its helpful effects in amelioration of diabetes-associated complications.

Bifidobacterium breve with α-linolenic acid alters the composition, distribution and transcription factor activity associated with metabolism and absorption of fat

This study focused on the mechanisms that fatty acid conjugating strains - Bifidobacterium breve NCIMB 702258 and Bifidobacterium breve DPC 6330 - influence lipid metabolism when ingested with α-linolenic acid (ALA) enriched diet. Four groups of BALB/c mice received ALA enriched diet (3% (w/w)) either alone or in combination with B. breve NCIMB 702258 or B. breve DPC 6330 (10⁹ CFU/day) or unsupplemented control diet for six weeks. The overall n-3 PUFA score was increased in all groups receiving the ALA enriched diet. Hepatic peroxisomal beta oxidation increased following supplementation of the ALA enriched diet with B. breve (P < 0.05) and so the ability of the strains to produce c9t11 conjugated linoleic acid (CLA) was identified in adipose tissue. Furthermore, a strain specific effect of B. breve NCIMB 702258 was found on the endocannabinoid system (ECS). Liver triglycerides (TAG) were reduced following ALA supplementation, compared with unsupplemented controls (P < 0.01) while intervention with B. breve further reduced liver TAG (P < 0.01), compared with the ALA enriched control. These data indicate that the interactions of the gut microbiota with fatty acid metabolism directly affect host health by modulating n-3 PUFA score and the ECS.

Serum levels of appetite-regulating hormones and pro-inflammatory cytokines are ameliorated by a CLA diet and endurance exercise in rats fed a high-fat diet

PURPOSE

This study examined whether conjugated linoleic acid (CLA) supplementation and endurance exercise affect appetite-regulating hormones and pro-inflammatory cytokines in rats.

METHODS

Seven-week-old male Sprague-Dawley rats were divided randomly into the high-fat diet sedentary group (HS, n=8), the 1.0% CLA supplemented high-fat diet sedentary group (CS, n=8), and the 1.0% CLA supplemented high-fat diet exercise group (CE, n=8). Rats in the CE group swam 60 min/day, 5 days/week for 4 weeks.

RESULTS

Leptin and insulin levels in the CS and CE groups were significantly lower than those in the HS group (p<0.001), whereas leptin (p<0.01) and insulin (p<0.05) levels decreased significantly in the CE compared to those in the CS group. Interleukin (IL)-1β (p<0.001) and IL-6 (p<0.01) levels in the CS and CE groups decreased significantly compared to those in the HS group. Leptin (IL-1β: r=0.835, p<0.001), IL-6 (r=0.607, p<0.05), insulin (IL-1β: r=0.797, p<0.01), and IL-6 (r=0.827, p<0.01) levels were positively related with pro-inflammatory cytokine levels.

CONCLUSION

Endurance exercise may play an important role during CLA supplementation of rats on a high-fat diet.

Sources and Bioactive Properties of Conjugated Dietary Fatty Acids

The group of conjugated fatty acids known as conjugated linoleic acid (CLA) isomers have been extensively studied with regard to their bioactive potential in treating some of the most prominent human health malignancies. However, CLA isomers are not the only group of potentially bioactive conjugated fatty acids currently undergoing study. In this regard, isomers of conjugated α-linolenic acid, conjugated nonadecadienoic acid and conjugated eicosapentaenoic acid, to name but a few, have undergone experimental assessment. These studies have indicated many of these conjugated fatty acid isomers commonly possess anti-carcinogenic, anti-adipogenic, anti-inflammatory and immune modulating properties, a number of which will be discussed in this review. The mechanisms through which these bioactivities are mediated have not yet been fully elucidated. However, existing evidence indicates that these fatty acids may play a role in modulating the expression of several oncogenes, cell cycle regulators, and genes associated with energy metabolism. Despite such bioactive potential, interest in these conjugated fatty acids has remained low relative to the CLA isomers. This may be partly attributed to the relatively recent emergence of these fatty acids as bioactives, but also due to a lack of awareness regarding sources from which they can be produced. In this review, we will also highlight the common sources of these conjugated fatty acids, including plants, algae, microbes and chemosynthesis.

Incorporation and effects of punicic acid on muscle and adipose tissues of rats

BACKGROUND

This study evaluated the effect of pomegranate seed oil (PSO) supplementation, rich in punicic acid (55 %/C18:3-9c,11 t,13c/CLNA), on the lipid profile and on the biochemical and oxidative parameters in the gastrocnemius muscle and adipose tissues of healthy rats. Linseed oil (LO), rich in linolenic acid (52 %/C18:3-9c12c15c/LNA) was used for comparison.

METHODS

Male Wistar rats (n = 56) were distributed in seven groups: control (water); LNA 1 %, 2 % and 4 % (treated with LO); CLNA 1 %, 2 % and 4 % (treated with PSO), po for 40 days. The percentages were compared to the daily feed intake. Fatty acid profile were performed by gas chromatography, antioxidant enzymes activity by spectrophotometer and the adipocytes were isolated by collagenase tissue digestion. Analysis of variance (ANOVA) was applied to check for differences between the groups (control, LNAs and CLNAs) and principal component analysis (PCA) was used to project the groups in the factor-place (PC1 vs PC2) based on the biochemical responses assessed in the study.

RESULTS

The fatty acids profile of tissues showed that the LNA percentages were higher in the animals that were fed LO. However, PA was only detected in the adipose tissues. Conjugated linoleic acid (CLA) was present in all the tissues of the animals supplemented with PSO, in a dose dependent manner, and 9c11t-CLA was the predominant isomer. Nevertheless there were no changes in the total weight gain of the animals, the weights of the tissues, and the oxidative stress parameters in the muscle. In addition, there was an increase in the size of the epididymal fat cells in the groups treated with PSO. Principal component analysis (PCA) showed that the CLNAs groups were arranged separately with a cumulative variance of 68.47 %.

CONCLUSIONS

The results show that PSO can be used as a source of CLAs but that it does not cause changes in body modulation and does not interfere in the antioxidant activity of healthy rats.

Involvement of dietary Fatty acids in multiple biological and psychological functions, in morbidly obese subjects

BACKGROUND

Fatty acid (FA) profile is often altered, in morbidly obese subjects, both before and after bariatric surgery. We measured FA plasma levels before and 6 months after Roux-en-Y gastric bypass (RYGB), in order to evaluate their relationship with different biological and psychological parameters and the impact of RYGB on the FA plasma levels.

METHODS

Thirty eight morbidly obese patients were investigated before RYGB, and 28 of them were reexamined 6 months postoperatively. Anxiety, depression, and quality of life were evaluated by validated questionnaires. Plasma FA (saturated, monounsaturated, polyunsaturated ω-6 and ω-3), vitamins A and E, fasting insulinemia, and high-sensitive C-reactive protein (hs-CRP) were measured.

RESULTS

Before surgery, ω-3 polyunsaturated FA and vit A showed significant negative relationship with fasting insulinemia (γ-linolenic p = 0.03, eicosapentaenoic, vit A p = 0.01) and hs-CRP (eicosapentaenoic p = 0.03, vit A p = 0.02) and a positive link with HDL cholesterol (γ-linolenic p = 0.03, vit A p = 0.02). Depression score was significantly and negatively linked with palmitoleic (p = 0.03), γ-linolenic (p = 0.006), dihomo-γ-linolenic (p = 0.02), and α-linolenic (p = 0.03) acids. After surgery, FA and both vit A and E were significantly reduced. Vit A levels were below 2.4 μmol/l in 63 % of the patients, preoperatively, and in 79 % after surgery. Preoperative levels of linoleic acid were significantly related with the postoperative weight reduction (p = 0.0006).

CONCLUSIONS

FA are involved in several biological and psychological functions. The RYGB-induced reduction of FA could have deleterious consequences on vitamin absorption, metabolism, and depression. Thus, the surveillance of FA levels is of primary importance both before and after RYGB.

Effects of postweaning administration of conjugated linoleic acid on development of obesity in nescient basic helix-loop-helix 2 knockout mice

Conjugated linoleic acid (CLA) has been reported to prevent body weight gain and fat accumulation in part by improving physical activity in mice. However, the effects of postweaning administration of CLA on the development of obesity later in life have not yet been demonstrated. The current study investigated the role of postweaning CLA treatment on skeletal muscle energy metabolism in genetically induced inactive adult-onset obese model, nescient basic helix-loop-helix 2 knockout (N2KO) mice. Four-week-old male N2KO and wild type mice were fed either control or a CLA-containing diet (0.5%) for 4 weeks, and then CLA was withdrawn and control diet provided to all mice for the following 8 weeks. Postweaning CLA supplementation in wild type animals, but not N2KO mice, may activate AMP-activated protein kinase (AMPK) and peroxisome proliferator-activated receptor-δ (PPARδ) as well as promote desensitization of phosphatase and tensin homologue (PTEN) and sensitization of protein kinase B (AKT) at threonine 308 in gastrocnemius skeletal muscle, improving voluntary activity and glucose homeostasis. We suggest that postweaning administration of CLA may in part stimulate the underlying molecular targets involved in muscle energy metabolism to reduce weight gain in normal animals, but not in the genetically induced inactive adult-onset animal model.

Modulation of peroxisome proliferator-activated receptor gamma (PPAR γ) by conjugated fatty acid in obesity and inflammatory bowel disease

Conjugated fatty acids including conjugated linoleic acid (CLA) and conjugated linolenic acid (CLNA) have drawn significant attention for their variety of biologically beneficial effects. Evidence suggested that CLA and CLNA could play physiological roles by regulating the expression and activity of PPAR γ. This review summarizes the current understanding of evidence of the role of CLA (cis-9,trans-11 CLA and trans-10,cis-12 CLA) and CLNA (punicic acid and α-eleostearic acid) in modulating the expression or activity of PPAR γ that could in turn be employed as complementary treatment for obesity and inflammatory bowel disease.

Conjugated linolenic acids and their bioactivities: a review

Conjugated linolenic acid (CLNA) is a mixture of positional and geometric isomers of octadecatrienoic acid (α-linolenic acid, cis9,cis12,cis15-18:3 n-3) found in plant seeds. Three 8,10,12-18:3 isomers and four 9,11,13-18:3 isomers have been reported to occur naturally. CLNA isomers such as punicic acid, α-eleostearic acid and jacaric acid have been attributed to exhibit several health benefits that are largely based on animal and in vitro studies. This review has summarized and updated the evidence regarding the metabolism and bioactivities of CLNA isomers, and comprehensively discussed the recent studies on the effects of anti-carcinogenic, lipid metabolism regulation, anti-inflammatory, anti-obese and antioxidant activities of CLNA isomers. The available results may provide a potential application for CLNA isomers from natural sources, especially edible plant seeds, as effective functional food ingredients and dietary supplements for the above mentioned disease management. Further research, especially human randomized clinical trials, is warranted to investigate the detailed physiological effects, bioactivity and molecular mechanism of CLNA.

Apoptosis- and differentiation-inducing activities of jacaric acid, a conjugated linolenic acid isomer, on human eosinophilic leukemia EoL-1 cells

Conjugated linolenic acids (CLNAs) are a group of naturally occurring positional and geometrical isomers of the C18 polyunsaturated essential fatty acid, linolenic acid (LNA), with three conjugated double bonds (C18:3). Although previous research has demonstrated the growth-inhibitory effects of CLNA on a wide variety of cancer cell lines in vitro, their action mechanisms and therapeutic potential on human myeloid leukemia cells remain poorly understood. In the present study, we found that jacaric acid (8Z,10E,12Z-octadecatrienoic acid), a CLNA isomer which is present in jacaranda seed oil, inhibited the in vitro growth of human eosinophilic leukemia EoL-1 cells in a time- and concentration-dependent manner. Mechanistic studies showed that jacaric acid triggered cell cycle arrest of EoL-1 cells at the G0/G1 phase and induced apoptosis of the EoL-1 cells, as measured by the Cell Death Detection ELISAPLUS kit, Annexin V assay and JC-1 dye staining. Notably, the jacaric acid-treated EoL-1 cells also underwent differentiation as revealed by morphological and phenotypic analysis. Collectively, our results demonstrated the capability of jacaric acid to inhibit the growth of EoL-1 cells in vitro through triggering cell cycle arrest and by inducing apoptosis and differentiation of the leukemia cells. Therefore, jacaric acid might be developed as a potential candidate for the treatment of certain forms of myeloid leukemia with minimal toxicity and few side effects.

Effect of high hydrostatic pressure on the production of conjugated fatty acids and trans fatty acids by Bifidobacterium breve LMC520

This study was performed to investigate the effect of high hydrostatic pressure (HHP) on the conversion of linoleic acid, conjugated linoleic acid (CLA), and α-linolenic acid (α-LNA) as substrates by Bifidobacterium breve LMC520 and to optimize the HHP condition. Cell mixture were tested under HHP in a variety of conditions such as temperature, time, pressure, and pre- or post-treatment with substrates. The cis-9,trans-11 CLA producing activity of B. breve LMC520 was increased by HHP, whereas trans-9,trans-11 CLA producing activity was decreased. Optimal HHP conditions for the highest CLA production were obtained at 100 MPa for 12 h at 37 °C. Post-treatment groups showed higher conversion activity of substrates than pretreatment groups. Post-treatment groups decreased trans-9,trans-11 CLA and other CLnA, whereas the pretreatment groups increased them. It is concluded that HHP treatment could be an important factor to enhance CLA and CLnA production and for reducing trans-fatty acids.

Bitter melon seed oil-attenuated body fat accumulation in diet-induced obese mice is associated with cAMP-dependent protein kinase activation and cell death in white adipose tissue

The aim of this study was to investigate the antiadiposity effect of bitter melon seed oil (BMSO), which is rich in the cis-9, trans-11, trans-13 isomer of conjugated linolenic acid. In Expt. 1, C57BL/6J mice were fed a butter-based, high-fat diet [HB; 29% butter + 1% soybean oil (SBO)] for 10 wk to induce obesity. They then continued to receive that diet or were switched to an SBO-based, high-fat diet alone (HS; 30% SBO) or containing bitter melon seed oil (BMSO) (HBM; 15% SBO + 15% BMSO) for 5 wk. The body fat percentage was significantly lower in mice fed the HBM diet (21%), but not the HS diet, compared with mice fed the HB diet. In Expt. 2, mice were fed an SBO-based, high-fat diet containing 0 (HS), 5 (LBM), 10 (MBM), or 15% (HBM) BMSO for 10 wk. In the LBM, MBM, and HBM groups, the body fat percentage was significantly lower by 32, 35, and 65%, respectively, compared with the HS control. The reduction in the HBM group was significantly greater than that in the LBM or MBM group. BMSO administration increased phosphorylation of acetyl-CoA carboxylase, cAMP-activated protein kinase (PKA), and signal transducer and activator of transcription 3 in the white adipose tissue (WAT), suggesting that PKA and leptin signaling might be involved in the BMSO-mediated reduction in lipogenesis and increase in thermogenesis and lipolysis. However, compared with the HS control, the HBM group had a significantly higher TNFα concentration in the WAT accompanied by TUNEL-positive nuclei. We conclude that BMSO is effective in attenuating body fat accumulation through mechanisms associated with PKA activation and programmed cell death in the WAT, but safety concerns need to be carefully addressed.

cis-9, trans-11, trans-13-Conjugated linolenic acid induces apoptosis and sustained ERK phosphorylation in 3T3-L1 preadipocytes

OBJECTIVE

The aim of this study was to investigate the adipogenic effect of cis-9, trans-11, trans-13-conjugated linolenic acid (c9,t11,t13-CLN), a fatty acid naturally present in bitter melon.

METHODS

The 3T3-L1 murine preadipocyte cell line was used to test the effect of saponifiables from whole bitter melon and of commercially prepared pure c9,t11,t13-CLN on adipocyte differentiation. The effect of c9,t11,t13-CLN on 3T3-L1 cell viability was also tested at proliferation, mitotic clonal expansion, and terminal differentiation stages.

RESULTS

Compared to the free fatty acid control mixture, the proadipogenic effect on 3T3-L1 was less potent using saponifiables obtained from bitter melon. C9,t11,t13-CLN, unlike its non-conjugated counterpart linolenic acid (LN) or other common fatty acids such as oleic acid or linoleic acid, exerted no proadipogenic effect on 3T3-L1. In contrast to LN displaying no cytotoxic effect at a concentration ≤100 μM, c9,t11,t13-CLN caused a dose-dependent reduction in the viability of pre- and postconfluent preadipocytes associated with apoptosis. Sustained ERK/MAPK activation, accompanied by increased peroxisome proliferator-activated receptor γ phosphorylation, was seen in c9,t11,t13-CLN-treated cells at initiation of differentiation.

CONCLUSION

C9,t11,t13-CLN is less adipogenic for 3T3-L1 cells than LN and this is partly due to its apoptotic effect on proliferating preadipocytes and to the sustained ERK phosphorylation seen during mitotic clonal expansion.

Production of a conjugated fatty acid by Bifidobacterium breve LMC520 from α-linolenic acid: conjugated linolenic acid (CLnA)

This study was performed to characterize natural CLnA isomer production by Bifidobacterium breve LMC520 of human origin in comparison to conjugated linoleic acid (CLA) production. B. breve LMC520 was found to be highly active in terms of CLnA production, of which the major portion was identified as cis-9,trans-11,cis-15 CLnA isomer by GC-MS and NMR analysis. B. breve LMC520 was incubated for 48 h using MRS medium (containing 0.05% L-cysteine · HCl) under different environmental conditions such as atmosphere, pH, and substrate concentration. The high conversion rate of α-linolenic acid (α-LNA) to CLnA (99%) was retained up to 2 mM α-LNA, and the production was proportionally increased nearly 7-fold with 8 mM by the 6 h of incubation under anaerobic conditions at a wide range of pH values (between 5 and 9). When α-LNA was compared with linoleic acid (LA) as a substrate for isomerization by B. breve LMC520, the conversion of α-LNA was higher than that of LA. These results demonstrated that specific CLnA isomer could be produced through active bacterial conversion at an optimized condition. Because many conjugated octadecatrienoic acids in nature are shown to play many positive roles, the noble isomer found in this study has potential as a functional source.

Cancer chemopreventive ability of conjugated linolenic acids

Conjugated fatty acids (CFA) have received increased interest because of their beneficial effects on human health, including preventing cancer development. Conjugated linoleic acids (CLA) are such CFA, and have been reviewed extensively for their multiple biological activities. In contrast to other types of CFAs including CLA that are found at low concentrations (less than 1%) in natural products, conjugated linolenic acids (CLN) are the only CFAs that occur in higher quantities in natural products. Some plant seeds contain a considerably high concentration of CLN (30 to 70 wt% lipid). Our research group has screened CLN from different plant seed oils to determine their cancer chemopreventive ability. This review describes the physiological functions of CLN isomers that occur in certain plant seeds. CLN are able to induce apoptosis through decrease of Bcl-2 protein in certain human cancer cell lines, increase expression of peroxisome proliferator-activated receptor (PPAR)-γ, and up-regulate gene expression of p53. Findings in our preclinical animal studies have indicated that feeding with CLN resulted in inhibition of colorectal tumorigenesis through modulation of apoptosis and expression of PPARγ and p53. In this review, we summarize chemopreventive efficacy of CLN against cancer development, especially colorectal cancer.

The health promoting properties of the conjugated isomers of α-linolenic acid

The bioactive properties of the conjugated linoleic acid (CLA) isomers have long been recognised and are the subject of a number of excellent reviews. However, despite this prominence the CLA isomers are not the only group of naturally occurring dietary conjugated fatty acids which have shown potent bioactivity. In a large number of in vitro and in vivo studies, conjugated α-linolenic acid (CLNA) isomers have displayed potent anti-inflammatory, immunomodulatory, anti-obese and anti-carcinogenic activity, along with the ability to improve biomarkers of cardio-vascular health. CLNA isomers are naturally present in high concentrations in a large variety of seed oils but can also be produced in vitro by strains of lactobacilli and bifidobactena through the activity of the enzyme linoleic acid isomerase on α-linolenic acid. In this review, we will address the possible therapeutic roles that CLNA may play in a number of conditions afflicting Western society and the mechanisms through which this activity is mediated.

Dietary bitter melon seed increases peroxisome proliferator-activated receptor-γ gene expression in adipose tissue, down-regulates the nuclear factor-κB expression, and alleviates the symptoms associated with metabolic syndrome

The objective of this study was to examine the extent to which bitter melon seed (BMS) alleviates the symptoms associated with metabolic syndrome and elucidate the mechanism by which BMS exerts beneficial effects. Three-month-old female Zucker rats were assigned to following groups: lean control (L-Ctrl), obese control (O-Ctrl), and obese + BMS (O-BMS). The control groups were fed AIN-93M purified rodent diet, and the O-BMS group was fed AIN-93M diet modified to contain 3.0% (wt/wt) ground BMS for 100 days. After 100 days of treatment, BMS supplementation in the obese rats lowered the total serum cholesterol by 38% and low-density lipoprotein-cholesterol levels by about 52% and increased the ratio of serum high-density lipoprotein-cholesterol to total cholesterol compared to the O-Ctrl group. The percentage of total liver lipids was about 32% lower and serum triglyceride levels were 71% higher in the O-BMS group compared to the O-Ctrl group. Serum glucose levels were significantly lowered partly because of the increase in the serum insulin levels in the BMS-based diet groups. BMS supplementation increased the expression of peroxisome proliferator-activated receptor-γ (PPAR-γ) in the white adipose tissue of the obese rats significantly (P < .05) and down-regulated the expression of PPAR-γ, nuclear factor-κB (NF-κB), and interferon-γ mRNA in heart tissue of the obese rats. The findings of this study suggest that BMS improves the serum and liver lipid profiles and serum glucose levels by modulating PPAR-γ gene expression. To our knowledge, this study for the first time shows that BMS exerts cardioprotective effects by down-regulating the NF-κB inflammatory pathway.

Effect of pomegranate seed oil on hyperlipidaemic subjects: a double-blind placebo-controlled clinical trial

In vitro and in vivo studies have shown that punicic acid, a type of conjugated fatty acid and the main constituent of pomegranate seed oil (PSO), has anti-atherogenic effects. The present study aimed at determining the effect of PSO treatment on serum lipid profiles. This double-blind placebo-controlled randomised clinical trial included fifty-one hyperlipidaemic subjects, diagnosed according to National Cholesterol Education Program definition, and randomly assigned to the PSO and the control groups. The PSO and placebo groups received 400 mg PSO and placebo twice daily, respectively and were followed up for 4 weeks. Serum concentrations of lipids and lipoproteins were measured before and 4 weeks after intervention. Mean concentration of TAG and the TAG:HDL cholesterol (HDL-C) ratio were significantly decreased after 4 weeks in the PSO group as compared with baseline values (2.75 (sd 1.40) v. 3.45 (sd 1.56) mmol/l, P = 0.009 and 5.7 (sd 4.6) v. 7.5 (sd 5.0), P = 0.031, respectively). The treatment effect was statistically significant in the PSO group as compared with controls in diminution of cholesterol:HDL-C ratio (5.4 (sd 1.5) v. 5.9 (sd 1.4), P < 0.05) adjusted for baseline values. We found a mean difference for PSO v. placebo in HDL-C concentration (0.13 v. - 0.02 mmol/l) and cholesterol:HDL-C ratio ( - 0.42 v. 0.01, P < 0.05). Serum cholesterol, LDL cholesterol and glucose concentrations and body composition variables remained unchanged. It is concluded that administration of PSO for 4 weeks in hyperlipidaemic subjects had favourable effects on lipid profiles including TAG and TAG:HDL-C ratio.