Effects of pomegranate seed oil on glucose and lipid metabolism-related organs in rats fed an obesogenic diet

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.

Functional Compounds of Cold-Pressed Pomegranate Seed Oil: Fatty Acids and Phytosterols Profile as Quality Biomarkers for Origin Discrimination

Cold-pressed pomegranate seed oil (PSO) is a product of the extraction of non-edible pomegranate seeds. Its unique chemical composition in terms of both polyunsaturated fatty acids, especially punicic acid (PA), and secondary metabolites, such as phytosterols, tocopherols and phenols, make it an interesting functional ingredient for food enrichment. It is not clear if the biomarkers profile of PSO depends to factors connected to the geographical origin of seeds. This work presents a statistical comparative analysis, concerning biomolecules composition and geographical origin of 32 commercial cold-pressed PSOs, performed by principal component analysis. The study discriminates between Turkish and Italian PSOs, on the base of the fatty acid profile and phytosterols, and not on the tocopherols and phenols. These results confirmed PA as the main characteristic biomarker of oil genuineness and, for the first time, disclosed a statistically relevant variability of phytosterols, which can be proposed as quality biomarkers for discrimination of geographical origins.

Metabolic, structure-activity characteristics of conjugated linolenic acids and their mediated health benefits

Conjugated linolenic acid (CLnA) is a mixture of octadecenoic acid with multiple positional and geometric isomers (including four 9, 11, 13-C18:3 isomers and three 8, 10, 12-C18:3 isomers) that is mainly present in plant seeds. In recent years, CLnA has shown many promising health benefits with the deepening of research, but the metabolic characteristics, physiological function differences and mechanisms of different isomers are relatively complex. In this article, the metabolic characteristics of CLnA were firstly reviewed, with focus on its conversion, catabolism and anabolism. Then the possible mechanisms of CLnA exerting biological effects were summarized and analyzed from its own chemical and physical characteristics, as well as biological receptor targeting characteristics. In addition, the differences and mechanisms of different isomers of CLnA in anticancer, lipid-lowering, anti-diabetic and anti-inflammatory physiological functions were compared and summarized. The current results show that the position and cis-trans conformation of conjugated structure endow CLnA with unique physical and chemical properties, which also makes different isomers have commonalities and particularities in the regulation of metabolism and physiological functions. Corresponding the metabolic characteristics of different isomers with precise nutrition strategy will help them to play a better role in disease prevention and treatment. CLnA has the potential to be developed into food functional components and dietary nutritional supplements. The advantages and mechanisms of different CLnA isomers in the clinical management of specific diseases need further study.

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.

Punicic acid ameliorates obesity and liver steatosis by regulating gut microbiota composition in mice

This study aimed to elucidate the effect of punicic acid (PUA, cis9,trans11,cis13-18 : 3) on obesity and liver steatosis in mice induced by high-fat diet (HFD), and to explore the possible mechanism. Mice were fed with either a HFD or a control diet for 8 weeks. Half of HFD-mice received daily supplementation of PUA. Supplementation with PUA ameliorated the liver steatosis and obesity in mice fed by HFD, as demonstrated by the decreased hepatic triglyceride accumulation, body weight gain and fat weight. A HFD increased the ratio of Firmicutes to Bacteroidetes, whereas supplementation with PUA effectively restored it. PUA supplementation counteracted the upregulation in family Desulfovibrionaceae and Helicobacteraceae, and the downregulation in Muribaculaceae and Bacteroidaceae induced by HFD. Correspondingly, the family of Desulfovibrionaceae was positively related, whereas Muribaculaceae was negatively related to the amount of epididymal and perirenal fat, and the level of liver triglyceride and total cholesterol. The family Helicobacteraceae was also positively related to the amount of epididymal and perirenal fat. Moreover, PUA supplementation counteracted the increase in the population of Anaerotruncus, Faecalibaculim, Mucispirillum, and the decrease in the population of Lactobacillus, Roseburia, Oscillibacter at the genus level induced by HFD. These results demonstrated that PUA can at least in part ameliorate obesity and liver steatosis in mice induced by HFD by regulating gut microbiota composition.

A unique understanding of traditional medicine of pomegranate, Punica granatum L. and its current research status

ETHNOPHARMACOLOGICAL RELEVANCE

Pomegranate, Punica granatum L., has been used in traditional medicine in China and several regions of the world including Ayurveda, Islamic, and Persian for the treatment of atherosclerosis, diabetes, hypertension, hyperlipidemia, and several types of cancer, as well as for peptic ulcer and oral diseases for hundreds of years. Presently, pomegranate is treated as both a "medicine food homology" herbal medicine and a healthy food supplemental product.

AIM OF THE STUDY

The aim of this work is to develop an overview of pomegranate in the context of the status of its traditional medicine theories, the spread along the Silk Road, ethnopharmacological uses, chemical compositions, pharmacological activities, toxicology, and the involved pathways.

MATERIALS AND METHODS

Information on P. granatum L. was acquired from published materials, including monographs on medicinal plants, ancient and modern recorded classical texts; and pharmacopoeias and electronic databases (PubMed, Science Direct, Web of Science, Google Scholar, CNKI, and Wanfang Data).

RESULTS

Pomegranate has been used in many traditional medical systems throughout history. It is widely cultivated in Central Asia and spread throughout China along the Silk Road. Many phytochemicals, such as tannins, organic acids, flavonoids, alkaloids, and volatile oils have been identified from different parts of pomegranate, these compounds have a wide range of activities, including antioxidant, antimicrobial, and anti-oncogenic properties, as well as conferring resistance to cerebrovascular disease. Furthermore, A summary of the four promising pharmacological pathways is provided.

CONCLUSIONS

The traditional uses, chemical compositions, pharmacological activities, and signaling pathways of pomegranate are summarized comprehensively in the review. It can be treated as a guidance for the future clinical and basic research. The information provided in this review will be very useful for further studies to develop novel therapeutic directions for application of pomegranate.

Modulation effect of chenpi extract on gut microbiota in high-fat diet-induced obese C57BL/6 mice

The current study employed high-fat diet (HFD) induced murine model to assess the relationship between the lipid-lowering effect of aged citrus peel (chenpi) extract and the alterations of gut microbiota. The results showed that intake of chenpi extract for 12 week dose-dependently suppressed HFD-induced body weight, food intake, Lee's index, together with decreased the level of fasting blood glucose, total cholesterol, triglyceride, and low-density lipoprotein cholesterol. Moreover, chenpi extract administration up-regulated the abundance and diversity of fecal microbiota and down-regulated the ratio of Firmicutes-to-Bacteroidetes, which was characterized by the lower family of Lachnospiraceae, Helicobacteraceae, and Desulfovibrionaceae, and higher family of Bacteroidales_S24-7, Bacteroidaceae, Rikenellaceae, and Ruminococcaceae. Consistently, at the genus levels, chenpi extract treatment reversed the expansions of Helicobacter, Lachnospiraceae_UCG-006, and Desulfovibrio, while increased the abundance of Bacteroides, Rikenellaceae_RC9_gut_group, and Alistipes (belonging to Rikenellaceae family), Anaerotruncus and Odoribacter (belonging to Ruminococcaceae family), which were significantly negatively correlated with the levels of the serum lipid parameters. In conclusion, our findings indicated that anti-obesity ability of chenpi extract might be related to the improvement of gut microbiota imbalance. PRACTICAL APPLICATIONS: With the improvement of living standards, the incidence of metabolic diseases such as obesity, hypertension, and diabetes has increased significantly, and it has become a public health problem that seriously affects the health of the people. Chenpi contains a large amount of active ingredients, flavonoids, and other compounds, which can promote the absorption of the digestive system and have good effects on diseases such as the cardiovascular system. Our previous study has confirmed that the chenpi extract effectively regulated the glucose and lipid metabolism disorder induced by high-fat diet. However, it is not clear whether the effect is closely related to the improvement of gut microbiota. Accordingly, our result would provide a theoretical basis for future research on the relationship between obesity, chenpi extract, and gut microbiota, and support additional understanding of its potential anti-obesity effects.

High-Protein Diet Associated with Bocaiuva Supplementation Decreases Body Fat and Improves Glucose Tolerance in Resistance-Trained Rats

High-protein diets (HPDs) are widely used for health and performance. However, the combination of whey protein and natural foods (i.e., fruits) is still unclear. Thus, we evaluated the role of supplemental HPD with Bocaiuva (Acrocomia sp.) in metabolic and body composition parameters of rats submitted to resistance training (RT). Wistar rats (203.3 ± 30 g) were randomly allocated to five groups: normoproteic control (CON, n = 5), sedentary high-protein (SH, n = 5), RT + H (trained high-protein [TH], n = 5), sedentary+Bocaiuva (SH+B, n = 4), and RT+Bocaiuva (TH+B, n = 4) diet groups. After 12 weeks of RT, the maximal strength increased in both trained groups (P < .05). The TH + B group had lower values of adiposity index (AI) (3.8 ± 0.7% vs. 6.8 ± 1.3%) and visceral fat (0.038 ± 0.004 g/g vs. 0.067 ± 0.012 g/g) compared with the SH group, respectively (P < .05). The other groups did not show differences in values of AI (CON, 5.4 ± 1.6%, TH, 5.4 ± 1.3%, and SH+B, 5.5 ± 1.2%). In addition, the fasting glucose of trained groups (TH, 106.0 ± 4.5, and TH+B, 100.4 ± 13.5 dL/mg) was significantly lower when compared with controls (SH, 120.0 ± 14.4, and SH+B, 119 ± 6.4 dL/mg) (P < .05). Bocaiuva combined with an HPD reduced visceral fat and AI in addition to improving glucose tolerance of rats submitted to RT.

Hypocholesterolemic Effects of Expeller-Pressed and Solvent-Extracted Fruit Seed Oils and Defatted Pomegranate Seed Meals

Consumptions of fruit seed oils and meals could potentially improve cardiovascular health by reducing plasma total cholesterol and low-density lipoprotein (LDL). The study objective was to compare the effectiveness of expeller-pressed and solvent-extracted grape, tomato, pomegranate seed oils, and defatted pomegranate meals in lowering plasma and hepatic cholesterol using hamster models. Hamsters were fed with fruit seed oils (FSO), defatted pomegranate seed meals (PDM), or control diets. After a 3-week feeding period, plasma total triglycerides of treatment diets were significantly lower. FSO also reduced total, very-low-density lipoprotein- (VLDL), and LDL-cholesterols, while PDM only lowered VLDL-cholesterols. Decreases in low-density and high-density lipoproteins (LDL/HDL) ratios were also observed in most treatments. In liver, triglycerides, total, and free cholesterol levels did not vary between control and treatments. There were no significant differences in lipid modulating properties between solvent-extracted and expeller-pressed oils. In conclusion, partial replacements of saturated fat in high-fat diets with tomato, pomegranate, and grape seed oils could effectively reduce plasma triglyceride levels and improve HDL/LDL ratios.

Effect of pomegranate seed oil supplementation on the GLUT-4 gene expression and glycemic control in obese people with type 2 diabetes: A randomized controlled clinical trial

Abnormality in glucose transporter type 4 (GLUT-4) function and insulin secretion are the main causes of type 2 diabetes mellitus (T2DM). Due to adverse effects of antidiabetic drugs, nowadays, nutraceuticals have been of much interest to investigators. The aim of the present study was to determine the effect of pomegranate seed oil (PSO) on the GLUT-4 gene expression and glycemic control in obese people with T2DM. This randomized clinical trial was conducted on 52 obese type 2 diabetic patients for 8 weeks in Tabriz, Iran, in 2018. Patients were divided into the intervention group (n = 26; who consumed daily three capsules containing 1 g PSO) and the placebo group (n = 26; the same amounts paraffin). GLUT-4 gene expression and glycemic indices were evaluated by standard methods. GLUT-4 gene expression was increased significantly in the PSO group. Within-group changes in fasting blood sugar (FBS) and quantitative insulin sensitivity check index were significant in the PSO group. After adjusting the age, gender, and baseline values, FBS was significantly decreased. Insulin concentration, HbA1C, HOMA-IR, and HOMA-β did not manifest significant changes. PSO increased the GLUT-4 gene expression in diabetic patients without any side effects. However, future clinical studies are needed to confirm the obtained results.

Punicic acid: A potential compound of pomegranate seed oil in Type 2 diabetes mellitus management

Diabetes is one of the most prevalent diseases in the worldwide. Type 2 diabetes mellitus (T2DM), the most common form of the disease, has become a serious threat to public health and is a growing burden on global economies. Due to the unexpected adverse effects of antidiabetic medicines, the use of nutraceuticals as a complementary therapy has drawn extensive attention by investigators. In this issue, a novel nutraceutical, Punicic acid (PA)-the main ingredient of pomegranate seed oil (PSO) that has potential therapeutic effects in T2DM-has been investigated. PA is a peroxisome proliferator-activated receptor gamma agonist, and unlike synthetic ligands, such as thiazolidinediones, it has no side effects. PA exerts antidiabetic effects via various mechanisms, such as reducing inflammatory cytokines, modulating glucose homeostasis, and antioxidant properties. In this review, we discussed the potential therapeutic effects of PSO and PA and represented the related mechanisms involved in the management of T2DM.

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.

Effects of Pomegranate Seed Oil on Metabolic State of Patients with Type 2 Diabetes Mellitus

BACKGROUND

Rapid increasing prevalence of diabetes mellitus is a serious health concern in the world. New data determined that the pathogenesis of diabetes mellitus is chronic low-grade inflammation, resulting insulin resistance. Pomegranate seed oil (PSO) has anti-inflammatory effects; though it may reduce insulin resistance and improve glycemia in diabetes mellitus. The present study has been designed to investigate the effects of PSO as a natural dietary component on metabolic state of patients with Type 2 diabetes mellitus.

METHODS

In a randomized double-blind clinical trial study, 80 patients (28 men) with Type 2 diabetes were randomly allocated to the intervention and control groups. The intervention group consumed PSO capsules, containing 1000 mg PSO twice daily (2000 mg PSO), whereas controls take placebo for 8 weeks. The participants followed their previous dietary patterns and medication use. Dietary factors and metabolic factors including lipid profile, fasting plasma sugar, and insulin and were assayed at the baseline and after 8 weeks.

RESULTS

Participants in two intervention and control group were similar regarding anthropometric and the dietary factors at baseline and after trial (P > 0.05). Mean level of total cholesterol, triglyceride, low-density lipoprotein-cholesterol, and high-density lipoprotein was not different significantly between groups after trial (P > 0.05). Consumption of PSO did not significantly affect the levels of parameters such as fasting blood sugar (FBS), insulin, HbA1c, alanine transferase, and homeostasis model assessment-insulin resistance.

CONCLUSIONS

Consumption of 2000mg PSO per day for 8 weeks had no effect on FBS, insulin resistance and lipid profile in diabetic patients.

Health Benefits of Punicic Acid: A Review

Punicic acid (PA) is a polyunsaturated fatty acid (18:3 n-5), which is classified as a conjugated linolenic acid. PA is also referred as a "super CLnA" whose effect is even more potent than that of an ordinary CLnA. It is found mainly in the seeds of pomegranate fruit (Punica granatum) and Trichoxanthes kirilowii and some other minor sources. It possesses a wide array of biological properties including antidiabetic, antiobesity, antiproliferative, and anticarcinogenic activity against various forms of cancer. In spite of this, PA has not been explored as a nutraceutical or as an ingredient of food products which can be aimed at specific consumer target groups. This review details the various health-beneficial properties of PA and explores the possibilities of its utilization as an active ingredient in various food products.

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.