Agnieszka Białek

Influence of diet enriched with conjugated linoleic acids on their distribution in tissues of rats with DMBA induced tumors

BackroundConjugated linoleic acids (CLA) are a group of positional and geometric isomers of linoleic acid with proven beneficial influence on health. They show e.g. anticarcinogenic, antiobesity, and antiatherogenic effect. Milk, dairy products and meat of poligastric animals are their most valuable dietary sources, with cis-9, trans-11 CLA (RA - rumenic acid) being the predominant isomer. Dietary supplements with CLA became very popular, mainly among the overweight and bodybuilders.The aim of this study was to examine the influence of the food supplements with conjugated linoleic acid on carcinogenesis in female Sprague-Dawley rats and evaluation of CLA and other fatty acids distribution in their bodies.Animals were divided into four groups depending on the diet supplementation (oil or Bio-C.L.A. (Pharma Nord Denmark) given intragastrically) and presence or absence of carcinogenic agent (7,12-dimethylbenz[a]antharcene). Animals were decapitated at 21st week of experiment and serum and microsomes were extracted.Results and conclusionsThe mammary tumours (adenocarcinoma) occurred in groups treated with DMBA. Diet enriched with CLA decreased the cancer morbidity (67% in Bio-C.L.A. compared to 88% in oil) and delayed the cancer induction (p = 0.0018). There were no differences in body and organs weight.The supplement used in the study was a mixture of several fatty acids with the greatest proportion of CLA isomers: trans-10, cis-12 (33%) and cis-9, trans-11 (31%). Both of them were present in tissues but the content of rumenic acid was greater. Dietary supplementation had also significant impact on other fatty acids content, both in serum and in microsomes.

Fatty acid profile of new promising unconventional plant oils for cosmetic use

Oils have been used on the cosmetic application since antiquity. With the growing interest in cosmetic formulation of strictly natural origin there has been also an increased interest in the use of alternative oils obtained from nuts, herbs, fruit and vegetable seeds. Due to lack of good scientific reports on the cosmetic plant oils available in Poland, the aim of our research was to characterize fatty acids (FA) profile and oxidative quality of selected unconventional plant oils, which are used as cosmetics or potential cosmetic ingredients.

The Effect of Conjugated Linoleic Acids (CLA) Supplementation on the Activity of Enzymes Participating in the Formation of Arachidonic Acid in Liver Microsomes of Rats—Probable Mechanism of CLA Anticancer Activity

The aim of the present research was to examine the effect of conjugated linoleic acids (CLA) supplementation on the activity of enzymes that take part in the synthesis of arachidonic acid (AA) and also to investigate the relation between their activity and the neoplastic process. The enzyme activities were established indirectly, because their measure was the amount of AA formed in vitro, being developed from linoleic acid as determined in liver microsomes of Spraque-Dawley rats. In addition, the indices of Δ6-desaturase (D6D) and Δ5-desaturase (D5D) were determined. To this aim, the method of high per-formance liquid chromatography with UV/VIS detection was used. Between the examined groups, statistically significant differences were observed in the activities of enzymes as well as D6D. The carcinogenic agent applied (DMBA) was found to significantly increase the activity of the examined enzymes. Negative correlation was found between the activities of desaturases and CLA supplementation, whereas the activity of those enzymes was a little higher in the group of rats with chemically induced cancer process. The neoplastic process has a stimulating effect on the activity of D6D. The decrease of D6D activity, resulting from the presence of CLA in the animals’ diet, may confirm the anticancer properties of these isomers.

Effect of conjugated linoleic acid mixture supplemented daily after carcinogen application on linoleic and arachidonic acid metabolites in rat serum and induced tumours

Conjugated linoleic acid (CLA) is thought to exert anticarcinogenic, antiatherogenic, anti-inflammatory and weight loss effects. The impact on eicosanoid biosynthesis may be one of the mechanisms of its action. The aim of this study was to establish whether CLA mixture supplemented daily after administration of carcinogen (7, 12-dimethylbenz[a]anthracene, DMBA) influenced the concentration of linoleic and arachidonic acid metabolites: 13- or 9-hydroxyoctadecadienoic acids (13-, 9-HODE) and 15-, 12- or 5-hydroxyeicosatetraenoic acids (15-, 12- or 5-HETE) and prostaglandin E2 (PGE2) in rat serum and DMBA-induced tumours. The correlations between polyunsaturated fatty acids (PUFA) and HETE and HODE contents in serum were also investigated. Female Sprague-Dawley rats divided into three groups according to the diet (1% Bio-C.L.A., 2% Bio-C.L.A. and plant oil in the control group) were used in the study. On the 50th day of life some of the animals in every dietary group were administered DMBA to induce tumours. Since that day, the rats were fed one of the above-mentioned diets. After 15weeks the animals were sacrificed and blood and tumours were collected. HETE and HODE were extracted using a solid-phase extraction (SPE) method on C18 columns and analysed with LC-MS/MS. The results of our study showed that CLA daily supplementation after carcinogen administration influence LA and AA metabolite levels in serum and tumours. However, the ratios of eicosanoids having opposite effects (e.g. 12-HETE/15-HETE), not concentrations of particular compounds, appear to be better indicators of pathological processes.

Fatty acid composition and oxidative characteristics of novel edible oils in Poland

ABSTRACT Plant oils are sources of unsaturated fatty acids (FA) and antioxidant compounds. Herbs, spices, and fruit seeds are potential source of oils which may be used as functional food and dietary supplements. FA profile and oxidative quality of oils (n = 28) were investigated by the chromatographic and titration methods. Peroxidability index (PI) was calculated and cluster analysis was performed. Differences in FA content show which of them is responsible for clusters allotment and also for similarities within each cluster. Oils from cluster S1 were characterized by high content of C18:2 n-6, whereas oils from cluster S2 by higher content of C16:1 and C18:1 n-9. Oils from S3 cluster were distinguished by higher amount of C18:3 n-3. A total of 4 of 17 FAs detected in all samples significantly differed among clusters. Novel oils may be an interesting functional food component, but detailed analysis is needed to confirm their applicability and human health influence.

Influence of maternal diet enrichment with conjugated linoleic acids on lipoxygenase metabolites of polyunsaturated fatty acids in serum of their offspring with 7,12-dimethylbenz[a]anthracene induced mammary tumors

Conjugated linoleic acids (CLA), which are a group of naturally occurring in food isomers of linoleic acid, seem to be active in each step of cancer development. There are many possible mechanisms of this action, and interactions with polyunsaturated fatty acids (PUFA) in lipoxygenase (LOX) and cyclooxygenase (COX) pathways are among the most likely ones. The aim of this study was to assess the influence of diet supplementation with CLA of pregnant and breastfeeding Sprague-Dawley female rats on selected polyunsaturated fatty acids and their LOX metabolites concentrations in serum of the progeny with chemically induced mammary tumors. We confirmed that higher supply of CLA in the diet of female rats corresponded with the lower susceptibility to chemically induced mammary tumors in their female offspring. It also influenced the polyunsaturated n-3 and n-6 fatty acid concentrations in serum, as well as the concentrations of their LOX metabolites. The significant negative correlation between the concentrations of two CLA isomers in serum and linoleic acid (p=0.0144, p=0.0098), eicosapentaenoic acid (p=0.0158, p=0.0124), and 5-HEPE (p=0.0014, p=0.01690) and between cis-9, trans-11 CLA and 15-HEPE was detected, whereas arachidonic acid concentration positively correlated with CLA concentration in serum (p=0.0150, p=0.0231). Our results indicate that CLA can compete with PUFA and influence serum concentration of PUFA and their LOX metabolites, which could partly explain the anticancerogenic action of CLA.

[Conjugated linolenic acids (CLnA, super CLA)--natural sources and biological activity].

Polyunsaturated fatty acids (PUFA) have a wide range of biological activity. Among them conjugated fatty acids are of great interest. Conjugated linoleic acids (CLA), which exert a multidirectional health-benefiting influence, and conjugated linolenic acids (CLnA, super CLA) are examples of this group of fatty acids. CLnA are a group of positional and geometric isomers of octadecatrienoic acid (C18:3), which possess double bonds at positions 9, 11, 13 or 8, 10, 12 of their chain. Some vegetable oils are rich sources of CLnA, e.g. bitter melon oil (from Momordica charantia seeds) and pomegranate oil (from Punica granatum seeds). The aim of this paper was to present information concerning natural sources and health-promoting activities of conjugated linolenic acids. The presented data reveal that conjugated linolenic acids may be very useful in prevention and treatment of many diseases, especially diabetes, arteriosclerosis , obesity and cancers (mammary, prostate and colon cancer). Among many potential mechanisms of their action, the fact that some CLnA are converted by oxidoreductases into CLA is very important. It seems to be very reasonable to conduct research concerning the possibility of CLnA use in prevention of many diseases.

Heating of vegetable oils influences the activity of enzymes participating in arachidonic acid formation in Wistar rats

Dietary intake of lipids and their fatty acids profile influence many aspects of health. Thermal processing changes the properties of edible oils and can also modify their metabolism, for example, eicosanoids formation. The aim of our study was to verify whether the activity of desaturases can be modified by lipids intake, especially by the fatty acids content. The experimental diets contained rapeseed oil, sunflower oil, and olive oil, both unheated and heated (for 10 minutes at 200 °C each time before administration), and influenced the fatty acids composition in serum and the activity of enzymes participating in arachidonic acid (AA) formation. The activity of desaturases was determined by measuring the amounts of AA formed in vitro derived from linoleic acid as determined in liver microsomes of Wistar rats. In addition, the indices of ∆(6)-desaturase (D6D) and ∆(5)-desaturase (D5D) have been determined. To realize this aim, the method of high-performance liquid chromatography has been used with ultraviolet-visible spectrophotometry detection. Diet supplementation with the oils rich in polyunsaturated fatty acids affects the fatty acids profile in blood serum and the activity of D6D and ∆(5)-desaturase in rat liver microsomes, the above activities being dependent on the kind of oil applied. Diet supplementation with heated oils has been found to increase the amount of AA produced in hepatic microsomes; and in the case of rapeseed oil and sunflower oil, it has also increased D6D activity.

Effect of Bitter Melon Aqueous Extract and Pomegranate Oil on Glucose Concentration and Lipid Profile in Blood of Rats - Preliminary Study

Conjugated fatty acids is a term given to a group of polyunsaturated fatty acids with conjugated double bonds systems in their carbon chains. Conjugated linolenic acids (CLnA) are present in seeds of certain plants e.g. � - eleostearic acid (cis-9, trans-11, trans-13 C18:3) in bitter melon (Momordica charantia, Cucurbitaceae) or punicic acid (cis-9, trans-11, cis-13 C18:3) in pomegranate (Punica granatum, Punicaceae), where usually they are most prevalent among fatty acids. Bitter melon and pomegranate have been widely investigated as they are commonly consumed plants which also have been used in traditional medicine, mainly in Asia, for treatment of many diseases, such as diabetes and atherosclerosis. The aim of this study was to evaluate the influence of a diet supplemented with an aqueous extract of bitter melon fruits and/or with pomegranate oil on health status and lipid profile of blood. Sprague-Dawley female rats were divided into four groups with different diet supplementation: pomegranate oil (G), aqueous extract of bitter melon (M), pomegranate oil and aqueous extract from bitter melon (M+G), and control group (C). During the experiment fasting glucose concentration and total cholesterol (TC), HDL, LDL, and triglyceride (TG) concentration were measured in blood collected intravitally from the tail vein. The modifications introduced into the diets did not influence negatively overall health condition of the animals. Bitter melon fruits extract slightly decreased the fasting glucose concentration during the experiment but its action was not statistically significant (p>0.05). Pomegranate oil caused an increase of fasting glucose level in G group (p=0.03657) but in M+G group its influence was diminished by the opposite activity of bitter melon fruits extract (p>0.05). TC was the lowest in G group and it did not change during the time of experiment, which can suggest that the diet supplementation with pomegranate oil prevents the age-related increase in cholesterol level. TC in blood of G group was significantly lower than in other groups in 14th (p=0.01057) and 21st (p=0.01433) weeks respectively. Aqueous extract of bitter melon fruits slightly diminished age-related TG increase, whereas pomegranate oil strongly prevents this tendency, as the TG content in G group was significantly lower than TG content in C and M groups at 14th (p=0.00060) and 21st (p=0.00003) week respectively. Similar activity, although not so pronounced, was visible as far as the M+G group was concerned.

Impact of conjugated linoleic acid administered to rats prior and after carcinogenic agent on arachidonic and linoleic acid metabolites in serum and tumors

The objective of the study was to assess the influence of conjugated linoleic acid (CLA) daily supplementation prior and after carcinogenic agent on the concentrations of eicosanoids - metabolites of arachidonic acid (15-, 12- or 5-hydroxyeicosatetraenoic acids (15-, 12-, 5-HETE), prostaglandin E2 (PGE2)) and linoleic acid (13- or 9-hydroxyoctadecadienoic acids (13-, 9-HODE)) in rat serum and 7,12-dimethylbenz[a]anthracene (DMBA)-induced tumors. Female rats were randomised into six groups, receiving 1% or 2% Bio-C.L.A or plant oil since the 37th day of life throughout the whole experiment. Some rats (50-day-old) were administered DMBA to induce tumors. Eicosanoids were analyzed with LC-MS/MS. The study indicated that CLA supplemented daily to rats prior and after carcinogen administration affected concentrations of arachidonic and linoleic acid metabolites in rat serum and induced tumors. However, ratios of eicosanoids exerting opposite activities (e.g. 12-HETE/15-HETE) appear to act as more precise factors reflecting pathological changes in an organism than individual compounds.