Determinación de antioxidantes endógenos lipofílicos en plasma y HDL. Evaluación del efecto del consumo de acites de oliva enriquecidos en compuestos fenólicos

La Dieta Mediterránea posee un papel protector frente al riesgo de padecer enfermedades cardiovasculares gracias a los alimentos que la constituyen, entre los que destaca el aceite de oliva como principal fuente de grasas. La hipótesis de la que se parte en el presente trabajo es que el aceite de oliva enriquecido en compuestos fenólicos podría actuar como nutracéutico modulando el sistema antioxidante endógeno, contribuyendo así en la defensa antioxidante del plasma y de las partículas HDL.

Prevalença d'hipolipidèmies en població sana treballadora

Les disminucions del perfil lipídic per sota del valor òptim es denominen hipolipidèmies. Les hipolipidèmies poden ser de causa primària, és a dir d'origen genètic, o secundàries a patologies com l’hipotiroïdisme o la caquèxia. Presentar valors per sota dels estàndards de normalitat és un factor de risc de patir desnutrició, retràs en el creixement, dèficit de vitamina E i/o A, malalties cardíaques i hepàtiques. A més, el colesterol forma part de les membranes cel·lulars, i si no es troba en les quantitats adequades les membranes perden la seva resistència i funcionalitat la qual pot produir hemorràgies cerebrals o demències. Per tant, per evitar aquest risc cal seguir una dieta vairada i equilibrada amb un percentatge lipídic adequat (<30%). Es recomana un consum adequat de lípids saludables com els monoinsaturats i els poliinsaturats, i una ingesta controlada en grasses saturades.

When cholesterol is not cholesterol: a note on the enzymatic determination of its concentration in model systems containing vegetable extracts

Background: Experimental evidences demonstrate that vegetable derived extracts inhibit cholesterol absorption in the gastrointestinal tract. To further explore the mechanisms behind, we modeled duodenal contents with several vegetable extracts. Results: By employing a widely used cholesterol quantification method based on a cholesterol oxidase-peroxidase coupled reaction we analyzed the effects on cholesterol partition. Evidenced interferences were analyzed by studying specific and unspecific inhibitors of cholesterol oxidase-peroxidase coupled reaction. Cholesterol was also quantified by LC/MS. We found a significant interference of diverse (cocoa and tea-derived) extracts over this method. The interference was strongly dependent on model matrix: while as in phosphate buffered saline, the development of unspecific fluorescence was inhibitable by catalase (but not by heat denaturation), suggesting vegetable extract derived H2O2 production, in bile-containing model systems, this interference also comprised cholesterol-oxidase inhibition. Several strategies, such as cholesterol standard addition and use of suitable blanks containing vegetable extracts were tested. When those failed, the use of a mass-spectrometry based chromatographic assay allowed quantification of cholesterol in models of duodenal contents in the presence of vegetable extracts. Conclusions: We propose that the use of cholesterol-oxidase and/or peroxidase based systems for cholesterol analyses in foodstuffs should be accurately monitored, as important interferences in all the components of the enzymatic chain were evident. The use of adequate controls, standard addition and finally, chromatographic analyses solve these issues.

Effect of feed fat by-products with trans fatty acids and heated oil on cholesterol and oxycholesterols in chicken

Chicken is the most widely consumed meat all over the world due to chickens being easy to rear, their fast growth rate and the meat having good nutritional characteristics. The main objective of this paper was to study the effects of dietary fatty by-products in low, medium and high levels of oxidized lipids and trans fatty acids (TFAs) on the contents of cholesterol and oxycholesterols in meat, liver, and plasma of chickens. A palm fatty acid distillate, before and after hydrogenation, and a sunflower-olive oil blend (70/30, v/v) before and after use in a commercial frying process were used in feeding trials after adding 6% of the fats to the feeds. Highly oxidized lipid and TFA feeds significantly increased the contents of cholesterol and oxycholesterols in all tissues of chicken (0.01 < p <= 0.05). The contents of oxycholesterols in chicken meat, liver and plasma obtained from TFA feeding trials varied between 17 and 48 μg/100 g in meat, 19-42 μg/100 g in liver and 105-126 μg/dL in plasma. In contrast, in the oxidized lipid feeding trials, oxycholesterols varied between 13 and 75 μg/100 g in meat, 30-58 μg/100 g in liver and 66-209 μg/dL in plasma. Meat from chickens fed with feeds containing high levels of TFAs or oxidized lipids may contribute to higher ingestion of cholesterol and oxycholesterols by humans.

Changes in the phenolic content of low density lipoprotein after olive oil consumption in men. A randomized crossover controlled trial

Olive oil decreases the risk of CVD. This effect may be due to the fatty acid profile of the oil, but it may also be due to its antioxidant content which differs depending on the type of olive oil. In this study, the concentrations of oleic acid and antioxidants (phenolic compounds and vitamin E) in plasma and LDL were compared after consumption of three similar olive oils, but with differences in their phenolic content. Thirty healthy volunteers participated in a placebo-controlled, double-blind, crossover, randomized supplementation trial. Virgin, common, and refined olive oils were administered during three periods of 3 weeks separated by a 2-week washout period. Participants were requested to ingest a daily dose of 25 ml raw olive oil, distributed over the three meals of the day, during intervention periods. All three olive oils caused an increase in plasma and LDL oleic acid (P,0·05) content. Olive oils rich in phenolic compounds led to an increase in phenolic compounds in LDL (P,0·005). The concentration of phenolic compounds in LDL was directly correlated with the phenolic concentration in the olive oils. The increase in the phenolic content of LDL could account for the increase of the resistance of LDL to oxidation, and the decrease of the in vivo oxidized LDL, observed in the frame of this trial. Our results support the hypothesis that a daily intake of virgin olive oil promotes protective LDL changes ahead of its oxidation.

El consumo de probiótico Lactobacillus plantarum CECT 7315/7316 mejora el estado de salud general en personas de edad avanzada

Fundamentos: Con la edad avanzada se producen cambios en la microflora intestinal que pueden afectar al estado de salud general. En este trabajo analizamos el efecto de Lactobacillus plantarum CECT 7315/7316 sobre la regulación del tránsito intestinal y el estado nutricional. Métodos: Hemos realizado un estudio clínico dobleciego, controlado por placebo y aleatorizado. Hemos evaluado la evolución de la frecuencia de defecación semanal y los niveles en sangre de proteínas totales, albúmina,colesterol y proteína C-reactiva. Resultados: Lactobacillus plantarum CECT 7315/7316 ayuda a regular el tránsito intestinal y mejora el estado nutricional en personas mayores. Conclusiones: El consumo de productos funcionales que contengan L. plantarum CECT 7315/7316 mejora la calidad de vida de personas de la tercera edad.

Constituintes químicos das cascas do caule de Cenostigma macrophyllum: ocorrência de colesterol

Phytochemical investigation of the bark of Cenostigma macrophyllum (Leguminosae-Caesapinioideae) resulted in the isolation and identification of valoneic acid dilactone, ellagic acid, lupeol, alkyl ferulate, four free sterols (cholesterol, campesterol, stigmasterol and sitosterol), a mixture of sitosteryl ester derivatives of fatty acids, sitosterol-3-O-beta-D-glucopyranoside, stigmasterol-3-O-beta-D-glucopyranoside and saturated and unsaturated fatty acids. The structures of the isolated compounds were identified by ¹H and 13C NMR spectral analysis and comparison with literature data. The mixtures of 3-beta-hydroxysterols and fatty acids were analysed by GC/MS.

Desenvolvimento de metodologia analítica para determinação de colesterol em ração para ruminantes através de planejamento experimental fatorial

A chromatographic method was developed for cholesterol determination in feed for ruminants using response surface methodology. Among the five approaches of sample preparation methods tested, the saponification of the sample without heating presented less interference in the gas chromatography. The method presented a relative standard deviation (RSD) of 4.3%, recoveries between 84 and 87% and detection limit of 0.001 mg of cholesterol per g of feed.

Argilas como catalisadores verdes na esterificação do colesterol: caracterização espectroscópica e identificação de polimorfos por métodos de análise térmica. Uma proposta laboratorial interdisciplinar para o 1º ciclo universitário

A laboratory experiment that enables the professor to introduce the problematic of sustainable development in pharmaceutical chemistry to undergraduate students is proposed, using a simple synthetic procedure. Cholesteryl acetate is prepared by the esterification of cholesterol using Montmorillonite K10 as heterogeneous catalyst. Cholesterol and cholesteryl acetate are characterized by spectroscopic (¹H RMN, 13C RMN, FTIR) and thermal analysis techniques. The thermal methods are used to introduce the concepts of polymorphism and the nature of mesophases.

Reação peritoneal tardia ao calculo biliar humano, de colesterol, deixado na cavidade abdominal de ratos

Foram avaliados os resultados tardios da colocação de cálculos biliares humanos, de colesterol, na cavidade peritoneal de ratos. Constituíram-se cinco grupos: cinco ratos foram apenas laparotomizados com manuseio da cavidade; cinco foram laparotomizados e receberam um ponto com fio monofilamentar cinco zeros no sulco paracólico direito e mesentério; dez receberam cálculos que foram deixados livres na cavidade peritoneal; em dez, os clculos foram fixados no sulco paracólico direito e, finalmente, dez tiveram clculos fixados no mesentério. Os animais foram mortos após cinco meses de pós-operatório quando se observou a cavidade abdominal e foi coletado material para estudo histopatológico. Concluiu-se que os cálculos não foram absorvidos, desenvolveram uma reação peritoneal do tipo corpo estranho com formação de plastrão e foram envolvidos por tecido fibroso e células inflamatórias.

Lipídios plasmáticos após esplenectomia total e parcial em cães

OBJETIVO: Avaliar o efeito da esplenectomia total e parcial (hemiesplenectomia e esplenectomia subtotal) no lipidograma de cães. MÉTODO: Foram operados 38 animais, adultos, machos, mestiços, com peso entre 13kg e 15kg. No pré-operatório, depois do exame clínico e jejum de 12 horas de uma dieta-padrão, foram realizados hemograma e lipidograma. Após anestesia geral com tiopental sódico os cães foram submetidos à laparotomia mediana supra e infra-umbilical. Procedeu-se no grupo 1, de sete cães, apenas à manipulação do baço (simulado); no grupo 2, de nove cães, à hemiesplenectomia cranial; no grupo 3, de nove cães, à esplenectomia subtotal, com preservação do pólo inferior do baço, após ligadura e secção dos troncos principais dos vasos esplênicos próximos ao hilo; e no grupo 4, de 13 cães, à esplenectomia total. RESULTADOS: No grupo 4 (esplenectomia total), quando comparamos os valores do lipidograma dos diferentes períodos pós-operatórios com os do pré-operatório, os nossos resultados mostraram que houve aumento significante do colesterol total em todos os períodos pós-operatórios (p < 0,05, p < 0,01). O HDL aumentou significantemente no 7º (p < 0,01) e 28º dias de pós-operatório (PO) (p < 0,05), e não significantemente (p>0,05) no 56º PO. O LDL aumentou significantemente no 56º PO (p < 0,01) em relação também aos demais períodos do pós-operatório. Os triglicerídeos e VLDL não apresentaram alterações significantes. Nos animais dos grupos 1 e 3 não houve alterações significantes. Nos do grupo 2, houve aumento significante do colesterol no 7º PO. Não houve diferença estatisticamente significante de peso entre os remanescentes das esplenectomias parciais. CONCLUSÕES: A análise dos resultados nos permitiu concluir que a esplenectomia total induz aumento significante do colesterol total, das frações HDL e LDL, enquanto os níveis de triglicerídios e a fração VLDL não sofrem alterações; a conservação da metade inferior do baço ou a esplenectomia subtotal, com preservação do pólo inferior, protege o animal de alterações lipídicas significantes.