Can pumpkin save us of doxorubicin induced cardiotoxicity? / ¿Puede la calabaza salvarnos de la cardiotoxicidad inducida por doxorrubicina?

SUMMARY: Doxorubicin (DOX) is one of the drugs necessary for the treatment of the 10 most common types of cancer. The leading adverse effect limiting clinical use of DOX is cardiotoxicity. Given that literature data indicate a protective role of carotenoids in doxorubicin-induced toxicity, in our study we compared the cardioprotective effect of a mixture of pumpkin carotenoids and a commercially available antioxidant preparation. Animals were distributed in 8 groups (Control - S; NADES - N; Doxorubicin - Dox; Carotenoids - Car; CardiofortIN - CF; NADES-Doxorubicin - N-Dox; Carotenoids-Doxorubicin - Car-Dox; CardiofortIN-Doxorubicin - CF-Dox). Histological sections were stained with the hematoxylin-eosin (HE) and analyzed for the presence of myocardial damage by doxorubicin damage score (DDS). From the heart tissue homogenate were determined the intensity of lipid peroxidation and specific antioxidative enzyme activity (superoxide dismutase; catalase; glutathione S-transferase; glutathione peroxidase). In Car-DOX and CF-DOX groups, lipid peroxidation is significantly reduced compared to DOX group. Pretreatment of animals with carotenoids and in lesser extent with CardiofortIN led to higher antioxidative enzymes activity, compared to DOX group. Pretreated with carotenoids, only 50 % of animals had some degree of myocardial damage, and no animals had extensive damage. CardiofortIN pretreatment showed less protective effect. Pretreatment with carotenoid extract, reduced DDS significantly, so Car-DOX group has changes equivalent to mild myocardial damage. Although CardiofortIN pretreatment lowered DDS score values, animals still had moderate level of myocardium damage. This in vivo study and its findings indicate that carotenoids extracted from pumpkin may be a promising cardioprotective agent against doxorubicin induced cardiotoxicity, at least in part mediated through inhibition of DOX-induced oxidative stress.

La doxorrubicina (DOX) es uno de los fármacos necesarios para el tratamiento de los 10 tipos más comunes de cáncer. El principal efecto adverso que limita el uso clínico de DOX es la cardiotoxicidad. Debido a que los datos de la literatura indican un papel protector de los carotenoides en la toxicidad inducida por doxorrubicina, en nuestro estudio comparamos el efecto cardioprotector de una mezcla de carotenoides de calabaza y una preparación antioxidante disponible comercialmente. Los animales se distribuyeron en 8 grupos (Control - S; NADES - N; Doxorrubicina - Dox; Carotenoides - Car; CardiofortIN - CF; NADES-Doxorrubicina - N-Dox; Carotenoides-Doxorrubicina - Car-Dox; CardiofortIN- Doxorrubicina - CF-Dox). Las secciones histológicas se tiñeron con hematoxilina-eosina (HE) y se analizaron para detectar la presencia de daño miocárdico mediante la puntuación de daño por doxorrubicina (DDS). A partir del homogeneizado de tejido cardíaco se determinó la intensidad de la peroxidación lipídica y la actividad enzimática antioxidante específica (superóxido dismutasa, catalasa, glutatión S-transferasa, glutatión peroxidasa). En los grupos Car-DOX y CF-DOX, la peroxidación lipídica se redujo significativamente en comparación con el grupo DOX. El pre tratamiento de los animales con carotenoides y, en menor medida, con CardiofortlN condujo a una mayor actividad de las enzimas antioxidantes, en comparación con el grupo DOX. Al ser pre tratados con carotenoides, solo el 50 % de los animales tenían algún grado de daño miocárdico y ningún animal tenía daño extenso. El pre tratamiento con CardiofortIN mostró un efecto protector menor. El pre tratamiento con extracto de carotenoides redujo significativamente el DDS, por lo que el grupo Car-DOX mostró cambios equivalentes a un daño miocárdico leve. Aunque el pre tratamiento con CardiofortIN redujo los valores de la puntuación DDS, los animales aún tenían un nivel moderado de daño al miocardio. Este estudio in vivo y sus hallazgos indican que los carotenoides extraídos de la calabaza pueden ser un agente cardioprotector prometedor contra la cardiotoxicidad inducida por doxorrubicina, al menos en parte mediada por la inhibición del estrés oxidativo inducido por DOX.

Parâmetros zootécnicos e desenvolvimento da moela de frangos de corte em dietas de sorgo grão e a inclusão de carotenoides / Zootechnical parameters and gizzard development of broilers fed with sorghum grain and carotenoid supplementation

Objetivou-se avaliar a substituição do milho pelo sorgo grão, moído ou inteiro, e a inclusão de carotenoides sintéticos em rações de frangos de corte, sobre parâmetros zootécnicos e desenvolvimento da moela. Utilizaram-se 960 frangos, machos e fêmeas, da linhagem Cobb 500, que foram submetidos a quatro dietas: à base de milho (M), à base de sorgo moído (SM) ou ainda acrescido de carotenoides sintéticos (SMC) e à base de sorgo inteiro (SI). Foram avaliados peso vivo, consumo de ração, conversão alimentar, rendimento de carcaça e cortes, peso de moela. A ração de SI proporcionou maior desenvolvimento de moela, embora, aos sete dias, não tenha havido diferenças no peso vivo e na conversão alimentar entre as dietas. SM e SMC proporcionaram maiores valores de peso vivo aos 28 dias do que SI. As conversões alimentares real e tradicional aos 40 dias foram semelhantes para as rações de sorgo, com um melhor rendimento de carcaça em SM e SMC. O sorgo moído pode substituir integralmente o milho nas rações para frangos de corte, sem comprometimento de desempenho e rendimento de carcaça, e, na forma grão inteiro, é zootecnicamente viável.(AU)

This study aimed to evaluate the replacement of corn with ground or whole grain sorghum and the inclusion of carotenoids in broiler feed on zootechnical parameters and gizzard development. A total of 960 Cobb 500 broilers, half of each sex, were submitted to four feeds: ground corn (M), ground sorghum (SM) ground sorghum with carotenoid supplementation (SMC) and whole grain sorghum (SI). Body weight, feed intake and feed conversion, carcass and cuts yield, gizzard weight were evaluated. SI feed provided a greater development of gizzard, however at 7 days there were no differences in body weight and feed conversions between diets. SM and SMC provided higher values of body weight at 28 days than SI feed. Feed conversion at 40 days were the same for the sorghum feeds with a better carcass yield in SM and SMC. Ground sorghum can completely replace corn in broiler diets without compromising performance and carcass yield, and whole grain sorghum is zootecnaly viable.(AU)

Topical action of Buriti oil (Mauritia flexuosa L) in myositis induced in rats

Abstract Purpose: To analyze the topical effects of Buriti oil (Mauritia flexuosa L.) in induced myositis in rats. Methods: Thirty six male rats divided into three groups: Control group (C), induced myositis group (MI) and induced myositis group reated with Mauritia flexuosa L. (MT). After inducing myositis with 1% acetic acid, was topically applied 0.5 ml of Mauritia flexuosa L.extract on the posterior region of the right gastrocnemius muscle in animals belonging to group MT, for 7 and 14 days. Results: The neutrophil number there was statistically significant difference, after 7 and 14 days, between groups C and MI (p <0.001) (p<0.01). The group MT there was a significant difference in relation to MI group in both experimental times with (p<0.001). The number of fibroblasts in the 14 days showed that when comparing the groups M and MT the differences were also significant (p<0.001). As for the DLL, in 7 days, there was a significant difference between group C and MI group (p <0.001). When considering the MT group, there was a significant difference in relation to the MI group (p <0.001). Conclusion: The extract of Mauritia flexuosa L. leaves lessened acute and chronic inflammation, increased fibroblast proliferation and reduced macroscopically edema.

Intake of oral photoprotectors by postmen in Porto Alegre

Introduction: Postmen are daily exposed to high levels of solar radiation, and lack of protection can result in many health damages. The present study aimed to identify cutaneous phototypes and evaluate the intake of oral photoprotectors by postmen. Methods: Cross-sectional study, carried out from August 2011 to December 2012 in the city of Porto Alegre, state of Rio Grande do Sul, Brazil. Socioeconomic and behavioral data regarding daily solar exposure were collected through a questionnaire. To evaluate the intake of beta-carotene, lycopene and omega-3, two 24-hour dietary recalls were applied. Cutaneous phototypes were assessed by Fitzpatrick's classification. Results: A total of 181 postmen were analyzed, whose mean age was 40.2±11.4 years old, and 140 (77.3%) were male. The cutaneous phototypes II, III and IV were the most prevalent (n=138), totaling 76.3% of the sample. The median for the oral photoprotectors intake was 1.16 mg (0.46-2.29) of beta-carotene, 3.60 mg (1.01-6.31) of lycopene and 0.95 g (0.61-1.45) of n-3 fatty acids, all values significantly lower than the minimal doses to obtain photoprotective effect (p<0.001). The individuals in the group of phototypes V and VI showed lower adherence to the use of sunscreen and lower intake of beta-carotene, comparing to the other groups. Conclusions: The intake of oral photoprotectors is low in this population. Future studies may evaluate the real effect of oral photoprotectors, so that preventive measures using this approach can be included in photoprotection education actions for outdoor workers (AU)

Porcentagem de proteína em suplementos para ovinos mantidos em pasto de capim-aruana na época seca / Protein percentage in supplements for sheep grazing Aruana grass on dry season

Objetivou-se avaliar o consumo de forragem e o desempenho de ovinos mantidos em pastagem de capim-aruana, submetidos a porcentagens crescentes de proteína bruta (PB) no suplemento, na época seca. Vinte borregos da raça Santa Inês foram utilizados em delineamento inteiramente ao acaso, com cinco tratamentos e quatro repetições. Os suplementos foram fornecidos em 1,0% do peso corporal, nas porcentagens de 0, 15, 20, 25 e 30%. O aumento de proteína bruta influenciou o consumo total de matéria seca (kg/dia) e a porcentagem do peso vivo, com valores máximos estimados de 1.296g (3,2% de MS) com 21,48 e 21,89% de PB no suplemento, respectivamente. O consumo de forragem máximo, estimado de 893g/dia, ocorreu com a PB de 21,5%. O aumento de PB nos suplementos resultou em efeito quadrático sobre o ganho médio diário, com valor máximo de 104g/dia com a PB de 23% no suplemento. Recomenda-se o uso de suplementos múltiplos com 21 a 23% de PB fornecidos na proporção de 1% do peso corporal (PC) para ovinos mantidos em pastos de capim-aruana na época seca...

The aim of this study was to evaluate the forage intake and grazing sheep performance keep on Aruana grass subjected to increasing crude protein (CP) levels in the supplement on dry season. Twenty Santa Ines male lambs were used, with initial body weight of 31.80kg by a completely randomized design with five treatments and four replications. The supplements were provided daily at 1% of body weight, with protein levels of 0, 15, 20, 25 and 30%. The increase of the crude protein levels promoted a squarely effect on dry matter intake (kg/day and % of BW), with maximum estimated values of 1296g and 3.2% of DM in CP levels of 21.48 and 21.89, respectively. The maximum forage intake estimated of 893g/day occurred in CP level de 21.51%. The increased of crude protein level in supplements increased squarely the average daily gain, with a maximum of 104g/day, for the 23% crude protein in the supplement. Thus, the use of the multiple supplements supplied in 1% of body weight with CP levels ranged 21 a 23% is indicated for sheep grazing Aruana grass on dry season...

Protective effects of lycopene on oxidative stress, proliferation and autophagy in iron supplementation rats

Lycopene is common in diet and known for its antioxidant activities. However, the impact of lycopene on iron metabolism is poorly investigated. In this study, we hypothesize that lycopene can prevent iron-mediated oxidative stress, proliferation and autophagy in liver and use a rat model of nutritional iron supplementation to confirm its intervention in these defence mechanisms. We found that iron supplementation induced cell proliferation predominantly in non parenchymal cells compared with hepatocytes, but not apoptosis. In addition, iron was accumulated within the hepatic lysosomes where it triggered autophagy as evidenced by the formation of autophagic vesicles detected by LC3-B staining. Iron supplementation also induced morphologic alterations of the mitochondrial membranes probably due to increased lipid peroxidation as indicated by elevated iron and malondialdehyde concentrations in serum and tissues. Lycopene reduced iron-catalyzed lipid peroxidation by decreasing the malondialdehyde level in the liver and colon and enhancing the total superoxide dismutase activities in serum and tissues. The result suggest that lycopene prevents iron-induced oxidative stress, proliferation and autophagy at both biochemical and histological levels due to its potent free radical scavenging and antioxidant properties.

El consumo elevado de licopeno sumado a una ingestión reducida de carnes rojas aumenta el poder antioxidante total

Los sistemas antioxidantes del cuerpo humano son capaces de remover a los radicales libres, protegiendo así al organismo del daño que estos pueden ocasionar, y pueden ser valorados en conjunto mediante la determinación del poder antioxidante total (TAS, por sus siglas en inglés). Este biomarcador es modulado por la alimentación mediante la incorporación de sustancias con propiedades antioxidantes o prooxidantes. El objetivo del presente trabajo fue estimar la ingestión de nutrientes antioxidantes y grupos específicos de alimentos y correlacionarla con el TAS. Fueron seleccionados al azar 45 sujetos de sexo masculino, entre 50 y 75 años, de una consulta médica de rutina. El trabajo consistió en una evaluación de TAS mediante técnica ABTS más una entrevista nutricional donde se evaluó la composición corporal mediante antropometría y la ingestión habitual de nutrientes y grupos específicos de alimentos mediante un recordatorio de 24 h y un cuestionario de frecuencia de consumo de alimentos validado para tal fin. El análisis estadístico se realizó mediante Coeficiente de Correlación de Pearson o Spearman según la normalidad de la muestra (p<0,05). El TAS se correlacionó positivamente con el consumo de licopeno (r=0,295; p=0,049) y negativamente con la ingestión de carnes rojas (r= -0,403; p=0,007). Los demás nutrientes o alimentos no se correlacionaron con el TAS. Por lo tanto, una ingestión elevada de licopeno y un consumo reducido de carnes rojas ayudarían a mejorar el sistema antioxidante del organismo.

High intake of lycopene together with low intake of red meat increases the total antioxidant status. The body's antioxidant systems are able to remove free radicals, thus protecting the body from the damage they may cause. They can be estimated, as a whole, through the determination of total antioxidant status (TAS). This biomarker can be modulated by dietary factors through the incorporation of substances with antioxidant or prooxidant properties. The aim of this study was to estimate the intake of antioxidant nutrients and specific food groups, and its correlation with TAS. Fortyfive male volunteers between 50 and 75 years were randomly selected from a medical consultation. The study included a TAS determination by ABTS and a nutritional interview where corporal composition was studied through anthropometry and the habitual consumption of nutrients was estimated by means of 24 hour diary and food consumption frequency questionnaire. Statistical analysis was performed by using Pearson or Spearman correlation coefficient (p <0.05). TAS was positively correlated with lycopene consumption (r=0,295; p=0,049), and negatively with red meat intake (r= -0,403; p= 0,007), while intake of other studied antioxidant nutrients did not correlate significantly with TAS. In conclusion, high intake of lycopene and reduced red meat consumption increase TAS.

Lycopene in the management of oral lichen planus: A placebo-controlled study.

Context: Oxidative stress has been implicated in the pathogenesis of lichen planus, and a lower level of lycopene has been reported in erosive and atrophic oral lichen planus (OLP) patients. However, its efficacy in the management of OLP has not been reported. Aim: This study was designed to assess the efficacy of systemic lycopene in the management of OLP. Settings and Design: This prospective, randomized, double-blind, placebo-controlled study was done in the Oral Medicine Department of a postgraduate teaching dental hospital in India. Materials and Methods: Thirty symptomatic OLP patients, randomly divided into two groups of 15 each, were administered lycopene 8 mg/day and an identical placebo, respectively, for 8 consecutive weeks. Burning sensation using visual analogue scale and overall treatment response using Tel Aviv-San Francisco scale were recorded at every visit. The data obtained were analyzed statistically using Wilcoxon Rank test, Mann-Whitney and Fischer's Exact test. Results: A higher (84%) reduction in burning sensation was seen in lycopene than in the placebo group (67%). All 15 (100%) patients in the lycopene group showed 50% or more benefit and 11 (73.3%) patients showed 70-100% benefit, while this number was only 10 and 4 (26.7%), respectively, in the placebo group. Conclusion: Lycopene was very effective in the management of OLP, and oxidative stress may have a role in disease pathogenesis.

Carotenoides y su función antioxidante: Revisión / Carotenoids and their antioxidant function: A review

Los antioxidantes naturales presentes en los vegetales y en algunos animales han sido estudiados por su papel en la protección de diversas enfermedades como ciertos tipos de cáncer, enfermedades del corazón y la degeneración macular relacionada con la edad. Evidencia experimental sugiere que estos compuestos son importantes en la protección de macromoléculas biológicas contra el daño oxidativo. La búsqueda de nuevos y más eficientes antioxidantes al parecer va dirigida a los carotenoides, que han demostrado que a través de su consumo puede disminuir la incidencia de ciertas enfermedades. Además representan una fuente de provitamina A, y presentan una actividad antioxidante en la célula al actuar en la neutralización de especies reactivas de oxígeno y nitrógeno producidas como parte del metabolismo celular. Esta publicación tiene como objetivo revisar aspectos básicos y clínicos de investigaciones realizadas que asocian la ingesta de carotenoides con cáncer, enfermedades del corazón y la degeneración macular relacionada con la edad. Primero se identificaron los conceptos básicos sobre el papel que desempeñan los carotenoides en el metabolismo; posteriormente se revisó la evidencia clínica que muestra como la ingesta de carotenoides reducen ciertas enfermedades. Por último se discuten algunos de los resultados de investigaciones.

Natural antioxidant in vegetables, and in some animals have been studied by their action in the protection of a considerable number of diseases, such as, certain types of cancer, cardiovascular diseases, and age-related macular degeneration. Experimental evidences suggest that these compounds are important for protecting biological macro-molecules against oxidative damage. The search of new and more efficient antioxidants appears to be directed with carotenoids which have demonstrated that their consumption may reduce the incidence of certain diseases. In addition they represent a provitamin A source, and their actual antioxidant activity in the cell by participating in the neutralization of reactive oxygen species, and nitrogen produced, as a part of the cellular metabolism. This paper is focused to review basic and clinical aspects of investigations which have been associated with the intake of carotenoids with cancer, heart diseases, and age-related macular degeneration; the above all, we have tried to identify basic concepts of the role of the carotenoids and their metabolism; after that, we have reviewed clinical evidence that show how the intake of carotenoids reduces certain diseases. Finally, we discuss some of the results of investigation.

Nucleótidos y carotenoides naturales / Nucleotides and carotenoids

El concepto de los nucleótidos no es nuevo; máxime que son elementos que hacen parte de los componentes naturales de la leche materna. Casi todos los estudios señalan que el consumo de carotenoides, previenen el desarrollo de enfermedades crónicas en la edad adulta, posiblemente por su efecto antioxidante que disminuye el estrés oxidativo, mejorando enfermedades degenerativas y malignas.

The concept of nucleotides is not new, especially since they are elements that are part of the natural components of human milk. Most studies indicate that the consumption of carotenoids, prevent the development of chronic diseases in adulthood, possibly by its antioxidant effect that reduces oxidative stress, improving degenerative diseases and malignancies.

Disponibilidade de energia e de carotenóides nos domicílios brasileiros / Availability of energy and carotenoids in Brazilian households

O objetivo deste trabalho foi analisar a disponibilidade de energia e de carotenóides para as famílias residentes nas áreas rurais e urbanas do Brasil. Utilizou-se como base de dados as informações obtidas por meio da Pesquisa de Orçamentos Familiares (POF) 2002/2003 do Instituto Brasileiro de Geografia e Estatística (IBGE). As análises de energia foram viabilizadas por meio da utilização do software Virtual Nutri e, para identificação do conteúdo de carotenóides nos alimentos, adotaram-se as informações contidas na tabela Nutrient Database for Standard Reference Release 19 – United States of Department Agriculture (USDA). Os resultados mostram reduzida disponibilidade de energia para as famílias brasileiras e particularmente para aquelas moradoras das áreas urbanas do país. Observou-se ainda, baixa disponibilidade de carotenóides, e um aumento no conteúdo disponível desses compostos conforme ocorre crescimento dos rendimentos.

Effect of different doses of carotenoids in isoniazid-rifampicin induced hepatotoxicity in rats.

AIM: Isoniazid (INH) and Rifampicin (RIF) are hepatotoxic drugs. Oxidative stress has been reported as one of the mechanisms of INH+RIF induced hepatotoxicity. METHODS: Intragastric administration of INH and RIF (50 mg/kg body weight/day each) for 28 days in Wistar rats is hepatotoxic, indicated by raised transaminases and histology. Carotenoids have antioxidant properties. Therefore, different doses of carotenoids (2.5, 5, 10 and 20 mg/kg body weight/day) were administered to study the hepatoprotective effect against INH+RIF. RESULTS: The higher doses of carotenoids i.e.10 and 20 mg/kg body weight/day showed partial hepatoprotection indicated by return to normal of liver transaminase level and of liver histology in 33.3% of rats. There was no further protective effect seen by increasing the dose of carotenoids from 10 to 20 mg/kg body weight/day. Lower doses of carotenoids, i.e., 2.5 and 5 mg/kg body weight/day were not effective. CONCLUSION: Thus, a minimum dose with maximum hepatoprotection (10 mg/kg b.wt/ day) was selected as the optimum dose in the present study. The hepatoprotective nature of carotenoids in INH+RIF treated rats may be attributed to their antioxidative property.

Effect of the consumption of tomato paste on plasma prostate-specific antigen levels in patients with benign prostate hyperplasia

The consumption of tomatoes and tomato products has been associated with a reduced risk of prostate cancer. We observed a decrease of 10.77 percent in prostate-specific antigen (PSA) levels in patients with benign prostate hyperplasia who were submitted to daily ingestion of tomato paste. This was an experimental rather than a controlled study with a sample of 43 men ranging in age from 45 to 75 years, all with histological diagnoses of benign prostate hyperplasia and plasma PSA levels of 4-10 ng/mL. All patients received 50 g of tomato paste once a day for 10 consecutive weeks and PSA levels were analyzed before, during and after the consumption of tomato paste. ANOVA for repeated measures was used to compare PSA levels before, during and after the consumption of tomato paste. The mean ± SD PSA level was 6.51 ± 1.48 ng/mL at baseline and 5.81 ± 1.58 ng/mL (P = 0.005) after 10 weeks. Acceptance was good in 88.3, regular in 9.3, and poor in 2.3 percent of the patients. Dietary ingestion of 50 g of tomato paste per day for 10 weeks significantly reduced mean plasma PSA levels in patients with benign prostate hyperplasia, probably as a result of the high amount of lycopene in tomato paste. This was not a prostate cancer prevention study, but showed some action of tomato paste in prostate biology. The development of prostate cancer is typically accompanied by an increase in plasma PSA levels, thus any intervention that affects plasma PSA levels can suggest an impact in the progression of disease.

Prostate cancer: altering the natural history by dietary changes.

The importance of diet on the development and progression of prostate cancer was initially suggested by epidemiological studies. Since then, there has been a vast amount of research in this field. Compelling evidence now provides hope that evidence-based dietary alterations may markedly alter the natural history of this disease. Is there enough evidence for clinicians to be able to advise dietary modifications? The preliminary results no doubt are encouraging, but at present there seems to be no evidence to justify the widespread use of these proposed dietary interventions. However, as public awareness increases, all physicians involved with the care of patients with cancer of the prostate will need to be better armed with the current updates and advice on this issue.

Carotenoids and human health

After the discovery of vitamin A in 1913, the yellow pigments of fruits and vegetables were soon implicated as compounds with similar nutritional affects B-carotene was shown to be converted intro vitamin A by moore in 1929, and chemical structures of both vitamin A and ß-carotone were determined two years later. Thus, the sole function of ß-carotene in human health was considered to be its conversion into vitamin A. On the basis of observational epidemiologic studies, conducted in the mid-1970s, however, carotenoids were implicated as protective agents, firts against lung cancer and then against a variety of other chronic diseases. Intervention trials employing ß-carotene, however, either have shown no preventive effect or indeed, in two cases, have echanced the incidence of lung cancer in middle-aged male smokers and asbestos workers. The possible protective action of carotenoids can be attributed to their properties as singlet oxygen quenchers and antioxidants, whereas their cancer-enchancing actions in lung can be ascribed to the prooxidant action of carotenoid free radicals in damaged cells. Apart from chronic disease, ß-carotene has shown significant therapeutic value in individuals suffering from photosensitivity disorders and provides temporary relief to persons afflicted with leukoplakia. Apart from a medical contex, the colored carotenoids found in many living organisms and in many foods delight both the eye and the palate. Thus, human health and the enjoyment of life are greatly benefited by the presence of these interesing pigments in nature, whether or not they ultimately prove to have more specific protective affects againts chronic diseases

The role provitamin A carotenoids in the prevention and control of vitamin A deficiency

El hecho de que el ß-caroteno es la fuente principal de la vitamina A en frutas y vegetales ha sido conocido por muchos años. Varios estudios han sido conducidos para evaluar la bioconversión del ß-caroteno en vitamina A en animales. Más recientemente, estudios de bioconversión con ß-caroteno marcado con isótopos estables han sido utilizados para evaluar la bioconversión en humanos. La eficiencia de la conversión de ß-caroteno en vitamina A aceptada es seis, sin embargo este valor puede variar dependiendo del status en vitamina A. Este articulo discute los estudios en humanos con suplementos de ß-caroteno puro o consumo de frutas y verduras, efectuados para averiguar si el ß-caroteno puede alterar el estado de vitamina A de poblaciones deficientes. La conclusión es que faltan datos de estudios bien diseñados para mostrar que, con la posible excepción del aceite de palma roja. Los alimentos ricos en ß-caroteno son tan efectivos como los suplementos de vitamina A en la eliminación de la deficiencia de vitamina A. Sin embargo, los datos muestran que alimentos ricos en carotenoides pueden ser importantes para la prevención de la deficiencia de vitamina A

Changes in carotenoids during processing and storage of foods

Por ser altamente insaturados, los carotenoides son susceptibles a la isomerización y oxidación durante el procesamiento de los alimentos. La isomerización de trans- para cis-carotenoides, promovida por el contacto de ácidos, tratamiento con calor y exposición a la luz disminuye el calor y la actividad de vitamina A de los carotenoides. El principal causante de las pérdidas, sin embargo, es la oxidación por vías enzimáticas y no enzimáticas, la cual depende de la disponibilidad de oxígeno y la estructura del carotenoide: esta es estimulada por la luz, el calor, ciertos metales, enzimas y peróxidos y es inhibida por anti-oxidantes. Si bien los datos sobre pérdidas porcentuales, durante el procesamiento y almacenamiento, son un tanto conflictivas, no hay duda de la degradación aumenta con el grado de destrucción de las estructuras celulares, el incremento del área superficial o porosidad, tiempo y severidad de las condiciones del proceso, duración temperatura del almacenamiento, transparencia a la luz permeabilidad del embalaje al 02. En contraste con la oxidación en lípidos, donde el mecanismo se encuentra bien definido, al oxidación de carotenoides no ésta elucidada. Esta comienza con epoxidación, formación de apocarotenoides e hidroxilación, fragmentaciones subsecuentes presumiblemente llevan a una serie de compuestos de pequeña masa molecular. Después de perder su color y sus actividades biológicas, los carotenoides dan origen a compuestos que contribuyen al aroma/sabor, los cuales pueden ser deseables como en té vino, pero indeseables en productos como zanahoria deshidratada. El procesamiento también puede influenciar la biodisponibilidad de los carotenoides, tema actualmente de gran interés

Chromatographic separation of carotenoids

Devido ao longo sistema de duplas ligaçoes conjugadas, os carotenóides sâo altamente reativos e consequentemente instáveis: Várias precauçoes, tais como conduçao da análise no menor tempo possível, exclusao de oxigênio, proteçao contra luz, uso de baixa temperatura e de antioxidantes, devem entâo serem tomadas durante o isolamento e cromatografia. Os alimentos, preferencialmente in natura, sâo homogenizados, e imediatamente os carotenóides sao extraídos com solventes orgânicos. A saponificaçâo é empregada com o objetivo de hidrolisar os ésteres de carotenóides, promover retirada de lipídeos e destruiçâo de clorofila. Esta etapa opcional facilita a posterior separaçao, identificaçao e quantificaçao dos carotenóides. Os carotenóides sao separados por cromatografia em coluna, cromatografia em camada delgada ou cromatografia líquida de alta eficiencia (HPLC), tanto em escala analítica como preparativa. Várias fases estacionárias podem ser empregrados tais como alumina, sílica, Ca(OH)2, MgO e fase reserva (C18 e C30). Os principais fatores que devem ser considerados na escolha do método cromatográfico sao: quantidade de amostra, composiçao de carotenóides, pureza, resoluçao e velocidade necessárias. Serao apresentados e discutidos exemplos de separaçao de carotenóides em diversas fases estacionárias

Sources of errors in the quantitative analysis of food carotenoids by HPLC

Varios factores hacen inherentemente difícil la determinación de carotenoides. A pesar de los avances en la instrumentación analítica, se pueden encontrar en la literatura internacional, discrepancias en los resultados cuantitativos relacionados a los carotenoides. Una gran parte de los errores provienen de las etapas precromatográficas tales como: esquema de muestreo que produce muestra representativa del lote en estudio; preparación de muestra que no mantenga la representatividad y garantice la homogeneidad de la muestra analítica; extracción incompleta; pérdidas físicas de los carotenoides durante las varias etapas, especialmente durante la partición o lavado y por absorción en las paredes de vidrios de los recipientes; isomerización y oxidación de los carotenoides durante el análisis. Sin embargo, a pesar de que actualmente el método escogido para análisis de carotenoides es HPLC, éste está sujeto a varias fuentes de errores, tales como: incompatibilidad del solvente de inyección y la fase móvil, resultando en picos distorsionados o divididos; identificación errónea; indisponibilidad, impureza e inestabilidad de los patrones de carotenoides; cuantificación de picos altamente superpuestos; baja recuperación de las columnas de HPLC; errores en la preparación de las soluciones de patrones y en el procedimiento de calibración; errores de cálculo. Se presentan ilustraciones de los posibles errores en la cuantificación de carotenoides por HPLC