Study of anti-diabetic, beta-carotene-bleaching inhibiting and iron chelating properties of Carissa opaca root extracts

Abstract Degenerative diseases diabetes and oxidative stress constitute a major health concern worldwide. Medicinal plants are expected to provide effective and affordable remedies. The present research explored antidiabetic and antioxidant potential of extracts of Carissa opaca roots. Methanolic extract (ME) was prepared through maceration. Its fractions were obtained, sequentially, in hexane, chloroform, ethyl acetate and n-butanol. An aqueous decoction (AD) of the finely ground roots was obtained by boiling in distilled water. The leftover biomass with methanol was boiled in water to obtain biomass aqueous decoction (BAD). The extracts and fractions showed considerable porcine pancreatic α-amylase inhibitory activity with IC50 in the range of 5.38-7.12 mg/mL while acarbose had 0.31 mg/mL. The iron chelating activity in terms of EC50 was 0.2939, 0.3429, 0.1876, and 0.1099 mg/mL for AD, BAD, ME, and EDTA, respectively. The EC50 of beta-carotene bleaching activity for AD, BAD, ME, and standard BHA were 4.10, 4.71, 3.48, and 2.79 mg/mL, respectively. The total phenolic content (TPC) and total flavonoid content (TFC) of AD and BAD were also considerable. In general, ethyl acetate fraction proved to be the most potent. Thus, the C. opaca roots had excellent antioxidant activity while having moderate α-amylase inhibitory potentia

Yellow sweet potato flour: use in sweet bread processing to increase carotene content and improve quality

ABSTRACT Yellow sweet potato is mostly produced by small farmers, and may be a source of energy and carotenoids in the human diet, but it is a highly perishable crop. To increase its industrial application, yellow sweet potato flour has been produced for use in bakery products. This study aimed to evaluate the technological quality and the carotenoids content in sweet breads produced with the replacement of wheat flour by 0, 3, 6, and 9% yellow sweet potato flour. Breads were characterized by technological parameters and β-carotene levels during nine days of storage. Tukey's test (p<0.05) was used for comparison between means. The increase in yellow sweet potato flour concentrations in bread led to a decrease of specific volume and firmness, and an increase in water activity, moisture, orange coloring, and carotenoids. During storage, the most significant changes were observed after the fifth day, with a decrease in intensity of the orange color. The β-carotene content was 0.1656 to 0.4715 µg/g in breads with yellow sweet potato flour. This work showed a novel use of yellow sweet potato in breads, which brings benefits to consumers' health and for the agricultural business.

Fatty acid composition from the marine red algae Pterocladiella capillacea (S. G. Gmelin) Santelices & Hommersand 1997 and Osmundaria obtusiloba (C. Agardh) R. E. Norris 1991 and its antioxidant activity

ABSTRACT This study evaluated the chemical composition and antioxidant activity of fatty acids from the marine red algae Pterocladiella capillacea (S. G. Gmelin) Santelices & Hommersand 1997 and Osmundaria obtusiloba (C. Agardh) R. E. Norris 1991. The gas chromatography mass spectrometry (GC-MS) identified nine fatty acids in the two species. The major fatty acids of P. capillacea and O. obtusiloba were palmitic acid, oleic acid, arachidonic acid and eicosapentaenoic acid. The DPPH radical scavenging capacity of fatty acids was moderate ranging from 25.90% to 29.97%. Fatty acids from P. capillacea (31.18%) had a moderate ferrous ions chelating activity (FIC), while in O. obtusiloba (17.17%), was weak. The ferric reducing antioxidant power (FRAP) of fatty acids from P. capillacea and O. obtusiloba was low. As for β-carotene bleaching (BCB), P. capillacea and O. obtusiloba showed a good activity. This is the first report of the antioxidant activities of fatty acids from the marine red algae P. capillacea and O. obtusiloba.

Phenolic compounds and vitamins in wild and cultivated apricot (Prunus armeniaca L) fruits grown in irrigated and dry farming conditions

BACKGROUND: Turkey is the main apricot producer in the world and apricots have been produced under both dry and irrigated conditions in the country. In this study, phenolic compounds and vitamins in fruits of one wild (Zerdali) and three main apricot cultivars ('Cataloglu', 'Hacihaliloglu' and 'Kabaasi') grown in both dry and irrigated conditions in Malatya provinces in Turkey were investigated. RESULTS: The findings indicated that higher content of phenolic compounds and vitamins was found in apricot fruits grown in irrigated conditions. Among the cultivars, 'Cataloglu' had the highest rutin contents both in irrigated and dry farming conditions as 2855 µg in irrigated and 6952 µg per 100 g dried weight base in dry conditions and the highest chlorogenic acid content in irrigated and dry farming conditions were measured in fruits of 'Hacihaliloglu' cultivar as 7542 µg and 15251 µg per 100 g dried weight base. Vitamin C contents in homogenates of fruit flesh and skin was found to be higher than ß-caroten, retinol, vitamin E and lycopen contents in apricot fruits both in irrigated and dry farming conditions. CONCLUSION: The results suggested that apricot fruits grown in both dry and irrigated conditions had high health benefits phytochemicals and phytochemical content varied among cultivars and irrigation conditions as well. However, more detailed biological and pharmacological studies are needed for the demonstration and clarification of health benefits of apricot fruits.

Efeito do betacaroteno sobre o estresse oxidativo e a expressão de conexina 43 cardíaca / Effect of beta-carotene on oxidative stress and expression of cardiac connexin 43

FUNDAMENTO: Estudos de intervenção mostraram aumento da mortalidade em pacientes que receberam betacaroteno. Contudo, não são conhecidos os mecanismos envolvidos nesse fenômeno. OBJETIVO: Avaliar a influência do betacaroteno sobre o estresse oxidativo e a expressão de conexina 43 em coração de ratos. MÉTODOS: Ratos Wistar, pesando aproximadamente 100 g, foram alocados em dois grupos: Grupo Controle (n = 30), que recebeu a dieta usada de rotina em nosso laboratório, e Grupo Betacaroteno (n = 28), que recebeu betacaroteno (na forma de cristal, adicionado e misturado à dieta) na dose de 500 mg de betacaroteno/kg de dieta. Os animais receberam tratamento até que atingissem entre 200 e 250 g, quando eram sacrificados. Foram coletados sangue, fígado e coração para realização de Western blotting e imunoistoquímica para conexina 43; foram realizados estudos morfométricos, dosagens de betacaroteno por cromatografia líquida de alta eficiência bem como de glutationa reduzida, glutationa oxidada e hidroperóxidos de lipídeos por análises bioquímicas. RESULTADOS: O betacaroteno foi detectado apenas no fígado dos animais do Grupo Betacaroteno (288 ± 94,7 µg/kg). Os níveis de glutationa reduzida/glutationa oxidada foram maiores no fígado e no coração dos animais do Grupo Betacaroteno (fígado - Grupo Controle: 42,60 ± 1,62; fígado - Grupo Betacaroteno: 57,40 ± 5,90; p = 0,04; coração: - Grupo Controle: 117,40 ± 1,01; coração - Grupo Betacaroteno: 121,81 ± 1,32 nmol/mg proteína; p = 0,03). O conteúdo de conexina 43 total foi maior no Grupo Betacaroteno. CONCLUSÃO: O betacaroteno apresentou efeito benéfico, caracterizado pelo aumento da comunicação intercelular e melhora do sistema de defesa antioxidante. Nesse modelo, os mecanismos não explicam a maior mortalidade observada com a suplementação de betacaroteno em estudos clínicos. (Arq Bras Cardiol. 2013; [online].ahead print, PP.0-0).

BACKGROUND: Intervention studies have shown an increased mortality in patients who received beta-carotene. However, the mechanisms involved in this phenomenon are still unknown. OBJECTIVE: Evaluate the influence of beta-carotene on oxidative stress and the expression of connexin 43 in rat hearts. METHODS: Wistar rats, weighing approximately 100 g, were allocated in two groups: Control Group (n=30), that received the diet routinely used in our laboratory, and Beta-Carotene Group (n = 28), which received beta-carotene (in crystal form, added and mixed to the diet) at a dose of 500 mg of beta-carotene/kg of diet. The animals received the treatment until they reached 200-250g, when they were sacrificed. Samples of blood, liver and heart were collected to perform Western blotting and immunohistochemistry for connexin 43; morphometric studies, dosages of beta-carotene by high-performance liquid chromatography as well as reduced glutathione, oxidized glutathione and lipids hydroperoxides were performed by biochemical analysis. RESULTS: Beta-carotene was detected only in the liver of Beta-Carotene Group animals (288 ± 94.7 µg/kg). Levels of reduced/oxidized glutathione were higher in the liver and heart of Beta-Carotene Group animals (liver - Control Group: 42.60 ± 1.62; liver - Beta-Carotene Group: 57.40 ± 5.90; p = 0.04; heart: - Control Group: 117.40 ± 1.01; heart - Beta-Carotene Group: 121.81 ± 1.32 nmol/mg protein; p = 0.03). The content of total connexin 43 was larger in Beta-Carotene Group. CONCLUSION: Beta-carotene demonstrated a positive effect, characterized by the increase of intercellular communication and improvement of anti-oxidizing defense system. In this model, mechanism does not explain the increased mortality rate observed with the beta-carotene supplementation in clinical studies. (Arq Bras Cardiol. 2013; [online].ahead print, PP.0-0).

Effects of some parameters in upscale culture of Haematococcus pluvialis Flotow / Efeito de alguns parâmetros no cultivo em larga escala de Haematococcus pluvialis Flotow

Growth rate and medium parameters between two bench scale volumes (13-L and 250-L) were compared. Experiments were maintained batch mode and culture parameters were periodically measured during a 13-day period. Culture growth during the cultivation of algae Haematococcus pluvialis was determined qualitatively by cell counting, optical density, dry weight, ash content, amount of chlorophyll-a, total organic carbon content and by direct measuring of medium nutrients and some abiotic aspects. Vegetative cell growth was higher when cultured in 13-L with 1.33 x 105 cells.mL−1 on the 12th day than when cultured in 250-L. Significant difference (p < 0.05) in the biology and water culture of H. pluvialis, with the exception of dry weight, ash, nitrite and ammonia, was reported between the volumes. Data obtained in current study for the upscale culture maintenance of H. pluvialis in laboratory conditions shows that it should be undertaken in a 13-L volume due to a greater time span of cells in a vegetative state, greater cell density, lipids and chlorophyll-a contents. Light was of paramount importance on the direct performance of H. pluvialis on the algal biological conditions.

Foram avaliadas a taxa de crescimento e condições do meio de cultura em volumes de 13-L e 250-L em sistema estático, durante o período de 13 dias para a microalga Haematococcus pluvialis. Foi determinada qualitativamente a contagem de células, densidade, peso seco, teor de cinzas, clorofila-a, teor de carbono orgânico total e avaliação de nutrientes e fatores abióticos do meio de cultura. O crescimento foi mais elevado em volume de 13-L com 1,33 x 105 células.mL−1 no décimo segundo dia, do que em volume de 250-L. Em relação ao meio de cultivo e aspectos biológicos de H. pluvialis, foram observadas diferenças significativas (p < 0,05) entre os dois volumes com exceção do peso seco, cinzas, nitrito e amônia. Para cultivo em larga escale de H. pluvialis é recomendado nestas condições laboratoriais, o volume de 13-L devido ao maior tempo das células em estado vegetativo, maior densidade celular e elevados teores de lipídios e clorofila-a. A luz interferiu diretamente nas condições biológicas de H. pluvialis.

Ocorrência de isômeros do beta-caroteno em raízes de cinco cultivares de mandioca (Manihot esculenta Crants) do Estado de São Paulo / Beta-carotene isomers in roots of five manioc (Manihot esculenta Crantz) cultivars of São Paulo State

Raízes de cinco cultivares de mandioca (Manihot esculenta Crantz), provenientes do Instituto Agronômico de Campinas, a saber: Branca de Santa Catarina (SRT-59), Pioneira (SRT-13l0), Ouro do Vale (SRT-797), IAC-576-70 e IAC 289-70. As análises visaram a identificação dos principais carotenóides presentes nas raízes dos cultivares de mandioca produzidos no Estado de são Paulo, bem como a determinação da atividade pró-vitamínica A dos mesmos. Pelo cozimento das raízes ou a transformação em farinha, foi possível avaliar as perdas do teor vitamínico A de correntes do processamento. As análises foram realizadas no período de julho/86 a janeiro/87, sendo, desta maneira, possível avaliar as prováveis perdas decorrentes do armazenamento. Os resultados das análises permitiram concluir que os principais carotenóides presentes nas raízes dos cultivares de mandioca estudados foram o neo-ß-caroteno B, o ß-caroteno todo¬-trans e o neo-ß-caroteno U. |Os teores de vitamina A nas mandiocas estudadas, expressos em equivalentes de retinol/l00g, variaram de 2,8 a 13,9 para as amostras cruas e de 0,4 a 10,7 para as amostras processadas, sendo que o cozimento promoveu uma diminuição da atividade pró-vitamínica A, que variou de 20 a 55%. Dos cultivares estudados o IAC 289-70 foi o que apresentou menor porcentagem de perda de atividade pró-vitamínica A com o cozimento. Quanto ao armazenamento, foi possível observar que a mandioca crua com casca armazenada por 6 meses em freezer a –20°C não apresentou perdas na sua atividade pró-vitamínica A enquanto que o armazenamento das farinhas à temperatura ambiente, ao abrigo da luz, pelo mesmo período de tempo, apresentou total degradação de seus carotenóides

Roots of five following cultivars of cassava (Manihot esculenta Crantz) from "Instituto Agronômico de Campinas" were analyzed: "Branca de Santa Catarina" (SRT-59), "Pioneira" (SRT-1310), "Ouro do Vale" (SRT-797), "IAC 576-70" and "IAC 289-70". The analyses were made for the identification of the main carotenoids present in roots of the cassava cultivars produced in São Paulo State, as well as for determination of their pro-vitamin A activity. The cooking of the roots or their transformation as flour made possible to evaluate the loss of the pro-vitamin A value which occurs with processing. The analyses were made from July/1986 to January/1987. This permitted to evaluate the possibility of losses during storage. The results of the analyses allowed to conclude that the main carotenoids present in roots of the studied cassava cultivars were neo-ß-carotene B, all-trans-ß-carotene and neo-ß-carotene U. The vitarnin A values in these cassava expressed as retinol equivalents/lOOg varied from 2,8 to 13,9 for the raw samples; and with cooking, a diminution of the pro-vitarnin A activity occurred, which varied from 20 to 55%.Of all the studied cultivars, the "IAC 289-70" was the one that showed the greatest percentages of loss of pro-vitamin A activity with the cooking. The raw cassavas stored at –20°C for 6 months didn't show losses of their pro-vitamin A value, while the storage of the flour, at room temperature with no light, for the same period of time, showed total degradation of their carotenoids

Concentrações séricas de retinol de éguas gestantes em haras do Vale do Rio Doce e Sul de Minas Gerais / Retinol serum concentration in pregnant mares in farms of Vale do Rio Doce and Sul de Minas Gerais, Brazil

Foram analisadas as concentrações séricas de retinol de 16 éguas gestantes em haras de duas diferentes regiões de Minas Gerais (Vale do Rio Doce e Sul de Minas). Os animais foram mantidos em pastagens com sal mineral à vontade, sem qualquer suplementação concentrada. Amostras de sangue foram coletadas a cada 30 dias, nos meses de maio a novembro de 2002, objetivando verificar a necessidade de suplementação das éguas com vitamina A nos meses de seca. A concentração de betacaroteno das pastagens também foi correlacionada com as concentrações sorológicas de vitamina A, a fim de verificar a utilização da reserva hepática dessa vitamina pelos eqüinos. As análises do retinol sorológico e do betacaroteno das pastagens foram realizadas por cromatografia líquida de alta eficiência (HPLC). O experimento foi em parcelas subdivididas, no delineamento inteiramente ao acaso, e os resultados foram comparados pelo teste Duncan. A correlação entre as concentrações séricas de retinol e betacaroteno das pastagens foi estimada pelo método de Pearson. Os resultados demonstraram que, no ano de 2002, não houve necessidade de suplementação das éguas dos haras das regiões estudadas nos meses de seca e que não houve correlação entre os teores de retinol plasmático das éguas com os de betacaroteno das pastagens.

Retinol serum concentrations were analyzed from 16 pregnant mares raised in farms of two different regions of Minas Gerais state, Brazil (Vale do Rio Doce and Sul de Minas). The animals were maintained on pasture with free access to mineral supplement without grain concentrate supplementation. Blood samples were collected monthly from May to November 2002, aiming to verify the need of vitamin A supplementation during the dry season. The concentration of beta-carotene from pasture samples was also correlated with blood plasma concentration to verify the utilization of hepatic stock of vitamin A. High performance liquid chromatography (HPLC) was used to determine vitamin A and beta-carotene concentrations. The used statistics was the split plot design and the results were compared by Duncan test. The Pearson correlation between the serum concentration of retinol and beta-carotene from pasture was estimated. The results demonstrated that the supplementation of pregnant mares in farms of the studied regions was not necessary during the dry season and that no significant correlation between the serum concentration of retinol and beta-carotene from pasture was observed.

Lycopene and ß-carotene protect in vivo iron-induced oxidative stress damage in rat prostate

It has been suggested that iron overload may be carcinogenic. In the present study, we evaluated the effect of plasma and prostate carotenoid concentration on oxidative DNA damage in 12-week-old Wistar rats treated with intraperitoneal (ip) ferric nitrilotriacetate (Fe-NTA) (10 mg Fe/kg). Plasma ß-carotene and lycopene concentrations were measured as a function of time after ip injection of carotenoids (10 mg kg-1 day-1 ß-carotene or lycopene) in rats. The highest total plasma concentration was reached 3 and 6 h after ip injection of lycopene or ß-carotene, respectively. After 5 days of carotenoid treatment, lycopene and ß-carotene were present in the 0.10-0.51 nmol/g wet tissue range in the prostate. Using a sensitive method to detected 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo) by HPLC/EC, the level of 8-oxodGuo in rat prostate DNA was significantly higher (6.3 ± 0.6 residues/10(6) dGuo) 3 h after Fe-NTA injection compared with control rats (1.7 ± 0.3 residues/10(6) dGuo). Rats supplemented with lycopene or ß-carotene for 5 days prior to Fe-NTA treatment showed a reduction of about 70 percent in 8-oxodGuo levels to almost control levels. Compared with control rats, the prostate of Fe-NTA-treated animals showed a 78 percent increase in malondialdehyde accumulation. Lycopene or ß-carotene pre-treatment almost completely prevented lipid damage. Epidemiological studies have suggested a lower risk of prostate cancer in men reporting a higher consumption of tomato products. However, before associating this effect with tomato sauce constituents, more information is required. The results described here may contribute to the understanding of the protective effects of carotenoids against iron-induced oxidative stress.

Hydrophilic and lipophilic antioxidant activities of guava fruits.

The objectives of this study were to evaluate the hydrophilic antioxidant activity (AOAH) and the lipophilic antioxidant activity (AOAL); and their correlations with vitamin C, and total phenolic and beta-carotene contents in fresh guava fruits of one white flesh clone ('Allahabad Safeda') and three pink flesh clones ('Fan Retief', 'Ruby Supreme,' and an advanced selection). A ferric reducing antioxidant power assay was used to estimate both AOAH and AOAL from methanol and dichloromethane extracts, respectively. The white flesh clone, 'Allahabad Safeda,' showed higher levels of both AOAH [33.3 microM Trolox equivalents (TE)/g fresh weight (FW)] and AOAL (0.25 microM TE/g FW) than the pink flesh clones that ranged from 15.5 to 30.4 and from 0.12 to 0.13 microM TE/g FW for AOAH and AOAL, respectively. The AOAH was positively correlated with vitamin C (r = 0.92, p < 0.01) and total phenolic (r = 0.97, p < 0.01) but was negatively correlated with beta-carotene (r = -0.73, p = 0.03). The AOAL was not correlated with these antioxidants.

Monócitos como indicadores de atividade inflamatória e oxidativa em idosos sem déficit cognitivo e com doença de Alzheimer / Monocytes as indicators of inflammatory activity and oxidative in seniors without cognitive deficit and with Alzheimer's disease

A Doença de Alzheimer é uma doença neurodegenerativa progressiva e de início tardio, que compromete principalmente as areas da cognição, julgamento e estabilidade emocional. Esta doença se caracteriza por dois tipos de lesões cerebrais características: emaranhados neurofibrilares e placas senis. Os emaranhados neurofibrilares são compostos por uma proteína do citoesqueleto (proteína tau) hiperfosforilada e agregada. As placas senis são formadas por agregados da proteína ‘beta’-amilóide. A doença de. Alzheimer é resultado da interação de vários fatores ainda incompletamente elucidados; não obstante, o estresse oxidativo e os processos inflamatórios ocupam posição de destaque dentre esses fatores. Neste trabalho, avaliamos as atividades das enzimas eritrocitárias superóxido dismutase, catalase e glutationa peroxidase, assim como o conteúdo plasmático de glutationa total, vitamina C, ‘alfa’-tocoferol, ‘beta’-caroteno, licopeno e coenzima ‘Q IND 10’. A esses parâmetros antioxidantes foram contrapostas medidas de oxidação de lipídios e proteínas plasmáticas. Adicionalmente, efetuamos a avaliação das expressões monocitárias de HLA-DR e CD-11b, e das citocinas IL-6, IL-1’alfa’ e TNF-’alfa’. Nossos resultados mostram que os pacientes de .doença de Alzheimer possuem níveis circulantes de atocoferol inferiores aos pacientes controles, e possuem monócitos que apresentam maior expressão basal de HLA-DR e maior produção de IL-1’alfa’ quando estimulados por LPS: Esses resultados fortalecem a hipótese inflamatória na doença de Alzheimer, de acordo com trabalhos recentes que apontam bons resultados com o ‘alfa’-tocoferol na sua prevenção e tratamento

Estudio comparativo de la utilización biologica de beta-caroteno sintético y de fuentes naturales en ratas / Comparative study of the biological utilization of beta-carotene from synthetic and natural sources in rats

The purpose of this study was to evaluate the change in concentration of retinol and beta-carotene (BC) in blood serum and liver tissue of rats, after supplementation with synthetic BC and commonly consumed carotenoid-rich vegetables (carrot and spinach). Weanling male Wistar rats were randomly assigned in four groups of 16 rats each. The four groups of rats were supplemented according to the following feeding treatments: 1) Control group (0G), 0.2 mL corn oil; 2) Pure BC group (BCG), 60 micrograms RE in 0.2 mL corn oil; 3) Carrot group (CG), 60 micrograms RE in 0.2 mL corn oil; 4) Spinach group (SG), 60 micrograms RE in 0.2 mL corn oil. Analysis of retinol and BC contents in serum and liver was performed by HPLC procedures. The variance analysis showed no significant differences (a = 0.05) in the increase of weight of the animals and in the increase of retinol and BC levels in serum and in liver of the four treatments during the four weeks of supplementation. The correlation analysis between levels of retinol and BC in serum and in liver showed no relation between these two parameters. A regression analysis of liver BC levels in the four treatments showed the following slopes of the regression lines: BCG, 0.909; CG, 0.451; SG, 0.444, and 0G, 0.203. These results indicate that the highest BC absorption was in the BCG treatment, whereas the BC absorption in the CG and SG treatments was approximately one half.

Antioxidant activity of the microalga Spirulina maxima

Spirulina maxima, which is used as a food additive, is a microalga rich in protein and other essential nutrients. Spirullina contains phenolic acids, tocopherols and Beta-carotene which are known to exhibit antioxidant properties. The aim of the present study was to evaluate the antioxidant capacity of a Spirulina extract. The antioxidant activity of a methanolic extract of Spirulina was determined in vitro and in vivo. The in vitro antioxidant capacity was tested on a brain homogenate incubated with and without the extract at 37 degrees Celsius. The IC(50) (concentration which causes a 50 per cent reduction of oxidation) of the extract in this system was 0.18 mg/ml. The in vivo antioxidant capacity was evaluated in plasma and liver of animals recceiving a daily dose of 5 mg for 2 and 7 weeks Plasma antioxidant capacity was measured in brain homogenate incubated for 1 h at 37 degrees Celsius. The production of oxidized compounds in liver after 2 h of incubation at 37 degrees Celsius was measured in terms of thiobarbituric acid reactant substances (TBARS) in control and experimental groups. Upon treatment, the antioxidant capacity of plasma was 71 per cent for the experimental group and 54 per cent for the control group. Data from liver spontaneous peroxidation studies were not significantly different between groups. The amounts of phenolic acids, alpha-tocopherol and Beta-carotene were determined in Spirulina extracts. The results obtained indicate that Spirulina provides some antioxidant protection for both in vitro and in vitro and vivo systems.

Prediction of structure of antenna proteins of photosystem II.

Membrane spanning regions of 43 kDa and 47 kDa antenna proteins of photosystem II of thylakoid membranes are theoretically predicted. Prediction of topology of chlorophyll-a and beta-carotene molecules in the proteins and interaction of the proteins with 33 kDa extrinsic protein on the lumenal side of thylakoid membrane is based on the findings reported earlier. Each antenna protein is predicted to have six transmembrane alpha-helices with twelve chlorophyll-a and five beta-carotene molecules binding to it. Both N- and C- terminal ends are proposed to be on the stromal side of thylakoid membrane. The proposed structural model conforms to the reported experimental results from the literature.

Análise de vitaminas e ß-caroteno em leite bovino / Vitamins analyse and ß-carotene in milk

Os teores de retinol, ß-caroteno, `ALFA'-tocoferol, tiamina, riboflavina e piridoxina foram analisados por cromatografia líquida de alta eficiência em leites em pó, pasteurizados e esterilizados, comercializados na cidade de Säo Paulo. Após saponificaçäo e extraçäo, os compostos lipossolúveis foram determinados simultaneamente utilizando-se coluna de fase normal com fase móvel constituída por hexano: isopropanol (99:1), fluxo de 2,0mL/min. O retinol e o ß-caroteno foram determinados no detector UV/visível e o `ALFA'-tocoferol no detector de fluorescência, ligado em série com o anterior. As vitaminas hidrossolúveis foram extraídas com ácido tricloroacético 5 por cento, permanecendo sob vibraçäo ultra-sônica durante 1 hora...

Caracterizaçäo química e avaliaçäo da biodisponibilidade do ß-caroteno e da proteína da folha de mandioca (Manihot esculenta Crantz) desidratada / Chemical caracterization and evaluation of the ß-carotene's bioavailability and the dehydrated cassava leaf protein (Manihot esculenta Crantz)

Foram analisadas folhas de mandioca desidratadas (Manihot esculenta Crantz), CV Branca de Santa Catarina, provenientes do Centro de Raízes Tropicais (CERAT) da UNESP, campus de Botucatu. As análises visaram determinar nutrientes e fatores antinutricionais presentes nas folhas desidratadas. Foram realizados dois ensaios biológicos, com o objetivo de se determinar a biodisponibilidade do ß-caroteno e o valor biológico da proteína da folha desidratada. Os resultados das análises permitiram concluir que as folhas desidratadas continham ß-caroteno, minerais, altos teores de fibra e ao redor 20 por cento de proteina, apresentando um bom perfil de aminoácidos. os fatores antinutricionais presentes nas folhas foram: cianeto, fenólicos, taninos e ácido fítico...