Phenolic-linked biochemical rationale for the anti-diabetic properties of Swertia chirayita (Roxb. ex Flem.) Karst.

The crude extract of Swertia chirayita, an important medicinal plant of Nepal, is locally used for many diseases including type 2 diabetes. In this study, crude aqueous and 12% ethanol solution extracts of S. chirayita collected from nine districts of Nepal were analyzed for anti-diabetic-linked anti-hyperglycemia potential using in vitro biochemical assays. There was moderate-to-high positive correlation between antioxidant activity and total phenolic content of both extracts and moderate-to-high α-glucosidase inhibitory activity. Although the anti-diabetic property of S. chirayita is mainly attributed to the phytochemical swerchirin present in its hexane fraction, we propose that the crude extract of this plant used in local healing also has anti-hyperglycemia potential. The crude extracts indicated the presence of three main phytochemicals mainly mangiferin, swertiamarin, and amarogentin and their derivatives. Among the standard compounds (mangiferin, swertiamarin, and amarogentin), mangiferin showed α-glucosidase and 2,2-diphenyl-1-picrylhydrazyl radical inhibitory activity indicating anti-hyperglycemia potential.

Varietal influences on antihyperglycemia properties of freshly harvested apples using in vitro assay models.

The well-known health benefits of apples have been attributed in part to the presence of polyphenols and related antioxidant capacity. The consumption of apples could provide health benefits by reducing the risk for chronic diseases such as metabolic syndrome disease, including type 2 diabetes. Thus, the objective of this study was to investigate the phenolic-linked antihyperglycemia bioactive factors in aqueous and 12% ethanol extracts of peel and pulp from 10 different freshly harvested apple varieties commonly consumed in the United States. The extracts were analyzed for total soluble phenolics, 2,2-diphenyl-1-picrylhydrazyl-linked antioxidant activity, and their associated in vitro α-glucosidase and α-amylase inhibitory activities. In general, peel extracts had higher total soluble phenolic content and related antioxidant capacity than pulp extracts. Quercetin derivatives, protocatechuic acid, chlorogenic acid, and p-coumaric acid were detected, and the amount varied significantly between aqueous and ethanolic extracts. Honeycrisp and Red Delicious varieties had the highest total phenolic contents and a significant correlation with antioxidant capacity (r = 0.91). In addition, high α-amylase and α-glucosidase inhibitory activities in aqueous pulp extracts were found. However, the peel extracts had the highest α-glucosidase inhibitory activity along with low α-amylase inhibitory activity. No correlation between α-amylase inhibitory activity and total phenolic content was observed. However, positive correlations between α-glucosidase inhibitory activity and total phenolics in aqueous (r = 0.50) and ethanolic (r = 0.70) extracts were observed. This study provides the biochemical rationale for animal and clinical studies to determine the suitable varieties with optimum bioactive factors with antihyperglycemia potential.

Commercial soy protein ingredients as isoflavone sources for functional foods.

The knowledge of the contents and profile of isoflavones present in soy protein ingredients, as well as the effect of industrial processing, is important for the development of functional foods rich in these compounds. The results obtained here showed that the total isoflavone content varied significantly among products. For defatted and whole soy flours the total isoflavone content ranged from 120 to 340 mg/100 g, for soy protein isolates from 88 to 164 mg/100 g, and for commercial textured soy proteins, from 66 to 183 mg/100 g (wet basis, expressed as aglycones). The highest isoflavone content was found for soy hypocotyl flours, from 542 to 851 mg/100 g. Compared to hypocotyl and whole and defatted flours, soy ingredients presented a decrease of malonylglycosides and deesterified beta-glycosides with a significant increase in the percentage of aglycones, mainly for soy fibers (65-76%). While defatting was shown to cause isoflavone concentration without altering conjugation, extrusion process caused destruction of isoflavones and a significant increase in the amount of acetylglycosides, but this effect was less intense for the concentrates. From the results obtained it can be concluded that differences in isoflavone concentration and profile may be related to oscillations in the isoflavone content present in the raw material and to the type of processing.

Avaliação do teor de isoflavonas de "suplementos nutricionais à base de soja" / Isoflavone content of soy dietary supplements

Devido aos possíveis efeitos benéficos, diversos produtos à base de soja (gérmen, extrato), na forma de cápsulas ou comprimidos, surgiram recentemente no mercado como fontes de isoflavonas. Neste trabalho avaliaram-se o teor e o perfil de isoflavonas dos produtos comercializados em drogarias e farmácias locais (São Paulo), para verificar se estavam de acordo com o especificado pelos fabricantes. A determinação foi realizada através de cromatografia líquida de alta eficiência com detetor com arranjo de diodos, de acordo com Genovese & lajolo (2001b). Os resultados mostraram que os produtos à base de soja apresentam teor de isoflavonas muito abaixo do valor indicado nos rótulos, entre 27 por cento e 86 por cento a menos...

Estudo das interações isoflavonas e proteínas da soja: efeitos sobre a digestibilidade e capacidade antioxidante / Study of interactions between isoflavones and soy protein: effect on the digestibility and antioxidant capacity

Embora a soja em grão seja pouco consumida pela população brasileira, seus derivados protéicos são utilizados como ingredientes em diversos alimentos e a tendência é um aumento significativo do seu uso com a aprovação pela FDA e pela ANVISA da alegação funcional referente ao consumo de proteína de soja. Em paralelo, um número crescente de pesquisas sobre as isoflavonas, fitoestrógenos presentes em quantidades significativas na soja, vem demonstrando diversos efeitos benéficos destes compostos, entre os quais a sua ação antioxidante, anticarcinogênica e hipocolesterolêmica. O objetivo foi estudar as interações entre isoflavonas e proteínas da soja, seu efeito na biodisponibilidade in vitro e in vivo e o status antioxidante das isoflavonas. Os resultados sugerem que a presença da proteína reduz a quantidade e leva a um retardo no tempo de absorção das isoflavonas em relação à administração na forma livre. O efeito sobre a capacidade antioxidante do plasma e sobre a atividade e expressão gênica das enzimas CAT, GPx e SOD divergiu para a suplementação de isoflavonas ou proteínas separadamente ou em associação...