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.

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.

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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.

The overall results confirm that dietary soy isoflavones have a positive effect on antioxidant status, enhancing antioxidant capacity of plasma and antioxidant enzymes in various tissues, but the effects are dependent on the form of administration and on a complex mechanism of antioxidant status balance on the organism.

Fresh pear consumption could provide health benefits by reducing the risk of chronic diseases such as hyperglycemia linked to type 2 diabetes. This in vitro study investigated the phenolic‐linked antihyperglycemia bioactive factors in aqueous and ethanolic extracts of peel and pulp from eight different freshly harvested and long‐term stored pear varieties. Total soluble phenolics, 2,2‐diphenyl‐1‐picrylhydrazyl radical scavenging‐based antioxidant activity and associated in vitro alpha‐glucosidase, alpha‐amylase and angiotensin I‐converting inhibitory activities were analyzed. Peel extracts had higher total soluble phenolic content and related antioxidant capacity than pulp extracts. Comice variety had the highest total phenolic contents with positive correlation to total antioxidant activity. Aqueous pulp extracts had high alpha‐amylase inhibitory activities with no correlation to phenolic content. However, the peel ethanolic extracts had the highest alpha‐glucosidase inhibitory activity with positive correlation to total phenolics. This research provides the biochemical rationale for further clinical studies to include pear as part of healthy diet. PRACTICAL APPLICATIONS Using in vitro structure‐function relevant bioassays to screen a range of fruits and vegetables helps to develop biochemical rationale to target and strategize the increased use of these fresh fruits and vegetables for better health and wellness. Pears, because of their phenolic bioactives, have potential to be included as a part of a comprehensive diet for managing early stages of hyperglycemia linked to type 2 diabetes. This study provides foundation for screening of pears for improving dietary strategies for managing this chronic disease and can be the biochemical rationale for further clinical studies.

This study provides further in vitro evidence for inhibition by apple extracts of alpha‐glucosidase and alpha‐amylase for potential antihyperglycemia benefits and angiotensin converting enzyme inhibitory activity for associated antihypertension potential. This was investigated in peel and pulp aqueous and ethanol extracts from 10 different long‐term stored apple cultivars. “Red Delicious” and “Cortland” cultivars had significantly higher total phenolic content and inhibitory antioxidant capacity, with high correlation between both assays. Quercetin derivatives, catechin, chlorogenic acid and p‐coumaric acid were detected, and the composition and amount varied significantly between aqueous and ethanolic extracts. Red Delicious cultivar had high alpha‐amylase and alpha‐glucosidase inhibitory activities. These phenolic‐linked bioactive potential of apple cultivars indicate that they may impart health benefits when consumed even after long‐term storage and should be considered as valuable source of antioxidants with additional antihyperglycemia potential relevant for the management of early‐stage type 2 diabetes following further clinical studies. PRACTICAL APPLICATION This study explored the potential health benefits of phenolic‐linked antioxidants from long‐term stored apple cultivars and evaluated the association to potential prevention of postprandial hyperglycemia linked to type 2 diabetes using in vitro bioassay models. It was confirmed that the apple cultivar “Red Delicious” and other cultivars commonly consumed in the U.S.A. have relevance for hyperglycemia management, and apples can be included as part of the overall diet in an environment where starch and sugar consumption is increasingly high. This in vitro biochemical rationale from this study provides further phenolic bioactive‐linked, structure–function basis for additional animal and clinical studies to rationalize effective designs of whole foods, fruits and vegetables for long‐term diet‐based management of type 2 diabetes.

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% e 86% a menos. Em relação à distribuição de isoflavonas, os produtos foram divididos em dois grupos: os que apresentam predominância de daidzeína e derivados e os que apresentam predominância de genisteína e derivados. Isso sugere a necessidade de padronização e maior controle de qualidade desses produtos, considerando o seu uso para mulheres na menopausa.