In vitro studies of eggplant (Solanum melongena) phenolics as inhibitors of key enzymes relevant to type 2 diabetes and hypertension

Laboratory of Food Biotechnology, Department of Food Science, Chenoweth Building, University of Massachusetts, Amherst, MA 01003, USA.
Bioresource Technology (Impact Factor: 4.49). 06/2008; 99(8):2981-8. DOI: 10.1016/j.biortech.2007.06.035
Source: PubMed


National Diabetes Education Program of NIH, Mayo Clinic and American Diabetes Association recommend eggplant-based diet as a choice for management of type 2 diabetes. The rationale for this suggestion is the high fiber and low soluble carbohydrate content of eggplant. We propose that a more physiologically relevant explanation lies in the phenolic-linked antioxidant activity and alpha-glucosidase inhibitory potential of eggplant which could reduce hyperglycemia-induced pathogenesis. Results from this study indicate that phenolic-enriched extracts of eggplant with moderate free radical scavenging-linked antioxidant activity had high alpha-glucosidase inhibitory activity and in specific cases moderate to high angiotensin I-converting enzyme (ACE) inhibitory activity. Inhibition of these enzymes provide a strong biochemical basis for management of type 2 diabetes by controlling glucose absorption and reducing associated hypertension, respectively. This phenolic antioxidant-enriched dietary strategy also has the potential to reduce hyperglycemia-induced pathogenesis linked to cellular oxidation stress. These results provide strong rationale for further animal and clinical studies.

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    • "Severe oxidative stress can cause many chronic and degenerative diseases such as cancer, diabetes and cardiovascular diseases [2]. Again, enzyme inhibitors are an important treatment strategy in major health problems including Alzheimer's disease and Diabetes mellitus [3] [4]. It is for this reason that new studies on wild or cultured medicinal plants are a need for food and pharmaceutical applications. "

    Current Bioactive Compounds 09/2015; 11(999). DOI:10.2174/1573407211666151002002314
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    • "Kritchevsky et al. (1975) reported a hypocholesteremic effect in rabbits with the absorption of dietary cholesterol. The findings of Kwon et al. (2008) and Hanhineva et al. (2010) revealed eggplant has an impact on Type 2 diabetes by controlling glucose absorption. "
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    ABSTRACT: Helyes et al.: The simultaneous effect of heat stress and water supply on total polyphenol content of eggplant-583-APPLIED ECOLOGY AND ENVIRONMENTAL RESEARCH 13(2): 583-595. ● ISSN 1589 1623 (Print) ● ISSN 1785 0037 (Online) Abstract. Eggplant is considered as one of the healthiest vegetables due to its nutritional values. A 2-year open field experiment was set up in 2011 and 2012 to observe the effects of heat stress and different irrigation volumes on the amount of phenolic compounds, fibre and dry matter in eggplant fruits. The optimal irrigation volume (IO) was calculated from the daily potential evapotranspiration and was compared to a treatment utilising 50% of the optimal water volume (I50). We concluded that there was no significant difference between the irrigation levels in the aspect of total polyphenol and dry matter, but there was a decrease in fibre content. Yield was increased by 19.6% with irrigation in 2011 and by 4.44% in 2012. The effect of heat stress is closely related to harvest time. In our study we proved that more heat stress resulted in more total polyphenol content in eggplant, the equation describing this relation is y=39.322+0.501x. Heat stress also stimulated dry matter and fibre content, and this influence was also significant.
    Applied Ecology and Environmental Research 01/2015; 13(2):583-595. DOI:10.15666/aeer/1302_583595 · 0.56 Impact Factor
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    • "Therefore, inhibition of these carbohydrate-hydrolyzing enzymes can significantly decrease the postprandial hyperglycemia after a mixed carbohydrate diet and can be a key strategy in the control of diabetes mellitus (Hirsh et al., 1997). Though there are synthetic drugs used in the treatment of hyperglycemia such as acarbose and miglitol but these drugs are associated with gastrointestinal side effects including abdominal discomfort, bloating, flatulence and diarrhoea (Kwon et al., 2008a) which are allegedly caused by the excessive inhibition of pancreatic αamylase (Horii et al., 1987). "
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    ABSTRACT: Inhibition of some carbohydrate metabolizing enzymes is one of the modes of action of antihyperglycemic agents. The aim of this study was to investigate the in vitro inhibition of α-amylase and α-glucosidase by extracts of N. tabacum leaf. Powdered leaves were extracted with acetone, ethanol and water, and tested for their ability to inhibit α-amylase from Aspergilus oryzae and α- glucosidase from Saccharomyces cerevisae. The results revealed that aqueous extract of the plant was most effective inhibitor of α-amylase (IC50 5.70 mg/ mL) while acetone extract exhibited the best inhibitory potential on α- glucosidase (IC50 4.50 mg/mL). Kinetic studies showed that the mode of inhibition of α-amylase by aqueous extract was non-competitive while that of the acetone extract on α-glucosidase was competitive. The observed inhibitions of α-amylase and α-glucosidase suggest that the leaf extracts of N. tabacum may be useful in the management of Diabetes mellitus, which may due to the presence of phytochemicals.
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