Year-end Sale % OFF 
Abstract
Beta-glucans are soluble fibers with physiological functions, such as interference with absorption of sugars and reduction of serum lipid levels. The objective of the present study was to analyze the distribution of beta-glucans in different tissues of the African grass species Rhynchelytrum repens and also to evaluate their hypoglycemic activity. Leaf blades, sheaths, stems, and young leaves of R. repens were submitted to extraction with 4 M KOH. Analysis of the fractions revealed the presence of arabinose, glucose, xylose, and traces of rhamnose and galactose. The presence of beta-glucan in these fractions was confirmed by hydrolyzing the polymers with endo-beta-glucanase from Bacillus subtilis, followed by HPLC analysis of the characteristic oligosaccharides produced. The 4 M KOH fractions from different tissues were subjected to gel permeation chromatography on Sepharose 4B, with separation of polysaccharides with different degrees of polymerization, the highest molecular mass (above 2000 kDa) being found in young leaves. The molecular mass of the leaf blade polymers was similar (250 kDa) to that of maize coleoptile beta-glucan used for comparison. The 4 M KOH fraction injected into rats with streptozotocin-induced diabetes showed hypoglycemic activity, reducing blood sugar to normal levels for approximately 24 h. This performance was better than that obtained with pure beta-glucan from barley, which decreased blood sugar levels for about 4 h. These results suggest that the activity of beta-glucans from R. repens is responsible for the use of this plant extract as a hypoglycemic drug in folk medicine.
Highlights
Carbohydrates are extensively used as food for humans and animals
Growing young leaves presented a considerably higher percentage of uronic acid in the 4 M KOH fraction, 52.2%, whereas expanded leaf blades, sheath and stem presented an average of 7-9% uronic acids
This suggests that, whereas the 4 M KOH fraction was possibly contaminated with a limited amount of pectin, the presence of uronic acids in the other three plant part extracts might be related to the presence of glucuronoarabinoxylan (GAX)
Summary
Carbohydrates are extensively used as food for humans and animals. They are very important as sources of raw materials for alcoholic beverages, as food additives and in the pharmaceutical industry. Plant carbohydrates present in food consumed by humans and animals contain soluble or insoluble fiber-like polymers [1]. There are two types of dietary fibers: insoluble and soluble, that can be distinguished by their solubility in aqueous solutions. Whereas the insoluble fibers (cellulose, lignin and some hemicelluloses) are insoluble in water, the soluble ones (hemicelluloses and pectins) form viscous solutions in water. Soluble fibers can form an unstirred water layer in the gut, which decreases absorption of sugars and lipids. To some extent, soluble fibers can be used to prevent the postprandial increase of glucose, being useful for the treatment of diabetes at certain levels [2]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Brazilian Journal of Medical and Biological Research
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
