Journal of Animal and Plant Sciences
J. Anim. Plant Sci. [ISSN 2071 - 7024]
Volume 5 (3): 550 - 558. Published January 25, 2010.
Effect of solvent type on extraction of polyphenols from twenty three Ivorian plants
Koffi E*, SeaT**, DodeheY*** and Soro S****
*Food Science Laboratory; ** Biotechnology Laboratory; ***Pharmacodynamy and Biochemistry Laboratory, University of Cocody, 22 BP 582 Abidjan 22 Abidjan, Côte d’Ivoire
*Corresponding author E-mail: koffiernest@yahoo.comSUMMARY
Powdered fruits or parts of Ivorian plants were obtained after drying and grinding. Water, ethanol, acetone and methanol were tested as extractants of total polyphenols from these powders. The results showed that ethanol was better than acetone, water or methanol for extraction of total phenols from plant byproduct powders. The average total phenol contents of ethanolic, aqueous and methanolic extracts were 9000, 2500, 2000 and 1000 mg Gallic acid equivalent (GAE) / 100 g dry weight in decreasing order (P< 0.05), respectively. Total phenol contents of Terminalia catappa (leaves and fruit pulp), Combretum molle (leaves), Arachis hypogea (skin of the seed), Annona senegalensis (leaves) and Hibiscus sabdariffa (petals) were 12,000; 11,000; 9,000; 7,000; 6,000; and 4,000 mg GAE/ 100 g dry weight in decreasing order (P< 0.05), respectively and are potential sources of polyphenols (natural antioxidants and nutraceuticals). The other investigated plants had lower phenol contents (~3,000 mg GAE/ 100 g dry weight). Aqueous extracts from the plants were tested for their ability to inhibit α-amylase and α-glucosidase from snail (Archachatina ventricosa) digestive tract. Among the extracts tested, five were inhibitors of α-amylase and there was a 7-fold difference between the least and most effective extracts. In order of effectiveness, the potent inhibitors were from Dioscorea alata > Musa paradisiaca > Citrus sinensis > Terminalia catappa > Theobroma cacao. Comparatively, there was an 8-fold difference between the least and most potent inhibitor of α-glucosidase. The inhibitory effects were in the order of Solanum macrocarpin > Solanum distichum > Solanum melongena > Dioscorea cayenensis > Arachis hypogea. These results encourage us to conduct toxicological tests and identify the molecules responsible for these inhibitory effects that have potential application in the management of diabetes mellitus.
Key words: polyphenols, α-amylase, α-glucosidase, diabetes
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