Antioxidant Potential and Type II Diabetes-Related Enzyme Inhibition of Cassia obtusifolia L.: Effect of Indigenous Processing Methods
ABSTRACT The methanolic extract of Cassia obtusifolia L. (Sicklepod) seed, an underutilized food legume from India, was analyzed for antioxidant and health relevant functionality. The total free phenolic content of the raw seeds was 13.33 ± 1.73 g catechin equivalent/100 g extract. The extract exhibited 1,292 mmol Fe[II] per milligram extract of ferric reducing/antioxidant power, 49.92% inhibition of ß-carotene degradation, 65.79% of scavenging activity against DPPH, and 50.78% of superoxide radicals. The in vitro starch digestion bioassay of the extract showed 79.80% of α-amylase and 81.04% of α-glucosidase enzyme inhibition characteristics. Sprouting + oil frying caused an apparent increase on the total free phenolic content with significant improvement on the antioxidant and free radical scavenging capacity of C. obtusifolia seeds, while soaking + cooking as well as open-pan roasting treatments show diminishing effects. Inhibition of α-amylase and α-glucosidase enzyme activity was 23.81% and 42.36%, respectively, following sprouting + oil-frying treatment. These enzyme inhibition values were similar to that of synthetic antidiabetic agent acarbose.
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ABSTRACT: COB1B1S2 was isolated from an alkaline extract of Cassia obtusifolia seeds, and purified by anion-exchange and gel permeation chromatography. It contains arabinose, xylose, and glucuronic acid, in the molar ratio of 5:81:14, with an apparent molecular weight estimated to be 70.4kDa. Elucidated by using chemical and spectroscopic methods, COB1B1S2 was shown to have a backbone consisting of 1,4-linked β-d-Xylp, with one single-unit terminal α-d-GlcpA or α-l-Araf substituted at O-2 for nearly every five 1,4-linked Xylp. COB1B1S2 is structurally different from typical glucuronoxylans by its absence of methylation at O-4 of GlcA. The native COB1B1S2 showed no significant inhibition on the tube formation of human microvascular endothelial cells (HMEC) and on the growth of liver and colon cancer cells. On the contrary, COB1B1S2-Sul, prepared as the sulfated derivative of COB1B1S2, exhibited a significant inhibition on tube formation of HMEC in a dose-dependent manner, and on the growth of Bel7402 liver cancer cells. These results indicated that the introduction of sulfate groups significantly enhanced the biological activity of glucuronoxylan.Carbohydrate Research 07/2014; 393. DOI:10.1016/j.carres.2014.04.016 · 1.97 Impact Factor