Abstract

LOPEZ-MARTINEZ, Leticia X.; AGUILAR CISNEROS, Luisa M.  and  DUBLAN-GARCIA, Octavio. Antioxidant and inhibitory activity against α-glucosidase and α-amylase from three varieties of onion (Alllium cepa L.). Nova scientia [online]. 2014, vol.6, n.12, pp.234-347. ISSN 2007-0705.

The onion (Allium cepa L.) has been cultivated for thousands of years and is an important component of human diet. Recent studies suggest that onion can be used to reduce or prevent health problems such as asthma, cardiovascular diseases and diabetes due to its high antioxidant effect. Extract aqueous and ethanolic from three (purple, yellow and white) varieties of onion were studied for their total phenolic content, capacity and inhibitory activity against α-glucosidase and α- amylase. The total phenolic content varied between 6.59 to 9.25 mg/100 g and 24.3 a 42.7 mg/100 g the antioxidant capacity expressed as the percentage of inhibition of DPPH^- radical ranged from 46.8 to 89.2% and 20.4% to 39.6% for ethanolic and aqueous extracts respectively. All ethanolic extracts showed capacity of inhibition for α-glucosidase y α-amylase from 58% to 34% and 33% to 22% respective while the aqueous extracts showed less effectiveness. Among the extracts, ethanolic extract of purple onion have the maximum concentration of total phenolic compounds, the highest antiradical capacity and α-glucosidase inhibition. Differences in free-radical scavenging and inhibition appeared to be dependent on the unique profile of phenolic compounds in each variety.

Keywords : α-amylase; α-glycosidase; Allium cepa; antiradical capacity; phenolic compounds.

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