Antioxidant Activity of Alcohol Extracts from Different Varieties of Yam Peel

The vegetable yam peel was taken as the research object. After drying, crushing and sieving, the ethanol solution of different concentration of vegetable yam peel powder were extracted by reflux. Determining the contents of polyphenols, flavonoids and saponins and some active substances in alcohol extraction, and the anti-oxidation ability of DPPH radicals, hydroxyl radicals, superoxide anion and the reducing power of iron ions were evaluated to select the optimal ethanol concentration. Then the best ethanol concentration was extracted from the, tiegun yam peel, Qichun yam peel, Lichuan yam peel and bergamot yam peel, and the difference of its active components and antioxidant capacity was analyzed. The results showed that vegetable yam peel extracts obtained by 70% ethanol alcoholhad higher active ingredient and antioxidant capacity. The different varieties of yam peel ethanol extracts difference of bioactive components and antioxidant capacity were significant (p<0.05), and there had a significant correlation between the active components and the antioxidant capacity of the alcohol extracts from different varieties of yam, the ethanol extract of Dioscorea opposita bergamot yam peel polyphenols, saponins, flavonoids and other active ingredient contents were significantly higher than the other four kinds of Chinese yam peel extracts (p<0.05), polyphenols, saponins, the total flavonoids and active ingredients were 2.46, 12.52, 6.12 and 21.06 mg/g. The DPPH radical scavenging rate, the hydroxyl radical scavenging rate, and theferric reducing power all at a high level while the superoxide anion scavenging rate and linoleic acid oxidation inhibition ability, bergamot yam peel extracts was not the optimal, but in the high the level. So the bergamot yam peel would be better than other three kind of of Chinese yam peel in antioxidant property.