H. Tamura et A. Yamagami, ANTIOXIDATIVE ACTIVITY OF MONOACYLATED ANTHOCYANINS ISOLATED FROM MUSCAT-BAILEY-A GRAPE, Journal of agricultural and food chemistry, 42(8), 1994, pp. 1612-1615
The antioxidative activity of four anthocyanins isolated from the Musc
at Bailey A grape, which has a malvidin nucleus, was evaluated accordi
ng to the amount of malonaldehyde formed by the autoxidation of linole
ic acid in Trizma buffer (pH 7.4). Thiobarbituric acid derivatives of
malonaldehyde were quantitatively analyzed by a spectrophotometer (at
535 nm). Malonaldehyde (20 nmol/mg of linoleic acid) was regularly det
ected after a 16-h inculation period without antioxidants. Malvidin 3-
O-(6-O-p-coumaroylglucosido)-5-glucoside showed only 2.6 nmol/mg of li
noleic acid malonaldehyde production. p-Coumaric acid attached to malv
idin 3-glucoside and malvidin 3,5-diglucoside was found to play an imp
ortant role in preventing malonaldehyde production from linoleic acid.
The antioxidative activity of an acylated anthocyanin was compared wi
th other chemicals. Malvidin 3-O-(6-O-p-coumaroylglucosido)-5-glucosid
e proved to be 2 times more effective than commercially available anti
oxidants such as (+)-catechin and alpha-tocopherol. From the results,
ii was found that the monoacylated anthocyanins from the pericarps of
grapes can be used as powerful antioxidants as well as for colorants.