Abstract

Prunus mume fruits have been used as a healthy food and traditional drug in China. The present study investigated the phenolic compounds and antioxidant activity of ethyl acetate extract from fruits of P. mume in China. Total phenol content was determined as gallic acid equivalents by the Folin-Ciocalteu method. The antioxidant activity was measured by DPPH and ABTS⁺ radicals scavenging and lipid peroxidation inhibition activities. Three chlorogenic acid isomers, namely, chlorogenic acid, neochlorogenic acid and cryptochlorogenic acid, were isolated and purified by preparative HPLC from the extract and identified by ultra-violet (UV), MS and NMR and the latter two compounds were identified in P. mume fruits for the first time. The contents of these isolated compounds were quantified by HPLC. Results showed that chlorogenic acid was of the highest level in these three isomers. The ethyl acetate extracts demonstrated activity to some degree in all the antioxidant assays. In all tested assays, all of the isolated chlorogenic acid isomers exhibited strong antioxidant activities, which were almost the same. The results showed that chlorogenic acid isomers are the key phenolic compounds which are responsible for antioxidant activity of the ethyl acetate extract from P. mume fruits in China.

Key words: Prunus mume, fruits, antioxidant activity, chlorogenic acid isomers, free radicals scavenging.