Abstract
The amounts of anthocyanins and chlorogenic acid in eggplants (Solanam melongena L.) having different peel colors (senryo-nigo, local name of naga-nasu ; kurowashi, local name of bei-nasu ; green-peel eggplant (midori-nasu) ; white-peel eggplant (siro-nasu)) were measured by HPLC. Extracts were obtained by extracting the peels, flesh and petals of each type of eggplant with 3% trifluoroacetic acid (crude extracts). The extracts and their Sep-pack Plus C18 cartridge-adsorbable fraction (partially purified extracts) were used for measuring the amounts of anthocyanins and chlorogenic acid by HPLC, and the DPPH radical scavenging activity. The relationships between the amounts of these compounds and the radical scavenging activity were also investigated. The results were as follows. (1) Anthocyanin was not detected in the peels of green- and white-peels eggplants, although the petals of these eggplants contained nasunin as a major anthocyanin. A major anthocyanin in the peels of the bei-nasu was identified as delphinidin 3-O-rutinoside, while delphinidin 3-O-rutinoside-5-O-glucoside was identified as a minor component. (2) The DPPH radical scavenging activity of both crude and partially-purified extracts showed strong correlations with the amount of chlorogenic acid present in eggplants, suggesting that the radical scavenging capacity of eggplants may be mainly determined by chlorogenic acid concentration levels.
