2016 Volume 22 Issue 5 Pages 713-718
This study attempted to isolate bioactive compounds from niihime, a sour Citrus fruit, and to evaluate their bioactivity by simultaneously monitoring superoxide generation and intracellular calcium ion levels in neutrophils. Seven aromatic compounds were isolated from a methanol extract of niihime peel and identified as 6-demethoxynobiletin, 6-demethoxytangeretin, nobiletin, tangeretin, sinensetin, 5,7-dimethoxycoumarin, and saccharic acid 1,4-lactone 3,5-di-O-ferulate. 6-Demethoxynobiletin, 6-demethoxytangeretin, and 5,7-dimethoxycoumarin were newly shown to be contained in niihime fruit. Bioactivity assay of 10 µM saccharic acid 1,4-lactone 3,5-di-O-ferulate revealed a significant increase in both superoxide generation and intracellular calcium ion concentration (p<0.05). This result indicates that saccharic acid 1,4-lactone 3,5-di-O-ferulate has immunostimulatory activity in neutrophils.