Water-soluble component in dried chrysanthemum flower stimulates tumor necrosis factor-α production by mouse macrophage-like cell line RAW264.7

To clarify immunoregulatory activity of "Shiranui Himekiku" (Chrysanthemum indicam × Erigeron annus), we examined the effect on tumor necrosis factor α (TNF-α) production by mouse macrophage-like cell line RAW264.7. The dried chrysanthemum flower (CF) petals were extracted with water, and the cells were cultured in the presence of the extract. CF extract significantly enhanced TNF-α production of the cells by the dose-dependent manner. Diluted CF solution did not significantly affect the cell number and viability; however, non-diluted solution suppressed the cell proliferation and decreased the cell viability. Heating CF extract at 100°C for 30 min enhanced the activity of water extract markedly, and freeze-thawing only moderately. The TNF-α production enhancing activity of the extract was observed within 3h. These results suggest that the TNF-α production enhancing activity of CF extract can be recovered efficiently by hot water extraction and preserved stably by freezing.