Five Bitter Compounds Display Different Anti-inflammatory Effects through Modulating Cytokine Secretion Using Mouse Primary Splenocytes in Vitro

Bitter foods are generally recognized as anti-inflammatory agents in traditional Chinese medicine. To verify the anti-inflammatory effects of some bitter compounds in foods or plants, five bitter compounds, aloperine, amygdalin, berberine, crotaline, and naringenin, were selected and added to primary mouse splenocytes in the absence or presence of lipopolysaccharide (LPS) under four different in vitro experimental models. Anti-inflammatory cytokine secretions such as interleukin (IL)-10 and pro-inflammatory cytokines such as IL-6 as well as tumor necrosis factor (TNF)-alpha were determined using enzyme-linked immunosorbent assay (ELISA). The results showed that all selected bitter compounds except amygdalin exhibited apparent cytotoxic effects. On the basis of changes in the secretion profiles between anti- and pro-inflammatory cytokines, the five selected bitter compounds demonstrated anti-inflammatory activities via modulating either IL-6/1L-10 or TNF-alpha/IL-10 ratios at noncytotoxic doses. Berberine and naringenin treatments showed the strongest potential for anti-inflammation among the five selected bitter compounds. Berberine especially displayed strong anti-inflammatory activity in both preventive and repair manners.