Anti-inflammatory activity of soymilk and fermented soymilk prepared with lactic acid bacterium and bifidobacterium

In the present study, anti-inflammatory activity of the methanol extracts of soymilk and soymilk fermented with Streptococcus salivarius subsp. thermophilus CCRC 14805 alone or in conjunction with Bificobacterium infantis CCRC 14603 was evaluated. It was found that extracts of soymilk and the prepared fermented soymilk dose-dependently suppress nitric oxide (NO) production of lipopolysaccharide (LPS)-induced macrophages, with soymilk showing the highest inhibition ability followed by S. thermophilus-fermented soymilk. Extracts of soymilk and fermented soymilk did not affect the activity of inducible nitric oxide synthase (iNOS). The extracts of the fermented soymilk inhibited the protein expression of iNOS in LPS-induced macrophages, but soymilk did not. Moreover, these extracts did not show obvious inhibition on cyclooxygenase-2 (COX-2) protein expression, while all showed the inhibitory effect on LPS-induced pro-inflammatory cytokines including tumor necrosis factor (TNF)-£\, interleukin (IL)-6, IL-1£] and prostaglandin E2 (PGE2) produced by RAW 264.7 macrophages.