Novel Benzoxazoles Containing 4-Amino-Butanamide Moiety Inhibited LPS-Induced Inflammation by Modulating IL-6 or IL-1β mRNA Expression

LPS induces inflammatory cytokines, including IL-1β, IL-6, and TNF-α, and causes an inflammatory response. The development of small molecules that have suppressive effect on those inflammatory cytokines is a desirable strategy for the treatment of inflammatory diseases. We synthesized 12 novel compounds with 4-amino-N-(4-(benzo[d]oxazol-2-ylamino)phenyl)butanamide moiety and evaluated their biological activities. Among them, 4 compounds (compound 5d, 5c, 5f, 5m and synthetic intermediate 4d) showed potent inhibition activities on IL-1β and IL-6 mRNA expression in vitro. Further, in vivo activity was evaluated with two compounds (5f and 4d) and mRNA levels of IL-1β, IL-6, and TNF-α were significantly decreased without hepatotoxicity. From the in vivo and in vitro test results, we confirmed that our synthesized compounds are effective for suppression of representative inflammatory cytokines.