Structure−Activity Relationship Studies of a Series of Novel δ-Lactam-Based Histone Deacetylase Inhibitors

We synthesized a series of δ-lactam-based HDAC inhibitors that were identified with various degrees of anti-inflammatory and cell growth inhibitory activities. Compounds possessing significant HDAC inhibitory activity exhibited both anti-inflammatory and cell growth inhibitory activities as well as significant tumor growth inhibition in the in vivo tumor xenograft experiments. Besides, these compounds demonstrated anti-inflammatory properties in vitro via suppression of the production of the proinflammatory cytokine TNF-α and nitric oxide by LPS-stimulated RAW264.7 cells.