Monoamine Oxidase B inhibitor 4 (compound 1l) is a selective inhibitor of human monoamine oxidase-B (hMAO-B) (IC50=8.3 nM). Monoamine Oxidase B inhibitor 4 also has anti-neuroinflammatory and low neurotoxicity. Monoamine Oxidase B inhibitor 4 can inhibit the release of NO, TNF-α and IL-1β stimulated by LPS and Aβ1-42, and can also attenuate Aβ(1-42)-induced cytotoxicity.