Shogaol but not gingerol has a neuroprotective effect on hemorrhagic brain injury: Contribution of the α, β-unsaturated carbonyl to heme oxygenase-1 expression.

We investigated the effects of shogaol, which has an α, β-unsaturated carbonyl group, and gingerol, which does not, on primary-cultured microglia to understand how the α, β-unsaturated carbonyl interacts with Kelch-like ECH-associated protein (Keap)1. Shogaol (1 μM) but not the same concentration of gingerol significantly increased heme oxygenase (HO)-1 protein levels in cultured microglia without cytotoxicity. In addition, shogaol suppressed the release of the inflammation marker nitric oxide induced by 30 U/ml thrombin treatment.