Inhibitors of Nitric Oxide Synthesis and TNF-α Expression from Magnolia obovata in Activated Macrophages

Abstract

Nitric oxide (NO) and tumor necrosis factor-α (TNF-α) are the major mediators produced in activated macrophages which contribute to the circulatory failure associated with septic shock. An activity-guided fractionation of an MeOH extract of stem bark of Magnolia obovata afforded two inhibitors of NO production in lipopolysaccharides (LPS)-activated macrophages by the suppression of i-NOS expression. Their structures were elucidated by spectroscopic methods to be magnolol and honokiol with IC₅₀ values of 16.8 and 6.4 μM, respectively. They also inhibited the production of TNF-α in LPS-activated macrophages. Thus, these compounds may be possible candidates for the development of new drugs to treat endotoxemia accompanied by the overproduction of NO and TNF-α.

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