This study was designed to find some potential natural products and/or constituents inhibiting proinflammatory
cytokine generation in
lung inflammation, since
cytokines such as
tumor necrosis factor-α (TNF-α) and
interleukin-6 (IL-6) are pivotal for provoking airway
inflammation. In our preliminary screening procedure, the 70%
ethanol extract of the leaves of Perilla frutescens (PFE) was found to clearly inhibit TNF-α production in the lung at 100 mg/kg, after intranasal
lipopolysaccharide treatment of mice. Based on this result, ten constituents including phenylpropanoids (allyltetramethoxybenzene,
caffeic acid,
dillapiole,
elemicin,
myristicin,
nothoapiole,
rosmarinic acid methyl ester,
rosmarinic acid) and
monoterpenes (
perilla aldehyde and
perilla ketone) were successfully isolated from the extract. Among them,
elemicin and
myristicin were found for the first time to concentration-dependently inhibit IL-1β-treated
IL-6 production from lung alveolar epithelial cells (A549) at concentrations of 10-100 μM. These findings suggest that the phenylpropanoids including
elemicin and
myristicin have the potential to be new inhibitory agents against
lung inflammation and they may contribute, at least in part, to the inhibitory activity of PFE on the lung inflammatory response.