Anti-Inflammatory Activity of Sugiol, A Diterpene Isolated from Calocedrus formosana Bark

Abstract

Sugiol is a diterpene which was isolated and purified from alcohol extracts of the bark of Calocedrus formosana Florin (Cupressaceae). Although sugiol has low inhibitory activity against the DPPH radical, it could effectively reduce intracellular reactive oxygen species (ROS) production in lipopolysaccharide (LPS)-stimulated macrophages. The present study investigated the potential anti-inflammatory activity of sugiol, and the relationship between signal transduction and inflammatory cytokines in vitro. A dose of 30 μM of sugiol was effectively inhibitory for proIL-1β, IL-1β and TNF-α production, suggesting that sugiol is bioactive against inflammation. Moreover, sugiol reveals a capacity for suppressing the activation of mitogen-activated protein kinases (MAPKs), including extracellular signal-regulated kinase (ERK), c-Jun NH₂-terminal kinase (JNK), and p38 mitogen-activated protein kinase (p38) activated by LPS-stimulation in J774A.1 murine macrophages. A low dosage of 10 μM of sugiol completely inhibited ERK1/2 phosphorylation, while 30 μM effectively inhibited JNK1/2 and p38 phosphorylation in LPS-stimulated macrophages. In addition, sugiol significantly inhibited LPS-induced ROS production. Our studies suggest that sugiol’s efficacy in inhibiting the inflammatory cytokines of IL-1β and TNF-α could be attributed to a reduction of the ROS that leads to a decrease in the phosphorylation of MAPKs.

Abbreviations

LPS:lipopolysaccharide

ROS:reactive oxygen species

MAPK:mitogen-activated protein kinase

ERK:extracellular signal-regulated kinase

JNK:C-Jun NH₂-terminal protein kinase

p38:p38 mitogen-activated protein kinase

Key words

Calocedrus formosana - Cupressaceae - sugiol - anti-inflammatory activity - TNF-α - IL-1β - MAPKs

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