Inhibition of Leukotriene and Platelet Activating Factor Synthesis in Leukocytes by the Sesquiterpene Lactone Scandenolide

Abstract

The sesquiterpene lactone scandenolide, isolated from the Philippines medicinal plant Mikania cordata, at a dose of 100 µM completely inhibited whole blood chemiluminescence in response to the activators PMA and zymosan. In isolated inflammatory rat leukocytes this compound inhibited both leukotriene B₄ and 5-HETE production with IC₅₀ of 15 µM and 30 µM, respectively. The formation of the cyclooxygenase product thromboxane B₂ was not inhibited in the concentration range 10 to 200 µM of scandenolide. The formation of the potent inflammatory mediator platelet activating factor (PAF) was suppressed by µM concentrations of scandenolide with an IC₅₀ of <20 µM. The presence of a compound in M. cordata which inhibits some of the inflammatory mediators such as leukotrienes and PAF may explain at least in part some of its medicinal properties.

Key words

Mikania cordata - sesquiterpene lactone - scandenolide - anti-inflammatory action