<i>In vitro</i> 5-lipoxygenase and anti-oxidant activities of <i>Warburgia salutaris</i> and drimane sesquiterpenoids

Abstract

The purpose of this investigation was to determine the in vitro 5-lipoxygenase inhibitory and anti-oxidant activities of Warburgia salutaris. Aqueous and methanol extracts of the leaves of W. salutaris were obtained and subjected to the 5-lipoxygenase assay and the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay to determine their anti-inflammatory and anti-oxidant activities, respectively. Furthermore, drimane sesquiterpenoids, mukaadial and warburganal, isolated from the same plant, were subjected to the same biological tests. The methanol extract of the leaves of W. salutaris displayed promising in vitro anti-inflammatory activity with an IC_50L value below 33µg ml^–1, while the aqueous extract of the same plant exhibited no activity in the same assay. The aqueous and methanol extracts of W. salutaris displayed promising anti-oxidant activities with IC₅₀ values of 34.43 + 0.74µg ml^–1 and 15.38 + 0.20µg ml^–1, respectively. The compounds mukaadial and warburganal displayed 5-lipoxygenase inhibitory activity and contribute to the in vitro anti-inflammatory activity of the crude extract of the same plant. Anti-oxidant activity of W. salutaris did not appear to be confined to the drimane sesquiterpenoides tested.

South African Journal of Botany 2005, 71(3&4): 447–449