Long-chain fatty alcohols from pomace olive oil modulate the release of proinflammatory mediators

Pomace olive oil is a by-product of olive oil extraction that is traditionally produced and consumed in Spain. The nonglyceride matter of this oil is a good source of interesting minor compounds, like long-chain fatty alcohols, which are present free or as part of waxes. In the present study, long-chain fatty alcohols were isolated from the nonglyceride fraction of pomace olive oil, and the composition was identified and quantified. The major components of long-chain fatty alcohols were tetracosanol, hexacosanol and octacosanol. We investigated the ability of long-chain fatty alcohols from pomace olive oil to inhibit the release of different proinflammatory mediators in vitro by cells involved in inflammatory processes. Long-chain fatty alcohols significantly and dose-dependently decreased nitric oxide production by RAW 264.7 murine macrophages stimulated with lipopolysaccharide. Western blot analysis showed that nitric oxide reduction was a consequence of the inhibition of inducible nitric oxide synthetase expression. Long-chain fatty alcohols also reduced tumor necrosis factor-α and prostaglandin E2 production, although the potency of inhibition for the latter was lower. On the other hand, long-chain fatty alcohols significantly reduced thromboxane A2 production in rat peritoneal neutrophils stimulated with the calcium ionophore A-23187. The reduction of eicosanoid release was related to the inhibition of phospholipase A2 enzyme activity by long-chain fatty alcohols, reaching an inhibitory concentration 50% value of 6.2 μg/ml. These results showed that long-chain fatty alcohols may have a protective effect on some mediators involved in the inflammatory damage development, suggesting its potential value as a putative functional component of pomace olive oil.