Andalusol, a Diterpenoid with anti-inflammatory Activity from Siderits foetens Clemen

The anti-inflammatory activity of andalusol (ent-13(16),14-labdadiene-6 alpha,8 alpha,18-triol), a diterpenoid obtained from the acetone extract of Sideritis foetens Clemen, has been investigated. This compound was able to inhibit acute inflammatory processes induced by carrageenan or 12-O-tetradecanoylphorbol acetate (TPA) after oral or topical administration. Quantitation of the neutrophil specific marker, myeloperoxidase (MPO), demonstrated that its topical anti-inflammatory effect was associated with reduction in neutrophil infiltration into inflamed tissues. Interaction of andalusol with leukocyte functions and histamine release from mast cells was analyzed in vitro. At a concentration of 100 microM andalusol decreased beta-glucuronidase release from calcium ionophore A23187-stimulated rat peritoneal leukocytes. However, it failed to affect superoxide generation on TPA-stimulated leukocytes and it was non toxic to leukocytes up to 100 microM (assayed in terms of lactate dehydrogenase release). Andalusol produced a dose-dependent inhibition on histamine release from rat peritoneal mast cells stimulated by compound 48/80 or calcium ionophore A23187. These results suggest that andalusol possesses an anti-inflammatory profile, and it is in part responsible for the anti-inflammatory activity attributed to this plant.