Antinociceptive effect of geranylgeraniol and 6±,7²-dihydroxyvouacapan-17²-oate methyl ester isolated from Pterodon pubescens Benth.

Resumo

Pterodon pubescens Benth. seeds are commercially available in Brazilian medicinal flora market and the crude alcoholic extracts of this plant is used in folk medicine as anti-inflammatory, analgesic and anti-rheumatic preparations. The aim of this study was to evaluate the role of compounds Geranylgeraniol (C1) and 6a,7b-dihydroxyvouacapan-17b-oate methyl ester (C2) in the analgesic activity of P.pubescens. Compounds were obtained from the dichlorometane crude extract using chromatographic methods. In order to evaluate the compounds participation in several mechanisms of pain modulation, male Swiss mice were used in the writhing, capsaicin, glutamate and hot-plate tests. The additional findings of the present work are that: both i.p. and p.o. treatment of compounds C1 and C2 reduced reactivity to the writhing test demonstrating differences in potency related to the route; compounds C1 and C2 may present synergic activity; both compounds C1 and C2 demonstrated activity related to vanilloid receptors VR1 and glutamate peripheral receptors, being C2 more potent by i.p. route and the antinociceptive activity of compounds C1 and C2 have no relationship to opioid receptors. These results allowed us to establish a relationship between the popular use of Pterodon pubescens seed's for pain relief, and the effectiveness of two major compounds isolated from this species with antinociceptive activity, using different "in vivo" experimental models each evaluating a specific modulation process (peripheral or central) corroborating the folk use of this species for different pain and inflammation disorders. (AU)