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Analgesic effects of the ethanolic extract from Magnolia ovata (Magnoliaceae) trunk bark and of N-acetylxylopine, a semi-synthetic analogue of xylopine

Mori, Lídia Sayuri, Boller, Shirley, Kassuya, Cândida Aparecida Leite, Stefanello, Maria Élida Alves, Zampronio, Aleksander Roberto
Phytomedicine 2011 v.18 no.2-3 pp. 143-147
Magnolia, acetic acid, analgesic effect, bark, dose response, inflammation, mice, models, nociception, oral administration, pain, plant extracts
This study investigated the antinociceptive effects of the ethanolic extract (EEMO) obtained from Magnolia ovata (A.St.-Hil.) Spreng and N-acetylxylopine (AXyl), a stable derivative of xylopine in different models of nociception. The EEMO and AXyl inhibited the nociception induced by acetic acid in mice, in a dose-dependent manner with a maximal inhibition of 91±9% and 50±11%, respectively. Oral administration of EEMO or AXyl also significantly inhibited the inflammatory phase of formalin-induced nociception with maximal reduction of 87±3.9% and 71±10%, respectively. Confirming the effectiveness of the extract and the isolated compound in inflammatory responses, EEMO or AXyl inhibited carrageenan-induced mechanical allodynia with percentage of inhibition of 40±6% for EEMO and 82±8% for AXyl. Intraplantar injection of AXyl in the ipsilateral paw, but not in the contralateral paw, also reduced carrageenan-induced mechanical allodynia in mice. The response of the animals for maximal doses tested of EEMO and AXyl in the hot-plate or rota-rod models were not altered. These results show that the extract from M. ovata and the stable derivative AXyl possess analgesic properties towards inflammatory pain acting on peripheral sites.