Antinociceptive Effects of Aza-Bicyclic Isoxazoline-Acylhydrazone Derivatives in Different Models of Nociception in Mice.

BACKGROUND: In a study recently published by our research group, the isoxazoline-acylhydrazone derivatives R-99 and R-123 presented promising antinociceptive activity. However, the mechanism of action of this compound is still unknown. OBJECTIVE: This study aimed to assess the mechanisms involved in the antinociceptive activity of these compounds in chemical models of pain. METHODS: Animals were orally pretreated and evaluated in the acetic acid-, formalin-, capsaicin-, carrageenan- and Complete Freund's Adjuvant (CFA)-induced pain models in mice. The effects of the compounds after pretreatment with naloxone, prazosin, yohimbine, atropine, L-arginine, or glibenclamide were studied, using the acetic acid-induced writhing test to verify the possible involvement of opioid, α1-adrenergic, α2-adrenergic or cholinergic receptors, and nitric oxide or potassium channels pathways, respectively. RESULTS: R-99 and R-123 compounds showed significant antinociceptive activity on pain models induced by acetic acid, formalin, and capsaicin. Both compounds decreased the mechanical hyperalgesia induced by carrageenan or CFA in mice. The antinociceptive effects of R-99 and R-123 on the acetic acid-induced writhing test were significantly attenuated by pretreatment with naloxone, yohimbine or atropine. R-99 also showed an attenuated response after pretreatment with atropine and glibenclamide. However, on the pretreatment with prazosin, there was no change in the animals' response to both compounds. CONCLUSION: R-99 and R-123 showed antinociceptive effects related to mechanisms that involve, at least in part, interaction with the opioid and adrenergic systems and TRPV1 pathways. The compound R-99 also interacts with the cholinergic pathways and potassium channels.

Synthesis, antitumour and antimicrobial activities of new peptidyl derivatives containing the 1,3-benzodioxole system.

Two series of 5 and 6-substituted 1,3-benzodioxole peptidyl derivatives were synthesized and evaluated as antitumour and antimicrobial agents. The compounds that could be conveniently prepared in a few steps processes from natural safrole have been characterised by IR and 1H-NMR spectroscopy. In vivo antitumor activity tests showed that some of the compounds were able to inhibit carcinoma S-180 tumour growth in mice. The in vitro antimicrobial activity of all compounds revealed that they are able to promote the growth of some organisms, including Bacillus subtilis.