Heliopsis longipes is used as analgesic in Mexican traditional medicine. The present study assesses the possible antinociceptive effect of Heliopsis longipes and describes the pharmacological mechanism of action of the antinociceptive effect of affinin, identified as the one active principle in Heliopsis longipes acetone extract. Intraperitoneal administration of H. longipes extract and affinin produced a dose-dependent antinociceptive effect when assessed in mice submitted to acetic acid and capsaicin tests. Affinin-induced antinociception (30 mg/kg, I. P.) was blocked by naltrexone (1 mg/kg, S. C.), P-chlorophenylalanine (80 mg/kg, I. P.) and flumazenil (5 mg/kg, S. C.) suggesting that its pharmacological effect could be due to the activation of opiodergic, serotoninergic and GABAergic systems. In addition, the antinociceptive effect of affinin was attenuated by pretreatment with 1 H-[1,2,4]oxadiazolo[1,2- A]quinoxalin-1-one (1 mg/kg, S. C.) and glibenclamide (10 mg/kg, S. C.) suggesting that the nitric oxide-K (+) channels pathway could be involved in its mechanism of action. These results suggest that affinin itself or its derivatives may have potential antinociceptive effects.

No abstract

Three new sesquiterpenes, 5alpha,7alpha,10betaH-3-patchoulen-2-one (1), 5alpha,7alpha10betaH-4(14)-patchoulen-2alpha-ol (2), and 9alpha,10beta-dihydroxy-2beta,4beta-peroxy-1alpha,5beta,7alphaH-guaiane (3), were isolated from the aerial parts of Croton arboreous along with 14 known compounds. The structures of these compounds were determined on the bases of their spectroscopic data (IR, UV, OR, 1D and 2D NMR, and MS). The anti-inflammatory activity against ear edema in mice produced by 12-O-tetradecanoylphorbol-13-acetate (TPA) was evaluated for all the pure compounds and showed that compounds 4-7 are active.

Secondary metabolites 5-acetyl-3beta-angeloyloxy-2beta-(1-hydroxyisopropyl)-2,3-dihydrobenzofurane (1), 5-acetyl-3beta-angeloyloxy-2beta-(1-hydroxyisopropyl)-6-methoxy-2,3-dihydrobenzofurane (2), espeletone (3), encecalinol (4), O-methylencecalinol (5), encecalin (6), sonorol (7), taraxerol (8), (+)-beta-eudesmol (9), and a mixture of beta-sitosterol and stigmasterol, were isolated from the aerial parts of Ageratina pichinchensis var. bustamenta. The antimicrobial activity of compounds 6, 8 and 9, together with derivatives 9a and 9b against the most important dermatophytes responsible for tinea pedis infection, Trichophyton rubrum and T. mentagrophytes, and against Candida albicans and Aspergillus niger were determined, showing that the three natural products were active against both Trichophyton species. Ageratina pichinchensis var. bustamenta is used in folk medicine to treat skin infections and wounds, and this study confirms that the n-hexane extract contains metabolites which are responsible for these utilities.