Bioassay-guided fractionation of the bark extract of Annona foetida afforded a new antileishmanial pyrimidine-beta-carboline alkaloid, N-hydroxyannomontine (1), together with the previously reported annomontine (2), O-methylmoschatoline (3), and liriodenine (4). The structure of compound 1 was established on the basis of extensive 1D and 2D NMR and MS analyses. This is the third reported pyrimidine-beta-carboline-type alkaloid and is particularly important for Annona genus chemotaxonomy. In addition, all compounds exhibit in vitro antileishmanial activity against promastigote forms of Leishmania braziliensis. Compounds 2 and 4 showed better activity than compounds 1 and 3 against L. braziliensis. Compound 2 was not active against L. guyanensis.

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Some triterpenes and iridoids were previously isolated from the stem bark of Himatanthus sucuuba. The latex from Himatanthus sucuuba is used in popular amazonian medicine as an anti-inflammatory remedy. Fractions of the latex were pharmacologically evaluated with a view to verify this popular use in the carrageenan-induced rat paw edema and in the acetic acid-induced mouse constriction tests. The hexane fraction inhibited the edema formation by 35.9% at a dose of 200 mg/kg (p.o.) but no activity was observed at 100 mg/kg (p.o.). The triterpenes present in the hexane fraction were identified as lupeol acetate, alpha-amyrin and lupeol cinnamates. The fraction containing only cinnamates inhibited the edema and the abdominal constrictions by 50-40% and 57.9%, respectively, at 100 mg/kg (p.o.). Among all the fractions studied, the fraction containing only cinnamates showed the greatest anti-inflammatory activity which suggests that these compounds were responsible for the previously described activity of the crude extract.

Recebido em 2/1/08; aceito em 6/8/08; publicado na web em 15/12/08The essential oil from leaves of Annona foetida obtained by hydrodistillation was analyzed by GC/FID and GC/MS. The results showed that the major constituents were bicyclogermacrene (35.12%), (E)-caryophyllene (14.19%) and α-copaene (8.19%). The antimicrobial and antileishmanial activities were investigated. The oil showed potent antimicrobial activity against Candida albicans and Rhodococcus equi. The oil also showed significant antileishmanial activity, giving the best results against Leishmania guyanensis. A preliminary cytotoxicity assay for this oil was carried out on hamster and mice (Balb/c) peritoneal macrophages. The results obtained were similar to pentamidine and considered not to be cytotoxic to macrophages.