The effects produced by nine dihydro-beta-agarofuran sesquiterpenes isolated from Crossopetalum tonduzii (1-8) and Maytenus macrocarpa (9) (Celastraceae) on the reversion of the resistant phenotype on a multidrug-resistant Leishmania line and their binding to recombinant C-terminal nucleotide-binding domain of Leishmania P-glycoprotein-like transporter were studied. The structures of the new compounds (1-5) were elucidated by spectroscopic methods, including (1)H-(13)C heteronuclear correlation (HMQC), long-range correlation spectra with inversal detection (HMBC), ROESY experiments, and chemical correlations. The absolute configuration of one of them (1) was determined by CD studies. The structure-activity relationship is discussed.

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Twelve known diterpenes 1 - 11 and 13, and three known sesquiterpenes 14 - 16, along with a new C(20) - C(15) terpenoid 17, with a structure based on an unprecedented skeleton in which a labdane diterpene is linked to a monocyclic sesquiterpene by an ester bridge, were isolated from the oleoresin of the Peruvian medicinal plant Copaifera paupera (Herzog) Dwyer (Leguminosae). Their structures were elucidated on the basis of spectral analysis, including homo- and heteronuclear correlation NMR experiments (COSY, ROESY, HMQC and HMBC), and by comparison with data in the literature. The leishmanicidal, antimicrobial, cytotoxic, and aldose reductase inhibitory activities were studied. Compounds 1 and 11 showed significant antimicrobial activity (MIC < 10 microg/ml) against Gram-positive bacteria, comparable with cephotaxime used as control. Compound 2 exhibited moderate cytotoxic activity against four cancer cell lines.