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Six pentacyclic triterpenes were isolated from hexane extract of stems of Maytenus salicifolia Reissek, Celastraceae: 30-hydroxyfriedelan-3-one (1), 3,16-dioxofriedelane (2), friedeline (3), lupeol (4), betuline (5) and lup-20(29)-en-3,30-diol (6). The structure each one was established on the basis of detailed 1 H and 13 C NMR spectral investigation and by comparison with the respective literature values. For compound 1, the complete 2D NMR (HMBC, HMQC and NOESY) spectral data were herein reported for the first time. Compounds 1, 2, 5 and 6 were isolated for the first time from this plant. Antioxidant activity is described for some extracts from species of the Celastraceae family, then, the extracts from aerial parts of M. salicifolia were evaluated in relation to antioxidant potential using the DPPH method. Compared to quecertin, the AcEt extract (EAF) from leaves, AcEt (EAPF) and MeOH (EMPF) from pulp fruit and AcEt (EAT) and MeOH (EMT) from stems showed significant antioxidant property.

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In continuation of our work on Maytenus salicifolia, we report herein the isolation and structural elucidation of two new compounds, salicassin (1), a diterpene-chalcone adduct with an unprecedented Cframework, and (16b)-16-hydroxypristimerin (2), a quinone methide triterpenoid. Their structures were elucidated on the basis of spectroscopic analysis, including 1D-and 2D-NMR techniques (COSY, ROESY, HSQC, and HMBC). In addition, 22 known compounds were isolated and characterized by comparison of their spectra with reported data. Compound 2, structurally related to the well known cytotoxic quinone methide triterpenoids, exhibited an antiproliferative effect on HeLa, A-549, and HL-60 human cell lines, with IC 50 values of 2.2, 3.2, and 2.7 mm, respectively.Introduction. -The Maytenus genus, with more than 225 species, is widely distributed in the tropical and subtropical regions of the world, and represents the most diverse and richest genus of the Celastraceae family. In Brazil, 80 species of this genus have so far been documented as being present. Many traditional properties attributed to the Maytenus species have been experimentally verified, and these include antimitotic, antioxidant, and DNA polymerase b-lyase inhibitory activities [1].The species of the Celastraceae biosynthesize dimeric [2] and trimeric [3] triterpenes, and octacyclic sesquiterpeneÀtriterpene adducts [4], possibly through hetero-DielsÀAlder reactions via the formation of a C(1)ÀC(4) dioxane system. Uragogin (triterpeneÀneolignan ester) and blepharodin (heptacyclic arylpropa-noidÀnortriterpene phenol) isolated from Crossopetalum uragoga and Maytenus magellanica, respectively, are examples of hetero-DielsÀAlder adducts endowed with dioxane bridges [5]. Furthermore, the isolation of DielsÀAlder decacyclic C 20 -C 30 adducts [6] and diterpene dimers [7] [8] have also been reported for Celastraceae.Maytenus salicifolia Reissek is endemic in the state of Minas Gerais, southeast of Brazil, and is commonly known as cafezinho. Its leaves have been used in traditional