In vitro anti-Trypanosoma cruzi evaluation of sesquiterpenes from the branches of Oxandra sessiliflora

In this work, the CH2Cl2 phase from the EtOH extract of Oxandra sessiliflora (Annonaceae) branches was subjected to chromatographic fractionation to afford six sesquiterpenoids: 4α,10β-aromadendranediol (1), 4β,10α-aromadendranediol (2), 4α,10α-aromadendranediol (3), 1β,6α-dihydroxy-4(15)-eudesmene (4), 4β,10α-dihydroxy-guai-6-ene (5), and 4β,6β,7β,10α-tetrahydroxy-guaiane (6), the last one identified as a new natural product. The structures of isolated compounds were identified by analysis of NMR and HRESIMS spectral data. Compounds 1–6 exhibited activity against T. cruzi with EC50 values ranging from 16.3–47.5 μM. Additionally, no cytotoxicity to mammalian cells (NCTC- L929 clone) was observed for tested compounds at the highest concentration (200 μM). Sesquiterpenes 5 and 6 exhibited higher selectivity index (SI) with values higher than 12.3 and 11.4, respectively. This data suggests that guaiane sesquiterpenes 5 and 6, isolated from O. sessiliflora, may contribute as scaffolds for the design of novel and selective drug candidates for treatment of neglected diseases, mainly for Chagas disease.