This study aimed to investigate the chemical composition, as well as antitrypanosomal activity of essential oils from leaves, twigs and inflorescences of N. barbellata. Fresh plant material was collected and individually submitted to hydrodistillation in a Clevenger apparatus. Crude oils were chemically analyzed by GC/FID and GC/MS, in combination with calculation of respective Kovats indices and it was possible to identify 82.6%, 84.0% and 88.5% of the compounds in the oils from leaves (NBL), twigs (NBT) and inflorescences (NBI), respectively. The main components were aristolochene (7.90%) and γ-gurjunene (7.86%) in NBL, costic acid (32.39%) and globulol (12.97%) in NBT, and α-pinene (13.57%) and α-gurjunene (12.29%) in NBI. The in vitro anti-T. cruzi potential against trypomastigote forms and the evaluation of cytotoxicity in mammalian cells (NCTC clone L929) of essential oils were evaluated (Table 1).
Biological analysis revealed that NBL and NBI displayed higher antitrypanosomal potential with EC50 values of 12.1 and 14.9 μg mL-1, respectively, compared to NBT (EC50 of 20.2 μg mL-1). Regarding citotoxicity, NBT did not exhibit toxicity against NCTC cells (CC50 > 200 μg mL-1). Therefore, selectivity indexes of studied oils were calculated at 8.3 (NBL), > 9.9 (NBT), and 6.6 (NBI) being that calculated for NBT with similar value of positive control benznidazol (> 16.1). Thus, this work reports for the first time the chemical composition of essential oils from different tissues of N. barbellata, in addition to showing that this species can produce bioactive substances for the parasite T. cruzi.