CHEMICAL COMPOSITION, ANTIOXIDANT POTENTIAL, AND CHOLINESTERASE INHIBITORY ACTIVITY OF ESSENTIAL OILS FROM THREE Thunbergia SPECIES GROWING WILD IN NORTHEAST BRAZIL

Essential oils from the leaves and flowers of Thunbergia grandiflora, Thunbergia alata and Thunbergia erecta occurring in urban fragments of the Atlantic Forest in the state of Pernambuco, Brazil, were analyzed by GC-FID (gas chromatography with flame ionization detector) and GC-MS (gas chromatography mass spectrometry). A total of 76 compounds were identified, representing more than 95% of the oils. Differences in the chemical profile were found among the oils. Germacrene D (leaves: 0.61 ± 0.02 to 20.49 ± 0.78%; flowers: 0.84 ± 0.10 to 21.71 ± 0.77%) was the only sesquiterpene identified in abundance in all oils. The chemical compositions of the oils were compared using principal component analysis and hierarchical cluster analysis, which revealed significant differences. All three species exhibited antioxidant and cholinesterase activity. The oil from leaves of T. erecta achieved the best results on the DPPH (2,2-diphenyl-1-picrylhydrazyl) test and with the ABTS (2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid) radical. The oil of T. erecta exerted a significant inhibition effect on the enzymes AChE (acetylcholinesterase), and BuChE (butyrylcholinesterase). Moreover, none of the oils tested showed toxicity against Artemia salina.