In this study, the oil constituents of Lippia gracilis were identified by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). The antioxidant and antifungal activities were also evaluated. The leaf oil showed a yield of 3.7% and its main constituents were thymol (70.3%), p-cymene (9.2%), thymol methyl ether (5.4%) and p-methoxythymol (2.7%). The thin stem oil showed a yield of 0.4% and its major components were thymol (70.1%), thymol methyl ether (4.4%), p-methoxythymol (4.0%), p-cymene (3.8%), α-humulene (2.4%) and (E)-caryophyllene (2.1%). The aromatic monoterpenes found in the oils showed an average of 88%. The scavenging activity of the 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) for the leaf oil, expressed as half maximal effective concentration (EC50), was 35.7±3.3 µg/ml, indicating high antioxidant activity. The evaluation of fungicide activity for the leaf oil, using direct bioautography, showed also a significant value for lethal concentration (LC50 5.0 μg/ml) against Cladosporium sphaerospermum and C. cladosporioides fungi.
Key words: Essential oil composition, thymol and carvacrol, DPPH radical scavenging and bioautography
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