Comparative Study of the Chemical Composition of the Essential Oil of Plectranthus amboinicus from Different Sectors of Southern Ecuador

The aim of this study was to demonstrate the variability of essential oils (EOs) extracted from the culinary plant Plectranthus amboinicus in different locations, in order to determine their optimal utilization. The EO was extracted from fresh leaves by steam distillation at three locations in the south of Ecuador: Paccha (PAC), El Guabo (GUA), and Arenillas (ARE). Qualitative and quantitative analyses were performed by gas chromatography coupled with mass spectrometry (GC-MS) and flame ionization detection (GC-FID). A total of 41 compounds were identified in Paccha (97.37%), 38 compounds in Arenillas (97.43%), and 41 compounds in El Guabo (98.31%). The most abundant compounds identified were germacrene D (17.60%, 14.59%, and 12.85%), alfa humulene (10.88%, 4.65%, and 5.08%), alfa-terpinene (10.66%, 13.85%, and 6.79%), and carvacrol (5.11%, 5.97%, and 9.13%), in PAC, ARE, and GUA, respectively. In addition, the antioxidant activity was evaluated by ABTS and DPPH assays, as well as the total phenol content of the EOs. Finally, a principal compound analysis (PCA) was performed in order to evaluate the variation in compounds using the geographical location of the samples as a variable.