Essential oil composition, total phenolic and flavonoids contents, and antioxidant activity of Oliveria decumbens Vent. (Apiaceae) at different phenological stages

The Oliveria genus belongs to the Apiaceae family and encompasses only one species corresponding to Oliveria decumbens Vent. The aerial parts of O. decumbens were gathered at distinct developmental stages (vegetative, floral budding, full flowering and seed set) from wild settlements and the yield of essential oils (w/w %) determined. Then the chemical compositions were achieved by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). In the vegetative stage γ-terpinene (33.6%), carvacrol (16.9%) and thymol (16%) were the main components; whereas thymol (37.8%) and carvacrol (29.38%) dominated the oil during the flowering stage. Total phenolic and flavonoids compounds and antioxidant activity (DPPH assay) of the methanolic extracts were calculated in two main stages as well. At any rate, flowering stage is the best step for obtaining the highest amount of thymol and carvacrol in essential oil, and the best antioxidant capacity in the extracts. The results of this investigation indicated that the favorable harvesting time for production of this species and possible uses in food and pharmaceutical industries.