Variability in phytochemical composition and antioxidant activity of Saccocalyx satureioides essential oils due to harvest period

Abstract

ABSTRACT The present study tracked the seasonal variation in the volatile metabolites of Saccocalyx satureioides plant aerial parts and the of antioxidant activities which depend on the chemical composition. The essential oil samples were obtained by hydrodistillation using Clevenger type apparatus, quantified and identified by gas chromatography (GC) and GC/mass spectrometry (MS). The antioxidant activities of essential oils were determined by DPPH (2,2-di-phenyl-1-picrilhydrazyl) free radical scavenging and the FRAP (ferric reducing antioxidant power) assays. The essential oil yield varied from 1.96 to 3.07% (v/w). The main identified components were oxygenated monoterpenes: α-terpineol (32.48–45.15%), borneol (20.55–25.31%), and thymol (12.42–21.08%). The concentrations of both α-terpineol and borneol increased from April to July while the percentage of thymol decreased over the same period. The oxygenated monoterpenes representing the major identified class (~ 91.18%) increased during the season while the monoterpenes decreased during the same period. The correlation between the chemical composition and the antioxidant activity was established using agglomerative hierarchical clustering method and principal component analysis. Two groups were spotted upon these analyses, indicating that April was the best period of collection allowing the highest antioxidant activity for the essential oils.