Chemical composition of essential oils and in vitro antioxidant properties of extracts and essential oils of Calamintha origanifolia and Micromeria myrtifolia, two Lamiaceae from the Lebanon flora

There is a growing interest of industry to replace synthetic chemicals by natural products with bioactiveproperties from plant origin. The aim of this study was to determine the chemical composition of essen-tial oils of Calamintha origanifolia (Labill.) Boiss and Micromeria myrtifolia Boiss., two Lamiaceae speciescollected in Lebanon, and to characterize the in vitro antioxidant activities of their extracts and of theessential oils. The essential oils from aerial parts of the two plants were isolated by hydrodistillationtechnique using a Clevenger-type apparatus. The extracts were prepared with three solvents of differentpolarity (n-hexane, chloroform and methanol). A total of 97 constituents were identified in M. myrtifoliaand C. origanifolia oils using GC/MS; the main components detected were -caryophyllene together withcaryophyllene oxide and hexadecanoic acid in M. myrtifolia while isomenthone, menthone, pulegone and-bisabolol were the main compounds in C. origanifolia. The methanol extracts of both species exhibitedthe highest phenol content and were found to be significantly more active than chloroform and hexaneextracts when assayed by DPPH˙ radical scavenging and ferric ion reduction (FRAP) assays. The results ofthis study provide a clear picture of the volatiles of M. myrtifolia and C. origanifolia and demonstrate thatthese plant species have an huge potential as an alternative to chemical additives for the food industrydue to their antioxidant properties.