Diverse Terpenoids and Phenolic Compounds Extracted from Leaves of Majorana syriaca Growing Wild in Palestine

Abstract

Chemical variability in the essential oil from leaves of individual plants of Majorana syriaca (common names Syrian marjoram, zaatar, zahtar) plants growing wild at various locations in Palestine were analyzed using a static headspace gas chromatography mass spectrometry (HS-GC/MS). Although Palestine represents a relatively small geographical area, a wide range of variations in oil characteristics were observed, indicating the Palestinian region as an important center of diversity. Essential oil yield was based on steam distillation of air-dried leaves ranged from 10.5 to 54 mg g−1. The major oil constituents, α-phellandrene (1.62–8.13%), α-pinene (1.22%–4.61%), β-myrcene (0.5%–11%), m-cymene (1.86%–8.61%), p-cymene (8.44%–48.6%), γ-terpinene (11.96%–30.8%), thymol (0.26%–11.6%), and carvacrol (0.65%–21.7%), were identified throughout the harvesting period. An analysis of phenolic compounds revealed that wild growing Majorana syriaca could be characterized by the dominant presence of carvacrol. Conversely, water irrigation has showed a prominent effect on the thymol isomer production. Distribution of these isomers can be used as marker to distinguish wild from cultivated Majorana syriaca.