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. KEYWORDS: herbaromatic plantmedicinal plantwild thyme Origanum syriacum Origanum maru

BACKGROUND:A comparative analysis by using static headspace (HS) and steam distillation (SD) GC-MS of the volatile and the semi-volatile secondary metabolites from leaves of cultivated Majorana syriaca.METHODS:The essential oils endogenous to cultivated thyme were isolated and identified by HS-GC-MS technology and compared to those from SD-GC-MS.RESULTS:The HS-GC-MS results showed that the Palestinian cultivated thyme is rich in monoterpene hydrocarbons and phenolic monoterpenes such as alpha-phellandrene, alpha-pinene, beta-myrcene, m-cymene, p-cymene, gamma-terpinene, thymol and carvacrol. In all the samples gamma-terpinene, p-cymene, thymol and carvacrol were the most abundant compounds.CONCLUSIONS:HS and SD-GC-MS have proved that most of the cultivated thyme samples examined has thymol isomer as the major phenolic constituent.

Majorana syriaca (Zaatar in Arabic), belonging to the mint family, Labiates, is cultivated widely and grows wild in the mountains of Palestine between the months April to August. In order to determine the secondary metabolites from wild leaves of Palestinian M. syriaca, comparative analysis by static headspace (HS) and steam distillation (SD) GC-MS was used. Among the samples examined, the major constituents identified varied greatly throughout the different harvesting periods. Headspace revealed major volatiles and semi-volatiles of alpha-pinene, beta-myrecene, o-cymene, p-cymene, gamma-terpinene, thymol, and carvacrol. We found that the most abundant monoterpenes, i.e. gamma-terpinene and p-cymene were decreased in the month of May since they are the biogenetic precursors (via enzymic hydroxylation) of the phenolic terpenes, thymol and carvacrol. The harvesting time, location and the thyme type (i.e., wild) affects the yield of essential oils as reflected by normal steam distillation.

Three different unifloral Palestinian honey samples that originate from Thymus capitatus, Thymelaea hirsuta, and Tolpis virgata were analyzed by using Headspace-Solid Phase Microextraction Gas Chromatography–Mass Spectrometry (HS-SPME-GC–MS). The analysis performed exhibited chromatographic profiles that are characteristics for each type of examined honey. Therefore, the proposed analytical procedure demonstrated a rapid characterization method for the analysis of these types of honeys, by revealing the presence or absence of certain organic volatile constituents. A variety of volatiles, particularly phenols, aldehydes, ketones, acids, and alcohols were detected in these types of honeys. The compounds present in each specific honey offer a marker that can be utilized in relating a given honey to its floral origin. Thymus capitatus honey showed six marker compounds: 1,3-diphenyl-2-propanone, (3-methylbutyl)benzene, 3,4,5-trimethoxy benzaldehyde, 3,4-dimethoxy benzaldehyde, vanilline, and thymol. Thymelaea hirsuta honey is characterized by the presence of a group of alcohols and phenols particularly benzene propanol, benzylalcohol, nonanol, hexanol and 4-methoxyphenol. Tolpis virgata hooney, however, has two marker compounds 3,5-dihydroxytoluene, and tridecane.