Origanum syriacum Essential Oil Chemical Polymorphism According to Soil Type

Abstract

Background: Origanum syriacum L. is an aromatic plant growing wild in Lebanon. This species is highly used in Lebanese traditional medicine and is a staple food in Lebanese gastronomy. Due to the over-harvesting, this species has become a cultivated crop rather than being collected from the wild. This study aims to evaluate the chemical polymorphism according to soil type. Methods: Plant samples were cultivated in different soil types including manure, potting mix, professional agriculture mixture, vegetable compost, nursery soils, and natural agricultural soil inoculated with arbuscular mycorrhizal fungi. After 16 weeks of culture, fresh shoot biomass was measured. Root colonization rate was evaluated and foliar biomasses were used for essential oil (EO) extraction. EO yield was calculated and the identification of the main chemical compounds of EO samples was performed by gas chromatography (GC) and gas chromatography–mass spectrometry (GC/MS). Results: Our findings revealed that the soil type affects the O. syriacum chemotype. Indeed, the EO samples could be divided into two groups: thymol chemotype group including manure and vegetable compost soils and non-sterilized non-inoculated EO samples, and the thymol/carvacrol chemotype including potting mix, professional agriculture mixture, nursery mixture, sterilized non-inoculated, non-sterilized inoculated, and sterilized inoculated EO samples. These results showed that manure and vegetable compost soils promoted thymol synthesis, whereas potting mix, professional agriculture mixture, and nursery mixture soils were thymol/carvacrol chemotype. Moreover, mycorrhizal inoculation increased carvacrol and reduced thymol productions in comparison to non-inoculated conditions. Additionally, mycorrhizal inoculation showed significant enhancements in mycorrhizal rates and shoot biomass production with respect to the non-sterilized soil. Conclusions: These variations confirm the influence of the edaphic conditions on the chemical components biosynthesis pathways of oregano plants. The results of this investigation could be used for determining optimal soil type, leading to a good quality herb production.

Variation of Secondary Metabolite Profile of Zataria multiflora Boiss. Populations Linked to Geographic, Climatic, and Edaphic Factors

“…Also, a correlation between higher EO yields at decreasing altitudes was found in Origanum vulgare (Giuliani et al, 2013). Notwithstanding the effect of geographical condition, EO content and EO constituents can be affected by edaphic factors and climatic conditions, for example, the soil type affects Origanum syriacum chemotype (El-Alam et al, 2019). In our study EO yield showed a highly significant positive correlation with temperature, pH value, and Ca.…”

Comparative Chemical Profiles of the Essential Oils from Different Varieties of Psidium guajava L.

“…Therefore, this chemical polymorphism of the studied varieties supports that these varieties could be considered as genotypes of P. guajava . This phenomenon is known to exist for other species such as Thymus carnosus [ 23 ], Salvia fruticose [ 20 ], Calotropis procera [ 17 ], Origanum libanoticum [ 24 ], Origanum syriacum [ 20 ], and Cinnamomum osmophloeum [ 22 ]. The exogenous factors such as precipitation, light, season, altitude, and soil characteristics can modify either the qualitative or quantitative amounts of the chemical compounds in the EOs [ 18 , 19 , 29 , 33 ].…”

“…In addition, various endogenous factors such as anatomical, physiological, and genetic characteristics can modify either the qualitative or quantitative amounts of the EOs’ chemical compounds [ 17 , 18 , 19 ]. Chemical polymorphism is a phenomenon wherein the same species show variation in the chemical composition of the bioactive compounds [ 20 , 21 ]. This phenomenon is well known in the EOs of various plants [ 20 , 22 , 23 , 24 ].…”

“…Chemical polymorphism is a phenomenon wherein the same species show variation in the chemical composition of the bioactive compounds [ 20 , 21 ]. This phenomenon is well known in the EOs of various plants [ 20 , 22 , 23 , 24 ]. The study of the plants’ variations in chemotypes is essential from a taxonomic point of view, as well as for agronomic and pharmacological applications [ 6 , 25 ].…”

Origanum syriacum L. (Za’atar), from Raw to Go: A Review

“…The major components of O. syriacum essential oil are thymol, carvacrol, sabinene hydrate, γ-terpinene, and p-cymene. Many factors can affect plants’ essential oil, including genotype, geographical location, altitude, harvesting time, vegetative stage, plant part, soil, drying and storage conditions, extraction method, and others [ 15 ]. O. syriacum has been used in folk medicine, especially in Arab countries [ 14 ].…”