Chemometric Tools to Highlight the Variability of the Chemical Composition and Yield of Lebanese Origanum syriacum L. Essential Oil

Phytochemical Profile, GC-MS Profiling and In Vitro Evaluation of Some Biological Applications of the Extracts of Origanum syriacum L. and Cousinia libanotica D.C

Indigenous to Lebanon, Origanum syriacum L. and Cousinia libanotica D.C. are notable plants in the Middle East, with O. syriacum known for its aromatic qualities and C. libanotica being less explored. Both plants have a significant role in traditional medicine for treating various ailments. This study aimed to evaluate the phytochemical composition and biological properties of the extracts from these plants. The extracts were obtained through cold maceration with solvents of increasing polarity. The ethyl acetate extract of O. syriacum exhibited the highest total polyphenol content. High-performance liquid chromatography (HPLC) identified fifteen compounds in both C. libanotica and O. syriacum extracts, whereas gas chromatography-mass spectrometry (GC-MS) analysis unveiled 179 volatile compounds. Notably, the O. syriacum-MeOH extract showed moderate antioxidant activity. Both plants' methanolic extracts demonstrated significant anti-Alzheimer's potential. The O. syriacum-dichloromethane and C. libanotica-cyclohexane extracts displayed the highest cytotoxicities against the HCT-116 cell line. For anti-proliferative activity against the Caco-2 cell line, the O. syriacum-methanol and C. libanotica-cyclohexane extracts were the most effective. This study provides valuable insights into the phytochemistry and potential therapeutic applications of extracts from these two oriental plant species.

Biomass, Essential Oil Yield, and Composition of Marjoram as Influenced by Interactions of Different Agronomic Practices under Controlled Conditions

Origanum marjorana L. has been valued for centuries for its flavoring attributes and therapeutic properties. The growing demand for its various applications necessitates optimizing agronomic practices for its production. A glasshouse pot trial was conducted to identify optimum agronomic practices for increased herbage and oil yield, as well as oil quality. The effects of varying air temperature regimes (low, medium, and high levels), irrigation (low, medium, and high levels), nitrogen fertilizer application (N = 100, 150, and 200 kg/ha), and soil type (sandy loam, sandy clay loam, and loamy sand) on the productivity of marjoram plants were investigated. The results showed an increase in plant growth and herbage yield as well as chlorophyll content under conditions of high air temperature, low irrigation, and moderate to high nitrogen level applied to sandy loam soil, with an increase in oil yield with loamy sand soil. The major compounds observed in marjoram essential oil were terpinene-4-ol (22.63-36.72%) and (Z)-β-terpineol (6.85-16.60%), in which terpinene-4-ol was not found to be within the International Organization for Standardization (ISO) limits of acceptability while (Z)-β- terpineol had no reference limits available. A promising performance of marjoram cultivation under high regimes of air temperature (16.7 to 36.6 °C), nitrogen fertilization (200 kg ha^-1 N), and low irrigation (up to 60% soil water depletion from field capacity) on sandy loam soils was demonstrated for improved crop productivity.

Volatile Oil Components of Laurel (Laurus nobilis L.) Leaves Obtained from Plants Cultivated under Salinity Stress Conditions

Laurel (Laurus nobilis L.) is a strict endemic species of natural vegetation of the Mediterranean region, which is known for its medicinal, aromatic, forestry, ornamental and culinary properties. This species produces valuable essential oil (EO). The content of EO and its composition depend on different factors, e.g., genetic, cultural practices and environmental conditions. Among these, salt stress is a major limiting factor, which affects almost all plant functions. Similar to essential oils (EOs), biotic and abiotic stresses may stimulate or inhibit the emission of volatile compounds (VCs) in plant materials, suggesting that these substances can be responsible on stress defense strategies. Therefore, an experiment was conducted to assess the effect of different NaCl concentrations (0, 50, 100 and 150 mM) of the irrigation water on VCs of laurel leaves. Our results showed that salt stress affected the volatile metabolites compounds, mainly the major ones. For instance, 1,8-cineole and linalool were negatively affected by high salinity levels, while the opposite was observed for α-terpenyl acetate and methyl eugenol. The proportion of grouped compounds of laurel VCs also differed among the studied treatments. The relative content of oxygenated monoterpenes and monoterpene hydrocarbons, respectively the first and the second largest groups, decreased with increasing NaCl concentration. Differently, the relative amount of sesquiterpene hydrocarbon group increased, especially at 100 mM NaCl. These findings indicate that the cultivation of laurel in marginal lands, characterized by high salinity or low-quality water, must be carefully evaluated because it significantly varies the quality of its products.

Prospects for using Origanum Syriacum (L.) as a source of antimicrobial agents

Origanum syriacum (O. syriacum) (L.) belongs to Group B of the genus Origanum from (Lamiaceae), which is rich in essential oils that exhibit antimicrobial efficacy, anti-inflammatory efficacy, antioxidant activity, and antitumor efficacy. These processing activities are because of its richness in carvacrol and Thymol. In this article, we will focus on O. syriacum, discussing the antimicrobial efficacy for its essential oil and extracts, in addition, cast light on mechanism of essential oil antimicrobial action. This study was conducted from March 2019 to February 2021. We have analyzed the results of studies on antimicrobial efficacy of a plant O. syriacum in the PubMed, Google Scholar, Elsevier over the past 15 years using keywords. O. syriacum essential oil and its extracts have an extensive antimicrobial efficacy give it a great importance in pharmaceutical and medical purposes.

Effect of geographical origin on yield and composition of cone essential oils of Cedrus libani A. Rich. growing in Lebanese protected areas and variability assessment in comparison with literature survey

Gas chromatography-mass spectrometry analysis together with principal component analysis revealed that geographical origin influenced the yield and composition of the essential oils (EOs) extracted by hydrodistillation performed for 3 h using a Clevenger-type apparatus, from the cones of Cedrus libani A. Rich., growing wild at four Lebanese natural reserves and protected areas: Bsharri, Chouf, Ehden, and Tannourine, and from a cultivated cedar growing in Qartaba. Essential oil chemical variability established between the different studied provenances suggested the involvement of abiotic factors such as geographical conditions, cultivation conditions, soil composition, and environmental factors in the chemical polymorphism of C. libani cones EOs. α-Pinene/β-pinene characterized Ehden (β-pinene 35.6%/α-pinene 27.7%), Chouf (α-pinene 37.3%/β-pinene 26.1%), Bsharri (α-pinene 27.7%/β-pinene 21.4%), and Tannourine (α-pinene 25.1%/β-pinene 16.0%) samples, whereas Qartaba EO was distinguished by the dominance of myrcene (30.6%), α-pinene(26%), and limonene (14.1%). Comparison with the existing literature reinforced the chemical variability of C. libani EOs. This current study helped the estimation of a best harvest location for a good EO quality production, resource optimization, and pharmacological properties evaluation, according to the market demand.

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

The interest in za'atar has increased in recent years due to its economic, cultural, and functional importance. The traditional za'atar mix made from dried Origanum syriacum is now a demanded product nationally and internationally. Air-drying at low temperatures can preserve za'atar quality traits better than other techniques such as oven-drying. The Palestinian za'atar market has the potential to develop and increase its value. However, it is facing many challenges. Another valuable product of za'atar is essential oil. Za'atar essential oil quantity and quality are affected by many factors including geographical location, cultivation, harvesting season, soil, extraction method, temperature, and others. These factors interact with za'atar and with each other; therefore, some factors are more effective than others and further research is needed to determine the optimum condition for producing and obtaining za'atar essential oil. Antimicrobial and antioxidant activities are the main functionalities of za'atar essential oil that are behind its medicinal importance. One hundred and twenty-one compounds have been identified in za'atar essential oil. The most common compounds are thymol, γ-terpinene, carvacrol, and α-pinene. The variation in the composition among za'atar essential oil samples results from the different conditions of the studies during za'atar growth as well as essential oil extraction.

Evaluation of the in vitro anti-inflammatory and cytotoxic potential of ethanolic and aqueous extracts of Origanum syriacum and Salvia lanigera leaves

In this study, the chemical compositions of the ethanolic and aqueous extracts of the leaves of Origanum syriacum and Salvia lanigera were identified based on GC-MS spectrometric analyses. The in vitro anti-inflammatory potential of the different extracts was evaluated by determining the membrane stabilization of human red blood cells and the percent inhibition of the COX1/2, 5LOX, and sPLA2-V enzymes. Both ethanolic extracts showed maximum membrane stabilization (≤ 91%, at 100 μg/mL) compared to the aqueous extracts (≤ 45%) and the reference drug diclofenac sodium (90.75%). The membrane-stabilizing effects of the ethanolic extracts could be directly correlated to their anti-inflammatory activity. While both ethanolic fractions strongly inhibited the 5LOX and COX-1 enzymes at 100 μg/mL, only the O. syriacum ethanolic extract selectively inhibited sPLA2-V (99.35%, at 50 μg/mL). The differences in the pharmacological efficiencies of the different extracts could be attributed to the variation in their chemical compositions particularly the content of oxygenated monoterpenoids. Additionally, none of the ethanolic extracts demonstrated cytotoxicity to human colorectal cancer cell lines (HCT-116 and Lovo), even at the highest concentration tested (200 μg/mL). The safe profiles of these extracts towards the tested cell lines may be due to the absence of the toxic phthalic acid ester substances. Collectively, these findings clearly suggest that the studied ethanolic extracts of O. syriacum and S. lanigera can be considered interesting candidates for the treatment of human inflammatory diseases related to oxidative stress and microbial infections.

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

Geographic location and connected environmental and edaphic factors like temperature, rainfall, soil type, and composition influence the presence and the total content of specific plant compounds as well as the presence of a certain chemotype. This study evaluated whether geographic, edaphic, and climatic information can be utilized to predict the presence of specific compounds from medicinal or aromatic plants. Furthermore, we tested rapid analytical methods based on near infrared spectroscopy (NIR) coupled with gas chromatography/flame ionization (GC/FID) and gas chromatography/mass spectrometry (GC/MS) analytical methods for characterization and classification metabolite profiling of Zataria multiflora Boiss. populations. Z. multiflora is an aromatic, perennial plant with interesting pharmacological and biological properties. It is widely dispersed in Iran as well as in Pakistan and Afghanistan. Here, we studied the effect of environmental factors on essential oil (EO) content and the composition and distribution of chemotypes. Our results indicate that this species grows predominantly in areas rich in calcium, iron, potassium, and aluminum, with mean rainfall of 40.46 to 302.72 mm·year^-1 and mean annual temperature of 14.90°C to 28.80°C. EO content ranged from 2.75% to 5.89%. Carvacrol (10.56-73.31%), thymol (3.51-48.12%), linalool (0.90-55.38%), and p-cymene (1.66-13.96%) were the major constituents, which classified 14 populations into three chemotypes. Corresponding to the phytochemical cluster analysis, the hierarchical cluster analysis (HCA) based on NIR data also recognized the carvacrol, thymol, and linalool chemotypes. Hence, NIR has the potential to be applied as a useful tool to determine rapidly the chemotypes of Z. multiflora and similar herbs. EO and EO constituent content correlated with different geographic location, climate, and edaphic factors. The structural equation models (SEMs) approach revealed direct effects of soil factors (texture, phosphor, pH) and mostly indirect effects of latitude and altitude directly affecting, e.g., soil factors. Our approach of identifying environmental predictors for EO content, chemotype or presence of high amounts of specific compounds can help to select regions for sampling plant material with the desired chemical profile for direct use or for breeding.

Marjoram Relaxes Rat Thoracic Aorta Via a PI3-K/eNOS/cGMP Pathway

Despite pharmacotherapeutic advances, cardiovascular disease (CVD) remains the primary cause of global mortality. Alternative approaches, such as herbal medicine, continue to be sought to reduce this burden. Origanum majorana is recognized for many medicinal values, yet its vasculoprotective effects remain poorly investigated. Here, we subjected rat thoracic aortae to increasing doses of an ethanolic extract of Origanum majorana (OME). OME induced relaxation in a dose-dependent manner in endothelium-intact rings. This relaxation was significantly blunted in denuded rings. N(ω)-nitro-l-arginine methyl ester (L-NAME) or 1H-[1,2,4]oxadiazolo[4,3,-a]quinoxalin-1-one (ODQ) significantly reduced the OME-induced vasorelaxation. Cyclic guanosine monophosphate (cGMP) levels were also increased by OME. Moreover, wortmannin or LY294002 significantly reduced OME-induced vasorelaxation. Blockers of ATP-sensitive or Ca²⁺-activated potassium channels such as glibenclamide or tetraethylamonium (TEA), respectively, did not significantly affect OME-induced relaxation. Similarly, verapamil, a Ca²⁺ channel blocker, indomethacin, a non-selective cyclooxygenase inhibitor, and pyrilamine, a H1 histamine receptor blocker, did not significantly modulate the observed relaxation. Taken together, our results show that OME induces vasorelaxation via an endothelium-dependent mechanism involving the phosphoinositide 3-kinase (PI3-K)/ endothelial nitric oxide (NO) synthase (eNOS)/cGMP pathway. Our findings further support the medicinal value of marjoram and provide a basis for its beneficial intake. Although consuming marjoram may have an antihypertensive effect, further studies are needed to better determine its effects in different vascular beds.

Origanum syriacum Essential Oil Chemical Polymorphism According to Soil Type

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.

Chemical Variability of the Essential Oil of Origanum ehrenbergii Boiss. from Lebanon, Assessed by Independent Component Analysis (ICA) and Common Component and Specific Weight Analysis (CCSWA)

Origanum ehrenbergii Boiss., an endemic plant to Lebanon, is widely acknowledged in Lebanese traditional medicine. The aim of the present study was to evaluate the influence of the drying method, region, and time of harvest on yield and chemical composition of O. ehrenbergii essential oils (EOs). Plants were harvested monthly throughout 2013 and 2014, from two different regions, Aabadiye and Qartaba, then dried using two drying methods: lyophilization and shade-drying at 4 °C. EO was extracted by hydrodistillation and analyzed by GC/MS. GC-MS data, combined with independent component analysis (ICA) and common component and specific weight analysis (CCSWA), showed that drying techniques, region of harvest, and soil composition have no effect on the chemical composition of O. ehrenbergii EOs. Of the factors analyzed, only harvesting time affected the EO composition of this species. High and stable amounts of carvacrol, associated with reliable antimicrobial activities, were detected in material harvested between March and October. EOs obtained from plants harvested in Aabadiye in January and February showed high amounts of thymoquinone, related to anti-inflammatory and cytotoxic effects. The use of ICA and CCSWA was proven to be efficient, and allowed the development of a discriminant model for the classification of O. ehrenbergii chemotype and the determination of the best harvesting time.

Investigation of Origanum libanoticum Essential Oils Chemical Polymorphism by Independent Components Analysis (ICA)

The essential oils obtained from Origanum libanoticum Boiss., a plant endemic to Lebanon, were analyzed by GC/MS. Seventy compounds were identified, covering till 99.8% of the total oil composition. All samples were p-cymene and/or β-caryophyllene chemotype, with variable percentage of other compounds such as α-pinene, myrcene, α-phellandrene, limonene, etc. Compared to traditional drying method, lyophilized samples provided the highest essential oil (EO) yields and yields were higher at flowering stage (Chouwen: 0.33% in 2013 and 0.32% in 2014; Qartaba: 0.27% in 2013 and 0.37% in 2014). According to independent components analysis (ICA), date and site of harvest, altitude and drying technique had no effect on the variation of O. libanoticum EO chemical composition. An annual variation of EOs composition was observed since a particular variation in some major components concentration was revealed monthly and annually between 2013 and 2014.

Phytochemical screening and antityrosinase activity of carvacrol, thymoquinone, and four essential oils of Lebanese plants

OBJECTIVE

In our study, we aim to explore the ability of four essential oils (EO) of Lebanese plants to inhibit the tyrosinase activity and to correlate their efficiency level to their phytochemical compositions.

METHODS

The EO have been extracted by hydrodistillation using a Clevenger apparatus and have been studied by GC-MS analysis. Active compounds of Origanum species were identified and antityrosinase activities of EO and active molecules (carvacrol and thymoquinone) have been tested in tubo.

RESULTS

Antityrosinase activities were obtained as follows: EO of Origanum syriacum (80.41% ± 2.00%), EO of Origanum ehrenbergii (45.33% ± 2.20%), EO of Salvia fruticosa (14.62% ± 2.30%), EO of Calamintha origanifolia (16.51% ± 5.80%), Carvacrol (56.55% ± 3.10%), and Thymoquinone (19.49% ± 1.50%).

CONCLUSION

Origanum essential oils resulted in the highest antityrosinase activity due to their high content in carvacrol. However, when present together with carvacrol, thymoquinone decreases the efficiency of carvacrol, which is the case of O. ehrenbergii essential oil. Thus, for improved antityrosinase activity, O. syriacum and O. ehrenbergii should be harvested during flowering stage where carvacrol is present at its highest dosage and thymoquinone at its lowest.

Influence of Environmental Factors on Essential Oil Variability in Origanum compactum Benth. Growing Wild in Morocco

The present study aimed to evaluate the influence of environmental factors on essential oils (EOs) composition of Origanum compactum populations sampled all over the distribution area of the species in Morocco, and to determine the extent of the chemical profiles throughout the geographical distribution of the species. The chemical compositions were submitted to canonical correlation analysis and canonical discriminant analysis that indicated a significant relationship between oil components and some environmental factors. According to their chemical composition and edapho-climatic characteristics, two major groups of populations were differentiated. The first group was composed of samples growing in regions with humid climate, clayey, sandy, and alkaline soils. These samples showed high thymol, α-terpineol, linalool, and carvacryl methyl oxide content. The second group consisted of plants belonging to semi-arid climate, and growing at high altitudes and silty soils. These samples were characterized by high carvacrol, α-thujene, α-terpinene, and myrcene content. However, populations exposed to sub-humid climate, appeared less homogeneous and belong mainly either to the first or second group. A significant correlation between some edaphic factors (pH, K₂ O content, soil texture) and the EOs yield of O. compactum plants was evidenced. In spite of the correlation obtained for the oil composition with edapho-climatic factors and the variance explained by the environmental data set, the observed EO diversity might be also genetically determined.