High Resolution Melting (HRM) Genotyping in the Genus Origanum: Molecular Identification and Discrimination for Authentication Purposes.

Origanum L. (Lamiaceae) is an important genus of medicinal and aromatic plants used since ancient times as culinary herbs and remedies in traditional medicine. Although it is a relatively small genus, intra-generic species delineation, as well as its inter-generic relationships within tribe Mentheae, are still poorly understood. High resolution melting (HRM) analysis, coupled with microsatellite markers (SSRs), could facilitate the molecular identification and characterization of certain genotypes more efficiently and relatively faster when compared to other analytical methods. In this study, 38 Origanum samples corresponding to six Origanum taxa (O. dictamnus, O. majorana, O. onites, O. scabrum, O. sipyleum, and O. vulgare subsp. hirtum) were analyzed, using six microsatellite loci. Our goal was to molecularly identify and discriminate among the selected samples and to evaluate the ability of the HRM technique as an analytical tool for the discrimination of Origanum species from Greece. The temperature-shifted melting curves produced by the HRM analysis, resulted in 98 unique HRM profiles, which enabled the discrimination of the Origanum genotypes studied. According to the similarity dendrogram based on the HRM profiles, six unique clusters were formed, each one corresponding to a single taxon. In conclusion, HRM genotyping provided a fast, cost-effective method, well suited for the molecular characterization and identification of Origanum taxa and for the authentication of the original genetic material.

Influence of lipids and proteins amounts and pH values on the inhibitory effects of Origanum vulgare L. essential oil against Escherichia coli and Salmonella Typhimurium

Origanum vulgare L. (OVEO) essential oil has been considered a candidate antimicrobial for use in food conservation systems. However, studies on the influence of concomitant variations of different food components or physicochemical parameters on the antibacterial properties of OVEO are scarce. This study assessed the influence of concomitant variations in amounts of proteins - PTN (4.0, 6.0 or 8.0 g/100 mL) and lipids - LIP (3.75, 5.0 or 6.25 g/100 mL) and pH values (5.0, 5.5 or 6.0) in cultivation medium on the inhibitory effects of OVEO against Escherichia coli (EC) and Salmonella Typhimurium (ST). Lowest minimum inhibitory concentration values of OVEO against EC and ST were observed in media with the highest LIP amounts regardless the PTN amount and pH value. In absorbance based microtiter plate assay (MPA), for both EC and ST, OVEO caused the lowest Grmax values in medium containing the highest LIP and PTN amounts and lowest pH value. Highest Grmax values for EC and ST were observed in medium containing the lowest LIP and PTN amount and highest pH value. Grmax values estimated from viable counts of EC and ST in tested media with OVEO confirmed bacterial growth behavior similar to that observed in MPA. Overall, the LIP amount in media was as the most influential factor to enhance the antibacterial effects of OVEO. These results indicate that the concomitant influence of LIP and PTN amounts and pH values on the antibacterial effects of OVEO should be considered for optimizing its antimicrobial efficacy in foods.

Composition, antibacterial, antioxidant and antiproliferative activities of essential oils from three Origanum species growing wild in Lebanon and Greece.

The essential oils from Origanum dictamnus, Origanum libanoticum and Origanum microphyllum were analysed by GC-MS, finding carvacrol, p-cymene, linalool, γ-terpinene and terpinen-4-ol as major components. The antioxidant activity by the DPPH and FRAP tests and the antiproliferative activity against two human cancer cell lines, LoVo and HepG2, were investigated, showing that the essential oil of O. dictamnus was statistically the most inhibitory on both the cell lines, while all the oils exerted a weak antioxidant activity. Furthermore, the samples were tested against 10 Gram-negative and Gram-positive bacteria; all the oils were active on Gram-positive bacteria but O. dictamnus essential oil was the most effective (MIC = 25-50 µg/mL), showing also a good activity against the Gram-negative Escherichia coli (MIC = 50 µg/mL). Data suggest that these essential oils and particularly O. dictamnus oil could be used as valuable new flavours with functional properties for food or nutraceutical products.

Optimization of carvacrol, rosmarinic, oleanolic and ursolic acid extraction from oregano herbs (Origanum onites L., Origanum vulgare spp. hirtum and Origanum vulgare L.).

The aim of our study was to increase the extraction efficiency of carvacrol, rosmarinic, oleanolic and ursolic acid from the different species of oregano herbs (Origanum onites L., Origanum vulgare spp. hirtum and Origanum vulgare L.). Various extraction methods (ultrasound-assisted, heat-reflux, continuous stirring, maceration, percolation) and extraction conditions (different solvent, material:solvent ratio, extraction temperature, extraction time) were used, and the active substances were determined by HPLC. The lowest content of carvacrol, rosmarinic, oleanolic and ursolic acid was obtained by percolation. During heat-reflux extraction, the content of active substances depended on the solvent used: ethanol/non-aqueous solvent (glycerol or propylene glycol) mixture was more effective compared with ethanol alone. The results showed that for each species of oregano the most optimal extraction method should be selected to maximize the content of biologically active substances in the extracts.

Natural control of corn postharvest fungi Aspergillus flavus and Penicillium sp. using essential oils from plants grown in Argentina.

The objective in this study was to evaluate the antifungal activity of essential oils from native and commercial aromatic plants grown in Argentina against corn postharvest fungi and to link the essential oil bioactivity with lipid oxidation and morphological changes in fungus cell membrane. Essential oil (EO) of oregano variety Mendocino (OMen), Cordobes (OCor), and Compacto (OCom), mint variety Inglesa (Mi), and Pehaujo (Mp), Suico (Sui); rosemary (Ro), and Aguaribay (Ag) were tested in vitro against 4 corn fungi: A. flavus (CCC116-83 and BXC01), P. oxalicum (083296), and P. minioluteum (BXC03). The minimum fungicidal concentration (MFC) and the minimum inhibitory concentration (MIC) were determined. The chemical profiles of the EOs were analyzed by GC-MS. Lipid oxidation in cell membrane of fungi was determined by hydroperoxides and related with essential oil antifungal activity. The major compounds were Thymol in OCor (18.66%), Omen (12.18%), and OCom (9.44%); menthol in Mi and Mp; verbenone in Sui; dehydroxy-isocalamendiol in Ag; and eucaliptol in Ro. OCor, Omen, and OCom showed the best antifungal activity. No antifungal activity was observed in Ag and Ro EO. The hydroperoxide value depended on the fungi (P < 0.001) and the antimicrobial agent (P < 0.001).Membrane lipids were oxidized by Sui EO in A. flavus BXC01 and A. flavus CCC116-83 (0.021 and 0.027 meqO2 /kg, respectively). The results suggest that the EOs of OCor, OMen, OCom, Mi, Mp, and Sui grown in Argentina can be used as natural alternatives to control fungi that produce mycotoxin in maize.

Determinação de óleos essenciais de alfavaca (Ocimum gratissimum L. ), orégano (Origanum vulgare L. ) e tomilho (Thymus vulgaris L.) / Determination of essential oils of basil (Ocimum gratissimum L. ), oregano (Ocimum gratissimum L. ) and thyme (Thymus vulgaris L.)

O presente trabalho teve como objetivo a caracterização de plantas frescas e secas (comerciais) de alfavaca, orégano e tomilho, a obtenção dos óleos essenciais através do método de arraste a vapor e a quantificação dos compostos químicos por CG/EM. As plantas frescas e as secas comerciais foram submetidas às análises de umidade, extrato etéreo, proteína, fibra bruta, cinzas, extrato não nitrogenado, valor calórico, teor de óleo essencial e identificação dos compostos majoritários através da cromatografia gasosa-espectrometria de massas. Dentre a caracterização obtida os resultados na base seca mostraram-se promissores, sendo o teor de proteína e de cinzas na alfavaca seca comercial com 17,34 g 100 g-1 e 8,12 g 100 g-1, respectivamente; a fibra bruta no orégano seco comercial com 15,65 g 100 g-1; o extrato etéreo, o extrato não nitrogenado e o valor calórico no tomilho seco comercial com 9,30 g 100 g-1, 52,72 g 100 g-1 e 356,74 Kcal 100 g-1, respectivamente. Obteve-se o maior rendimento de óleo essencial na alfavaca seca comercial com 1,02%, enquanto a alfavaca fresca apresentou o menor rendimento, com apenas 0,13%. Na alfavaca fresca encontrou-se 87,38% de eugenol e 6,27% de timol, enquanto na alfavaca seca comercial observou-se redução no eugenol (71,12%) e aumento do timol (13,28%). No orégano fresco foram quantificados quatro picos o γ-terpineno (33,45%), 4-terpineol (25,59%), timol (14,21%) e carvacrol (2,30%). Já no óleo essencial de orégano seco comercial houve redução no γ-terpineno (28,73%) e aumento no 4-terpineol (27,58%), timol (19,71%) e carvacrol (3,67%). No óleo essencial do tomilho fresco foram quantificados três picos o borneol (66,66%), timol (13,41%) e linalol (3,24%). Por outro lado, no óleo essencial do tomilho seco comercial houve redução no borneol (37,90%) e aumento no timol (20,61%) e linalol (10,34%). Pode-se concluir que as folhas secas comerciais analisadas de alfavaca, orégano, e tomilho apresentam potencial para o enriquecimento dos alimentos ou para a obtenção dos óleos essenciais.

This study aimed to characterize commercial fresh and dry medicinal plants (basil, oregano and thyme), to obtain essential oil by the steam distillation method and to quantify chemical compounds by means of GC/MS. The fresh and dry plants were subjected to the following analyses moisture, ether extract, protein, crude fiber, ash, non-nitrogenous extract, caloric value, essential oil content and identification of major compounds by gas chromatography-mass spectrometry. Considering the obtained characterization, the following results on dry basis proved promising: protein and ash content in commercial dry basil with 17.34 g 100 g-1 and 8.12 g 100 g-1, respectively; crude fiber in commercial dry oregano with 15.65 g 100 g-1; ether extract, non-nitrogenous extract and caloric value in commercial dry thyme with 9.30 g 100 g-1, 52.72 g 100 g-1 and 356.74 Kcal 100 g-1, respectively. The highest essential oil yield was obtained for commercial dry basil with 1.02% and the lowest yield was obtained for fresh basil with only 0.13%. Chromatography indicated 87.38% eugenol and 6.27% thymol in fresh basil. For commercial dry basil, the chromatogram showed a reduction in eugenol (71.12%) and an increase in thymol (13.28%). Four peaks were quantified for fresh oregano the γ-terpinene (33.45%), 4-terpineol (25.59%), thymol (14.21%) and carvacrol (2.30%). For the essential oil of commercial dry oregano, there was a decrease in γ-terpinene (28.73%) and an increase in 4-terpineol (27.58%), thymol (19.71%) and carvacrol (3.67%). In the chromatogram of the essential oil of fresh thyme, three peaks were quantified: borneol (66.66%), thymol (13.41%) and linalool (3.24%). On the other hand, in the chromatogram of the essential oil of commercial dry thyme, there was a decrease in borneol (37.90%) and an increase in thymol (20.61%) and linalool (10.34%). It can be concluded that commercial dry leaves of basil, oregano and thyme are feasible to enrich foods or to obtain essential oils.

Chemical diversity in Indian oregano (Origanum vulgare L.).

The terpenoid composition of the essential oils of 17 different populations of Origanum vulgare L., collected from wild populations and subsequently grown under similar conditions in the sub-temperate region of the Western Himalaya, was studied. Analysis by GC (RI) and GC/MS allowed the identification of 51 components, representing 90.15 to 99.94% of the total oil. The two classes of the phenolic compounds and the monoterpenoids were predominant in all the essential oils. On the basis of the major constituents, i.e., marker compounds, and by comparison of the results with previous reports, new chemotypes could be identified. Principal component analysis was performed to determine the chemical variability within the different populations of O. vulgare collected and grown under similar conditions. Based on the marker compounds, six chemotypes with significant variations in their terpenoid profile were noticed within the 17 populations.

Dittany of Crete: a botanical and ethnopharmacological review.

Origanum dictamnus (Lamiaceae family), an endemic plant of the Greek island of Crete, is widely used as a traditional medicine since antiquity, all over Europe. The aim of the present review is to present comprehensive information of the plant's botanical taxonomy and morphology, as well as of the chemical constituents, biological and pharmacological research on O. dictamnus, which will be presented and critically evaluated. The paper also highlights particularly interesting aspects and common medicinal uses not previously described in the specific ethnobotanical literature. An increasing number of chemical and pharmacological studies have been reported recently, some of which strongly support its traditional medicinal uses against various illnesses such as sore throat, cough and gastric ulcer. A variety of compounds, including flavonoids, lipids and terpenoids (mainly carvacrol and thymol) have been identified from the plant. Current studies have showed that the extracts, the essential oil, as well as their active principles possess several pharmacological properties, like antimicrobial, antioxidant and anti-ulcer ones. The recent scientific data and the rich historical evidence of its medicinal uses could support further research as well as its use as a safe herbal medicinal product.

Biological and pharmacological activities of carvacrol and carvacrol bearing essential oils.

Oregano essential oils obtained from the genera Origanum, Thymus, Coridothymus, Thymbra, Satureja and Lippia are rich in carvacrol, a monoterpenic phenol isomeric with thymol. Turkey is the biggest exporter of oregano herb and oil to the world markets. Oregano is mainly used in food, spice and pharmaceutical industries. Carvacrol is responsible for the biological activities of oregano. Many diverse activities of carvacrol such as antimicrobial, antitumor, antimutagenic, antigenotoxic, analgesic, antispasmodic, antiinflammatory, angiogenic, antiparasitic, antiplatelet, AChe inhibitory, antielastase, insecticidal, antihepatotoxic and hepatoprotective activities and uses such as feed additive, in honeybee breeding and in gastrointestinal ailments have been shown. This paper highlights these activities and attempts to explain the possible in vivo mechanism of action of carvacrol.

Chemotaxonomy of aromatic plants of the genus Origanum via vibrational spectroscopy.

Fourier transformed-Raman (FT-Raman) and attenuated total reflection-infrared (ATR-IR) spectra of essential oils obtained from marjoram and oregano plants by hydrodistillation are presented. It is shown that the main components of the essential oils can be ascertained through both of these complementary techniques, using spectral information from the pure terpenoids. Spectroscopic analysis is based on the characteristic key bands of the individual volatile substances and therefore, in principle, these techniques allow us to discriminate between different essential oil profiles from individual oil plants of the same species (chemotypes). The combination of vibrational spectroscopy and hierarchical cluster analysis provides a fast, easy and reliable method for chemotaxonomy characterisation. The spectroscopic data presented here correlate very well with those found by gas chromatography (GC) analysis.

[Oregano: properties, composition and biological activity]. / El orégano: propiedades, composición y actividad biológica de sus componentes.

The oregano spice includes various plant species. The most common are the genus Origanum, native of Europe, and the Lippia, native of Mexico. Among the species of Origanum. their most important components are the limonene, gamma-cariofilene, rho-cymenene, canfor, linalol, alpha-pinene, carvacrol and thymol. In the genus Lippia, the same compounds can be found. The oregano composition depends on the specie, climate, altitude, time of recollection and the stage of growth. Some of the properties of this plant's extracts are being currently studied due to the growing interest for substituting synthetic additives commonly found in foods. Oregano has a good antioxidant capacity and also presents antimicrobial activity against pathogenic microorganisms like Salmonella typhimurium, Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis, among others. These are all characteristics of interest for the food industry because they may enhance the safety and stability of foods. There are also some reports regarding the antimutagenic and anticarcinogenic effect of oregano; representing an alternative for the potential treatment and/or prevention of certain chronic ailments, like cancer.