Lippia origanoides H.B.K. essential oil production, composition, and antioxidant activity under organic and mineral fertilization: Effect of harvest moment

Organic and mineral fertilization influence on biomass and essential oil production, composition and antioxidant activity of Lippia origanoides H.B.K.

Combining green manure and cattle manure to improve biomass, essential oil, and thymol production in Thymus vulgaris L.

Atriplex semibaccata R.Br. is a perennial halophyte that has received much attention for studies of revegetation of marginal lands in arid and semi-arid environments. It was, recently, demonstrated that there are no risks in terms of contamination of essential oil (EO) from growing plant on such land. Interest in exploring the antibacterial and antioxidant potential of A. semibaccata EO has consequently been renewed. The objective of this study was to investigate the chemical composition, as well as the antioxidant and antibacterial activities of A. semibaccata EO. The antibacterial activity was evaluated against native (drug-sensitive) and multidrug-resistant (MDR) bacteria by testing the EO alone and in combination with conventional antibiotics. The chemical composition of EO was analyzed by gas chromatography/mass spectrometry, 52 chemical compounds were identified, and 2-Methoxy-4-vinyl phenol (48.9%), benzaldehyde (6.7%), and benzyl alcohol (6.3%) were found to be the main constituents of EO. Furthermore, the antioxidant activity was evaluated using a 2,2-diphenyl-1-picrylhydrazyl reducing–scavenging test. The EO from this species possessed high antioxidant activity (938.65 μg TE/g EO). The antibacterial test demonstrated an inhibitory effect on six native and MDR bacterial strains. We found that Staphylococcus aureus (Gram+), Klebsiella pneumoniae (Gram−), and Escherichia coli (Gram−) were more sensitive than MDR strains, with an inhibition zone ranging from 11.16 mm to 12 mm. Moreover, the minimum inhibitory concentration ranged from 3.12 mg/mL to 6.25 mg/mL. The combination of gentamicin and EO revealed a high synergistic effect. The effect on S. aureus and K. pneumoniae showed lower fractional inhibitory concentration indices of 0.39 and 0.27, respectively. The results also revealed that A. semibaccata EO contained compounds with antibacterial potential against MDR bacteria, with antioxidant properties, and with a moderate synergistic effect in combination with gentamicin. The EO from A. semibaccata could be considered a new and potential source of natural antioxidant and antibacterial agents. These findings make A. semibaccata an excellent choice for the revegetation of marginal lands with the subsequent use of biomass for the production of EO with significant potential in the control of microbial infection.

The aim of this study was to establish whether the type of the agricultural system has any influence on the essential oil production and antioxidant activity of industrial cultivated Rosa damascena Mill. in the Rose valley, Bulgaria. Six private farms from Kazanlak (Rose) Valley, Southern Bulgaria were included in the study conducted in the period 2019–2020. The first three selected farms are designated within the conventional farming and the other three are certificated as organic farms. GC/FID and GC/MS analyses were performed; the contents of total polyphenols and flavonoids in the methanol extracts from rose petals were determined. Additionally, the antioxidant activity of rose extracts was evaluated by four reliable methods: 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2´-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS), ferric reducing antioxidant power (FRAP), and cupric reducing antioxidant capacity (CUPRAC) assays. The impact of the agricultural system on the essential oil composition and antioxidant activity was evaluated by ANOVA statistical analysis. The results obtained showed that organic farming produced essential oil with a higher linalool and geraniol content and lower β-citronellol + nerol concentrations than conventional farming. It was found that organic farming production demonstrated a better antioxidant activity evaluated by the three DPPH, ABTS, and CUPRAC methods according to the averaged data for two years, 806.82, 797.66 and 1534.40 mM TE/g dw versus 510.34, 521.94 and 917.48 mM TE/g dw for CF, respectively, with high statistical significance for the DPPH and ABTS analyses. Consequentially, the rose extracts from the organic farming accumulated more phenolic compounds that corresponded to the higher antioxidant potential of the organic roses.

Chemical composition, antioxidant and antibacterial activities of the essential oils isolated from Tunisian Thymus capitatus Hoff. et Link.

Eugenia uniflora, known as the "Brazilian cherry", is an economically important neotropical Myrtaceae in the cosmetics and pharmaceutical industries due the production of essential oils with antioxidant activity. On account of its significant genetic variability, genotype evaluations are needed in order to identify genetic features related to the essential oil production that meet the industry requirements. The main objective of the present study was to evaluate the yield, composition, and antioxidant activity of essential oils isolated from the leaves of 36 genotypes of E. uniflora. Essential oil samples were obtained by hydrodistillation, and their composition was determined by gas chromatography coupled with mass spectrometry. A variation of 0.22% to 1.68% in the essential oil yield was observed, in which 78 compounds, namely oxygenated sesquiterpenes, were identified. According to the cluster analysis of the major compounds, six groups were revealed. The observed diversity demonstrates the genetic variability of the species. Also, the antioxidant activity was affected by the composition of the essential oils, ranging from 176.66 to 867.57 µM TEAC.

In the present study, the essential oil and aroma compositions of Nepeta heliotropifolia (NH) and N. congesta subsp. cryptantha (NC) were determined by gas chromatography-mass spectrometry (GC-MS) and gas chromatography-flame ionization detector (GC/FID), and their phenolic compounds by liquid chromatography-tandem mass spectrometry (LC-MS/MS). In addition, antioxidant, cytotoxic, anticholinesterase, urease, and tyrosinase activities of essential oils obtained from NH and NC aerial parts and ethanol extracts prepared from different parts of NH and NC were investigated. The major constituent of water-distilled essential oils was found to be germacrene D (36.7% and 38.5%, respectively), and their main aroma component was eucalyptol (48.0% and 24.7%, respectively). Among the studied parts of NH and NC, their flowers extracts were found to be the richest in phenolic compounds and in which the most abundant compound was rosmarinic acid (8,909.91 and 4,317.20μg/g, respectively). NH and NC flower extracts exhibited also strong antioxidant activity in DPPH, ABTS, and CUPRAC assays. Among the tested samples, NH essential oil indicated the best cytotoxic effect against PDF, HT-29, and MCF-7 (IC50 52.34, 25.89, and 44.70μg/ml, respectively), and the highest butyrylcholinesterase (77.21±1.12% inhibition) and moderate acetylcholinesterase (41.36±0.69% inhibition) inhibitory activities. PRACTICAL APPLICATIONS: This is the first report on the essential oil and aroma compositions, the phenolic compounds, the antioxidant with total phenolic and flavonoid contents, cytotoxic, anticholinesterase, urease, and tyrosinase activities of Nepeta heliotropifolia and N. congesta subsp. cryptantha, except for their essential oil compositions. The reported results suggested that Nepeta heliotropifolia and N. congesta subsp. cryptantha flowers being rich in rosmarinic acid and having strong antioxidant potential, and NH essential oil possessing significant cytotoxic and butyrylcholinesterase inhibitory effect could be source for nutraceutical, food, and drug industries.

This work aimed to investigate the chemical composition, antioxidant, and antifungal activities of cumin essential oil (EO) grown under two climatic vegetation stages in Morocco namely Subhumid and Saharan. EO components were identified by gas chromatography coupled to tandem mass spectrometry and assessed for their antifungal and antioxidant activities. Results showed that major components of local cumin EO are cumin aldehyde (CA) (29.90±1.90%) γ-terpinene-7-al (10.63±2.18%), α-terpinene-7-al (11.85±0.68%), γ-terpinene-7-al (19.50±4.25%), p-menthatriene (8.28±4.14%), p-cymene (4.65±0.35%), limonene (2.78±1.03%), p-menth-2-en-7-ol trans (3.08±3.01%), β-pinene (0.58±0.58%), and β-phelandrene (1.30±0.25%), while 2-ethylidene-6-methyl-3,5heptadienal (6.80±±1.60%), α-proyl-benzenemethanol (3.07±0.76%), 1,4-p-menthadien-7-ol (2.87±0.82%), cumin alcohol (0.63±0.84%), and β-caryophyllene (0.47±0.62%) are specific to EO of imported cumin. Principal component analysis showed that the EO of local cumin is strongly correlated with CA and γ-terpinene, while imported cumin EO is strongly correlated with 2-Eth-6-methyl-3,5-heptadienal. The percentage of antioxidant activity of local cumin EO, as determined by the β-carotene bleaching test, revealed higher strength than that of EO extracted from imported cumin. The EO extracted from local cumin varieties proved more inhibitory to fungal growth than EO extracted from imported cumin.

Chemical composition, antioxidant, antifungal and hemolytic activities of essential oil from Baccharis trinervis (Lam.) Pers. (Asteraceae)

We have previously studied the chemical composition of essential oil (EO) from seeds of Anethum graveolens from Xinjiang Autonomous District in the PRC [1]. The component composition of essential oils is known to depend on the habitat. It seemed interesting to compare the composition and biological activity of EO from dill seeds growing in China and Uzbekistan. We used GC—MS to establish the structures of the isolated compounds. EO from seeds of A. graveolens (2007 harvest) that were collected in Tashkent Oblast was isolated by steam distillation in 4.2% yield. The chemical composition of the EO was studied using a Perkin—Elmer Turbo GC—MS. The component content of the oil was calculated using areas of GC peaks of total ion current without correlation coefficients. EO components were identified by comparing retention times and mass spectra of the component obtained in mass scanning mode and by using mass-spectral library data for standard oil components and pure compounds. A total of 22 chemical compounds was identified in EO of A. graveolens seeds growing in Uzbekistan. Table 1 lists the chemical composition of the EO. The principal EO components from dill seed growing in Uzbekistan were carvone (73.61%), limonene (14.69), cis-dihydrocarvone (5.87), diplaniol (1-allyl-2,5-dimethoxy-3,4-methylenedioxybenzene) (2.16), and 1,2-diethoxyethane (1.43%), which together made up 99.2% of the total EO component composition. The principal components of EO from dill seed growing in China were n-pentacosane (27.96%), dioctylester of 1,2-phenyldicarboxylic acid (25.10), octacosane (13.81), tricosane (9.14), and n-nonacosane (6.85%) [1]. A comparison of our data with that obtained earlier indicated that both the qualitative and quantitative composition of the principal EO components of A. graveolens growing in different geographic zones differed considerably. The high content in the studied EO of carvone, which is widely used as a growth inhibitor of bacteria [2-4] and certain fungi [5] and as a repellent [6] is noteworthy. Both S-(+)-carvone and R-(-)-carvone are used in the food industry to produce flavors [4] and in agriculture. For example, S-(+)-carvone is used in the Netherlands to prevent premature sprouting of potato tubers and tulip bulbs during storage [7, 8]. Carvone is an available and inexpensive reagent for organic synthesis in both enantiomeric forms. This makes it attractive for asymmetric synthesis of natural compounds [9]. Antimicrobial activity of EO fractions toward Candida albican and Staphylococcus aureus was estimated using the Barry method to determine the minimal inhibiting concentration (MIC) [10]. Growth of microorganisms decreased markedly upon addition of EO to nutrient medium. The experimental results are given below:

Plants belonging to the Artemisia genus (Asteraceae) are widely distributed worldwide and have many ethnopharmacological, traditional, therapeutic, and phytochemical aspects. Artemisia monosperma is an important aromatic plant due to its traditional and therapeutic uses and phytochemical diversity, including essential oils (EOs). The EO chemical profile of aromatic plants has been reported to be affected by exogenous and endogenous factors. Geographic and seasonal variations are crucial factors shaping the chemical composition of the EO. Herein, the variations of the yields, chemical profiles, and allelopathic and antioxidant activities of A. monosperma EOs collected from three regions in four seasons were assessed. A slight variation in the oil yields was observed among regions and seasons, while the chemical profile, characterized via GC-MS, exhibited significant quantitative and qualitative variation among either regions or seasons. Sesquiterpenes were the main components of all EOs, with significant variation in concentration. In most EO samples, the summer-plant samples had the highest concentration of sesquiterpenes, followed by spring, winter, and autumn. The 7-epi-trans-sesquisabinene hydrate, 6-epi-shyobunol, dehydro-cyclolongifolene oxide, isoshyobunone, diepicedrene-1-oxide, dehydro-aromadendrene, and junipene were the main compounds of all the EO samples. The extracted EOs of the A. monosperma samples showed considerable allelopathic activity against the weed Dactyloctenium aegyptium and the crop Lactuca sativa. A significant variation in allelopathic activity was observed among samples collected during different seasons, while the samples of the autumn and summer seasons had more potential. Also, L. sativa was more affected by the EO compared to D. aegyptium, reflecting that weeds are more resistant to allelochemicals. In this context, the EOs of A. monosperma samples exhibited substantial antioxidant activity with the same pattern of allelopathic activity, whereas the samples of the autumn and summer seasons showed higher antioxidant activity. These biological activities of the EOs could be ascribed to the higher content of oxygenated compounds. The present study revealed that seasons have a substantial effect on EO production as well as composition. In consequence, the biological activities varied with the variation of the chemical profile of the EO. These results show the importance of season/timing for sampling aromatic plants.

Essential oil composition, antioxidant and antimicrobial activity of the galbuli of six juniper species

In the last decades, the use of essential oils have been increased significantly to affect various aspects of human daily life (cosmetics, pharmacy,pesticide and food industry). The present work aims to study the chemical composition and antioxidant activity of essential oils of Juniperus oxycedrus local (Mostaganem Algeria) extracted by hydrodistillation and steam distillation. The comparative study has permitted to highlight the influence of various parameters on the yield of essential oils (drying, extraction time). Forty components were identified. The characterisation by (GC-MS) showed that the extraction by hydrodistillation gave a better result which was characterised by the presence of α-pinene (37.163 %), sabinene (12.829 %), and limonene (5.795 %) as main chemical constituents. The method of extraction showed that there was a significant influence on the composition of the essential oil. The essential oil of Juniperus oxycedrus showed a strong antioxidant activity. The activity of the oils obtained by hydrodistillation was higher than that obtained by steam entrainment (IC50 = 120 mg ml−1 and IC50 = 160 mg ml−1) with DPPH and β-carotene bleaching tests, respectively. Essential oils of J. oxycedrus could therefore represent good component to be used as an antioxidant agent.

In recent years, essential oils (EOs) have received increased attention from the research community, and the EOs of cinnamon, patchouli, and geranium have become highly recognized for their antibacterial, antifungal, antiviral, and antioxidant effects. Due to these properties, they have become valuable and promising candidates for addressing the worldwide threat of antimicrobial resistance and other diseases. Simultaneously, studies have revealed promising new results regarding the effects of physical fields (magnetic and electric) and LASER (MEL) exposure on seed germination, plant growth, biomass accumulation, and the yield and composition of EOs. In this frame, the present study aims to investigate the influence of MEL treatments on cinnamon, patchouli, and geranium EOs, by specifically examining their composition, antimicrobial properties, and antioxidant activities. Results showed that the magnetic influence has improved the potency of patchouli EO against L. monocytogenes, S. enteritidis, and P. aeruginosa, while the antimicrobial activity of cinnamon EO against L. monocytogenes was enhanced by the electric and laser treatments. All exposures have increased the antifungal effect of geranium EO against C. albicans. The antioxidant activity was not modified by any of the treatments. These findings could potentially pave the way for a deeper understanding of the efficiency, the mechanisms of action, and the utilization of EOs, offering new insights for further exploration and application.

Podophyllotoxin and essential oil profile of Juniperus and related species