Leaf Essential Oil Research Articles

Chemical Variability of the Leaf Essential Oil of Two Subspecies of Juniperus oxycedrus L. From Northwestern Algeria.

Thirty-seven essential oil samples have been isolated from leaves of individual plants of Juniperus oxycedrus (subspecies oxycedrus and macrocarpa) growing wild in Tlemcen and Aïn Témouchent provinces (Northwestern Algeria). Analysis of eight selected oil samples by GC(RI), GC/MS and 13C NMR, allowed the identification of 88 components that accounted for 84.4-99.5 % of the whole compositions. The 37 compositions were subjected to statistical analysis which suggested the existence of groups and sub-groups I, IIA and IIB. Group I, the most important group with 24 oil samples out of 37, differed from sub-groups IIA and IIB, essentially by the high content of α-pinene (mean value, 69.2 %; SD 6.24). Sub-groups IIA and IIB were differentiated by their content of α-pinene (Mean values, 49.7 % and 27.3 %, respectively) as well as δ-3-carene (10.3 %, sub-group IIA), sabinene and (Z)-6-pentadecen-2-one (8.7 % and 4.9 %, respectively, sub-group IIB).

Comparative analysis of antioxidant and antibacterial activities of leaf and zest essential oils from "Citrus limon”

This work is part of the study of the antibacterial and antioxidant activity of Algerian aromatic and medicinal plants. We conducted a study on a plant widely used by the local population, Citrus limon, an aromatic plant from the Ghardaïa region. Essential oils were extracted from Citrus limon (zest and leaves) using hydrodistillation, yielding 1.12% for the zest and 0.71% for the leaves. The essential oils were analyzed using GC/MS, identifying 35 constituents in the leaf oils, with 19.41% L-Limonene and 15.02% Nerol acetate, and 25 constituents in the zest oils, with 45.62% L-Limonene, 9.40 Beta-Pinene and 8.3% 3-Carene as major compounds. The antioxidant activity of the essential oils was evaluated using three methods. The first method was the DPPH free radical scavenging test, where the zest showed an IC50 of 135.678 mg/mL, higher than that of the leaf essential oil (IC50 of 34.238 mg/mL). The second method, potassium ferricyanide reduction (FRAP), showed that the essential oils of the leaves had an antioxidant activity of EC50 = 63.3773 mg/mL, and the zest showed EC50 = 200.875 mg/mL. The third method, ammonium phosphomolybdate, based on molybdate reduction (TAC), gave antioxidant activities for the leaves and zest, respectively, of EC50 = 1.5722 mg/mL and EC50 = 1.9604 mg/mL. The antibacterial activity was tested against six reference bacterial strains, with Klebsiella pneumoniae being the most sensitive to both essential oils, showing inhibition zones of 48 mm for the leaf oil and 40 mm for the zest oil. According to the obtained results, the essential oils appear to exhibit excellent antioxidant and antibacterial activity.

Enhancing grape preservation: The synergistic effect of curry leaf essential oil in buckwheat starch-chitosan composite coatings

A novel edible composite coating composed of buckwheat starch (BS) and chitosan (CH) with varying levels of curry leaf essential oil (CLEO) was synthesized in the present study. Initially, starch was extracted from buckwheat groats, and its proximate analysis revealed a high amylose content (21.91 ± 0.32%), which makes it an excellent base material for coating formation. The composite coatings were created by blending BS and CH with CLEO in different concentrations. The coatings underwent a comprehensive evaluation, including physico-chemical, functional, thermal analyses, and microstructural characterization. Cytotoxicity tests on human cell lines (Caco-2) confirmed that the coatings were non-toxic. Among the various formulations, the coating with 2.0% CLEO (referred to as F5) exhibited the highest antimicrobial activity, maximum antioxidant properties, and the lowest water solubility. Following this, the coatings were applied to green grapes (Vitis vinifera) via dip coating technique. The performance of coatings was assessed by storing the grapes under room temperature (25 ± 1 °C) and refrigeration conditions (4 ± 1 °C). From visual appearance and physio-chemical tests, it was concluded that the F5 coating was potentially active in extending the shelf life of grapes to 12 days at room temperature and to 20 days under refrigeration storage. Overall, the BS-CH-CLEO composite coating emerges as a refined and eco-conscious bioactive packaging solution, elegantly extending the shelf life of grapes while providing both sustainability and cost-efficiency.

Integrated omics profiles for exploring the potential mechanism underlying aroma formation in the terpenoid-rich aromatic plant Opisthopappus taihangensis and the bioactivity of its leaf essential oil

Integrated omics profiles for exploring the potential mechanism underlying aroma formation in the terpenoid-rich aromatic plant Opisthopappus taihangensis and the bioactivity of its leaf essential oil

Seasonal and diurnal variations in leaf aroma volatiles of Cinnamomum tamala (Buch.-Ham.) T. Nees & Eberm as evidenced from metabolite profiling, histochemical and ultrastructural analyses.

Though the leaves of Cinnamomum tamala is extensively employed in culinary applications due to its rich aroma and therapeutic properties, the produce exhibits variability in composition and contents of leaf essential oil due to fluctuations in climatic conditions and harvesting time. This work evaluated the impact of seasonal and diurnal variations on the composition and contents of aroma volatiles in the mature leaves of C. tamala. In summer, the profile of aroma volatile was dominated by phenylpropanoids (112.96±24.11μg/g of freeze-dried leaf tissue) while in winter monoterpenes (58.45±8.194μg/g of freeze-dried leaf tissue) acquired the dominance. The variability in the contents of primary metabolites was shown to be influenced by the harvesting season and time. Organic acids and sugars showed highest accumulation in leaves harvested during summer evening and winter morning, respectively. Histochemical study showed the presence of lipids and terpenes in the secretory cells as revealed through sudan III and NaDi staining. The ontogeny of secretory oil cells that accumulate essential oil were elucidated through ultrastructural study.

Major Sesquiterpenoids in Psychotria laui Leaf Essential oil Exhibit Anti-Inflammatory and Cytotoxic Properties

Objective: This study aims to investigate the chemical constituents and biological properties of the essential oil derived from Psychotria laui, a plant recognized for its medicinal applications, particularly in traditional Vietnamese medicine, where it is utilized for the treatment of digestive and inflammatory disorders. Methods: Fresh leaves of Psychotria laui were gathered in Quangtri, Vietnam, and subjected to hydro-distillation using a Clevenger-type apparatus to obtain the essential oil. The chemical composition of the essential oil was analyzed by gas chromatography-mass spectrometry (GC-MS). The antioxidant potential was measured using the DPPH (2,2-Diphenyl-1-picrylhydrazyl) assay, while the inhibition of nitric oxide production was tested in lipopolysaccharide-stimulated RAW264.7 cells. Cytotoxicity against the SK-LU-1 cell line (human lung adenocarcinoma) was evaluated using the sulforhodamine B (SRB) assay. Results: The essential oil from Psychotria laui contained 78 distinct constituents. The major compounds identified were spathulenol (10.4%), thujopsan-2- α-ol (9.5%), 7- epi- α-eudesmol (6.5%), 14-hydroxy-9- epi-( E)-caryophyllene (4.4%), epi- α-cadinol (3.9%), α-muurolol (3.8%), 1- epi-cubenol (3.5%), and δ-cadinene (3.2%). The essential oil showed no antioxidant activity, with an IC50 (half-maximal inhibitory concentration) value greater than 500 µg/mL, in contrast to the positive control, L-ascorbic acid, which had an IC50 of 7.78 ± 0.39 µg/mL in the DPPH assay. However, its anti-inflammatory activity was evident by its ability to inhibit nitric oxide production, with an IC50 of 19.48 ± 1.53 µg/mL in lipopolysaccharide-stimulated RAW264.7 macrophages. Moreover, the essential oil exhibited potent cytotoxicity against the SK-LU-1 cancer cell line, with an IC50 of 8.49 ± 0.73 µg/mL in the SRB assay. Conclusion: The essential oil from Psychotria laui leaves contains numerous bioactive compounds and exhibits significant anti-inflammatory and cytotoxic properties, although it lacks antioxidant activity.

Utilization of Cinnamon Leaves (Cinnamomum burmannii, Blume) and Effectiveness Test as Mouthwash against Oral Microbes

Oral health is an important aspect to pay attention to because it is part of the digestive system. Disorders in oral health function can impact other bodily health. The use of mouthwash is necessary to improve the cleanliness and health of the mouth, especially when brushing alone is not optimal. The active compounds in mouthwash enhance cleanliness and effectively inhibit the growth of pathogenic oral microflora. Cinnamon leaves have not been widely utilized and are often left unused or discarded. Previous research has been conducted on the potential of the compounds in cinnamon leaves. This research was carried out by determining the best essential oil content of cinnamon leaves through several preliminary treatments and varying distillation times. Active compounds such as cinnamaldehyde, L-linalool, and cinnamyl acetate were found in the cinnamon leaves, making them a potential ingredient for mouthwash formulation. The aim of this study is to produce an effective mouthwash that reduces the growth of pathogenic oral microflora using underutilized local materials. The mouthwash preparation method was modified from several active ingredient mouthwash preparation methods by varying the concentration of cinnamon leaf essential oil at 5%, 10%, and 15%. The formulations were then evaluated for organoleptic properties, stability, homogeneity, and antibacterial activity against S. mutans using the disc diffusion method. The results showed that the preparations remained physically stable and homogeneous during 30 days of storage at room temperature. The cinnamon leaf mouthwash exhibited antibacterial activity against S. mutans, with average inhibition zones of 15.25 mm, 19.06 mm, and 24.34 mm for formulations I, II, and III, respectively. Based on these results, it can be concluded that the cinnamon leaf mouthwash has the potential to inhibit the growth of S. mutans bacteria."

Microemulsion-based topical hydrogels containing lemongrass leaf essential oil (Cymbopogon citratus (DC.) Stapf) and mango seed kernel extract (Mangifera indica Linn) for acne treatment: Preparation and in-vitro evaluations.

Current treatments for severe acne include combinations of synthetic anti-inflammatory and antibacterial drugs, which possess numerous side effects. Therefore, this study developed microemulsion-based hydrogel containing lemongrass leaf essential oil (Cymbopogon citratus (DC.) Stapf) and mango seed kernel extract (Mangifera indica Linn) as a potential natural therapy for inflammatory acne. To this end, the microemulsions were first prepared using pseudo-ternary phase diagrams with soybean oil and coconut oil, cremophor RH40, and PEG 400. The optimal formula could load 1% lemongrass oil and 10% mango extract, possessed a spherical droplet size of ~18.98 nm, a zeta potential of -5.56 mV, and a thermodynamic stability. Secondly, the microemulsion-based hydrogel was developed by simple mixing the optimal microemulsion in carbopol-940 hydrogel (3.5% w/w). The product showed a viscosity of ~3728 cPs, a pH of 5.4-6.2, a spreadability of ~24 cm, an in-vitro Franz-cell cumulative release rate of ~80% for polyphenol content and ~60% for citral within 12 h, and a good physicochemical stability of > 3 months. Thirdly, the skin compatibility/irritability of the microemulsion-based hydrogel was determined by the HET-CAM assay, which showed non-irritation level. Finally, the anti-inflammatory activities of the hydrogel, using heat-induced BSA denaturation assay and LPS-stimulated RAW 264.7 NO inhibition assay, was 4-times higher than that of the reference drug Klenzit-C® (adapalene and clindamycin gel). Moreover, the hydrogel possessed strong anti-biofilm activity in Cutibacterium acnes, comparable with Klenzit-C®. Conclusively, the microemulsion-based hydrogel containing lemongrass oil and mango seed extract demonstrated much potentials to be a promising natural drug for acne treatment.

The leaf essential oils of Meiogyne virgata (Blume) Miq., M. vietnamica Jaikhamseub, T.A.Le & Chaowasku, and Orophea polycarpa A.DC.: Chemical composition, antimicrobial activity, molecular docking, and toxicity profiling

The present study aims to describe the chemical composition of essential oils from three Vietnamese Annonaceae species, Meiogyne virgata, M. vietnamica, and Orophea polycarpa, and their antimicrobial activity. Essential oils were extracted by hydro-distillation. From the GC-FID/MS (gas chromatography-flame ionization detection and mass spectrometry) analysis, the leaf essential oil of M. virgata was reported to contain the major compound germacrene D (42.48%). Spathulenol (24.51%), bicyclogermacrene (18.58%), β-selinene (11.14%), and germacrene D (8.20%) can be seen as the main compound in M. vietnamica leaf essential oil. α-Phellandrene (39.35%), bicyclogermacrene (13.07%), β-phellandrene (10.87%), and limonene (8.27%) represented O. polycarpa leaf essential oil. Essential oil of M. virgata leaves exhibited strong antimicrobial activity against the Gram (+) bacterium Bacillus subtilis ATCC 5230, the Gram (-) bacterium Escherichia coli ATCC 8739, and the fungus Aspergillus niger ATCC 9587 with the same MIC value of 16 μg/mL. The docking method showed that germacrene D has the ΔGbinding (binding affinity) values of –6.68, –5.265, and –5.602 kcal/mol with the proteins E. coli DNA gyrase, B. subtilis TasA, and A. niger PhyA, respectively. Alkyl and pi-alkyl interactions are the main contributors to the binding affinity between the studied proteins and ligands. Furthermore, germacrene D is predicted to have low toxicity and is not active against any of the considered organ targets.

The Mitigating Effects of Perilla Leaf Essential Oil on the Phytotoxicity of Fenoxaprop-P-Ethyl in Rice Seedlings.

Fenoxaprop-P-ethyl (FE) can effectively control weeds in rice fields, but it has been found to cause phytotoxicity in rice. In this study, the phytotoxicity of FE was mitigated by perilla leaf essential oil (PEO) in rice seedlings. The injury recovery rates (IRRs) for shoot length and fresh weight treated with 800 mg/L of PEO were 101.51% and 99.05%, respectively. Moreover, the damage of s-metolachlor and pretilachlor was also alleviated when co-applied with 800 mg/L PEO; the IRR of s-metolachlor phytotoxicity was 26.07% and 27.34%, respectively, and the IRR of pretilachlor phytotoxicity was 127.27% and 124.39%, respectively. However, PEO had no significant effect on the phytotoxicity of pinoxaden, mesotrione, penoxsulam, mesosulfuron-methyl, and nicosulfuron. The results of GC-MS analysis showed that a total of 23 components were detected in PEO, among which linalool (36.49%), linalyl formate (26.96%), α-terpineol (10.63%), 2-hexanoylfuran (5.81%), geranyl acetate (4.13%), and neryl acetate (2.30%) were the primary components. Among them, 2-hexanoylfuran was the most effective component to alleviate FE damage, for which the IRR of shoot length and fresh weight was 73.17% and 73.02%, respectively, followed by the geranyl acetate, for which the IRR was 72.32% and 60.56%, respectively, and neryl acetate, for which the IRR was 65.28% and 58.11%, respectively. Furthermore, the application of 50 mg/L of 2-hexanofuran significantly improved the tolerance of shoot length and fresh weight to FE stress by factors of 5.32 and 5.35, respectively. This research demonstrates that PEO and 2-hexanoylfuran have the potential to serve as natural safeners to reduce phytotoxicity.

Chemical analysis and bioactivity evaluation of Citrus limon leaves volatile oil from Palestine: investigating phytochemical, anti-inflammatory, antimicrobial, and cytotoxic properties

IntroductionScientists consider repurposing discarded waste into valuable resources for the pharmaceutical, cosmetic, and food flavoring manufacturing industries a challenge to generate new revenue streams, lower production costs, and reduce waste. Therefore, the current study aimed to identify Citrus limon leaf volatile oil (VO) constituents from Palestine and assess its in vitro antimicrobial, anti-inflammatory, and cytotoxic properties. MethodsThe components of the VO were analyzed using Gas Chromatography/Mass Spectrometry (GC/MS). The antimicrobial activity of VO was assessed using a microdilution technique. The cyclooxygenases (COX-1 and COX-2) assay was utilized to assess the anti-inflammatory effect. An aqueous one solution cell proliferation (MTS) assay was employed to determine the cytotoxic effect of the VO. ResultsThirty-six molecules were identified in the oil, and geranial, neral, and limonene are the most abundant molecules, comprising 31.06%, 23.98%, and 14.32%, respectively. The antimicrobial results showed that the VO has notable inhibition against Proteus vulgaris, Methicillin-resistant Staphylococcus aureus, and Candida albicans. The COX IC50 calculations revealed that it has high potency against COX-2 IC50=9.32±0.88µg/ml. The most potent cytotoxic effect of C. limon VO was noticed against MCF-7, with an IC50 dose of 162.90±1.85 mg/ml. ConclusionThe GC-MS analyses revealed that geranial, neral, and limonene are the predominant compounds in the VO of C. limon leaves from Palestine. The biological test results demonstrated that the VO has potential inhibitory actions against some cancer cells, bacterial and fungal species, and COX-2 enzyme, suggesting it may be a viable choice for treating or preventing microbial infections, cancer, and inflammatory illnesses.

Comparative study of chemical constituents and biological potency in Lantana camara Linn. leaf essential oil collected from two different sites in Northeast India

The ubiquitous occurrence of Lantana camara highlights its exceptional ecological versatility. Leaves of L. camara were obtained for this study from two different locations of NE, India. Hydro distillation was used to extract the essential oils from the leaves, and gas chromatography-mass spectrometry (GC-MS) and gas chromatography-flame ionization detection (GC-FID) were used to study the chemical profiles of the isolated oils. The essential oil analysis detected 35 components in total essential oil from Location 1 (BLCEO) while in Location 2 essential oil (JLCEO), 29 components were identified. Caryophyllene, humulene and sabinene were present in considerably major amounts in both BLCEO and JLCEO, though variation in area percentage was seen. The anti-oxidant properties of BLCEO were better than that of JLCEO. The BLCEO has also exhibited better results in inhibiting acetylcholinesterase. However, both the essential oils did not show any prominent results in α-amylase inhibitory assay and anti-tyrosinase activity. In this study, the phytochemical composition and their effect on the bioactivity of both samples were observed. The chemical constitution of L. camara essential oils (LCEO) and its possible ecological ramifications have also been well explained.

Comparative evaluation of anticancer potential of Spilanthes paniculata leaf and flower essential oil using annexin V and orosphere formation in oral cancer cell line.

Spilanthes paniculata, a member of the Asteraceae family, is predominantly used as a traditional remedy in addressing oral ailments, particularly gum infections and sore throat. The flowers are chewed to alleviate toothache immediately. This study evaluated a comparison between the essential oils of leaf and flower derived from Spilanthes paniculata targeting the SCC9 oral cell lines using in vitro and in silico approaches. The anticancer activity was performed through an MTT assay, apoptosis assays using annexin V and orospheres formation assays. Molecular docking was performed between five selected phytocompounds against the p53 protein by using AutoDock 4.2.6 software. The results confirmed that the flower essential oil significantly reduced the cell viability in a dose-dependent manner, with an IC50 value of 113.95µg/mL. The apoptosis assays showed that the flower essential oil was approximately 2.5 times more effective in inducing early apoptosis at 50µg/mL compared to the essential oil of the leaf. The orosphere formation assays further confirmed the anticancer potential of the flower essential oil. Spathulenol exhibited strong hydrogen bonding with the p53 protein. The ADMET prediction tools were used to predict the in silico pharmacokinetics and drug-like properties of the phytoconstituents. The results suggested that Spathulenol and Nerolidol have high gastrointestinal absorption (GIA), with estimated solubility (ESOL) values of -3.17 and -3.22, respectively, falling within the optimal range. These findings suggest that the flower's essential oil efficiently prevented the proliferation of oral cancer and observed a notable degree of cell death, inducing apoptosis and suggesting its significant antiproliferative activity against cancerous cell line which could be explored further for therapeutic applications.

Acute oral toxicity and genotoxicity assessment of the essential oil from Croton pulegiodorus Baill (Euphorbiaceae) leaves in mice

Essential oils obtained from Croton pulegiodorus leaf are renowned for their biological activities; however, data on their toxicity are limited. Therefore, this study aimed to evaluate the acute oral toxicity and genotoxicity of a C. pulegiodorus leaf essential oil (CPLEO). Chemical characterization of CPLEO was conducted by gas chromatography coupled to mass spectrometry (GC-MS). In vitro assay was performed to verify the hemolytic capacity of the oil in mice erythrocytes. Next, an acute oral toxicity study was conducted on female mice at CPLEO doses of 2000, 1000, 500, 250, 100, and 50 mg/kg. Hematological, biochemical, and histopathological markers were assessed in mice from groups were no death occurred. Relative consumption of water and food and the weight of animals and their organs were also recorded. Finally, a genotoxicity analysis was performed using the micronucleus and comet assays. The extraction yield of CPLEO was 1.149% and its major compounds were ascaridole (23.18%), eucalyptol (17.20%), camphor (14.20%), p-cymene (7.91%), α-terpineol (4.69%), and isobornyl acetate (4.57%). CPLEO showed a hemolytic effect only at high concentrations (185.5–1000 mg/mL). It showed acute oral toxicity in mice with a LD50 of 460.42 mg/kg. CPLEO (50–250 mg/kg) caused some significant changes in hematological and biochemical parameters. Histopathological evaluation indicated alterations in liver and kidneys but transaminases, urea and creatinine levels remained like the negative control. CPLEO administration impaired weight gain and reduced water and food consumption. Finally, it was not genotoxic by both comet and micronucleus tests. The results highlight the need for attention when choosing doses to evaluate the bioactivities of CPLEO.

Isolation and Antibacterial Activity of Sembung (Blumea balsamifera) Leaf Essential Oil L., DC

Sembung leaf essential oil is a complex mixture in the form of oily yellow liquid with a unique aroma. It contains various volatile components that have antibacterial, antifungal, antioxidant and cytotoxic activities. This study aims to determine the antibacterial activity of essential oil Blumea balsamifera L., DC against Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. Isolation of essential oil using steam distillation method with 0.21% rendement. Inhibition activity was performed by test tube method with variation concentrations of essential oil were 10%, 20%, 40%, 80%, and 100% for each bacteria. Results of this study showed that the highest antibacterial activity on Escherichia coli at 80% concentration with an inhibition zone diameter of 27.53 mm, 100% concentration for Pseudomonas aeruginosa with an inhibition zone diameter 25.72 mm and 100% concentration for Staphylococcus aureus with inhibition zone diameter 27.31 mm. Essential oil from (Blumea balsamifera) L., DC leaves have a strong activity inhibition category against Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus.

The Effect of Using Eugenol Essential Oil of Clove Leaf as a Feed Additive on The Carcass Percentage and Carcass Components of Broiler Chickens

Eugenol, derived from clove leaf essential oil, possesses antibiotic, antifungal, anti-inflammatory, and antioxidant properties. This study aimed to evaluate the effects of eugenol as a feed additive on carcass percentage and carcass components in broiler chickens. A Completely Randomized Design (CRD) was used, with four treatments and five replications. Two hundred 1-week-old chicks with an average initial body weight of 142.25±7.75 g were allocated into 20 cage plots. The treatments were: E0 (Basal ration), E1 (Basal ration + 0.5% eugenol), E2 (Basal ration + 1.0% eugenol), and E3 (Basal ration + 1.5% eugenol). Carcass percentage and carcass component percentages were measured. Analysis of variance revealed a highly significant effect (P0.01) on carcass percentage and upper thigh percentage; a significant effect (P0.05) on the percentage of breast, wings, and back; and no significant effect (P0.05) on the percentage of the lower thigh. The 1% eugenol treatment achieved the highest carcass percentage (77.75±1.04%), breast percentage (39.02±0.61%), and upper thigh percentage (17.80±0.09%) compared to other treatments.

Chemical profiling and spectroscopic studies of leaf volatile oil of Eucalyptus globulus from Botswana isolated by conventional hydrodistillation and ultrasound assisted hydrodistillation

Environmental factors have an influence on the chemistry and percentage recovery of volatile oils. Therefore, the chemical composition of Eucalyptus globulus (E. globulus) volatile oil from Botswana was determined. The volatile oil was isolated from the leaves of E. globulus plant by means of the conventional hydrodistillation and ultrasound assisted hydrodistillation at 50 W and 300 W. The extraction method that gave a better recovery of the volatile oil was ultrasound assisted hydrodistillation at 300 W with a yield of 2.50%. The volatile oil obtained by hydrodistillation and ultrasound assisted hydrodistillation at 50 W had comparable recovery yields of 2.24% and 2.20% respectively. Eucalyptol was identified as the major component in the oil. The amount of eucalyptol present in E. globulus volatile oil extracted by ultrasound assisted hydrodistillation (65%) show that the oil has a potential to be explored for therapeutic purposes.

Chemical composition and antimicrobial activity of Plinia rivularis essential oil against multidrug-resistant bacteria

IntroductionThe increasingly common occurrences of multidrug-resistant bacteria represent a global health threat and the discovery of new alternative remedies is necessary. The use of essential oils (EOs) in the treatment of many pathogenic bacteria is promising and several examples have already been highlighted regarding their inhibitory action. Among the botanical families, Myrtaceae stands out for presenting important species that supply bioactive products. MethodsIn this work we investigate the chemical composition of Plinia rivularis (Myrtaceae) leaf EO and its antibacterial activity against resistant and non-resistant bacteria. The EO was obtained by two methods, hydrodistillation and steam distillation. Gas chromatography-flame ionization detector (GC-FID), gas chromatograph-mass spectrometry (GC-MS), nuclear magnetic resonance spectroscopy (NMR) and Fourier transform infrared spectroscopy (FTIR) were the techniques used in the EO chemical characterization. ResultsThe EOs were obtained with yields of 0.37 and 0.16% by hydrodistillation and steam distillation methods, respectively. The analyzes revealed the EOs chemical profile showing the compounds 2H-benzocyclohepten-2-one,3,4,4a,5,6,7,8,9-octahydro-4a-methyl (synonym: 4a-methyl-3,4,4a,5,6,7,8,9-octahydro-2H-benzo[7]annulen-2-one), rosifoliol, β-eudesmol and the diterpene kaurene as main constituents. Through preparative thin-layer chromatography (PTLC), it was possible to obtain the diterpene kaurene with a content of 91%, which was also characterized by NMR. The minimum inhibitory concentrations of EO against bacteria ranged from 0.56 to 2.25 mg.ml−1 and 2.25–36 mg.ml−1 for sensitive and resistant bacteria, respectively. Also, EO showed synergistic activity with amikacin and cefotaxime against carbapenem-resistant Pseudomonas aeruginosa (KPC). ConclusionsThis is the first report on the chemical composition of P. rivularis EO. Comparison of extraction methods showed variation in yields and small changes in component content. The EO demonstrated activity against resistant and non-resistant bacteria. In addition, the synergistic effect of EO against resistant bacteria may be explored in future studies.

Influence of Plant Phenology on Chemical Composition of Monarda fistulosa L. Organs and their Bioactive Properties.

Monarda fistulosa L. above-ground organs, collected at three phases of plant phenology, were investigated as potential raw materials for application in the food industry. They were evaluated regarding essential oil (EO) content, composition, and antimicrobial activity, as well as characteristics of phenolic fractions and antioxidant properties, which may determine health benefits and potential use in food preservation. The dominant constituent of leaf EO was carvacrol. In the inflorescence EO carvacrol content was especially high at the full flowering phase (45.12%), while during the fruit setting phase its content was lower than that of p-cymene (39.75%) and thymoquinone (25.04%). In the agar dilution test, leaf and inflorescence EOs inhibited the growth of the six tested microorganisms at the concentration range of 0.156-0.625 µL/mL. Leaves collected at the vegetative phase of plant growth were characterised by the highest content of rosmarinic acid and didymin. Inflorescences harvested during the flowering of plants were rich in linarin. Flavonoid content was highly correlated with antioxidant activity of extracts. Due to these properties, M. fistulosa extracts and essential oils could be used in the food industry as natural preservatives or antioxidants, thereby contributing to the development of safer and more sustainable food products.

Chemical compositions and biological properties of the leaf essential oil of three Melaleuca species

Chemical compositions and biological properties of the leaf essential oil of three <i>Melaleuca</i> species