Antibacterial activity of the essential oil and main components of two Dracocephalum species from Iran

The antibacterial activity of Dracocephalum polychaetum and D. surmandinum essential oils and two main components were investigated. Essential oils of the plants were analysed by GC and GC-MS. Twenty-three components were characterised in the essential oil of D. polychaetum. The oil was rich in oxygenated (73.1%) and hydrocarbon (25.0%) monoterpenes including perilla aldehyde (63.4 %) and limonene (22.1%) as the major constituents. From 25 identified compounds (97.8%) in the oil of D. surmandinum perilla aldehyde (54.3%) and limonene (30.1%) were the main constituents. The bioassays exhibited that all of the Gram-positive and Gram-negative bacteria tested were highly inhibited in the presence of the oils and main components investigated. The most sensitive microorganism to the oils was found to be Staphylococcus epidermidis with the lowest MIC value of 0.3?mgmL(-1). The resistant Gram-negative Pseudomonas aeruginosa was highly inhibited by the oil of D. polychaetum with MIC value of 2.4?mgmL(-1).     

Encapsulation of essential oils within a polymeric liposomal formulation for enhancement of antimicrobial efficacy

Essential oils and their constituents are known to possess antimicrobial activity; however, their inherent volatility is a limiting factor. In order to exploit the antimicrobial efficacy of essential oils, encapsulation within polymeric liposomal systems was undertaken. The liposomes were subsequently polymer-coated in order to further enhance the stability of the formulations. Essential oils distilled from Artemisia afra, Eucalyptus globulus and Melaleuca alternifolia were encapsulated into diastearoyl phosphatidylcholine and diastearoyl phosphatidylethanolamine liposomes employing a reverse phase evaporation methodology. A polyelectrolyte coating was then applied via the layer-by-layer self-deposition technique. A batch of the liposomes was polymer-coated with a 0.15%w/v chitosan solution. Using the minimum inhibitory concentration assay, the liposome-encapsulated, unencapsulated and polymer-coated liposome-encapsulated essential oils were compared in order to observe whether the antimicrobial efficacy was improved with encapsulation and polymer coating. Fractional inhibitory concentrations (FICs) were calculated in order to determine the antimicrobial interactions amongst the lipoid components, polymer coating and essential oils (synergistic, additive, indifferent and antagonistic interactions). With the exception of A. afra, microbial growth was inhibited at lower concentrations for the encapsulated formulations in comparison with the nonencapsulated oils. Synergistic to additive interactions were noted for encapsulated E. globulus (sigmaFIC values 0.25-0.45) and M alternifolia (sigmaFIC values 0.26-0.52) formulations. The addition of the polymer coating did not enhance antimicrobial activity, but owing to their positive effects on membrane stability, its presence is important as a means of extending the shelf life of these formulations. Additionally, the presence of the polymeric coating availed the essential oil at a slower rate. This investigation is a stepping stone towards the promotion of the antimicrobial use of essential oils. The added benefits are that essential oils not only provide effective antimicrobial efficacy, but also promote a "greener" consumerism. Within liposomes, they will enhance dermato-cosmetic properties and increase the marketing image of the final product.     

Chemical composition, antimicrobial and antioxidant activities of essential oils from organically cultivated fennel cultivars

Essential oils of the fruits of three organically grown cultivars of Egyptian fennel (Foeniculum vulgare var. azoricum, Foeniculum vulgare var. dulce and Foeniculum vulgare var. vulgare) were examined for their chemical constituents, antimicrobial and antioxidant activities. Gas chromatography/mass spectrometry analysis of the essential oils revealed the presence of 18 major monoterpenoids in all three cultivars but their percentage in each oil were greatly different. trans-Anethole, estragole, fenchone and limonene were highly abundant in all of the examined oils. Antioxidant activities of the essential oils were evaluated using the DPPH radical scavenging, lipid peroxidation and metal chelating assays. Essential oils from the azoricum and dulce cultivars were more effective antioxidants than that from the vulgare cultivar. Antimicrobial activities of each oil were measured against two species of fungi, two species of Gram negative and two species of Gram positive bacteria. All three cultivars showed similar antimicrobial activity.     

Composition and antimicrobial activity of the essential oil of Heracleum thomsonii (Clarke) from the cold desert of the western Himalayas

Volatile oil composition of hydro-distilled (HD) and supercritical carbon dioxide (SC-CO(2)) essential oil of freshly collected aerial parts of Heracleum thomsonii (Umbeliferae) from the western Himalayas was studied by GC-FID and GC-MS. Results revealed qualitative and quantitative dissimilarity in the composition of hydro-distilled and SC-CO(2) extracted oils. Nineteen constituents, which accounted for 89.32% of total constituents in HD oil, represented by limonene (4.31%), (Z)-β-ocimene (3.69%), terpinolene (22.24%), neryl acetate (36.19%), nerol (9.51%) and p-cymene-8-ol (2.61%) were identified. In SC-CO(2) extracted oil, 24 constituents representing 89.95% of total constituents were identified. Terpinolene (5.08%), germacrene D (2.17%), neryl acetate (51.62%), nerol (9.78%), geranyl acetate (2.06%), α-bisabolol (2.48%) and 1-nonadecanol (4.96%) were the dominating constituents. In?vitro antimicrobial activity of hydro-distilled oil was conducted against microrobial strains including two Gram-positive (Staphylococcus aureus and Bacillus subtilis) and five Gram-negative (Burkholderia cepacia, Escherichia coli, Enterobacter cloacae, Klebseilla pneumoniae and Pseudomonas aeruginosa) bacteria as well as seven fungi (Candida albicans, Issatchenkia orientalis, Aspergillus flavus, Aspergillus niger, Aspergillus parasiticus, Aspergillus sydowii and Trichophyton rubrum) using broth microdilution method. The results of bioassay showed that the oil exhibited moderate to high antimicrobial activity against fungi C. albicans (MIC 625 μg?ml(-1)), A. parasiticus (MIC 312.5 μg?ml(-1)), A. sydowii (MIC 312.5 μg?ml(-1)), T. rubrum (MIC 625 μg?ml(-1)), Gram-positive bacteria B. subtilis (MIC 625?μg?ml(-1)) and Gram-negative bacteria P. aeruginosa (MIC 312.5 μg?ml(-1)).     

Chemical composition, and antioxidant and antimicrobial activities of essential Oil of Phyllostachys heterocycla cv. Pubescens varieties from China

The essential oils of Phyllostachys heterocycla cv. Pubescens, Phyllostachys heterocycla cv. Gracilis, Phyllostachys heterocycla cv. Heterocycla and Phyllostachys kwangsiensis leaves were obtained by steam distillation. Their chemical components were separated and identified by gas chromatography/mass spectrometry (GC/MS). Meanwhile, the effect of scavenging free radicals of essential oil was assayed by using the DPPH·method with Trolox? as control to evaluate their antioxidant capacities. Gram-positive (Staphyloccocus aureus) and Gram-negative (Escherichia coli) were selected as the indicator microorganisms to evaluate the antimicrobial activity. Antimicrobial properties were estimated by the agar diffusion method. The results show that 63 components were separated and identified by GC/MS from these varieties of bamboo leaves. cis-3-Hexenol, whose content in cv. Pubescens, Gracilis, Heterocycla and Ph. kwangsiensis was 27.11%, 24.62%, 30.51% and 34.65%, respectively, was the main constituent. The relative content of alcohol compounds in these varieties of essential oils ranged from 39.8% to 46.64%. All of the bamboo leaf essential oils possessed certain antioxidant capacity; the corresponding IC?? values were 3.1622, 4.9353, 4.2473, and 5.4746 μL/mL, respectively. Essential oils of all tested bamboo spp. were active against Staphylococcus epidermidis and E. coli, showing a positive correlation with the essential oil concentration of 50.42-300 μL/mL. The results indicated there were no significant differences among three varieties and the related species with respect to their antioxidant and antimicrobial activities. This paper provides evidence for studying the essential composition from different varieties of bamboo leaves.     

Toxic effects of Citrus aurantium and C. limon essential oils on Spodoptera frugiperda (Lepidoptera: Noctuidae)

Citrus aurantium and C. limon were selected in the search for natural plant insecticides. The essential oils of C. aurantium and C. limon and ethanol extracts of the seeds, pulp, albedo, and peel of C. aurantium were incorporated into the larval diet of the lepidopteran pest Spodoptera frugiperda. Larval and pupal mortality were quantified and adult malformation was observed. C aurantium essential oil had antifeedant action and the mixture of albedo ethanol extract and C aurantium essential oil had toxic effects on S. frugiperda larvae at early stages, when they had not yet produced major damage to the crop. Our results indicated that a mixture of ethanol extract of albedo and C. aurantium essential oil (250 microg of extract mix per g of diet) deterred feeding by 46% and had the highest larval mortality (100%) of the materials tested. The peel extract (250 microg per g of diet) produced an increment in growth rate and diet consumption. However, 40% of the larval and 45% of the pupal populations died after 96 h of treatment. The blend of essential oil and C. aurantium albedo ethanol extract showed the lowest consumption and a poor nutrient conversion into biomass. Finally, the presence of D-limonene and nootkatone in the peel ethanol extract, and C. limon and C. aurantium essential oils, may be the cause of the response in the feeding behavior and toxic effects found on S. frugiperda.     

Chemical composition and antimicrobial activity of some oleogum resin essential oils from Boswellia spp. (Burseraceae)

The chemical composition of Boswellia carteri (Somalia), B. papyrifera (Ethiopia), B. serrata (India) and B. rivae (Ethiopia) oleogum resin essential oils was investigated using GC-MS to identify chemotaxonomy marker components. Total ion current peak areas gave good approximations to relative concentrations based on GC-MS peak areas. B. carteri and B. serrata oleogum resin oils showed similar chemical profiles, with isoincensole and isoincensole acetate as the main diterpenic components. Both n-octanol and n-octyl acetate, along with the diterpenic components incensole and incensole acetate, were the characteristic compounds of B. papyrifera oleogum resin oil. Hydrocarbon and oxygenated monoterpenes were the most abundant classes of compounds identified in the B. rivae oleogum resin oil. The antimicrobial activities of the essential oils were individually evaluated against different microorganisms including fungi, Gram-positive and Gram-negative bacteria strains. The essential oils with the best activity against fungal strains were those obtained from B. carteri and B. papyrifera with MIC values as low as 6.20 microg/ml. The essential oil of B. rivae resin showed the best activity against C. albicans with a MIC value of 2.65 microg/ml.     

GC×GC/qMS analyses of Campomanesia guazumifolia (Cambess.) O. Berg essential oils and their antioxidant and antimicrobial activity

The present study investigated the essential oil obtained from Campomanesia guazumifolia (Cambess.) O. Berg, an aromatic plant used in Brazilian folk medicine. The chemical composition was performed by GC×GC/qMS. The antioxidant and antimicrobial activities were evaluated by DPPH and BCB and, MIC assays, respectively. Sixty-eight compounds were identified in the oil, where the major compounds were bicyclogermacrene (15%), globulol (5%) and spathulenol (5%). Sesquiterpene hydrocarbons (29 compounds) and oxygenated sesquiterpenes (20 compounds) were the most representative classes of terpenes. DPPH (IC₅₀ value 26.1 ± 0.5 μg/mL) and BCB (68.3 ± 1.5%) values indicated a significant antioxidant activity. The essential oil strongly inhibited Staphylococcus aureus (MIC 15 ± 0.1 μg/mL), Escherichia coli (MIC 25 ± 0.2 μg/mL) and Candida albicans (MIC 5 ± 0.1 μg/mL). The results give a deeper understanding of the chemical composition and report for the first time the antioxidant and antimicrobial potential of the C. guazumifolia essential oil.     

Antimicrobial activities of essential oil and methanol extract of Coriaria nepalensis

Plant extracts and products have been used for centuries in traditional medicine; for most of them, in addition to the scant scientific credibility, the chemical composition and spectrum of activity are yet to be explored. To put forward this effort and to identify novel antimicrobial agents, the inhibitory activities of methanolic extract and essential oil from Coriaria nepalensis against various microorganisms including pathogenic yeast, and Gram-positive and negative bacteria were evaluated. Chemical compositions of C. nepalensis methanolic extract and essential oil were analysed by gas chromatography-mass spectrometry. In vitro susceptibility tests against all the tested isolates were performed in terms of minimum inhibitory concentration (MIC), and well diffusion assay using standard protocols. All microorganisms tested were profoundly found susceptible to both the C. nepalensis extract and oil with MIC values of 1.3-2.1?mg?mL?1 (Gram-positive bacteria), 1.4-2.2?mg?mL?1 (Gram-negative bacteria) and 0.9-1.6?mg?mL?1 (yeasts). The extent of inhibition was shown more by methanolic extract than by essential oil. This study is the first to report the antimicrobial activity of extracts obtained from the C. nepalensis. It can be concluded that the observed antimicrobial characteristics of C. nepalensis indicate that it might be a promising antimicrobial agent.     

Chemical composition, antioxidant and antibacterial properties of Achillea collina Becker ex Heimerl s.l. and A. pannonica Scheele essential oils

The in vitro antioxidant and antimicrobial activities of two Achillea millefolium (Adanson) Koch s.l species essential oils (A. collina Becker ex Heimerl s.l. and A. pannonica Scheele, Asteraceae) originating from the Golija and Radan mountains (Serbia) were investigated. The chemical profiles of the essential oils were evaluated by GC-MS. Antioxidant activity was assessed as free radical scavenging capacity (RSC) towards 2,2-diphenyl-1-picrylhydrazil (DPPH) radicals, together with effects on lipid peroxidation (LP). Antibacterial activity was examined on 21 bacterial strains. Based on the chemical composition of the essential oil, A. collina s.l. from Mount Golija was classified as a chamazulene chemotype (tetraploid). The high percentage of oxygenated monoterpenes and absence of azulene in the essential oil obtained from A. pannonica from Radan pointing that this population is octaploid. Essential oil of A. pannonica expressed stronger antimicrobial activity on almost all tested bacteria. Furthermore, this essential oil expressed higher scavenging effects on DPPH radical (IC(50) = 0.52 comparing to 0.62 mug/mL). Only in the LP evaluation, essential oil of A. collina s.l. from Golija exhibited stronger antioxidant activity (IC(50) = 0.75 comparing to 2.12 mug/mL).     

Composition of Satureja kitaibelii essential oil and its antimicrobial activity

The composition of the essential oil obtained by hydrodistillation from the aerial parts of Satureja kitaibelii from Rtanj mountain (Serbia), collected during three years, was studied. Thirty-nine components were identified in each sample of S. kitaibelii essential oil, representing about 87% of the oils. p-Cymene was the most dominant compound in all three oils (27.9%, 14.7% and 24.4%, respectively). The simple formulation of a lozenge with 0.2% of S. kitaibelii essential oil was prepared and the antimicrobial activity of the essential oil and the lozenge with essential oil was tested using a broth microdilution assay. Both essential oil and lozenge possessed strong antimicrobial activity with MIC values of 0.10-25 microg/mL, and 0.97-15.6 mg/mL, respectively.     

Chemical composition and antimicrobial activity of Satureja kitaibelii essential oil against pathogenic microbial strains

Plant species Satureja kitaibelii Wierzb. ex Heuff. is used as a spice and as a natural preservative for food and herbal tea, owing to its characteristic scent and flavor as well as high antimicrobial activity. In the present study, the antimicrobial activity of isolated essential oil of S. kitaibelii was tested against a panel of 30 pathogenic microorganisms (foodborne microbes, selected multiresistant bacterial isolates from the patient wounds and dermatophyte isolates). Limonene (15.54%), p-cymene (9.99%), and borneol (8.91%) appeared as the main components in 44 identified compounds representing 98.44% of the oil. Essential oil of S. kitaibelii showed significant activity against a wide spectrum of foodborne microbes (MIC=0.18-25.5 microg mL(-1)) and multiresistant bacterial isolates (MIC=6.25-50.0 microg mL(-1)), as well as against dermatophyte strains (MIC=12.5-50.0 microg mL(-1)). These results demonstrate that S. kitaibelii essential oil could be used as a natural potential antimicrobial agent against pathogenic strains in the treatment of foodborne disease, wound and skin infections.     

Chemical diversity and anti-acne inducing bacterial potentials of essential oils from selected Elsholtzia species

Essential oils from the aerial parts of four Elsholtzia species; Elsholtzia stachyodes, Elsholtzia communis, Elsholtzia griffithii and Elsholtzia beddomei were obtained by steam distillation and their chemical components were analysed by gas chromatography-mass spectrometry (GC-MS). Principle Component Analysis was used to identify the chemical variations in the essential oils from these plants, which could be categorised into two groups according to their main chemical components which are acylfuran derivatives and oxygenated monoterpenes. Additionally, the anti-acne inducing bacterial activity against Staphylococcus aureus and Staphylococcus epidermidis were evaluated. The oil from E. stachyodes was the most efficacious against the growth of S. aureus and S. epidermidis having MIC values of 0.78 and 1.56 μL/mL, respectively, and exhibited five times more effective than erythromycin (standard antibiotic).     

Investigation of the chemical composition–antibacterial activity relationship of essential oils by chemometric methods

The antibacterial effects of Thymus vulgaris (Lamiaceae), Lavandula angustifolia (Lamiaceae), and Calamintha nepeta (Lamiaceae) Savi subsp. nepeta var. subisodonda (Borb.) Hayek essential oils on five different bacteria were estimated. Laboratory control strain and clinical isolates from different pathogenic media were researched by broth microdilution method, with an emphasis on a chemical composition–antibacterial activity relationship. The main constituents of thyme oil were thymol (59.95%) and p-cymene (18.34%). Linalool acetate (38.23%) and β-linalool (35.01%) were main compounds in lavender oil. C. nepeta essential oil was characterized by a high percentage of piperitone oxide (59.07%) and limonene (9.05%). Essential oils have been found to have antimicrobial activity against all tested microorganisms. Classification and comparison of essential oils on the basis of their chemical composition and antibacterial activity were made by utilization of appropriate chemometric methods. The chemical principal component analysis (PCA) and hierachical cluster analysis (HCA) separated essential oils into two groups and two sub-groups. Thyme essential oil forms separate chemical HCA group and exhibits highest antibacterial activity, similar to tetracycline. Essential oils of lavender and C. nepeta in the same chemical HCA group were classified in different groups, within antibacterial PCA and HCA analyses. Lavender oil exhibits higher antibacterial ability in comparison with C. nepeta essential oil, probably based on the concept of synergistic activity of essential oil components.     

Antifungal activity and chemical composition of essential oils from Smyrnium olusatrum L. (Apiaceae) from Italy and Portugal

The essential oils and supercritical CO? extracts of wild Smyrnium olusatrum L. growing in Sardinia (Italy) and in Portugal were investigated. For the study, oils were isolated from total plant aerial part (umbels containing seeds). The content of β-phellandrene (67.3% vs. 42.7%) and α-pinene (31.9% vs. 1.2%), respectively, the main components of Portuguese and Italian essential oils, declined during the maturation stage of the umbels. Contrarily, some other important components, particularly curzerene, germacrene B, germacrone, alexandrofuran, 1-β-acetoxyfurano-4(15)-eudesmene and 1-β-acetoxyfurano-3-eudesmene, increased in fruiting umbels. The chemical composition of the Sardinian oil is rather different from those of other origin. The composition of the supercritical extracts and the essential oils is markedly different, particularly due to the high amount of furanosesquiterpenoids in the supercritical fluid extraction. The minimal inhibitory concentration (MIC) and the minimal lethal concentration were used to evaluate the antifungal activity of the oils against Candida albicans, Candida tropicalis, Candida krusei, Candida guillermondii, Candida parapsilosis, Cryptococcus neoformans, Trichophyton rubrum, Trichophyton mentagrophytes, Microsporum canis, Microsporum gypseum, Epidermophyton floccosum, Aspergillus niger, Aspergillus fumigatus and Aspergillus flavus. The oils were particularly active against dermatophyte strains and C. neoformans, with MIC values in the range of 0.32-0.64?μL?mL?1.     

Antioxidant and antiproliferative activity of Laurus nobilis L. (Lauraceae) leaves and seeds essential oils against K562 human chronic myelogenous leukaemia cells

The antioxidant and antiproliferative activities of the essential oils from Laurus nobilis leaves and seeds in relation to their composition were analysed. The most abundant components of the leaf essential oil were 1,8-cineole, 1-p-menthen-8-ethyl acetate, linalool and sabinene, while the seed oil was characterised by β-ocimene, 1,8-cineole, α-pinene and β-pinene as main constituents. Both seed and leaf essential oils exhibited a scavenging effect on the DPPH radical, with IC?? values of 66.1 and 53.5?μg?mL?1, respectively. The leaf essential oil showed the strongest antioxidant activity in the β-carotene/linoleic acid system, with an IC?? value of 35.6?μg?mL?1 after 30?min of incubation. Both leaf and seed oils inhibited proliferation of the K562 tumour cell line with IC?? values of 95 and 75?μg?mL?1, respectively. The L. nobilis leaf oil showed a percentage of erythroide differentiation of 15% at a concentration of 10?μg?mL?1. A value of 12% was found for the seed essential oil at a concentration of 50?μg?mL?1. When the oils were added to a suboptimal concentration of the commercial drug, cytosine arabinoside, a clear synergic effect was observed.     

Comparison of compositions and antimicrobial activities of essential oils from chemically stimulated agarwood, wild agarwood and healthy Aquilaria sinensis (Lour.) gilg trees

The composition and antimicrobial activity of the essential oils which were obtained from agarwood originated from Aquilaria sinensis (Lour.) Gilg stimulated by the chemical method (S1) were characterized, taking wild agarwood (S2) and healthy trees (S3) respectively as the positive and negative controls. The chemical composition of S1 was investigated by gas chromatography-mass spectrometry (GC-MS). The essential oil of S1 showed a similar composition to that of S2, being rich in sesquiterpenes and aromatic constituents. However, the essential oil of S3 was abundant in fatty acids and alkanes. Essential oils of S1 and S2 had better inhibition activities towards Bacillus subtilis and Staphyloccus aureus, compared with essential oil of S3. Escherichia coli was not sensitive to any of them.     

Chemical Composition and Synergistic Potential of Mentha pulegium L. and Artemisia herba alba Asso. Essential Oils and Antibiotic against Multi-Drug Resistant Bacteria

The essential oils were obtained by hydrodistillation from aerial parts of Mentha pulegium L. (M. pulegium L.) and Artemisia herba alba (A. herba alba) Asso. and analyzed by gas chromatography–flame ionization detector chromatograpy (GC–FID) and gaz chromatography–mass spectrometry (GC–MS). The antibacterial activities of the oils were determined by the disk diffusion method and a microdilution broth assay against six bacteria stains. The combinations of these essential oils with antibiotics were evaluated against two multi-drug-resistant bacteria strains: imipenem-resistant Acinetobacter baumannii (IRAB S3310) and methicillin-resistant Staphylococcus aureus (MRSA S19). The chemical analysis of M. pulegium essential oil revealed the presence of pulegone (74.8%) and neoisomenthol (10.0%). A. herba alba essential oil was characterized by camphor (32.0%), α-thujone (13.7%), 1,8-cineole (9.8%), β-thujone (5.0%), bornéol (3.8%), camphene (3.6%), and p-cymene (2.1%). All strains tested except Pseudomonas aeruginosa were susceptible to these oils. The combinations of essential oils with antibiotics exerted synergism, antagonism, or indifferent effects. The best effect was observed with A. herba alba essential oil in association with cefoxitin (CX) against MRSA S19. However, for IRAB S3310, the strongest synergistic effect was observed with M. pulegium in association with amikacin (AK). This study demonstrated that M. pulegium and A. herba alba essential oils have antibacterial activities which could be potentiated by antibiotics especially in the case of IRAB S3310.     

Chemical composition and antimicrobial evaluation of the essential oils of Bocageopsis pleiosperma Maas

Essential oils from the leaves, twigs and barks of Bocageopsis pleiosperma Maas were obtained by using hydrodistillation and analysed by using gas chromatography coupled to mass spectrometry. Several compounds (51) were detected and identified, being β-bisabolene the main component in all aerial parts of the plant, with higher concentration in the leaves (55.77%), followed by barks (38.53%) and twigs (34.37%). In order to increase the biological knowledge about the essential oil of Bocageopsis species, antimicrobial activities were evaluated against the microorganisms Escherichia coli, Staphylococcus epidermidis, Enterobacter aerogenes, Candida tropicalis, Candida dubliniensis, Candida glabrata and Candida albicans. The essential oil obtained from the barks exhibited a moderate effect against S. epidermidis ATCC 1228 (MIC = 250 μg/mL), while the other oils did not exhibit antimicrobial activity. These results represent the first report about the chemical composition of B. pleiosperma and the first antimicrobial evaluation with a Bocageopsis species.     

Essential oil yield and chemical composition changes during leaf ontogeny of palmarosa (Cymbopogon martinii var. motia)

Changes in leaf biomass yield, essential oil yield, and chemical composition were investigated during leaf ontogeny of palmarosa {Cymbopogon martinii (Roxb.) Wats. var. motia Burk., family Poaceae}. Eleven leaves representing different developmental stages, serially numbered from the apex to the base of the plant were utilized for the study. Leaf biomass yield increased up to the eighth leaf. Essential oil recovery increased up to the third leaf; thereafter it decreased. Minimum essential oil recovery was observed in the eleventh leaf. Essential oil yield/leaf increased up to the sixth leaf. Essential oil yield and concentrations of linalool, alpha-terpineol, geranyl isobutyrate and geraniol were relatively higher in the essential oils of mature, older leaves. Essential oil recovery, and percentages of myrcene, beta-caryophyllene, geranyl acetate, (E,Z) farnesol and geranyl hexanoate were higher in the essential oils of young, expanding leaves.