Widely targeted metabolomics analysis reveals the differences in nonvolatile compounds of citronella before and after drying.

Citronella is used as a spice and a traditional herbal medicine. Dried citronella is easy to store and transport, and it is unclear whether dried citronella has more or fewer medicinal components compared to fresh citronella. In the present study, various metabolites in fresh and dry citronella were detected using a widely targeted metabolomics strategy. We identified 712 metabolites and classified them into 31 categories, and we identified 132 flavonoids. After citronella was dried, the quantities of most kinds of flavonoids increased, but the quantities of amino acids, organic acids, and vitamins decreased, and the quantity of quercetin increased significantly. Therefore, the medicinal value of dry citronella may have increased, and the nutritional value of amino acids and vitamins may have decreased. The results of this study can serve as a new theoretical reference to study citronella and promote its nutrition and medicinal chemical composition.

Composition, Chemical Variability and Biological Activity of Cymbopogon schoenanthus Essential Oil from Central Algeria.

Cymbopogon schoenanthus (L.) Spreng. (Poaceae) is an aromatic plant whose aerial parts and rhizome produced an essential oil with pleasant odor. A chemical variability has been observed depending of the countries where the plant grows wild, including Algeria. The chemical compositions of 24 oil samples isolated from plants harvested in Central Algeria have been investigated, to evidence homogeneity or chemical variability within a given area of harvest. Twenty of these were dominated by cis- and trans-p-menth-2-en-1-ols (22.6 %±3.6 and 14.3 %±1.7, resp.) beside four atypical compositions. Otherwise, aerial parts and rhizomes produced similar essential oils. Lastly, a fair antimicrobial activity was measured against Staphylococcus aureus strain, while the antioxidant potential was low.

Cymbopogon Citratus Functionalized Green Synthesis of CuO-Nanoparticles: Novel Prospects as Antibacterial and Antibiofilm Agents.

Chemically synthesized copper oxide nanoparticles (CuONPs) involve the generation of toxic products, which narrowed its biological application. Hence, we have developed a one-pot, green method for CuONP production employing the leaf extract of Cymbopogon citratus (CLE). Gas chromatography-mass spectrometry (GC-MS) analysis confirmed the capping of CuONPs by CLE esters (CLE-CuONPs). Fourier-transform infrared (FTIR) showed phenolics, sugars, and proteins mediated nucleation and stability of CLE-CuONPs. X-ray diffraction (XRD) and transmission electron microscopy (TEM) revealed CLE-CuONPs between 11.4 to 14.5 nm. Staphylococcus aureus-1 (MRSA-1), Staphylococcus aureus-2 (MSSA-2) exposed to CLE-CuONPs (1500 µg/mL) showed 51.4%, 32.41% survival, while Escherichia coli-336 (E. coli-336) exposed to 1000 µg/mL CLE-CuONPs showed 45.27% survival. Scanning electron microscopy (SEM) of CLE-CuONPs treated E. coli-336, MSSA-2 and MRSA-1 showed morphological deformations. The biofilm production by E. coli-336 and MRSA-1 also declined to 33.0 ± 3.2% and 49.0 ± 3.1% at 2000 µg/mL of CLE-CuONPs. Atomic absorption spectroscopy (AAS) showed 22.80 ± 2.6%, 19.2 ± 4.2%, and 16.2 ± 3.6% accumulation of Cu2+ in E. coli-336, MSSA-2, and MRSA-1. Overall, the data exhibited excellent antibacterial and antibiofilm efficacies of esters functionalized CLE-CuONPs, indicating its putative application as a novel nano-antibiotic against multi drug resistance (MDR) pathogenic clinical isolates.

Effect of citronella essential oil fumigation on sprout suppression and quality of potato tubers during storage.

Effect of citronella essential oil (CEO) fumigation on sprout suppression and quality of potato tubers during storage was investigated. Potato tubers were treated under conditions of single-phase (30 µL L-1, 0-10 d) and dual-phase (30 µL L-1, 0-10 d; 30 µL L-1, 35-90 d) fumigation. Changes in germination rate, weight loss, starch, reducing sugar, gibberellins (GA3), and α-solanine were measured. The results showed that CEO fumigation could control sprouting and improve the quality of potato tubers during storage compared to the non-treated tubers. CEO treatments inhibited the degradation of starch and the increase of reducing sugar content. The production of gibberellins (GA3) was suppressed, and the levels of α-solanine in the skin and flesh of potato tubers were decreased by CEO fumigation. Dual-phase CEO fumigation had a better effect on sprout suppression than single-phase fumigation, and possesses potential for postharvest application.

Influence of metals on essential oil content and composition of lemongrass (Cymbopogon citratus (D.C.) Stapf.) grown under different levels of red mud in sewage sludge amended soil.

Lemongrass is a commercially important perennial herb with medicinal value and ability to tolerate high alkaline and saline conditions. Essential oil bearing plants can grow safely in soil contaminated with heavy metals without severe effects on morphology and oil yield. The present study was aimed to assess the essential oil content and composition in lemongrass in response to elevated metals in above-ground plant parts. Pot experiment was conducted for six months using sewage sludge as soil amendment (soil: sludge: 2:1 w/w) followed by red mud treatments (0, 5, 10 and 15% w/w). Garden soil without sludge and red mud was control and there were ten replicates of each treatment. Oil content in leaves was differently affected due to presence of metals in soil under different treatments. Oil content under SRM5 (5% red mud) treatment was raised by 42.9 and 11.5% compared to the control and SRM0 treatment, respectively. Among identified compounds in oil under red mud treatments, 17 compounds contributed more than 90% of total volatiles (citral contributing approximately 70%). Under SRM10 treatment, essential oil showed maximum citral content (75.3%). Contents of Fe, Zn, Cu, Cd, Ni and Pb in above-ground plant parts exceeded, whereas Mn was detected within WHO permissible limits for medicinal plants. However, metal contents in essential oil were well within FSSAI limits for food. The study suggests utilization of 5 and 10% red mud in sludge amended soil for lemongrass cultivation to have better oil yield and quality, without metal contamination.

Cymbopogon species; ethnopharmacology, phytochemistry and the pharmacological importance.

Cymbopogon genus is a member of the family of Gramineae which are herbs known worldwide for their high essential oil content. They are widely distributed across all continents where they are used for various purposes. The commercial and medicinal uses of the various species of Cymbopogon are well documented. Ethnopharmacology evidence shows that they possess a wide array of properties that justifies their use for pest control, in cosmetics and as anti-inflammation agents. These plants may also hold promise as potent anti-tumor and chemopreventive drugs. The chemo-types from this genus have been used as biomarkers for their identification and classification. Pharmacological applications of Cymbopogon citratus are well exploited, though studies show that other species may also useful pharmaceutically. Hence this literature review intends to discuss these species and explore their potential economic importance.

Therapeutic switching: from antidermatophytic essential oils to new leishmanicidal products.

This study examined whether the antidermatophytic activity of essential oils (EOs) can be used as an indicator for the discovery of active natural products against Leishmania amazonensis. The aerial parts of seven plants were hydrodistilled. Using broth microdilution techniques, the obtained EOs were tested against three strains of dermatophytes (Trichophyton mentagrophytes, Microsporum gypseum and Microsporum canis). To compare the EOs antifungal and antiparasitic effects, the EOs activities against axenic amastigotes of L. amazonensis were concurrently evaluated. For the most promising EOs, their antileishmanial activities against parasites infecting peritoneal macrophages of BALB/c mice were measured. The most interesting antifungal candidates were the EOs from Cymbopogon citratus, Otacanthus azureus and Protium heptaphyllum, whereas O. azureus, Piper hispidum and P. heptaphyllum EOs exhibited the lowest 50% inhibitory concentration (IC50) values against axenic amastigotes, thus revealing a certain correspondence between both activities. The P. hispidum EO was identified as the most promising product in the results from the infected macrophages model (IC50: 4.7 µg/mL, safety index: 8). The most abundant compounds found in this EO were sesquiterpenes, notably curzerene and furanodiene. Eventually, the evaluation of the antidermatophytic activity of EOs appears to be an efficient method for identifying new potential drugs for the treatment of L. amazonensis.

Autopolyploidy differentially influences body size in plants, but facilitates enhanced accumulation of secondary metabolites, causing increased cytosine methylation.

Whole genome duplication leads to autopolyploidy and brings about an increase in cell size, concentration of secondary metabolites and enhanced cytosine methylation. The increased cell size offers a positive advantage to polyploids for cell-surface-related activities, but there is a differential response to change in body size across species and taxonomic groups. Although polyploidy has been very extensively studied, having genetic, ecological and evolutionary implications, there is no report that underscores the significance of native secondary metabolites vis-à-vis body size with ploidy change. To address this problem we targeted unique diploid-autotetraploid paired sets of eight diverse clones of six species of Cymbopogon- a species complex of aromatic grasses that accumulate qualitatively different monoterpene essential oils (secondary metabolite) in their vegetative biomass. Based on the qualitative composition of essential oils and the plant body size relationship between the diploid versus autotetraploid paired sets, we show that polyploidy brings about enhanced accumulation of secondary metabolites in all cases, but exerts differential effects on body size in various species. It is observed that the accumulation of alcohol-type metabolites (e.g. geraniol) does not inhibit increase in body size with ploidy change from 2× to 4× (r = 0.854, P < 0.01), but aldehyde-type metabolites (e.g. citral) appear to drastically impede body development (r = -0.895). Such a differential response may be correlated to the metabolic steps involved in the synthesis of essential oil components. When changed to tetraploidy, the progenitor diploids requiring longer metabolic steps in production of their secondary metabolites are stressed, and those having shorter metabolite routes better utilize their resources for growth and vigour. In situ immunodetection of 5-methylcytosine sites reveals enhanced DNA methylation in autopolyploids. It is underpinned that the qualitative composition of secondary metabolites found in the vegetative biomass of the progenitor diploid has a decisive bearing on the body size of the derived autotetraploids and brings about an enhancement in genome-wide cytosine methylation.

Phytostabilisation potential of lemon grass (Cymbopogon flexuosus (Nees ex Stend) Wats) on iron ore tailings.

The present pot culture study was carried out for the potential phytostabilisation of iron ore tailings using lemon grass (Cymbopogon flexuosus) a drought tolerant, perennial, aromatic grass. Experiments have been conducted by varying the composition of garden soil (control) with iron ore tailings. The various parameters, viz. growth of plants, number of tillers, biomass and oil content of lemon grass are evaluated. The studies have indicated that growth parameters of lemon grass in 1:1 composition of garden soil and iron ore tailings are significantly more (-5% increase) compared to plants grown in control soil. However, the oil content of lemon grass in both the cases more or less remained same. The results also infer that at higher proportion of tailings the yield of biomass decreases. The studies indicate that lemongrass with its fibrous root system is proved to be an efficient soil binder by preventing soil erosion.

Organic and conventional fertilisation procedures on the nitrate, antioxidants and pesticide content in parts of vegetables.

Different parts of plant foods are generally discarded by consumers such as peel, stalk and leaves, which could however possess a nutritional value. However, few studies have analysed the composition of these marginal foods. The phenolic compound, flavonoid, polyamine, nitrate and pesticide contents of parts of vegetables that are usually discarded--but which were cultivated according to conventional and non-conventional procedures--were analysed to provide suggestions on how to improve the consumption of these parts and to reduce the production of urban solid waste. Few, but significant, differences between the two manuring procedures were observed. Higher nitrate content and the presence of organochlorine pesticides were found in conventional cultivated papaya peel, lemon balm leaves, jack fruit pulp, and beet stalk and peel. Discarded parts of plant foods such as stalk, leaves and peels can be used as a source of antioxidant compounds, such as phenolic compounds.

Vermicomposting potentiality of Perionyx excavatus for recycling of waste biomass of Java citronella--an aromatic oil yielding plant.

Laboratory investigation on vermicomposting efficacy of Perionyx excavatus for recycling of distillation waste biomass of java citronella (Cymbopogon winterianus Jowitt) was carried out in two seasonal trials i.e. summer and winter periods. The experiment was conducted in earthen pots using a mixture of citronella waste material and cowdung in the proportion of 5:1. A control treatment without earthworms was setup for comparison of the results. The vermicompost had shown 5.8 folds reduction in C/N ratio and 5.6 folds enhancement in ash content. The nutrient contents (N, P, K, Ca and Mg) in the vermicompost had increase in the range of 1.2 - 4.1 fold than the initial level. The FT-IR spectra of the vermicompost confirmed increase in nitrogen rich compounds and decrease in aliphatic/aromatic compounds as compared to the initial level of the biowaste materials. The vermicomposting process is influenced by seasonal variation and summer was more productive than winter.

Controle fitopatológico do Fusarium subglutinans pelo óleo essencial do capim-citronela (Cymbopogon nardus L. ) e do composto citronelal / Fungitoxic activity of essential oil of citronella grass (Cymbopogon nardus L. ) and compound citronellal

Este trabalho teve como objetivo avaliar o efeito fungitóxico do óleo essencial de capim-citronela e do seu constituinte majoritário citronelal sobre a inibição micelial do fitopatógeno Fusarium subglutinans, agente causal da fusariose da cultura do abacaxi (Ananas comosus). Para avaliar o efeito do óleo essencial no crescimento micelial do fungo, foram utilizadas seis alíquotas (0, 5, 10, 15, 20 e 25 ìL) do óleo e do citronelal que foram distribuídas na superfície do meio BDA (batata-dextrose-ágar) antes da repicagem do fungo. O crescimento micelial foi medido após 48 h de instalação do experimento e em cinco épocas de avaliação (2, 4, 6, 8 e 10 dias após repicagem). Os resultados indicaram que o óleo essencial do capim-citronela demonstrou maior efeito inibitório do crescimento micelial do fungo F. subglutinans do que o composto citronelal. Em todas as alíquotas utilizadas o óleo essencial proporcionou menor taxa de crescimento micelial do que o citronelal.

This study aimed to evaluate the fungitoxic effect of the essential oil of citronella grass and its major constituent citronellal on the inhibition of mycelial pathogen Fusarium subglutinans, the causal agent of Fusarium culture of pineapple (Ananas comosus). To evaluate the effect of essential oil in the mycelial growth of the fungus were used six rates (0, 5, 10, 15, 20 and 25 mL) of oil that were distributed on the surface of PDA medium (potato dextrose agar) before subculturing of the fungus. Mycelial growth was measured after 48 h of the experiment and five times of assessment (2, 4, 6, 8 and 10 days after subculturing). The results indicated that the essential oil of citronella grass showed higher inhibitory effect of mycelial growth of the fungus F. subglutinans than compound citronellal. In all rates used of the essential oil gave lower growth rate than the mycelial citronellal.

Essential oil biosynthesis and regulation in the genus Cymbopogon.

Essential oils distilled from Cymbopogon species are of immense commercial value as flavors and fragrances in the perfumery, cosmetics, soaps, and detergents and in pharmaceutical industries. Two major constituents of the essential oil, geraniol and citral, due to their specific rose and lemon like aromas are widely used as flavors, fragrances and cosmetics. Citral is also used for the synthesis of vitamin A and ionones (for example, beta-ionone, methyl ionone). Moreover, Cymbopogon essential oils and constituents possess many useful biological activities including cytotoxic, anti-inflammatory and antioxidant. Despite the immense commercial and biological significance of the Cymbopogon essential oils, little is known about their biosynthesis and regulatory mechanisms. So far it is known that essential oils are biosynthesized via the classical acetate-MVA route and existence of a newly discovered MEP pathway in Cymbopogon remains as a topic for investigation. The aim of the present review is to discuss the biosynthesis and regulation of essential oils in the genus Cymbopogon with given emphasis to two elite members, lemongrass (C. flexuosus Nees ex Steud) and palmarosa (C. martinii Roxb.). This article highlights the work done so far towards understanding of essential oil biosynthesis and regulation in the genus Cymbopogon. Also, based on our experiences with Cymbopogon species, we would like to propose C. flexuosus as a model system for the study of essential oil metabolism beyond the much studied plant family Lamiaceae.

Cellulase production by six Trichoderma spp. fermented on medicinal plant processings.

Capabilities of cellulase production, using delignified bioprocessings of medicinal and aromatic plants, viz. citronella (Cymbopogon winterianus) and Artemisia annua (known as marc of Artemisia) and garden waste (chiefly containing Cynodon dactylon), by the six species of Trichoderma were comparatively evaluated. Among the members of Trichoderma studied, T. citrinoviride was found to be the most efficient producer of cellulases along with a high level of beta-glucosidase (produced 102.4 IU g(-1) on marc of Artemisia; 101.33 IU g(-1) on garden waste; 81.86 IU g(-1) on distillation waste of citronella and 94.77 IU g(-1) on pure cellulose). Although T. virens was noticed to be the minimal enzyme producer fungus, it interestingly could not produce complete cellulase enzyme complex on any test waste or pure cellulose, except on marc of Artemisia, where it produced all three enzymes of the complex. Immediate reduction in pH was also noticed during fermentation in the case of pure polymer (cellulose) by all tested fungi, while it was delayed with delignified agrowastes. The pH profile varied with the substrate used as well as with individual species of Trichoderma. On the other hand, no alteration in pH with any species of Trichoderma was noticed when grown on marc of A. annua, which might be due to the buffering capacity of this marc.

Insecticidal activity of three plants extracts on the cowpea pod sucking bug, Clavigralla tomentosicollis, STAL (Hemiptera: Coreidae).

In Burkina Faso, farmers commonly use insecticidal plants for crop protection. To understand how insecticidal plant works (their mode of action), we carried out a bioassay on Clavigralla tomentosicollis, the cowpea pod sucking bugs with three insecticidal plants, Cassia nigricans V., Cymbopogon schoenanthus S. and Cleome viscosa L. Three modes of exposures (1) direct contact application, (2) stomach poisoning activity (3) and inhalation toxicity activity, were tested. The results showed a potent contact and stomach toxicity on 1st instars larvae regardless of the three crude extracts. But the plant extracts was less effective with older stages of the insects. A highest effectiveness was recorded with inhalation of vapours of crude extracts regardless of insect stages and type of plants. Implications of these findings are discussed regarding the use of plant extract for controlling pod sucking bugs in cowpea fields.

Manipulation of rumen ecology by dietary lemongrass (Cymbopogon citratus Stapf.) powder supplementation.

This experiment was conducted to investigate the effect of lemongrass [Cymbopogon citratus (DC.) Stapf.] powder (LGP) on rumen ecology, rumen microorganisms, and digestibility of nutrients. Four ruminally fistulated crossbred (Brahman native) beef cattle were randomly assigned according to a 4 x 4 Latin square design. The dietary treatments were LGP supplementation at 0, 100, 200, and 300 g/d with urea-treated rice straw (5%) fed to allow ad libitum intake. Digestibilities of DM, ether extract, and NDF were significantly different among treatments and were greatest at 100 g/d of supplementation. However, digestibility of CP was decreased with LGP supplementation (P < 0.05), whereas ruminal NH(3)-N and plasma urea N were decreased with incremental additions of LGP (P < 0.05). Ruminal VFA concentrations were similar among supplementation concentrations (P > 0.05). Total viable bacteria, amylolytic bacteria, and cellulolytic bacteria were significantly different among treatments and were greatest at 100 g/d of supplementation (4.7 x 10(9), 1.7 x 10(7), and 2.0 x 10(9) cfu/mL, respectively). Protozoal populations were significantly decreased by LGP supplementation. In addition, efficiency of rumen microbial N synthesis based on OM truly digested in the rumen was enriched by LGP supplementation, especially at 100 g/d (34.2 g of N/kg of OM truly digested in the rumen). Based on this study, it could be concluded that supplementation of LGP at 100 g/d improved digestibilities of nutrients, rumen microbial population, and microbial protein synthesis efficiency, thus improving rumen ecology in beef cattle.

Effects of Cymbopogon citratus L. essential oil on the growth, lipid content and morphogenesis of Aspergillus niger ML2-strain.

The mycelial growth of Aspergillus niger van Tieghem was completely inhibited using 1.5 (microl/ml or 2.0 (microl/ml of Cymbopogon citratus essential oil applied by fumigation or contact method in Czapek liquid medium, respectively. This oil was found also to be fungicidal at the same concentrations. The sublethal doses 1.0 and 1.5 (microl/ml inhibited about 70% of fungal growth after five days of incubation and delayed conidiation as compared with the control. Microscopic observations using Light Microscope (LM), Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) were carried out to determine the ultra structural modifications of A. niger hyphae after treatment with C. citratus essential oil. The hyphal diameter and hyphal wall appeared markedly thinner. This oil also caused plasma membrane disruption and mitochondrial structure disorganization. Moreover, Ca+2, K+ and Mg+2 leakages increased from the fumigated mycelium and its total lipid content decreased, while the saturated fatty acids decreased and unsaturated fatty acids increased. These findings increase the possibility of exploiting C. citratus essential oil as an effective inhibitor of biodegrading and storage contaminating fungi and in fruit juice preservation.

Fungal pathogens associated with banana fruit in Sri Lanka, and their treatment with essential oils.

The crown rot pathogens isolated from banana samples collected from 12 localities in Sri Lanka were Lasiodiplodia theobromae, Fusarium proliferatum and Colletotrichum musae. Fungal pathogens isolated were able to cause crown rot disease alone or in combination. Disease severity was higher when combinations of virulent pathogens were used. Cymbopogon nardus and Ocimum basilicum oils displayed fungicidal activity against C. musae and F. proliferatum between 0.2-0.6% (v/v) in a Poisoned food bioassay. Slightly lower concentrations of the test oils were needed for similar activity during liquid bioassays. The combination of Cymbopogon nardus and O. basilicum oils demonstrated synergistic action during both in-vivo bioassays.

Effect of different organic manures/composts on the herbage and essential oil yield of Cymbopogon winterianus and their influence on the native AM population in a marginal alfisol.

Four organic amendments: leaf compost (LC), vegetable compost (VC), poultry manure (PM) and sewage sludge (SSL) applied at four doses (40, 80, 100 and 120 tha(-1)) were evaluated for their effect on the herbage yield, essential oil content and inoculum potential (IP) of native arbuscular mycorrhizal fungi (AMF) on three varieties of Java citronella, Cymbopogon winterianus Jowitt (Manjusha, Mandakini, and Bio-13). PM applied at 100 t ha(-1) followed by SSL increased the herbage, essential oil content and dry matter yield significantly. Bio-13 performed better and produced the highest herbage, essential oil and dry matter yield. The type and dose of the various organic amendments also significantly influenced the indigenous AMF infectious propagules in soil. Highest number of AMF propagules were recorded in the LC amended plots in all the three varieties. Amongst the varieties, highest native mycorrhizal inoculum was recorded in the Bio-13. Least number of AM infectious propagules were recorded in the Mandakini plants grown in 40 t ha(-1) SSL.

A phase II detoxification enzyme inducer from lemongrass: identification of citral and involvement of electrophilic reaction in the enzyme induction.

We have developed a simple system for the sensitive detection and measurement of glutathione S-transferase (GST) activity that detoxifies polycyclic aromatic hydrocarbons using the cultured rat normal liver epithelial cell line, RL34 cells. Citral (3,7-dimethyl-2,6-octadienal) was isolated from the methanol extract of lemongrass (Cymbopogon citratus) and identified as a novel inducer of GST. Citral, a mixture of the two stereoisomers geranial and neral, dose- and time-dependently induced the total and pi-class-specific activities of GST. The structure-activity relationship study revealed that geranial, an E-isomer, was mainly responsible for the inducing activity of citral mixture and the aldehyde group conjugated with a trans-double bond is an essential structural factor. The data were consistent with the in vitro observation that both glutathione (GSH) and protein thiol quickly and specifically reacted with the active isomer geranial, but not neral. Pretreatment of the cells with diethyl maleate significantly enhanced not only the basal activity but also the citral-stimulated activity of GST, while pretreatment with N-acetyl-cysteine inhibited it. Moreover, the treatment of RL 34 cells with geranial for 30 min significantly attenuated the intracellular GSH level, while application for 18 h enhanced it. These results strongly suggested that the electrophilic property characterized by the reactivity with intracellular nucleophiles including protein thiol or glutathione (GSH) plays an important role in the induction of GST. The present study also implied the antioxidant role of GST induction by citral in mouse skin, providing a new insight into skin cancer prevention.