Cardioprotective Potential of Cymbopogon citratus Essential Oil against Isoproterenol-induced Cardiomyocyte Hypertrophy: Possible Involvement of NLRP3 Inflammasome and Oxidative Phosphorylation Complex Subunits.

OBJECTIVE: Cymbopogon citratus (DC.) Stapf is a medicinal and edible herb that is widely used for the treatment of gastric, nervous and hypertensive disorders. In this study, we investigated the cardioprotective effects and mechanisms of the essential oil, the main active ingredient of Cymbopogon citratus, on isoproterenol (ISO)-induced cardiomyocyte hypertrophy. METHODS: The compositions of Cymbopogon citratus essential oil (CCEO) were determined by gas chromatography-mass spectrometry. Cardiomyocytes were pretreated with 16.9 µg/L CCEO for 1 h followed by 10 µmol/L ISO for 24 h. Cardiac hypertrophy-related indicators and NLRP3 inflammasome expression were evaluated. Subsequently, transcriptome sequencing (RNA-seq) and target verification were used to further explore the underlying mechanism. RESULTS: Our results showed that the CCEO mainly included citronellal (45.66%), geraniol (23.32%), and citronellol (10.37%). CCEO inhibited ISO-induced increases in cell surface area and protein content, as well as the upregulation of fetal gene expression. Moreover, CCEO inhibited ISO-induced NLRP3 inflammasome expression, as evidenced by decreased lactate dehydrogenase content and downregulated mRNA levels of NLRP3, ASC, CASP1, GSDMD, and IL-1ß, as well as reduced protein levels of NLRP3, ASC, pro-caspase-1, caspase-1 (p20), GSDMD-FL, GSDMD-N, and pro-IL-1ß. The RNA-seq results showed that CCEO inhibited the increase in the mRNA levels of 26 oxidative phosphorylation complex subunits in ISO-treated cardiomyocytes. Our further experiments confirmed that CCEO suppressed ISO-induced upregulation of mt-Nd1, Sdhd, mt-Cytb, Uqcrq, and mt-Atp6 but had no obvious effects on mt-Col expression. CONCLUSION: CCEO inhibits ISO-induced cardiomyocyte hypertrophy through the suppression of NLRP3 inflammasome expression and the regulation of several oxidative phosphorylation complex subunits.

Development and analysis of de novo transcriptome assemblies of multiple genotypes of Cymbopogon spp. reveal candidate genes involved in the biosynthesis of aromatic monoterpenes.

Despite the high economic value of the monoterpene-rich essential oils from different genotypes of Cymbopogon, the knowledge about the genes and metabolic route(s) involved in the biosynthesis of aromatic monoterpenes in this genus is limited. In the present study, a comprehensive transcriptome analysis of four genotypes of Cymbopogon, displaying diverse quantitative and qualitative profiles of volatile monoterpenes in their essential oils has been carried out. The comparative analysis of the deduced protein sequences corresponding to the transcriptomes of the four genotypes revealed 4609 genotype-specific orthogroups, which might contribute in defining genotype-specific phenotypes. The transcriptome data mining led to the identification of unigenes involved in the isoprenogenesis. The homology searches, combined with the phylogenetic and expression analyses provided information about candidate genes concerning the biosynthesis of monoterpene aldehyde, monoterpene alcohol, and monoterpene esters. In addition, the present study suggests a potential role of geranial reductase like enzyme in the biosynthesis of monoterpene aldehyde in Cymbopogon spp. The detailed analysis of the candidate pathway genes suggested that multiple enzymatic routes might be involved in the biosynthesis of aromatic monoterpenes in the genus Cymbopogon. The present study provides deeper insights into the biosynthesis of monoterpenes, which will be useful for the genetic improvement of these aromatic grasses.

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.

Comparative transcriptional analysis of metabolic pathways and mechanisms regulating essential oil biosynthesis in four elite Cymbopogon spp.

Cymbopogon is an important aromatic and medicinal grass with several species of ethnopharmaceutical importance. The genus is extremely rich in secondary metabolites, monoterpenes like geraniol and citral being principal constituents, also used as biomarker for classification and identification of Cymbopogon chemotypes. In the light of this, present study involved RNA sequencing and comparison of expression profiles of four contrasting Cymbopogon species namely C. flexuosus var. Chirharit (citral rich and frost resistant), C. martinii var. PRC-1 (geraniol rich), C. pendulus var. Praman (the most stable and citral-rich genotype), and Jamrosa (a hybrid of C. nardus var. confertiflorus × C. jwarancusa (rich in geraniol and geranyl acetate). The transcriptome profiles revealed marked differences in gene expression patterns of 28 differentially expressed genes (DEGs) of terpenoid metabolic pathways between the four Cymbopogon sp. The major DEGs were Carotenoid Cleavage Dioxygenases (CCD), Aspartate aminotransferase (ASP amino), Mevalonate E-4 hydroxy, AKR, GGPS, FDPS, and AAT. In addition, few TFs related to different regulatory pathways were also identified. The gene expression profiles of DEGs were correlated to the EO yield and their monoterpene compositions. Overall, the PRC-1 (C. martinii) shows distinguished gene expression profiles from all other genotypes. Thus, the transcriptome sequence database expanded our understanding of terpenoid metabolism and its molecular regulation in Cymbopogon species. Additionally, this data also serves as an important source of knowledge for enhancing oil yield and quality in Cymbopogon and closely related taxa. KEY MESSAGE: Unfolding the new secretes surrounding EO biosynthesis and regulation in four contrasting Cymbopogon species.

Anti-Inflammatory Activity of Geraniol Isolated from Lemon Grass on Ox-LDL-Stimulated Endothelial Cells by Upregulation of Heme Oxygenase-1 via PI3K/Akt and Nrf-2 Signaling Pathways.

Among the world's leading causes of cardiovascular disease, atherosclerosis is a chronic inflammatory disorder that affects the arteries. Both vasodilation and vasoconstriction, low levels of nitric oxide and high levels of reactive oxygen species and pro-inflammatory factors characterize dysfunctional blood vessels. Hypertension, and atherosclerosis, all start with this dysfunction. Geraniol, a compound of acyclic monoterpene alcohol, found in plants such as geranium, lemongrass and rose, is a primary constituent of essential oils. It shows a variety of pharmacological properties. This study aimed to investigate the impact of geraniol on Ox-LDL-induced stress and inflammation in human umbilical vein endothelial cells. In this study, HUVECs were treated with Ox-LDL or geraniol at different dose concentrations. MTT assay, Western blot, ROS generation and DNA fragmentation were used to evaluate geraniol's effects on Ox-LDL-induced HUVECs inflammation. The results show that geraniol pre-incubation ameliorates Ox-LDL-mediated HUVECs cytotoxicity and DNA fragmentation. The geraniol inhibited the production of pro-inflammatory cytokines by Ox-LDL, including TNF-α, IL-6 and IL-1ß. In Ox-LDL-stimulated HUVECs, geraniol suppresses the nuclear translocation and activity of NF-ᴋB as well as phosphorylation of IkBα. Moreover, geraniol activated the PI3K/AKT/NRF2 pathway in HUVECs, resulting in an increase in the expression of HO-1. Taking our data together, we can conclude that, in HUVECs, geraniol inhibits Ox-LDL-induced inflammation and oxidative stress by targeting PI3/AKT/NRF2.

Trace element accumulation potential in lemongrass varieties (Cymbopogon species) and prediction through regression model equations followed by path analysis: a field study.

A field investigation was conducted to monitor the trace element accumulation pattern and potential in lemongrass varieties when cultivated in varying concentrations of tannery sludge contaminated soils. Regression model equations were developed to predict the trace elements concentration in lemongrass plant parts. Model efficiency values ranged between 0.53 and 0.85 for roots and 0.50 to 0.77 for shoots. R2 for all the equations was high and ranged between 0.52 and 0.95 for roots and 0.50 to 0.91 for shoots. Path analysis coefficients revealed the status of interdependence between soil properties and heavy metal concentrations in plant tissues and their translocation pattern in the same. TF > 1 for Ni and Pb was recorded in all test varieties at different tannery sludge concentrations in soil and for Cd in Suwarna variety grown in sole TS. BAF>1 and BAC>1 for Ni and Pb was observed for all test varieties. BCF>1 for Cr was found in Suwarna variety at sole tannery sludge. It can be concluded that lemongrass can accumulate lead and nickel in its harvestable plant parts. Hence, it can act as a suitable phytoextractor for the same metals. Range of essential oil content (percentage) varied in all test varieties i.e. Shikhar (1.04-1.29), Krishna (0.94-1.05), Suwarna (0.82-0.95) and Chirharit (0.87-1.06) at different tannery sludge concentrations. Moreover, heavy metal content in the essential oil of all test varieties was found to be within the permissible limits, hence cultivation of lemongrass can be recommended at metal contaminated sites with minimum risk of food chain contamination.

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.

Biochar aided aromatic grass [Cymbopogon martini (Roxb.) Wats.] vegetation: A sustainable method for stabilization of highly acidic mine waste.

Dumping of acidic mine waste poses severe threats to the ecosystem due to high acidity, nutrient deficiency and mobility of toxic metals. The present study has been undertaken on phytoremediation by amending the acidic soil/mine waste with biochar (BC) and plantation of palmarosa (Cymbopogon martini (Roxb.) Wats. A greenhouse experiment in different combinations of biochar and acidic mine waste was conducted to assess the phytoremediation efficiency of palmarosa by BC amendments. Results indicate that the palmarosa tolerates multiple stresses effectively with a 54 % metal tolerance index (MTI) and capable of reducing acid production from the acidic mine waste alone. BC incorporation in the mine waste and soil treatments significantly enhanced the palmarosa biomass (1.11-3.3 times) and oil content by liming the acid, immobilization of metals and improving the soil quality. BC addition in highly acidic mine waste amplified the phytoremediation efficiency and mitigates abiotic oxidative stress on plants (MTI 84 % to >100 %). BC aided palmarosa plantation shifted the soil from high-risk assessment code (RAC) to low RAC for vegetation. Biochar amendments along with palmarosa plantation offer a sustainable technology for phytostabilization of highly acidic mine waste along with the production of industrially important essential oil.

Gamma rays induced acquisition of structural modification in chitosan boosts photosynthetic machinery, enzymatic activities and essential oil production in citronella grass (Cymbopogon winterianus Jowitt).

Oligomers derived through irradiation of marine polysaccharides have generated a lot of interest of plant biologists as the application of these molecules has yielded positive results regarding various plant processes. To comprehend the previously established growth-promoting activity of irradiated chitosan (ICH) and to gain insight of the structure-property relationship, gamma rays induced structural changes were analyzed using techniques such as Fourier Transform Infrared (FT-IR) spectroscopy, Ultraviolet-visible (UV-Vis) spectroscopy, 13C-Nuclear Magnetic Resonance (NMR) spectroscopy and Scanning Electron Microscopy (SEM). Moreover, to study the bioactivity of ICH samples a pot experiment was conducted on citronella grass (Cymbopogon winterianus) to access its response to foliar application of various levels (40, 60, 80 and 100 mg L-1) of ICH in terms of growth, physiological attributes and essential oil (EO) production. The application of ICH at 80 mg L-1(ICH-80) resulted in the maximum values of most of the attributes studied. Due to this treatment, the maximum improvement in the content (29.58%) and yield (90.81%) of EO in Cymbopogon winterianus were achieved. Gas chromatography-mass spectrometry (GC-MS) analysis revealed that ICH-80 also increased the content of citronellal (14.81%) and geraniol (18.15%) of the EO as compared to the control.

Physical properties, antifungal and mycotoxin inhibitory activities of five essential oil nanoemulsions: Impact of oil compositions and processing parameters.

The influence of homogenization conditions on selected essential oil (thyme, lemongrass, cinnamon, peppermint, and clove)-in-water nanoemulsion formation and stability was investigated. Physically stable essential oil nanoemulsions could be fabricated by a microfludizer under optimized processing conditions (10,000 psi and 2 passes). The chemical compositions of EOs was characterized using GC-MS. The antifungal activity and mycotoxin inhibitory activity of essential oils in both bulk and nanoemulsion forms were determined using two isolates of Fusarium graminearum. The major chemical components of essential oil had a remarkable impact on long term physical stability, antifungal activity, and inhibition of mycotoxin production. With regard to inhibition of mycotoxin production, the mycotoxin inhibitory activity of essential oils was enhanced considerably in nanoemulsion form, which was attributed to greater solubility of the essential oils. It was also noted that the same essential oils exhibited significant differences in inhibition of mycotoxin production in the two isolates of F. graminearum.

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.

An in situ study of growth of Lemongrass Cymbopogon flexuosus (Nees ex Steud.) W. Watson on varying concentration of Chromium (Cr+6) on soil and its bioaccumulation: Perspectives on phytoremediation potential and phytostabilisation of chromium toxicity.

Chromium (Cr) contamination in soil is a growing concern in sustainable agricultural production and food safety. Remediation of Cr from contaminated soils is a challenging task which may not only help in sustaining agriculture but also in minimizing adverse environmental impacts. Pot culture experiments were performed with the application of varied concentration of Cr+6 to assess the Chromium accumulation potential of Lemongrass and to study the impact of toxic concentration of Cr+6 on morphological, physiological and biochemical parameters of the plant. The results showed an increasing accumulation trend of Chromium with increasing Chromium concentrations in both root and shoot of 60 days old Lemongrass plants, while the protein and chlorophyll contents decreased. Similarly, accumulation of Cr increased the levels of proline and antioxidant enzymes indicating the enhanced damage control activity. The potentiality of the plant with the capacity to accumulate and stabilize Cr compound in Cr contaminated soil by phytoremediation process has been explored in the present investigation.

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.

Phytoremediation of metals using lemongrass (Cymbopogon citratus (D.C.) Stapf.) grown under different levels of red mud in soil amended with biowastes.

Due to hostile condition of red mud (RM), its utilization for vegetation is restricted. Therefore, RM with biowastes as soil amendment may offer suitable combination to support plant growth with reduced risk of metal toxicity. To evaluate the effects of RM on soil properties, plant growth performance, and metal accumulation in lemongrass, a study was conducted using different RM concentrations (0, 5, 10, and 15% w/w) in soil amended with biowastes [cow dung manure (CD) or sewage-sludge (SS)]. Application of RM in soil with biowastes improved organic matter and nutrient contents and caused reduction in phytoavailable metal contents. Total plant biomass was increased under all treatments, maximally at 5% RM in soil with SS (91.4%) and CD (51.7%) compared to that in control (no RM and biowastes). Lemongrass acted as a potential metal-tolerant plant as its metal tolerance index is >100%. Based on translocation and bioconcentration factors, lemongrass acted as a potential phytostabilizer of Fe, Mn, and Cu in roots and was found efficient in translocation of Al, Zn, Cd, Pb, Cr, As, and Ni from roots to shoot. The study suggests that 5% RM with biowastes preferably SS may be used to enhance phytoremediation potential of lemongrass.

Genome wide transcriptome profiling reveals differential gene expression in secondary metabolite pathway of Cymbopogon winterianus.

Advances in transcriptome sequencing provide fast, cost-effective and reliable approach to generate large expression datasets especially suitable for non-model species to identify putative genes, key pathway and regulatory mechanism. Citronella (Cymbopogon winterianus) is an aromatic medicinal grass used for anti-tumoral, antibacterial, anti-fungal, antiviral, detoxifying and natural insect repellent properties. Despite of having number of utilities, the genes involved in terpenes biosynthetic pathway is not yet clearly elucidated. The present study is a pioneering attempt to generate an exhaustive molecular information of secondary metabolite pathway and to increase genomic resources in Citronella. Using high-throughput RNA-Seq technology, root and leaf transcriptome was analysed at an unprecedented depth (11.7 Gb). Targeted searches identified majority of the genes associated with metabolic pathway and other natural product pathway viz. antibiotics synthesis along with many novel genes. Terpenoid biosynthesis genes comparative expression results were validated for 15 unigenes by RT-PCR and qRT-PCR. Thus the coverage of these transcriptome is comprehensive enough to discover all known genes of major metabolic pathways. This transcriptome dataset can serve as important public information for gene expression, genomics and function genomics studies in Citronella and shall act as a benchmark for future improvement of the crop.

Effect of H2O2 concentrations on copper removal using the modified hydrothermal biochar.

This study investigated effect of H2O2 concentrations on copper removal using H2O2 modified hydrothermal carbonization Cymbopogon schoenanthus L. Spreng (HLG). Sorption behaviors of Cu (II) on the modified HLG by 20% H2O2 (mHLG2) could be the most desirable. Based on Langmuir isotherm, the maximum amount of Cu (II) uptake was in the sequence of mHLG2 (53.8mgg(-1))>mHLG1 (44.2mgg(-1))>mHLG3 (42.0mgg(-1))>mHLG0 (35.8mgg(-1)), which was higher than the results from majority of previous studies, suggesting that H2O2 modification advanced sorption capacity of hydrothermal biochars evidently. Effect mechanisms exploration indicated that the difference of Cu (II) removal by biochars before and after the modification was mainly related to functional groups. Carboxylic group was responsible for the best sorption property of Cu (II) by mHLG2, which was attributed to its significant relationships with H2O2 modification and Cu (II) removal.

An investigation into the effectiveness of sand media amended with biochar to remove BOD5, suspended solids and coliforms using wetland mesocosms.

Constructed wetland ecotechnologies (CWEs) are a promising solution to effectively treat domestic wastewater in developing countries at low cost. This paper reports the findings of the effectiveness of sand media amended with woody biochar and two plants species (Melaleuca quinquenervia and Cymbopogon citratus) in removing biological oxygen demand (BOD5), suspended solids and coliforms. The experimental design consisted of 21 vertical flow (VF) mesocosms. There were seven media treatments using sand amended with varying proportions of biochar. During the first 8 months, the mesocosms were loaded with secondary clarified wastewater (SCW) then septage. The influent had a 4-day hydraulic retention time. Samples were monitored for BOD5, total suspended solids (TSS), total volatile solids (TVS), total coliforms and faecal coliforms. In the first 8 months, there were no significant performance differences between media treatments in the outflow concentrations of BOD5, TSS and TVS. The significant differences occurred during the last 3 months; using septage with biochar additions performed better than pure sand. For coliforms, the significant differences occurred after 6 months. In conclusion, the addition of biochar was not effective for SCW. The VF mesocosms system proved to be more effective in removing BOD5, TSS, TVS and coliforms when septage was loaded into the media.

Palmarosa [Cymbopogon martinii (Roxb.) Wats.] as a putative crop for phytoremediation, in tannery sludge polluted soil.

A field experiment using tannery sludge as a soil amendment material and palmarosa (Cymbopogon martinii) as a potential phytostabilizer was conducted to investigate their synergistic effect in relation to the improvement in soil quality/property. Three consecutive harvests of two cultivars of palmarosa-PRC-1 and Trishna, were examined to find out the influence of different tannery sludge doses on their herb, dry matter, essential oil yield and heavy metal accumulation. Soil fertility parameters (N, P, K, Organic carbon) were markedly affected by different doses of sludge. Enhanced soil nitrogen was positively correlated with herb yield (0.719*) and plant height (0.797*). The highest dose of tannery sludge (100 t ha(-1)) exhibited best performance than other treatments with respect to herb, dry matter and oil yield in all three harvests. Trishna was found to be superior to PRC-1 in relation to same studied traits. Quality of oil varied, but was insignificant statistically. Uptake of heavy metals followed same order (Cr>Ni>Pb>Cd) in roots and shoots. Translocation factor <1 for all trace elements and Bioconcentration factor >1 was observed in case of all heavy metals. Overall, tannery sludge enhanced the productivity of crop and metal accumulation occurred in roots with a meager translocation to shoots, hence it can be used as a phytostabiliser. The major advantage of taking palmarosa in metal polluted soil is that unlike food and agricultural crops, the product (essential oil) is extracted by hydro-distillation and there is no chance of oil contamination, thus is commercially acceptable.

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.