Citronellyl Formate Research Articles

Chemical Profile and Use of the Peat as an Adsorbent for Extraction of Volatile Compounds from Leaves of Geranium (Pelargonium graveolens L' Herit).

Volatile organic compounds (VOCs) from leaves of geranium (Pelargonium graveolens L’ Herit) were extracted by dynamic headspace using Porapak Q (HSD-P) as adsorbent and peat, a novel adsorbent in the extraction of plant volatiles, analyzed by gas chromatography–mass spectrometry (GC/MS) and gas chromatography–flame ionization (GC/FID), and the results were compared with those obtained by hydrodistillation (HD). The yield volatiles changed with the extraction method. HD was more efficient for extracting linalool (11.19%) and citronellyl formate (9.41%). Citronellol (28.06%), geraniol (38.26%) and 6,9-guaiadiene (9.55%) and geranyl tiglate (8.21%) were the major components identified by dynamic headspace using peat (HSD-T), while citronellol (16.88%), geraniol (13.63%), 6,9-guaiadiene (16.98%) and citronellyl formate (6.95%) were identified by dynamic headspace using Porapak Q (HSD-P). Furthermore, this work showed, for the first time, that in natura peat is useful to extract VOCs from leaves of geranium.

Use of plant growth promoting bacteria as an efficient biotechnological tool to enhance the biomass and secondary metabolites production of the industrial crop Pelargonium graveolens L'Hér. under semi-controlled conditions

Pelargonium graveolens L'Hér. well known as rose-scented geranium is used worldwide in perfume, cosmetic, pharmaceutical and food industries. The essential oil and phenolic concentrations for this species were reported to be very low which requires their improvement. The effect of three plant growth promoting bacteria namely Pseudomonas rhizophila S211, Halomonas desertis G11 and Oceanobacillus iheyensis E9 on P. graveolens transplants were evaluated with single, dual and consortium modalities under semi controlled conditions. Significant positive effects on the growth related parameters, leaf and root biomass, photosynthetic pigments and secondary metabolites production were observed with inoculum-specific response. The highest root biomass was recorded with the dual inoculation [H. desertis G11+ O. iheyensis E9] while the inoculum [P. rhizophila S211 + O. iheyensis E9] showed the highest ability to enhance fresh leaf biomass (12.27 ± 0.61 g) leading to an improvement rate of 43.34 % over the control. A significant increase in the amounts of total phenolics and flavonoids contents in the inoculated plants over the control was revealed for all the treatments. The consortium was the most efficient to enhance the contents of total phenolics (105.62 ± 2.95 mg GAE/g DW) and flavonoids (48.55 ± 1.25 mg RE/g DW) resulting in an increase over the control of 67.35 % and 53.59 %, respectively. The essential oil synthesis was enhanced significantly for all the inoculated transplants compared with the control conditions. The dual inoculations resulted in the highest levels of essential oil contents in P. graveolens leaves, followed by the consortium than individual inoculants. The dual inoculation [H. desertis G11 + O. iheyensis E9] gave the highest essential oil amount (0.49 ± 0.03 %) with an increase of 68.96 % over the control (0.29 ± 0.01 %). The GC–MS analyses of the essential oils resulted in the identification of 23 compounds. In all treatments, citronellol (25.84–40.02 %), geraniol (9.67–11.96 %), citronellyl formate (5.35–10.14 %), 2-phenylethyl tiglate (4.58–7.13 %), epi-γ-eudesmol (4.38–5.87 %) and linalool (2.56–4.07 %) are the main compounds with qualitative and quantitative variation. Interestingly, the three dual inoculations gave the highest amounts of citronellol, citronellyl formate and citronellyl tiglate compounds. The highest concentration of the high-value citronellol (40.02 %) which defines the commercial value of P. graveolens was recorded with the inoculum [H. desertis G11+ O. iheyensis E9] resulting in an increase rate of 54.87 % over the control (25.84 %). This study suggests the efficiency of the studied inoculums as promising biofertilizers with significant potentials to enhance P. graveolens biomass and secondary metabolites production which present an alternative biotechnological tool to limit the excessive use of chemical fertilizers.

Antifungal and aflatoxin B1 inhibitory efficacy of nanoencapsulated Pelargonium graveolens L. essential oil and its mode of action

The study reports the antifungal and aflatoxin B1 (AFB1) inhibitory mode of action of nanoencapsulated Pelargonium graveolens L. essential oil (Ne-PGEO). Nanoencapsulation of PGEO was prepared using chitosan nanoparticles and interactions were confirmed by scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) analysis. Chemical composition of PGEO was explored by gas chromatography-mass spectrometry (GC-MS) analysis where citronellyl formate (19.2%), linalool (15.2%), menthone (16.7%), and isomenthone (12.2%) were identified as the major compounds. Ne-PGEO inhibited the growth and aflatoxin B1 production by Aspergillus flavus at 1.00 μLmL−1, which was lower than the free PGEO at 1.25 μLmL−1. The antifungal and aflatoxin B1 inhibitory mechanism of Ne-BPEO were related to a decrease in ergosterol content, carbon source utilization, enhancement of ions leakage, and impairment in the functioning of the ver-1 gene. In addition, the Ne-PGEO effectively preserves the organoleptic (color, taste, odour, and texture) and nutritional properties of the model food (maize grain). In view of enhanced antifungal, anti-aflatoxin activity, and sensory attributes, the results suggested that Ne-PGEO could be used as a plant-based food preservative to enhance the shelf-life of food commodities.

The impact of UV-B radiation on antioxidant activity, essential oil composition and physiological factors of Pelargonium graveolens L’Hér.

Pelargonium graveolens L’Hér. is an important aromatic and medicinal plant, which is famous for its essential oils (EOS).The aim of this study was to evaluate the effects of UV-B on growth factors, essential oils components, antioxidant activity of essential oils and antioxidant enzymes activity, carbohydrate content, leaf pigments and total protein. Cuttings from potted plants were exposed to 0, 0.12, 0.26, and 0.38 W m-2 of UV-B radiation. The antioxidant enzyme activity, carbohydrate content and protein and pigments contents were measured by spectrophotometric methods. The composition of EOS was analyzed by GC-MS. The antioxidant activity of the EOS was analyzed by free radical scavenging activity using the 2,2-diphenyl-1-picrylhydrazyl (DPPH). Results demonstrated that the leaves’ fresh and dry mass, plant height, number of leaves, and the content of chlorophyll, protein and total carbohydrates were significantly (P ≤ 0.05) decreased, when plants were subjected to increased intensity of UV radiation. In contrast, the content of carotenoids and antioxidant enzymes activities increased. The chemical composition of EOS indicated that the main components in all treated plants were citronellol, geraniol, and citronellyl formate. The antioxidant activity of the essential oils increased with increasing UV-B radiation. The maximum and minimum IC50 values of essential oils were obtained in control plants and plants under 0.38 W m-2 UV-B radiation, respectively.

Antifungal Activity of Pelargonium graveolens Essential Oil and its Fractions Against Wood Decay Fungi

In order to valorize Moroccan aromatic and medicinal plants, this study focused on both the chemical characterization and the study of the antifungal activity of Pelargonium graveolens essential oil and its fractions against four fungi that are responsible for wood decay (Coniophora puteana, Coriolus versicolor, Poria placenta and Gloeophyllum trabeum). The essential oils were analyzed by Gas chromatography/Mass spectrometry (GC/MS) and evaluated for antifungal activity, using the macrodilution method for the determination of EC50. The GC/MS essential oil analysis has led to the identification of 54 components. Citronellol (25.24 %), geraniol (23.36 %), citronellyl formate (8.35 %), linalool (7.11 %), β-eudesmol (6.13 %), geranyl formate (4.26 %) and iso-menthone (3.37 %), were identified as the major components. Fractions 1, 2 and 3 essential oils have displayed qualitative similarities with the EO sample, and quantitative differences among the relative percentages of major compounds were observed. A significant difference (p < 0.0001) was shown in main compounds of fraction 3 obtained by fractional distillation. P. graveolens essential oil has inhibited all fungi with a value of EC50 between 0.255 to 1.022 mg/mL. The EC50 values of fractions 1 and 2 are ranging from 0.292 to 1.022 mg/mL. The fraction 3 exhibited a great antifungal activity against all tested fungi. These results support the potential use of P. graveolens essential oils and its fractions for wood protection against wood decay fungi.

Using RAPD and ISSR Molecular Markers to Analyze the Genetic Diversity of Rose scented Pelargonium Populations

AbstractIn the field, the chemical constituents of the essential oil of Pelargonium graveolens cutting (diploid) and polyploid seedlings are the same, but the principal components of geraniol, geranyl formate, and linalool in polyploid plants are remarkably higher than those of cutting seedlings. The contents of citronellol, citronellyl formate, and rose oxide are significantly lower in polyploid seedlings than in cutting seedlings. ISSR and RAPD molecular markers were used to analyze P. graveolens in two different genetic populations and to compare the genetic background of differences between cutting and polyploid seedlings. The genomic DNA of 60 cutting and polyploid seedlings was extracted for PCR amplification by using 3 ISSR primers and 11 RAPD primers for random sampling from adjacent cultivated fields. Among the primers, ISSR‐25 primer detected the highest diversity of the loci. Seven loci of variation were found in the two populations. The variation rates detected using 3 ISSR primers were 13.3% and 6.7% for the cutting and polyploid populations, respectively. Genetic polymorphisms in P. graveolens genome with mutation rates of 11.7% and 3.3% were respectively determined in cutting and polyploid seedlings by using 3 RAPD primers (B11, P4, and R19). Both types of molecular markers also revealed the mutation in cutting and polyploid seedlings. Results demonstrated that a genetic difference can be observed by the molecular markers, although no evident phenotypic difference exists in cutting and polyploid seedlings in fields. The trend of these molecular markers is consistent, that is, individual genetic differences in cutting seedlings are greater than those in polyploid seedlings. These results suggested that polyploid seedlings in a population are relative uniform and applicable to production.

Stable variety selection over locations and recommendations for rose-scented geranium (Pelargonium graveolens L’ Herit. ex Aiton.)

Objective: In this study, productivity and essential oil quality of rose-scented geranium (Pelargonium graveolens L’ Herit. ex Aiton.) varieties, namely CIMAP Bio-G-171, CIM-Pawan and Bourbon were assessed and compared in two locations of north India. Methods: A field experiment was conducted to evaluate the productivity, while the chemical composition of the essential oils was assessed by GC-FID and GC-MS. Result: Yields of fresh leaves and essential oil from CIMAP Bio-G-171 were significantly higher (173.64–174.42 q h-1 and 69.93–79.06 l h-1) than those of CIM-Pawan (158.08–160.56 q h-1 and 55.57–64.46 l h-1) and Bourbon (133.34–139.33 q h-1 and 44.19–48.38 l h-1). Major constituents of the oils were citronellol (20.9–39.5%), geraniol (10.9–26.5%), linalool (2.9–14.2%), isomenthone (7.4–9.4%), citronellyl formate (5.5–9.1%) and 10-epi-γ-eudesmol (5.2–9.0%). Conclusion: The essential oil yields and chemical compositions were substantially influenced by variety and location of growing. The variety CIMAP Bio-G-171 showed improvement up to 58.2–63.4% and 22.6–25.8% in essential oil productivity over the existing prevalent varieties, Bourbon and CIM-Pawan, respectively.

Chemical characterization and antimicrobial activity of Moroccan Pelargonium asperum essential oil

ABSTRACT In the aim of valorizing aromatic and medicinal plants from Morocco, this work focuses on the chemical characterization and antimicrobial activity of Pelargonium asperum essential oil against 11 microbial strains causing problems in the medical and food domain. The chemical profile of the volatile oil was investigated by GC/MS. The major compounds were citronellol (26.98%), geraniol (14.12%), isomenthone (8.80%), linalool (4.97%), citronellyl formate (3.1%), followed by geranyl formate (4.07%) and guai-6,9-diene (4.24%). The results of antimicrobial activity by using the broth microdilution method indicated that essential oil of Pelargonium asperum exhibited significant antimicrobial activity against all tested microorganisms with the strongest inhibitory effect against yeasts. The MICs values ranged from 0.003% to 0.25% (v/v) for all strains, except Pseudomonas aeruginosa, which was least susceptible and inhibited by 2% (v/v). These results suggest that Pelargonium asperum oil could be used for the development of new antimicrobial agents.

Influence of Gypsum and Farmyard Manure Application in Soil on Yield and Chemical Composition of Essential oil of Rose Scented Geranium (Pelargonium graveolens L'Herit.ex Ait.)

:A field experiment was conducted to evaluate the influence of farm yard manure (FYM) and gypsum application on the yield and chemical composition of essential oil of rose scented geranium. The herbage and essential oil yield of geranium was significantly increased (at 5 % level) by the combined application of FYM and gypsum along with recommended fertilizer application as compared to sole application of N, P and K fertilizer taken as control. The combined application of FYM and gypsum in soil was more effective to increase the herbage and essential oil yield of geranium by 35.4 % which was followed by the sole application of FYM (25.2 %) and gypsum (12.3 %) as compared to control. The chemical composition of the essential oil of geranium was affected differentially with the applied treatments. The content of citronellol, geraniol, linalool, citronellyl and geranyl formate in the essential oil of geranium were significantly increased by 48.9, 20.3, 62.3, 15.6 and 66.4 % respectively with the combined application of FYM and gypsum as compared to control but those were not significantly affected with the sole application of FYM and gypsum . The level of iso-menthone, trans-rose oxide were not affected but the content of cis-rose oxide was decreased and that of nerol and 10-epi-γ-eudesmol was increased in the essential oil of geranium with the application of FYM, gypsum and their combination as compared to control. The results suggest that the combined application of FYM and gypsum would be beneficial to obtain higher herb and essential oil yield of rose scented geranium with enhanced level of citronellol, geraniol along with their esters and other minor compounds like linalool, nerol, 10-epi-γ-eudesmol in the essential oil of geranium.

Chemical Composition and Application as Biomaterials of Essential Oils from &lt;i&gt;Ledum palustre&lt;/i&gt; of Changbai Mountain China

Ledum palustre is an important perfume plant in northeast China, and widely distributed at Changbai mountain of Jilin province. The components and contents of essential oils in Ledumpalustre were highly correlated with their growth environment. By using GC-MS, about 32 compounds were identified from Ledumpalustre essential oils of Changbai mountain. The chemical components were L-bornyl acetate (20.2%), 1,2,3,4-tetramethyl-benzene (16.5%), (−)-myrtenal (4.4%), terpinen-4-ol (4.3%), 2,6-dimethyl-2,6-octadiene (3.8%), trans-pinocarveol (3.7%), L(-)-borneol (3.0%), geranyl acetate (2.8%), (+)-aromandendrene (2.3%), ledol (1.7%), sabenene (1.6%), β-pinene (1.4%), camphene (1.1%), caryophyllene oxide (1.1%), and citronellyl formate (0.5%), which indicate the application of Ledumpalustre essential oils from Changbai mountain should be different from other areas.

Chemical Composition and In vitro Studies of the Essential Oil and Aqueous Extract of Pelargonium graveolens Growing in Jordan for Hypoglycaemic and Hypolipidemic Properties

Aims: This study aimed to analyze the chemical composition of essential oil of Pelargonium graveolens L. Her. ex Ait. growing in Jordan and to test the efficacy of the leaves aqueous extract and essential oil against pancreatic triacylglycerol lipase (PL), αamylase and α-glucosidase. Study Design: GC-MS analysis of the essential oil obtained by hydrodistillation and Solid Phase Microextraction (SPME) methods as well as in vitro enzymatic investigations. Place and Duration of Study: Faculty of Pharmacy, The University of Jordan, between November 2012 and August 2013. Results: The hydrodistilled oil of P. graveolens fresh leaves yielded twenty eight components, accounting for 95.83 % of the total oil content, while thirty seven components were detected from the fresh leaves by SPME (98.86%). Twenty six and thirty one components were identified in the hydrodistilled and SPME oils of the dried leaves amounting to 96.08 % and 97.83 %, respectively. Oxygenated monoterpenes Original Research Article European Journal of Medicinal Plants, 4(2): , 2014 221 predominated the volatile fractions of the leaves of both methods with citronellol, citronellyl formate and menthone/isomenthone as the major constituents. Similar to orlistat (PL IC50 of 114.0 ± 4.0 ng/mL), P. graveolens extract and volatile oil as well as their purified phyto-constituents inhibited highly substantially in a dose dependent trend PL in vitro (n=3). The P. graveolens extract PLIC50 was 207.4±15.2 μg/mL. As for their volatile oils’ components, PLIC50 (%) (V/V) in an ascending order were: menthone; 0.01±0.0 <geraniol; 0.34±0.02 < linalool; 0.7 ± 0.0 < caryophyllene; 1.17±0.12 <P. graveolens oil; 2.93 ± 0.27. Comparable to acarbose, P. graveolens leaves aqueous extracts (AEs) were identified as in vitro potent and efficacious dual inhibitors of αamylase and α-glucosidase with IC50: 4.6±0.1 mg/mL (p<0.001, n=3). Conclusion: Taken together, P. graveolens leaves, as a nutraceutical modulating gastrointestinal carbohydrate and lipid digestion and absorption, maybe advocated as candidate for obesity-diabetes/metabolic syndrome management.

Chemical composition, antifungal and antioxidant activity of Pelargonium graveolens essential oil

Article history: The present study describes the chemical composition, antifungal and antioxidant activity of Pelargonium graveolens essential oil. The essential oil profile was determined by GC and GC-MS. The main compounds were citronellol (24.54%), geraniol (15.33%), citronellyl formate (10.66%) and linalool (9.80%). Minimal inhibitory concentrations (MIC) and minimal fungicidal concentrations (MFC) were recorded using the microdilution and macrodilution methods. Commercial antimycotic bifonazol was used as a control. The concentration of 0.25-2.5 mg/ml showed fungicidal activity. The most resistant fungi were Mucor mucedo and Aspergillus species. The antioxidant activity of pure essential oil was evaluated by means of the 2,2-diphenyl-1-picrylhydrazil (DPPH) radical assay. The essential oil of P. graveolens was able to reduce DPPH radicals into the natural DPPH-H form, and this activity was dose-dependent. The oil exhibited antioxidant activity and reduced DPPH to 50% at EC50 value of 0.802 mg/ml of oil solution.

Essential oil composition of Pelargonium graveolens L’Her ex Ait. cultivars harvested in different seasons

To determine the seasonal influence on essential oil yield and composition of three rose-scented geranium cultivars, namely Bourbon type, CIM-Pawan and Kelkar, an experiment was carried out in western Himalayan region, India. The essential oil yield varied from 0.05% to 0.20%, from 0.10% to 0.25% and from 0.03% to 0.12% in fresh biomass of the cv. Bourbon type, CIM-Pawan and Kelkar, respectively. Gas chromatography/flame ionization detector (GC/FID) and /mass spectrometry (GC/MS) analyses revealed significant variations in the essential oil composition of rose-scented geranium due to cultivar and season of harvesting. The major components in the essential oil of cv. Bourbon type were geraniol (14.1–34.6%), citronellol (15.2–31.3%), linalool (2.9–9.2%), citronellyl formate (4.4–9.2%), isomenthone (4.5–6.6%), 10-epi-γ-eudesmol (4.7–6.7%) and geranyl formate (3.8–6.2%). The dominant constituents of the cv. CIM-Pawan essential oil were geraniol (11.9–31.9%), citronellol (16.1–30.2%), citronellyl formate (5.2–8.9%), linalool (3.7–6.4%), isomenthone (4.0–6.3%), 10-epi-γ-eudesmol (4.4–5.2%) and geranyl formate (4.3–5.0%). However, the chemical composition and odor of cv. Kelkar was quite different from the other two cultivars and the major components found in this oil were citronellol (51.0–63.4%) and isomenthone (9.8–17.8%).

Essential oil of Algerian rose-scented geranium (Pelargonium graveolens): Chemical composition and antimicrobial activity against food spoilage pathogens

The aim of this study was to analyse the chemical composition of essential oil of rose-scented geranium (Pelargonium graveolens L.) growing in Algeria and to test the efficacy of the oil against food spoilage and food-borne pathogens.The chemical composition of the oil was analysed by Gas Chromatography-Mass Spectrometry (GC–MS). A total of 45 compounds representing 94.2% of the essential oil were identified. The main constituents were citronellol (30.2%), citronellyl formate (9.3%) and geraniol (7.6%).The antimicrobial activity of essential oil was evaluated against 23 food spoilage microorganisms in liquid and vapour phase at three different concentrations (10, 20 and 30μl/disc).The oil exhibited promising antibacterial effect against Gram positive more than Gram negative bacteria and provides a good inhibitory effect against Candida strains. Furthermore, the zone of inhibition increased with increasing oil concentration. Significantly higher antimicrobial activity was observed in the vapour phase. This is the first report on the antimicrobial properties of the essential oil of Algerian rose geranium.Our results suggest that rose-scented geranium oil could be used for the development of novel types of antibacterial agents to control food spoilage and food-borne pathogens.

Authentication of Commercial Geranium Oil and Geranium Based Dietary Supplements and Workout Products

A series of four marker (target) compounds that are common to most geranium extracts and oils was determined. The functionally distinctive markers selected were a ketone (isomenthone), two alcohols (citronellol and geraniol) as well as an ester (citronellyl formate). An analytical method involving GC/MS in the selected ion monitor mode was developed and validated for the quantitative detection of the four marker compounds common to all geranium products. Moreover, the validated analytical method was applied to investigate a series of steam-distilled geranium oils, the n-hexane extracts of the leaf and stem portions of an authenticated Pelargonium graveolens plant, and three commercial pre-workout products containing DMAA (1,3-dimethylamylamine) supposedly derived from the stem portion of Pelargonium graveolens. All four markers were found present in the geranium oils and extracts. On the other hand, none of the three commercial products purportedly derived from geranium stems contained any of the four geranium marker compounds at a concentration greater than the limit of detection (0.05 – 0.5 µg/mL) of the analytical method.

Rose geranium essential oil as a source of new and safe anti-inflammatory drugs

BackgroundSince the available anti-inflammatory drugs exert an extensive variety of side effects, the search for new anti-inflammatory agents has been a priority of pharmaceutical industries.AimsThe aim of the present study was to assess the anti-inflammatory activities of the essential oil of rose geranium (RGEO).MethodsThe chemical composition of the RGEO was investigated by gas chromatography. The major components were citronellol (29.13%), geraniol (12.62%), and citronellyl formate (8.06%). In the carrageenan-induced paw edema, five different groups were established and RGEO was administered orally in three different doses.ResultsRGEO (100 mg/kg) was able to significantly reduce the paw edema with a comparable effect to that observed with diclofenac, the positive control. In addition, RGEO showed a potent anti-inflammatory activity by topical treatment in the method of croton oil-induced ear edema. When the dose was 5 or 10 µl of RGEO per ear, the inflammation was reduced by 73 and 88%, respectively. This is the first report to demonstrate a significant anti-inflammatory activity of Algerian RGEO. In addition, histological analysis confirmed that RGEO inhibited the inflammatory responses in the skin.ConclusionOur results indicate that RGEO may have significant potential for the development of novel anti-inflammatory drugs with improved safety profile.

Chemical Composition and Biological Activities of Polar Extracts and Essential Oil of Rose‐scented Geranium, Pelargonium graveolens

Pelargonium graveolens (Geraniaceae) was characterized with respect to its chemical composition, antioxidant potential and antimicrobial activities. This is the first investigation focusing on the comparison of both essential oil and polar extracts from this species. The chemical composition of the essential oil of the aerial parts of P. graveolens was analyzed by gas chromatography/mass spectrometry. The main constituents of the oil were found to be β-citronellol (21.9%), citronellyl formate (13.2%), geraniol (11.1%), 10-epi-γ-eudesmol (7.9%), geranyl formate (6.2%) and (l)-linalool (5.6%). Nine flavonoids were identified by high-performance liquid chromatography-MS in leaf and flower extracts. Kaempferol 3-O-rhamnoside-glucoside, isorhamnetin aglycone, quercetin 3-O-glucoside, kaempferol 3,7-di-O-glucoside, quercetin 3-O-pentose and kaempferol 3-O-glucoside, quercetin 3-O-rhamnoside-glucoside, quercetin 3-O-pentoside-glucoside, myrisetin 3-O-glucoside-rhamnoside flavonoids were detected in methanolic and aqueous extracts, respectively. The total flavonoids ranged between 29.9 and 78.2 mg QE/g in flower water and methanol extracts, respectively, and 22.5 and 71.2 mg QE/g dry weight in leaf water and methanol extracts, respectively. The highest antioxidant activities using two methods of free radical scavenging capacities were obtained with the essential oil (9.16 mM of Trolox and 2.68 µg/ml). All P. graveolens essential oil and polar extracts were active against at least one bacterium.

A Somaclonal Variant of Rose-Scented Geranium (Pelargonium spp.) with Moderately High Content of Isomenthone in its Essential Oil

Rose-scented geranium (Pelargonium spp.), which is highly valued for its essential oil, is exclusively propagated vegetatively. Hence no genetic improvement work is possible through conventional breeding. Somaclonal variation was generated with and without in vitro mutagenesis using N-nitroso-N-methyl urea (NMU) in an Indian cultivar 'Bourbon', and a clone 'Narmada'. A somaclonal variant (N75) with a moderately high content of isomenthone in its essential oil was isolated from somaclones generated after treatment of internodal explants of clone, 'Narmada' with 0.25 mM NMU for 1 h. The contents of isomenthone in its essential oil were 26% and 35%, respectively, in SC2/VM2 and SC3/VM3 generations (second and third vegetative generations, respectively, after in vitro mutagen treatment) as compared with 0.7% and 0.3%, respectively, in the parental clone, 'Narmada'. The contents of alcohols and their esters (linalool, citronellol, geraniol, citronellyl formate and geranyl formate) in the essential oil of N75 in SC2/VM2 and SC3/VM3 generations were 49% and 35%, respectively, as compared with 69% and 63%, respectively, in the parental clone, 'Narmada'. This is the first report on a chemovariant of rose-scented geranium with a moderately high content of isomenthone. All earlier reported isomenthone-rich variants of rose-scented geranium had quite high contents of isomenthone (64-71%) in their essential oils. The probable modes of origin of this somaclonal variant, its parental clone 'Narmada' (with very low content of isomenthone) and four earlier reported isomenthone-rich variants of Indian cultivars of geranium are discussed.

Insecticidal Activity of Individual and Mixed Monoterpenoids of Geranium Essential Oil Against Pediculus humanus capitis (Phthiraptera: Pediculidae)

The major components of geranium (Geranium maculatum L.) oil and their mixtures were tested against female Pediculus humanus capitis De Geer (Phthiraptera: Pediculidae). Chemical analysis by gas chromatography coupled to mass spectrometry revealed four major constituents: citronellol (38%), geraniol (16%), citronellyl formate (10.4%), and linalool (6.45%) (concentration expressed as percentage of total). Topical application demonstrated that the most potent component was citronellol and geraniol, with LD50 values 9.7 and 12.7 microg/insect, respectively. Linalool and Citronellyl formate were less toxic with LD50 values 24.7 and 38.5 microg/insect, respectively. Toxicity of these four major constituents in the same proportion as the natural oil, was greater than whole oil and each individual component. Removal of any four constituents produced a decreased in effectiveness. The absence of citronellol caused the greatest decrease in toxicity (DL50 from 2.2 to 10.9 microg/insect), leading us to conclude that this constituent is the major contributor to oil toxicity. The knowledge of the role of each constituent in the toxicity of the whole oil gives the possibility to create artificial blends of different constituents for the development of more effective control agents.

A quality control method for geranium oil based on vibrational spectroscopy and chemometric data analysis

Rose-scented geranium, a commercially important cultivar originating from Pelargonium graveolens L’Her. ex Ait., is a high value essential oil extensively used in flavour and fragrance formulations. The oil is variable in composition with ‘Bourbon geranium’ (from Reunion Island) regarded as the highest quality geranium oil. Quality assessment of geranium oil involves profiling seven major volatile constituents (geraniol, citronellol, geranyl formate, citronellyl formate, linalool, isomenthone and guaia-6,9-diene) using gas chromatography (GC). The aim of this study was to explore the feasibility of vibrational spectroscopy in tandem with chemometric methods as a rapid and low-cost alternative quality control method. Geranium oil samples ( n = 70) were obtained from different suppliers representing cultivation sites in South Africa, Egypt, India, Reunion Island, China and Madagascar. Reference analysis was performed using gas chromatography coupled to mass spectrometry (GC–MS). The mid-infrared (MIR) and near-infrared (NIR) spectra of the oils were recorded with a total of 32 scans accumulated for each sample. Partial least squares (PLS) multivariate calibration models were developed. The calibration models obtained for both MIR and NIR data produced good correlation coefficients ( R 2 > 0.90) between the predicted and reference values for all seven marker molecules. Generally, the error parameters (RMSEE and RMSEP) after external validation were low (<1.0%) for all compounds guaranteeing reliable predictions. The results show convincingly the potential of both MIRS and NIRS as alternative methods that can be used in quality assessment of geranium oil providing sufficiently accurate results.