Safety assessment of Ylang–Ylang (Cananga spp.) as a food ingredient

The chromosome-level genome assembly of Cananga odorata provides insights into its evolution and terpenoid biosynthesis

Cananga odorata is known as a natural perfume tree of the Annonaceae family in Magnoliales. However, its phylogenetic position and the molecular mechanisms involved in the biosynthesis of the floral volatile organic compounds (VOCs) remain unclear. Here, by combining a variety of sequencing platforms, we present a telomere-to-telomere (T2T) genome of C. odorata with 735.83 Mb, which represents the highest integrity and assembly quality of genome in magnoliid plants reported to date. Phylogenetic analysis based on multiple datasets and approaches showed that C. odorata, as a member of magnoliids, is sister to eudicots, after their divergence from monocots. Metabolomic of VOCs in the essential oil and flowers scent showed that sesquiterpenes, especially β-caryophyllene, were the major compounds. Two CoTPS21 homologues derived from tandem duplication events were highly expressed during flower development and were identified as the key sesquiterpene synthases for the production of β-caryophyllene. In addition, CoSPL3 and CoSPL9 were considered as potential transcription factors for activating the expression of CoTPS21 homologues. Our results shed light on the molecular mechanisms underlying the biosynthesis of the unique floral fragrance in C. odorata and provide new insights into the phylogenetic position of magnoliids.

Allergens grouping names on packaging: Are the substances similar enough to ensure safety? The worst case scenarios question this

OBJECTIVE

European Commission Regulation (EU) n°2023/1545 introduced the concept of grouping names in the cosmetics sector in July 2023. These groups bring together allergenic substances with the same level of skin sensitization. Their purpose is to lighten the list of ingredients on cosmetic packaging, by grouping together substances deemed to be similar under the same name. As this classification is based on a single toxic effect - skin sensitization - the present study aims to analyse the relevance of these groupings with regard to other toxic effects of substances in the same group.

METHODS

This study was carried out by consulting an available database, various reports from 5 committees, 2 books and 5 articles in order to complete the toxicological profile of each substance. Then, in order to highlight any discrepancies within the classification, the worst cases were identified. For this purpose, the data for each substance in a group were compared, and in the event of greater criticality for a toxic effect, this was qualified as a worst case. In addition, similar toxic effects between several substances within the same group were also recorded. The aim of this additional research was to validate the definition of the grouping name and the similarities between substances in the same group.

RESULTS

From the 17 grouping names, 5 presented worst cases. Two groups had 2 worst cases and the others only one. In total, from the 7 worst cases detected, 3 were due to the toxic effect "skin irritation". In most cases, the substances in the groupings shared the presence or absence of risk. Only the degree of risk criticality varied.

CONCLUSION

Classification by grouping names appears justified regarding the similarities between substances, particularly in terms of skin sensitization. However, the presence of worst cases qualifies it and highlights the importance of being vigilant when assessing the risk of cosmetic products including these grouping names in their list of ingredients.

In-vitro Antimicrobial Study of Non/irradiated Ylang-ylang Essential Oil Against Multi Drug Resistant Pathogens with Reference to Microscopic Morphological Alterations

Essential oils have proven to possess great potential in the field of biomedicine due to their ability to effectively eradicate a diverse range of pathogenic microbes. In this study, the antimicrobial activity of ylang-ylang essential oil (YY-EO) was screened against twelve multidrug-resistant pathogens. The YY-EO was effective up to 536 μg/ml, with the highest inhibition zone in case of S. aureus MMCC21 and Escherichia coli MMCC24. The least effect on both Bacillus cereus MMCC11 and Klebsiella pneumonia MMCC16. The major components of the essential oil were identified using GC-MS analysis. Different gamma irradiation doses against the YY-EO were evaluated as a tool of natural decontamination. Moreover, the antimicrobial assay after irradiation proved no significant changes regarding the antimicrobial activity before and after irradiation of EO at the applied dose. The minimum inhibitory concentration (MIC) for the EO against the tested pathogens was detected. The possible morphological changes in some of the bacterial and yeast cells at the recognized MIC and 2MIC were detected using the scanning electron microscope (SEM). Results revealed a notable change in terms of both the microbial cell population and the morphology of the tested bacterial and yeast cells. The cytotoxicity of ylang-ylang EO was evaluated against normal skin tissue culture and showed a potential cytotoxic effect at concentrated doses. These results refer to the importance of YY-EO as a natural antimicrobial agent and the possible application of YY-EO as a surface decontaminant, but they also draw attention to the importance of the EO concentration used in different applications to avoid possible toxic effects.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12088-023-01122-4.

Occurrence of Alkenylbenzenes in Plants: Flavours and Possibly Toxic Plant Metabolites

Alkenylbenzenes are naturally occurring secondary plant metabolites. While some of them are proven genotoxic carcinogens, other derivatives need further evaluation to clarify their toxicological properties. Furthermore, data on the occurrence of various alkenylbenzenes in plants, and especially in food products, are still limited. In this review, we tempt to give an overview of the occurrence of potentially toxic alkenylbenzenes in essential oils and extracts from plants used for flavoring purposes of foods. A focus is layed on widely known genotoxic alkenylbenzenes, such as safrole, methyleugenol, and estragole. However, essential oils and extracts that contain other alkenylbenzenes and are also often used for flavoring purposes are considered. This review may re-raise awareness of the need for quantitative occurrence data for alkenylbenzenes in certain plants but especially in final plant food supplements, processed foods, and flavored beverages as the basis for a more reliable exposure assessment of alkenylbenzenes in the future.

Inhalation of Cananga odorata essential oil relieves anxiety behaviors in autism-like rats via regulation of serotonin and dopamine metabolism

OBJECTIVE

Anxiety is one of the most common symptoms associated with autistic spectrum disorder. The essential oil of Cananga odorata (Lam.) Hook. f. & Thomson, usually known as ylang-ylang oil (YYO), is often used in aromatherapy as a mood-regulating agent, sedative, or hypotensive agent. In the present study, the effects and mechanisms of YYO in alleviating anxiety, social and cognitive behaviors in autism-like rats were investigated.

METHODS

The prenatal valproic acid (VPA) model was used to induce autism-like behaviors in offspring rats. The effectiveness of prenatal sodium valproate treatment (600 mg/kg) on offspring was shown by postnatal growth observation, and negative geotaxis, olfactory discrimination and Morris water maze (MWM) tests. Then three treatment groups were formed with varying exposure to atomized YYO to explore the effects of YYO on the anxiety, social and cognitive behaviors of the autistic-like offspring through the elevated plus-maze test, three-chamber social test, and MWM test. Finally, the monoamine neurotransmitters, including serotonin, dopamine and their metabolites, in the hippocampus and prefrontal cortex (PFC) of the rats were measured using a high-performance liquid chromatography.

RESULTS

Offspring of VPA exposure rats showed autism-like behaviors. In the VPA offspring, medium-dose YYO exposure significantly elevated the time and entries into the open arms in the elevated plus-maze test, while low-dose YYO exposure significantly enhanced the social interaction time with the stranger rat in session 1 of the three-chamber social test. VPA offspring treated with YYO exposure used less time to reach the platform in the navigation test of the MWM test. YYO exposure significantly elevated the metabolism of serotonin and dopamine in the PFC of VPA offspring.

CONCLUSION

YYO exposure showed the effects in alleviating anxiety and improving cognitive and social abilities in the offspring of VPA exposure rats. The role of YYO was related to the regulation of the metabolism of serotonin and dopamine. Please cite this article as: Zhang N, Wang ST, Yao L. Inhalation of Cananga odorata essential oil relieves anxiety behaviors in autism-like rats via regulation of serotonin and dopamine metabolism. J Integr Med. 2023; Epub ahead of print.

Tree Resin, a Macroergic Source of Energy, a Possible Tool to Lower the Rise in Atmospheric CO2 Levels

Tree resin is a macroergic component that has not yet been used for energy purposes. The main goal of this work is to determine the energy content of the resin of spruce, pine, and larch and of wood components—pulp and turpentine. The combustion heat of resin from each timber was determined calorimetrically. Approximately 1.0 g of liquid samples was applied in an adiabatic calorimeter. The energy values of the tree resin (>38.0 MJ·kg−1) were 2.2 and 2.4 times higher than that of bleached and unbleached cellulose, and the highest value was recorded for turpentine (>39.0 MJ·kg−1). Due to the high heating values of the resin, it is necessary to develop approaches to the technological processing of the resin for energy use. The best method of resin tapping is the American method, providing 5 kg of resin ha−1 yr−1. The tapped resin quantity can be raised by least 3 times by applying a stimulant. Its production cost compared to other feedstocks was the lowest. Tree resin can be applied as a means of mitigating global warming and consequently dampening climate change by reducing the CO2 content in the atmosphere. One tonne of tree resin burned instead of coal spares the atmosphere 5.0 Mt CO2.

Evaluation of Ylang Ylang essential oil on alcohol induced hepatotoxicity in rats

The present study is aimed to evaluate the effect of ylang ylang essential oil in alcohol induced hepatotoxicity in rats. Alcohol was used as an inducing agent and Silymarin as a standard molecule. Body weight was measured at a 3 days interval till the twenty first day and at the end of the study, serum AST, ALT, TP, TC, TG, and TB biomarkers were estimated. Further, the liver tissue was evaluated for antioxidant enzymes namely CAT, LPO, SOD and GSH level. Liver weight and histopathology was accessed at the end. Phytocompounds were shortlisted from literature and curated databases. Probable targets of each compound were identified using the SwissTargetPrediction web server. Probable mechanisms of phytocompounds against Alcohol induced hepatotoxicity were analyzed by the STRING and KEGG pathway database. The network between compounds, targets, and pathways was generated via Cytoscape ver. 3.6.1. Docking was performed by AutoDock vina using PyRx0.8v. YYEO group showed increased BW compared to alcohol group and also reversed the increased serum AST, ALT, TP, TC, TG, and TB biomarkers and also increased the level of antioxidant enzymes compared to alcohol induced group. YYEO 400 mg/kg exhibited normal liver weight and histology compared to alcohol. Enrichment and network analysis identified YYEO 63 compounds as beneficial modulators of protein molecules associated with hepatotoxicity via modulating Toll-like receptor, Adipocytokine, TNF, Sphingolipid, FoxO, AMPK, Relaxin, MAPK, NF-kappa B, HIF-1, Fc epsilon RI, IL-17, VEGF, T cell receptor, NOD-like receptor, mTOR, PI3K- Akt signaling pathway, etc. Canangaterpene 1 was identified as a potent inhibitor of aldose reductase.

Graphical abstract

Cananga odorata (Magnoliales: Annonaceae) Essential Oil Produces Significant Avoidance Behavior in Mosquitoes

Essential oil of Cananga odorata Hook. F. & Tomson is a source of insect repellent, but contact irritancy and noncontact repellency actions that stimulate insect's avoidance behavior (escape away from chemical source after direct physical contact or without making physical contact, respectively) have not been investigated. Therefore, an excito-repellency test chamber was used for measuring avoidance behavior of four insectary-reared mosquito species (Diptera: Culicidae) that escape from esposure to four concentrations (0.5, 1.0, 2.5, and 5.0% v/v) of C. odorata oil. The oil strongly repelled both Culex quinquefasciatus Say (85-97% escape) and Anopheles minimus Theobald (97-99%) at high concentrations (2.5-5.0%). For Anopheles dirus Peyton & Harrison and Aedes aegypti (L.), highest repellency (64 and 39% escape, respectively) was demonstrated at 2.5% concentration. For contact irritancy, the oil produced relatively high percent escape found in Cx. quinquefasciatus (90-100% escape) and An. minimus (83-100%). Whereas moderate contact irritancy was observed against An. dirus (40-50% escape) and Ae. aegypti (51-59%). The percent escape was then adjusted with repellency to estimate the effect of contact irritancy alone. We found that highest contact irritancy was presented at 0.5% concentration against An. minimus (67% escape). Knockdown and toxic actions were only found in Anopheles mosquitoes at 5.0% concentration. The results revealed that An. minimus and Cx. quinquefasciatus were more prone to be repelled by C. odorata oil. Detailed analysis of oil identified primary compounds as methyl benzoate (14.6%), α-gurjunene (12.8%), p-methyl-anisole (11.3%), and benzyl acetate (9.9%). Further investigations are needed to assess excito-repellency actions of these compounds alone or in combination.

Comparative toxicity, phytochemistry, and use of 53 Philippine medicinal plants

The study compares the toxicity of 53 selected medicinal plants commonly used in the Philippines to treat various diseases. It uses as a benchmark Vitex negundo L., which was approved by the Philippine Food and Drug Administration as an herbal drug for cough and asthma after passing clinical trials for safety and efficacy. The methods were chosen for their simplicity and accessibility even for resource-limited laboratories. Extracts (95 % ethanol) of the medicinal parts of the plants were (1) chemically profiled using qualitative phytochemical tests that detect the presence of key classes of bioactive compounds; and (2) evaluated for toxicity using the brine shrimp (Artemia sp.) lethality assay (BSLA). General phytochemical screening revealed the presence of tannins in 50 plant extracts, alkaloids in 43, glycosides in 33, flavonoids in 31, steroids in 21, triterpenoids in 20, anthraquinones in 10, and saponins in 8. Extracts from eight plants had LC50 values lower than the potassium dichromate control (approximately 12 μg/mL) and were considered highly toxic; extracts from 21 plants had LC50 values between 12 μg/mL and 100 μg/mL and were considered moderately toxic; extracts from 19 plant extracts, including Vitex negundo and some common vegetables, had LC50 values between 100 μg/mL and 500 μg/mL, and were considered mildly toxic and likely to have reasonable safety margins; five plant extracts, including common vegetables, had LC50 values above 500 μg/mL and were considered essentially nontoxic. No apparent correlation could be found between toxicity and chemical diversity or a specific class of phytochemicals present. Our findings may serve as a guide for herbal drug and nutraceutical development, especially in prioritizing plants for more detailed safety studies.

Assessment of nanoencapsulated Cananga odorata essential oil in chitosan nanopolymer as a green approach to boost the antifungal, antioxidant and in situ efficacy

In this study, a comparative efficacy of Cananga odorata EO (CoEO) and its nanoencapsulated formulation into chitosan nanoemulsion (CoEO-CsNe) against a toxigenic strain of Aspergillus flavus (AF-M-K5) were investigated for the first time in order to determine its efficacy in preservation of stored food from fungal, aflatoxin B₁ (AFB₁) contamination and lipid peroxidation. GC and GC-MS analysis of CoEO revealed the presence of linalool (24.56%) and benzyl acetate (22.43%) as the major components. CoEO was encapsulated into chitosan nanoemulsion (CsNe) through ionic-gelation technique and characterized by High Resolution-Scanning Electron Microscopy (HR-SEM), Fourier Transform Infrared spectroscopy (FTIR), and X-Ray Diffraction (XRD) analysis. The CoEO-CsNe during in vitro investigation against A. flavus completely inhibited the growth and AFB₁ production at 1.0 μL/mL and 0.75 μL/mL, respectively. Additionally, CoEO-CsNe showed improved antioxidant activity against DPPH^• and ABTS^•+ with IC₅₀ value 0.93 and 0.72 μL/mL, respectively. Further, CoEO-CsNe suppressed fungal growth, AFB₁ secretion and lipid peroxidation in Arachis hypogea L. during in situ investigation without causing any adverse effect on seed germination. Overall results demonstrated that the CoEO-CsNe has potential of being utilized as a suitable plant based antifungal agent to improve the shelf-life of stored food against AFB₁ and lipid peroxidation mediated biodeterioration.

Minor constituents of essential oils and aromatic extracts. Oximes derived from natural flavor and fragrance raw materials - Sensory evaluation, spectral and gas chromatographic characteristics

A small library of 57 low molecular weight oximes was prepared from fragrant aldehydes and ketones, and their olfactory profiles were determined. The most substantive and interesting in terms of the sensory impressions were (+)-isomenthone oxime (fresh, musty, green) and cyclocitral oxime (earthy with patchouli, moss and leather notes). The linear retention indices (LRI) were determined for DB-1, DB-5 and DB-WAX columns, and E/Z isomers of 22 out of 57 compounds were resolved on the DB-5 column. Attempts were made to resolve enantiomers of the chosen oximes on chiral GC columns. The best results were obtained by using a Cyclosil B column, on which the enantiomers of camphor, menthone, piperitone and carvone oximes were fully resolved. NMR and MS spectra were acquired to characterize the synthesized library. Gas chromatography-olfactometry was used to assess odoriferous properties of both isomers of oximes. In most cases both isomers possessed similar profile and intensity.

Cananga odorata essential oil reverses the anxiety induced by 1-(3-chlorophenyl) piperazine through regulating the MAPK pathway and serotonin system in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Cananga odorata essential oil, known as ylang-ylang essential oil (YYO), was commonly used in the aromatherapy for relaxation and mood adjusting use. In our previous study, YYO played anxiolytic effects on the mice in several behavioral tests that based on the instinctive responses to novel environments.

AIM OF THE STUDY

To investigate the effects and mechanisms of YYO reversing the anxiety induced by 5-HT2C receptor agonist 1-(3-chlorophenyl) piperazine (m-CPP).

MATERIALS AND METHODS

m-CPP was administrated to the male ICR mice to develop an anxiety model. The anxiolytic effect of YYO (0.1%, 1% and 10%, v/v) was evaluated in the elevated plus maze (EPM) test after odor exposure. Western blot was used to detect the phosphorylation levels of extracellular signal-regulated kinase 1/2 (ERK1/2) and cAMP response element-binding protein (CREB) and the expression of c-Fos in the prefrontal cortex (PFC) and hippocampus after the EPM test. Serotonin and its metabolite change in the brain were detected by liquid chromatogram with an electrochemical detector. The effect of YYO on the plasma corticosterone level was evaluated using enzyme-linked immunosorbent assay (ELISA) after the odor exposure.

RESULTS

The behavior analysis showed that m-CPP (2 mg/kg and 4 mg/kg) could induce anxiety behaviors in the mice while diazepam (2 mg/kg) reversed the anxiety behavior induced by m-CPP. YYO dose-dependently increased the time and number of entries in the open arms (p < 0.05) compared to the Tween 80 group. YYO reduced the phosphorylation levels of ERK1/2 (p < 0.05) in both PFC and hippocampus. Down-regulations of phosphor-CREB (p < 0.05) and c-Fos (p < 0.05) were only observed in the hippocampus. YYO also affected the brain serotonin metabolism and reduced the blood plasma corticosterone level of the m-CPP treated mice.

CONCLUSION

YYO odor exposure could reverse the anxiety behaviors generated by m-CPP. The anxiolytic effect of YYO was associated with the ERK1/2/CREB pathway in the hippocampus and relevant to the serotonin system.

Olfactory stimulation induces delayed responses in epilepsy

Precipitation and inhibition of seizures and epileptic discharges by sensory stimuli are receiving increasing attention because they provide insight into natural seizure generation in human epilepsies and can identify potential nonpharmacological therapies. We aimed to investigate modulation (provocation or inhibition) of epileptiform discharges (EDs) in mesial temporal lobe epilepsy (MTLE) versus idiopathic generalized epilepsy (IGE) by olfactory stimulation (OS) compared with standard provocation methods. The underlying hypothesis was that any response would be more likely to occur in MTLE, considering the anatomical connections of the temporal lobe to the olfactory system. This multicenter, international study recruited patients with either MTLE or IGE who were systematically compared for responses to OS using an EEG/video-EEG protocol including a 30-min baseline, twice 3-min olfactory stimulation with ylang-ylang, hyperventilation, and intermittent photic stimulation. The 95% confidence interval (CI) for the baseline EDs in each patient was calculated, and modulation was assumed when the number of EDs during any 3-min test period was outside this CI. A total of 134 subjects (55 with MTLE, 53 with IGE, and 26 healthy controls) were included. Epileptiform discharges were inhibited during OS in about half the patients with both MTLE and IGE, whereas following OS, provocation was seen in 29.1% of patients with MTLE and inhibition in 28.3% of patients with IGE. Olfactory stimulation was less provocative than standard activation methods. The frequent subclinical modulation of epileptic activity in both MTLE and IGE is in striking contrast with the rarity of reports of olfactory seizure precipitation and arrest. Inhibition during OS can be explained by nonspecific arousal. The delayed responses seem to be related to processing of olfactory stimuli in the temporal lobe, thalamus, and frontal cortex.

Traditional Uses, Phytochemistry, and Bioactivities of Cananga odorata (Ylang-Ylang)

Ylang-ylang (Cananga odorata Hook. F. & Thomson) is one of the plants that are exploited at a large scale for its essential oil which is an important raw material for the fragrance industry. The essential oils extracted via steam distillation from the plant have been used mainly in cosmetic industry but also in food industry. Traditionally, C. odorata is used to treat malaria, stomach ailments, asthma, gout, and rheumatism. The essential oils or ylang-ylang oil is used in aromatherapy and is believed to be effective in treating depression, high blood pressure, and anxiety. Many phytochemical studies have identified the constituents present in the essential oils of C. odorata. A wide range of chemical compounds including monoterpene, sesquiterpenes, and phenylpropanoids have been isolated from this plant. Recent studies have shown a wide variety of bioactivities exhibited by the essential oils and the extracts of C. odorata including antimicrobial, antibiofilm, anti-inflammatory, antivector, insect-repellent, antidiabetic, antifertility and antimelanogenesis activities. Thus, the present review summarizes the information concerning the traditional uses, phytochemistry, and biological activities of C. odorata. This review is aimed at demonstrating that C. odorata not only is an important raw material for perfume industry but also considered as a prospective useful plant to agriculture and medicine.

The floral transcriptome of ylang ylang (Cananga odorata var. fruticosa) uncovers biosynthetic pathways for volatile organic compounds and a multifunctional and novel sesquiterpene synthase

The pleasant fragrance of ylang ylang varieties (Cananga odorata) is mainly due to volatile organic compounds (VOCs) produced by the flowers. Floral scents are a key factor in plant-insect interactions and are vital for successful pollination. C. odorata var. fruticosa, or dwarf ylang ylang, is a variety of ylang ylang that is popularly grown in Southeast Asia as a small shrub with aromatic flowers. Here, we describe the combined use of bioinformatics and chemical analysis to discover genes for the VOC biosynthesis pathways and related genes. The scented flowers of C. odorata var. fruticosa were analysed by gas chromatography/mass spectrometry and a total of 49 VOCs were identified at four different stages of flower development. The bulk of these VOCs were terpenes, mainly sesquiterpenes. To identify the various terpene synthases (TPSs) involved in the production of these essential oils, we performed RNA sequencing on mature flowers. From the RNA sequencing data, four full-length TPSs were functionally characterized. In vitro assays showed that two of these TPSs were mono-TPSs. CoTPS1 synthesized four products corresponding to β-thujene, sabinene, β-pinene, and α-terpinene from geranyl pyrophosphate and CoTPS4 produced geraniol from geranyl pyrophosphate. The other two TPSs were identified as sesqui-TPSs. CoTPS3 catalysed the conversion of farnesyl pyrophosphate to α-bergamotene, whereas CoTPS2 was found to be a multifunctional and novel TPS that could catalyse the synthesis of three sesquiterpenes, β-ylangene, β-copaene, and β-cubebene. Additionally, the activities of the two sesqui-TPSs were confirmed in planta by transient expression of these TPS genes in Nicotiana benthamiana leaves by Agrobacterium-mediated infiltration.

Volatile organic compound emissions from different stages of Cananga odorata flower development

Headspace-solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) was used to identify the volatile organic compounds (VOCs) of the different flower development stages of Cananga odorata for the evaluation of floral volatile polymorphism as a basis to determine the best time of harvest. Electronic nose results, coupled with discriminant factor analysis, suggested that emitted odors varied in different C. odorata flower development stages, including the bud, display-petal, initial-flowering, full-flowering, end-flowering, wilted-flower, and dried flower stages. The first two discriminant factors explained 97.52% of total system variance. Ninety-two compounds were detected over the flower life, and the mean Bray–Curtis similarity value was 52.45% among different flower development stages. A high level of volatile polymorphism was observed during flower development. The VOCs were largely grouped as hydrocarbons, esters, alcohols, aldehydes, phenols, acids, ketones, and ethers, and the main compound was β-caryophyllene (15.05%–33.30%). Other identified compounds were β-cubebene, d-germacrene, benzyl benzoate, and α-cubebene. Moreover, large numbers of VOCs were detected at intermediate times of flower development, and more hydrocarbons, esters, and alcohols were identified in the full-flowering stage. The full-flowering stage may be the most suitable period for C. odorata flower harvest.

Improvement of ylang-ylang essential oil characterization by GC×GC-TOFMS

A single fraction of essential oil can often contain hundreds of compounds. Despite of the technical improvements and the enhanced selectivity currently offered by the state-of-the-art gas chromatography (GC) and mass spectrometry (MS) instruments, the complexity of essential oils is frequently underestimated. Comprehensive two-dimensional GC coupled to time-of-flight MS (GC×GC-TOFMS) was used to improve the chemical characterization of ylang-ylang essential oil fractions recently reported in a previous one-dimensional (1D) GC study. Based on both, the enhanced chromatographic separation and the mass spectral deconvolution, 161 individual compounds were identified and labeled as potentially characteristic analytes found in both low and high boiling fractions issued from distillation of mature ylang-ylang flowers. Compared to the most recent full GC-MS characterization, this represents 75 new compounds, essentially consisting of terpenes, terpenoid esters, and alcohols.

Comparative chemical and molecular variability of Cananga odorata (Lam.) Hook.f. & Thomson forma genuina (ylang-ylang) in the Western Indian Ocean Islands: implication for valorization

Cananga odorata (Lam.) Hook.f. & Thomson forma genuina (Annonaceae) is a tropical tree, grown for the production of ylang-ylang essential oil, which is extracted from its fresh and mature flowers. Despite its economic and social importance, very little information is available on its variability and the possible factors causing it. Therefore, the relationship between the genetic structure, revealed by amplified fragment length polymorphism (AFLP), and the essential oil chemical composition, determined by GC/MS analysis, of ylang-ylang grown in semi-managed systems in three Indian Ocean islands (Grande Comore, Mayotte, and Madagascar) was investigated. Our results revealed a low genetic variation within plantations and contrasted situations between islands. Variations of the chemical composition could be observed within plantations and between islands. The genetic differentiation pattern did not match the observed pattern of chemical variability. Hence, the chemical variation could not be attributed to a genetic control. As Grande Comore, Madagascar, and Mayotte present different environmental and agronomic conditions, it can be concluded that the influence of these conditions on the ylang-ylang essential oil composition is consistent with the patterns observed. Finally, several strategies were proposed to valorize the chemical composition variations.