Antioxidant Properties of Essential Oils: Autoxidation of Essential Oils from Laurel and Fennel and of Their Mixtures with Essential Oil from Coriander

Changes in the composition of essential oils from the seeds of laurel (Laurus nobilis L.) and fennel (Foeniculum vulgare Mill., var. dulce Thelling) and their mixture with essential oil from coriander were studied by capillary gas-liquid chromatography during storage in the dark and in light. Under these conditions, essential oil of laurel retained its composition for 12 months. Essential oil of fennel was rapidly oxidized in light. However, the rate of its oxidation in the dark was lower. The major component of essential oil of fennel, trans-anethol, had a lower antioxidant activity than essential oil of coriander. The mixture of essential oils from laurel and coriander possessed antioxidant properties and strongly inhibited the oxidation of components of the fennel oil.     

The essential oil of ginger from Fiji

The essential oil of ginger (Zingiber officinale) from Fiji was analysed by GC-MS and a number of sesquiterpenes not reported previously in ginger oil were identified including α-copaene, β-bourbonene, α-bergamotene, α-selinene, calamenene and cuparene. The composition of the oil was unusual in having a much higher neral and geranial content than oils reported from India, Australia, Japan and Africa.     

Essential oil chemotypes in Hyptis suaveolens from Brazilian Cerrado

The composition of nine samples of essential oil of individual plants in fruiting stage of Hyptis suaveolens from Brazilian Cerrado was investigated by GC–MS. Spathulenol, 1,8-cineole and (E)-caryophyllene were the principal constituents. The results were submitted to Principal Component and Chemometric Cluster Analysis which allowed three groups of essential oils to be distinguished with respect to the content of 1,8-cineole/sabinene, β-bourbonene and α-bulnesene. Latitude seems to be the most important environmental factor influencing the oil contents. Pattern of geographic-variation in essential oil composition indicated that sesquiterpenes are mainly produced in the samples grown at lower latitudes and altitudes.     

玫瑰精油的化学成分及其抗菌活性

通过水蒸汽同步蒸馏法提取玫瑰精油,采用GC-MS方法分析了玫瑰精油的化学组成,共鉴定出其中14个化学成分并测定其相对含量,占总含量的95.25%。香茅醇为玫瑰精油的主要成分,相对含量为90.37%。体外抑菌实验表明,玫瑰精油除对黑曲霉没有抗菌活性外,对其它7种供试菌均具有不同程度的抑制作用,其中对表皮葡萄球菌、金黄色葡萄球菌和大肠杆菌的最小抑菌浓度(MIC)为0.063%(v/v),对枯草芽孢杆菌、变形杆菌和白色念珠菌的最小抑菌浓度（MIC）为0.125%(v/v),而对绿脓杆菌(Pseudomonas aeruginosa)的抗菌活性相对较弱,MIC为0.5%(v/v)。抑菌直径结果也表明了玫瑰精油除对黑曲霉、绿脓杆菌的抗菌活性较弱外,对其它6种菌株的抑菌直径都大于8.5 mm。考察了玫瑰精油对3种敏感菌株包括金黄色葡萄球菌(革兰氏阳性菌)、大肠杆菌(革兰氏阴性菌)和白色念珠菌(真菌)的杀菌动态过程,为玫瑰精油的应用提供了理论依据。     

Essential oil composition of Eryngium rosulatum P.W. Michael ined.: A new undescribed species from eastern Australia

The essential oil composition from the aerial parts of a new Eryngium species from Australia, Eryngium rosulatum P.W. Michael ined., has been analysed by GC and GC/MS. A total of 34 compounds have been identified representing around 80% of the total oil. The main constituents of the oil were found to be β-elemene (16.0%) and bicyclogermacrene (12.5%). Other representative compounds were identified as δ-elemene (7.0%) and (E)-caryophyllene (5.9%). The sesquiterpene fraction (75.0%) was predominant in the essential oil of this species, most of these were hydrocarbons (53.8%). This paper represents the first study on this new, undescribed Australian species and its chemical composition.     

Variation in morphological characters,chemical composition,and anthocyanin content of different Chrysanthemum morifolium cultivars from Iran

The morphological traits, essential oil composition, and anthocyanin content of 17 Iranian C. morifolium cultivars were evaluated. Based on Shannon diversity index (I), such morphological characters as flower head diameter, ray floret, shape of apex, and main color of ray floret revealed more variability than the other traits. Significant genotypic variations were also observed in essential oil content (ranging from 0.1 to 0.56% (w/w)) and composition. Gas chromatography-mass spectrometry (GC-MS) analysis of the essential oil was conducted to identify 47 compounds in which camphor (0–44.6%), chrysanthenone (0–48.96%), chrysanthenyl acetate (0–16.22%), verbenol (0–11.78%), (+)-5-epi-neointermedeol (0–25.41%), and aromadendrene (0–14.98%) were the main constituents. Results of cluster analysis of essential oil compositions divided the cultivars into four groups. Hybridization among cultivars of divergent clusters led to heterotic effects for flower quality and phytochemical characters. The relationships established between the components revealed high correlations of anthocyanin with the two major aroma compounds of verbenol and chrysanthenyl acetate while they also provided a clue to the association between aroma compounds and color pigmentation. Moreover, a correlation was established between chrysanthenone and flower head diameter (r = −0.502). Based on the results obtained, it might be suggested that smaller flowers are capable of accumulating higher amounts of chrysanthenone. Clearly, the associations between morphological traits and essential oil components provide new insights for improved breeding programs in chrysanthemum.     

Relationship among some ecological factors and chemical composition of Ajuga chamaecistus Ging. plant species

Ajuga chamaecistus belongs to Lamiaceae plant family. Plant samples were collected from four habitats during vegetative and flowering periods for comparing the essential oil yield and composition. After drying, the essential oil was extracted by distillation method. Essential oil yields of plants in four habitats were calculated which the analysis and identification of essential oil composition was performed using GC and GC–MS. Ultimately, the PCA was used to determine the relationship between plant major components and environmental factors. The results showed that β-Pinene and Linalool compounds had the highest percentage of essential oil composition. Environmental factors including elevation, annual precipitation, mean annual temperature, annual evaporation, sand and clay content were identified as the most effective factors in the isolation of A. chamaecistus habitats. It appears that the difference between ecological and soil factors of four habitats can have a significant effect on the type and percentage of essential oil components.     

Influence of the Duration and Conditions of Storage on the Composition of the Essential Oil from Coriander Seeds

The composition of volatile components of the essential oil extracted from seeds of coriander (Coriandrum sativumL.) grown in different years in either Russia or Georgia was studied by capillary gas chromatography. Climatic conditions had a weaker effect on the essential oil composition than the region of growth. After one-year storage in the dark, minor changes were observed in the oil composition, and its organoleptic properties were virtually unchanged. However, the essential oil underwent significant chemical transformation of monoterpenes when stored in the light.     

Essential oil constituents derived from different organs of a relictual conifer Wollemia nobilis

The chemical composition of the essential oil of leaves (0.9%, w/v) and twigs (0.33%, w/v) of Wollemia nobilis (Araucariaceae) – a remnant species thought to have been extinct for 65 million years – was investigated by GC/MS. The main constituents of both leaf- and twig-derived oil samples were 16-kaurene (61.8% and 38.2%, respectively) and germacrene D (9.9% and 22%). The principal difference was a considerably more pronounced sesquiterpene presence in the twig-oil, amounting to 33.5%, than in its folial counterpart (23.4%). On the contrary, while remaining the dominant group in both oil samples under investigation, diterpenoids were relatively more abundant in leaf-derived oil constituting 65.3%, versus 41.7% detected in twigs. To our knowledge, this is the first report dealing with the essential oil composition of Wollemi pine twigs, as opposed to the leaf-derived volatiles.     

Antioxidant properties of essential oils: autoxidation of essential oils from laurel and fennel and effects of mixing with essential oil from coriander

Changes in the composition of essential oils from the seeds of laurel (Laurus nobilis L.) and fennel (Foeniculum vulgare Mill., var. dulce Thelling) and their mixture with essential oil from coriander were studied by capillary gas-liquid chromatography during storage in the dark and in light. Under these conditions, essential oil of laurel retained its composition for 12 months. Essential oil of fennel was rapidly oxidized in light. However, the rate of its oxidation in the dark was lower. The major component of essential oil of fennel, transanethol, had a lower antioxidant activity than essential oil of coriander. The mixture of essential oils from laurel and coriander possessed antioxidant properties and strongly inhibited the oxidation of components of the fennel oil.     

Chemical composition,intraspecies variation and seasonal variation in essential oils of Calendula arvensis L.

The essential oil composition of Calendula arvensis was established for the first time using GC and GC/MS. Eighty-five essential oil components were identified, which accounted for 90.3 g/100 g of essential oil. The oil contained a high concentration of sesquiterpenes, of which δ-cadinene and α-cadinol were the main components. The chemical composition of 25 Corsican C. arvensis oils was analyzed to determine intraspecies variation in essential oil composition. A matrix linking essential oil composition to sample location was composed to identify relationships between concentrations of volatile samples and the geographical origins of samples. Two main groups of compounds were identified according to the amount of sesquiterpenic compounds (hydrocarbons and alcohols) and soil characteristics. Seasonal variation (winter vs. spring) in the concentrations of two major compounds during the flowering period was observed.     

Antimicrobial,antibiofilm and antitumor activities of essential oil of Agastache rugosa from Xinjiang,China

In the study, we evaluated chemical composition and antimicrobial, antibiofilm, and antitumor activities of essential oils from dried leaf essential oil of leaf and flower of Agastache rugosa for the first time. Essential oil of leaf and flower was evaluated with GC and GC–MS methods, and the essential oil of flower revealed the presence of 21 components, whose major compounds were pulegone (34.1%), estragole (29.5%), and p-Menthan-3-one (19.2%). 26 components from essential oil of leaf were identified, the major compounds were p-Menthan-3-one (48.8%) and estragole (20.8%). At the same time, essential oil of leaf, there is a very effective antimicrobial activity with MIC ranging from 9.4 to 42 μg ml⁻¹ and potential antibiofilm, antitumor activities for essential oils of flower and leaf essential oil of leaf. The study highlighted the diversity in two different parts of A. rugosa grown in Xinjiang region and other places, which have different active constituents. Our results showed that this native plant may be a good candidate for further biological and pharmacological investigations.     

Chemosystematic comparison of essential oils from eight species of four genera of the New Zealand Apiaceae

The composition of the essential oils from the seeds of eight species and the leaves of two species of the New Zealand Apiaceae was determined. Gingidia and Scandia species provided seed oils in high yield (>6%) that contained high proportions of phenylpropanoids. Anisotome haastii provided an oil in moderate yield (1.7%), over half of which was comprised of monoterpenoids and no phenylpropanoids. The four Aciphylla species afforded seed essential oils in low yield (0.5%). Three of these contained neither terpenoids nor phenylpropanoids, but contained fatty acids instead. The oil from Aciphylla squarrosa was different as it contained an abundance of phenylpropanoids. The composition of the leaf essential oils of Scandia rosifolia and Gingidia montana differed significantly from those of the corresponding seed oils. Outstandingly, the seed essential oil of G. montana contained 62% estragole and that of Scandia geniculata contained 79% dill apiole. The results of this present work support the conclusions of Mitchell et al. (1998), about the taxonomy of these genera that were drawn from their work with ribosomal DNA sequences viz., that the Gingidia and Scandia genera were closely related to each other and that the Anisotome and Aciphylla genera were not closely related to each other, but were weakly related to the Gingidia and Scandia genera.     

Essential oil of Ayapana triplinervis from Reunion Island: A good natural source of thymohydroquinone dimethyl ether

Three specimens of Ayapana triplinervis (Vahl) R.M. King & H. Rob from Reunion Island (Indian Ocean) collected at two distant locations (North of the island; samples 1 and 2, South of the island; sample 3), in different growth phases (flowering; samples 1 and 3, vegetative; sample 2) were investigated for their leaf essential oil composition. This study reports the chemical character of this species on the island and investigates the relationship between essential oil composition, developmental stage and geographic location. Analysis by GC–FID and GC–MS enabled us to identify and quantify a total of 39 constituents accounting for 97.1–98.0% of the oils. The three essential oil samples, all obtained by hydrodistillation, showed a high percentage of the aromatic compound thymohydroquinone dimethyl ether (89.9–92.8%). All other minor components remained more or less unchanged both qualitatively and quantitatively with respect to the stage of growth. On the contrary, variations were observed with geographic distribution. The geographical variation of the chemical composition of the volatile oil of A. triplinervis from several sites in the world is also briefly discussed.     

The essential oils from Ligusticum mutellina of polish origin and the chemical relationship of its root essential oil with other Ligusticum species

The chemical composition of the essential oils obtained from inflorescences, the root and herb of Ligusticum mutellina of Polish origin was studied and compared to plants collected from other locations. Analyses of L. mutellina essential oils of Polish origin revealed α-pinene as a predominant compound in the root (49.49%) and herb (9.76%), while sabinene in flowers (23.97%). The chemical composition of root essential oils from other Ligusticum species was compared to L. mutellina chemical profile. On the basis of literature data and our study, the cluster and principal component analyses were made. Both analyses showed that L. mutellina essential oil differs essentially from the others. There is some similarity between the other oils; nevertheless, PC2 suggest that four clusters can be distinguished connected with the samples origin.     

Effect of conditions and duration of storage on composition of essential oil from coriander seeds]

The composition of volatile components of the essential oil extracted from seeds of coriander (Coriandrum sativum L.) grown in different years in either Russia or Georgia was studied by capillary gas chromatography. Climatic conditions had a weaker effect on the essential oil composition than the region of growth. After one-year storage in the dark, minor changes were observed in the oil composition, and its organoleptic properties were virtually unchanged. However, the essential oil underwent significant chemical transformation of monoterpenes when stored in the light.     

Chemical composition and antifungal activity of the essential oils of Lippia rehmannii from South Africa

Lippia rehmannii H.Pearson (Verbenaceae) is an aromatic bush, indigenous to the northern parts of South Africa. As far as could be ascertained, the essential oil composition has not been previously reported and forms the subject of this investigation. Aerial parts of the shrub were collected from two localities in Gauteng, South Africa, and the isolated essential oils were analysed by gas chromatography. Citral, a mixture of the E- and Z-isomers, was found to be the main constituent of the oils, while borneol, camphor, neryl acetate, isocaryophyllene, p-cymene, β-caryophyllene and β-caryophyllene oxide were other major compounds present. Oil compositions, within and between the two localities, did not differ significantly. The in vitro antifungal activity of L. rehmannii essential oil was compared to that of Cympopogon citratus (lemongrass) and pure citral, against a number of pre- and postharvest fungal food pathogens. At a concentration of 3000 µL/L, lemongrass oil and pure citral caused complete growth inhibition of all the pathogens tested. Lippia rehmannii, containing less citral than lemongrass oil, was effective at this concentration against the majority of pathogens, but only partially restricted the growth of Lasiodiplodia theobromae and Botrytis cinerea. This finding suggests that citral may be largely responsible for the observed antifungal activities. Essential oil from L. rehmannii appears to be a good candidate for the in vitro control of Fusarium oxysporum and Rhizoctonia solani and application of these oils in the field should be investigated.     

Extraction and characterization of essential oil components based on geraniol and citronellol from Java citronella (Cymbopogon winterianus Jowitt)

Citronella oil is the main product of Java citronella grass (Cymbopogon winterianus Jowitt) rich in geraniol and citronellol, widely used in mosquito repellents and perfumeries. The age of the plant plays a key role in oil composition and its yield such that young leaves have lesser oil content than the mature leaves. Also, a remarkable difference between fresh and dried leaves regarding oil yield is observed. The various methods of extracting essential oils from citronella grass with respect to yield (%) were studied. Average percent yield in the manual extraction and hydro-distillation procedure was 0.8 and 1 % respectively, which was better as compared to steam distilled oil (0.7 %). The chromatographic analysis of essential oils with respect to standards geraniol and citronellol were studied by high performance thin layer chromatography (HPTLC) with n-hexane and ethyl acetate (3:2) as mobile phase followed by its separation on plates. The developed plates showed geraniol, citronellol and citronellal as major bands. The analysis of all extracted oil samples by means of electrospray ionization-mass spectrometry (ESI-MS) in the positive ion mode showed rapid mass fingerprints of constituents present in the samples according to the observed mass of standards. Furthermore, the analysis of vibrational spectra was accomplished with Fourier transform infra-red spectroscopy (FTIR) specifying all the functional groups as major peaks confirming all of them as monoterpene alcohols with conjugated double bonds. Thus, HPTLC, ESI-MS and FTIR studies evidenced that the two essential oil components were majorly present in the methanol extract suggesting methanol as a good extractant in the manual extraction process.     

Chemical Composition and Biological Investigations of Eryngium triquetrum Essential Oil from Algeria

The chemical composition, antibacterial and antioxidant activities of the essential oil obtained from Eryngium triquetrum from Algeria were studied. The chemical composition of sample oils from 25 locations was investigated using GC‐FID and GC/MS. Twenty‐four components representing always more than 87% were identified in essential oils from total aerial parts of plants, stems, flowers and roots. Falcarinol is highly dominant in the essential oil from the roots (95.5%). The relative abundance of falcarinol in the aerial parts correlates with the phenological stages of the plant. Aerial parts of E. triquetrum produce an essential oil dominated by falcarinol during the early flowering stage, and then there is a decrease in falcarinol and rebalancing of octanal during the flowering stage. To our knowledge, the present study is the first report of the chemical composition of E. triquetrum essential oil. Evaluation of the antibacterial activity by means of the paper disc diffusion method and minimum inhibitory concentration assays, showed a moderate efficiency of E. triquetrum essential oil. Using the DPPH method, the interesting antioxidant activity of E. triquetrum essential oil was established. These activities could be attributed to the dominance of falcarinol. The outcome of our literature search on the occurrence of falcarinol in essential oils suggests that E. triquetrum from Algeria could be considered as a possible source of natural falcarinol.     

Antimicrobial activity and chemical composition of essential oil from Helichrysum microphyllum Cambess. subsp. tyrrhenicum Bacch., Brullo & Giusso collected in South-West Sardinia

The aim of this study was to evaluate the chemical composition and the antimicrobial activity of essential oils of Helichrysum microphyllum subsp. tyrrhenicum collected in four different stations in South-Western Sardinia.The composition of the essential oils was determined by gas chromatography and gas chromatography/mass spectrometry. The oil samples showed different chromatographic profiles. The oil of the station 4 revealed the presence of significant amount of neryl acetate (33.6%); in oils from stations 1 and 2 we found γ-curcumene (28%) and in station 3 γ-curcumene (12%) and linalool (11%), while there was no trace of neryl acetate. Standard microbiological assays demonstrated that essential oils obtained by plants collected in station 1 and 2, very rich in curcumene, showed an interesting anticandidal activity, dose- and time-dependent, which is enhanced by sub-inhibitory concentrations of chitosan.Our results suggest that the essential oil of Helichrysum microphyllum subsp. tyrrhenicum, associated with chitosan in innovative formulations, could be considered as a therapeutic alternative in the treatment of Candida opportunistic infections. The results of this study shows that the chemotypization of the species examined could lead to their targeted clinical use, in a concept of a rational scientific aromatherapy.