GC-MS analysis of the essential oils of Juniperus communis L. berries growing wild in the Molise region: Seasonal variability and in vitro antifungal activity

Juniperus communis L., also known as the common juniper, is a dioecious aromatic evergreen shrub and has been traditionally used in many countries as a diuretic, antiseptic, and digestive and as a flavor to aromatize certain alcoholic beverages. We analyzed the chemical variability in the volatile profiles from berries of J. communis, harvested in one of the oldest European parks, the National Park of Abruzzo, Lazio, and Molise (PNALM, Central Italy). We examined the berries in different phases of the biological cycle for 1 year (at six ripening stages). Hydrodistilled essential oils from the fresh berries were analyzed by gas chromatography–flame ionization detection (GC-FID), gas chromatography–mass spectrometry (GC-MS) and principal component analysis (PCA). A total of 90 components were detected, and remarkable qualitative and quantitative differences were observed in the chemical components during the ripening stages, from the green unripe berries to the bluish-black berries harvested at full maturity. The essential oils were an α-pinene (13.43–32.34%) chemotype. The monoterpene hydrocarbons decreased during the ripening with a progressive increase in sesquiterpenes such as germacrene D (12.29–17.59%) and β-caryophyllene (7.71–8.51%), which are the major components in ripe berry essential oils. The sesquiterpene hydrocarbon fraction (65.3–47.9%) also contained α-humulene, germacrene B, δ-cadinene, bicyclogermacrene, and eudesma 4(14),11 diene. Germacrene D and β-caryophyllene in high concentrations may be considered as marker components of the genus Juniperus from the Molise region. This particular chemical composition has been reported for the first time. It is interesting to note the presence of β-caryophyllene (7–11%), whose inhalation has been reported to affect anxiety and depression in a rat model. An in vitro antifungal assay showed that the essential oil from green and ripe berries inhibits the growth of Sclerotium rolfsii, a phytopathogen fungus that causes post-harvest diseases in many fruits and vegetables.     

Variability in essential oil composition of Piper dilatatum L.C. Rich

Twelve samples of air-dried aerial parts of Piper dilatatum L. C. Rich yielded essential oils and their volatile constituents were analyzed by GC and GC–MS. Sesquiterpenes, both hydrocarbons and oxygenated, were the most highly represented classes, the former ranging from 31.5% to 87.7% and the latter varying from 1.8% to 49.4%. Using hierarchical cluster analysis, the oils were divided into seven groups, whose main constituents were: (E)-caryophyllene, α-cadinol and germacrene D (group A); spathulenol, bicyclogermacrene and (Z)-β-ocimene, (group B); spathulenol, germacrene D and (E)-nerolidol, (group C); germacrene D, limonene, α-phellandrene and bicyclogermacrene (group D); β-elemene, germacrene D and β-pinene (group E); curzerene, p-cymene and α-eudesmol (group F); and (Z)-α-bisabolene, curzerene and germacrene D (group G). We have seen that Piper oils from the Amazon present as major constituents terpenoids and phenylpropanoids, always with the predominance of one over another. The essential oils of P. dilatatum presented in this paper, containing only mono- and sesquiterpenes as its major components, is further chemotaxonomic evidence of this dichotomy in the Piper genus.     

Essential oils of Phlomis leucophracta,Phlomis chimerae and Phlomis grandiflora var. grandiflora from Turkey

The essential oils of three species of Phlomis from Turkey, Phlomis leucophracta, Phlomis chimerae and Phlomis grandiflora var. grandiflora have been studied. The main constituents of P. leucophracta essential oil were β-caryophyllene (20.2%), α-pinene (19.2%) and limonene (11.0%). This species also contained three diterpene derivatives, 15-isopimaradiene, manoyl oxide and epi-13-manoyl oxide that summed 1.4%. In P. chimerae the principal compounds were β-caryophyllene (31.6%), α-pinene (11.0%), germacrene D (6.1%), limonene (5.5%) and linalool (4.7%). In P. grandiflora var. grandiflora, germacrene D (45.4%), β-caryophyllene (22.8%) and bicyclogermacrene (4.9%) were among the principal derivatives.     

Composition and antimicrobial activity of the essential oil of six Hypericum species from Serbia

The volatile composition of six Hypericum species has been studied. The essential oils were obtained by steam distillation in 500 mL H₂O for 2 h in a modified Clevenger apparatus with a water-cooled oil receiver to reduce hydrodistillation over-heating artifacts, and their analyses were performed by GC and GC–MS. Identification of the substances was made by comparison of mass spectra and retention indices with literature records. A total of 100 different compounds were identified. The main constituents of the investigated populations of each taxon have been revealed as follows: Hypericum alpinum: (−)-β-pinene, γ-terpinene, (−)-(E)-caryophyllene; Hypericum barbatum: (−)-α-pinene, (−)-β-pinene, (−)-limonene, (−)-(E)-caryophyllene, (−)-caryophyllene oxide; Hypericum rumeliacum: (−)-α-pinene, (−)-β-pinene, (−)-limonene, Hypericum hirsutum: nonane, undecane, (−)-(E)-caryophyllene, (−)-caryophyllene oxide; Hypericum maculatum: spathulenol, globulol; Hypericum perforatum: (−)-α-pinene, (Z)-β-farnesene, germacrene D; Monoterpene hydrocarbons were shown to be the main group of the taxa belonging to the section Drosocarpium, while the taxa of section Hypericum were more rich in sesquiterpene hydrocarbons.     

Essential oil composition of four Lomatium Raf. species and their chemotaxonomy

The composition of the essential oils of Lomatium dasycarpum ssp. dasycarpum, Lomatium lucidum, Lomatium macrocarpum var. macrocarpum and Lomatium utriculatum is described. Identification of components was determined from their GC, GC/MS data and many were confirmed by coinjections with authentic samples. Several components were isolated by liquid and gas chromatographic techniques and their structures confirmed from their ¹H and ¹³C NMR spectral data. 2-Methyl and 3-methylbutanoates were the major components of L. dasycarpum fruits as well as stems and leaves oils. β-Phellandrene/limonene, decanal, dodecanal, bornyl acetate, germacrene D, α-humulene and bicyclogermacrene were the major components of the corresponding L. lucidum oils. α-Pinene and β-pinene were the major components of the fruit oil of L. macrocarpum. Its stem and leaf oil was rich in peucenin 7-methyl ether, β-caryophyllene, (Z)-3-hexenol, palmitic acid, linoleic acid and (E)-2-hexenal. Sabinene, (Z)-ligustilide, terpinen-4-ol, β-phellandrene/limonene, β-caryophyllene, myrcene, α-pinene and β-pinene were the major compounds in L. utriculatum fruit oil, while its stem and leaf oil was rich in (Z)-ligustilide, palmitic acid, terpinen-4-ol, linoleic acid and germacrene D. (Z)-Falcarinol was a major component of all the four root oils.     

Essential oil of Stachys aleurites from Turkey

The essential oil obtained from the aerial parts of the Turkish endemism Stachys aleurites (Lamiaceae) has been studied. The main constituents were sesquiterpene hydrocarbons: β-caryophyllene (33.7%), bicyclogermacrene (14.5%) and germacrene D (9.6%). The main monoterpene was α-pinene (8.4%). Some chemotaxonomical considerations have been provided.     

Salvia verbenaca L. essential oil: Variation of yield and composition according to collection site and phenophase

The effect of the collection sites and phenophase on yield and chemical composition of Salvia verbenaca essential oils was evaluated. The essential oil constituents were assessed by gas chromatography (GC) and gas chromatography–mass spectrometry (GC–MS). The highest essential oil yields were observed for samples of the higher semi-arid bioclimate and at the flowering period. Eighty-five volatile constituents were identified and their percentages varied significantly (p < 0.05) depending on the collection site and the phenological stage. According to the plants origin, essential oils were dominated by monoterpene hydrocarbons, oxygenated monoterpenes and sesquiterpene hydrocarbons. The monoterpene hydrocarbons (31.9%) predominate at the flowering stage whereas oxygenated sesquiterpenes (27.5%) at the early fruiting stage. The sesquiterpene hydrocarbons (28.2%) was the most represented chemical class at late fruiting. On the basis of GC-MS data, the major identified volatile constituents were viridiflorol (3.4–17.7%), α-pinene (0.7–15.9%), β-caryophyllene (1.0–15.3%) and p-cymene (1.3–14.2%). S. verbenaca contains a diversity of bioactive constituents which shows large variations as affected by the collection sites and phenophase.     

Modification of light intensity influence essential oils content,composition and antioxidant activity of thyme,marjoram and oregano

Thymus vulgaris L. (thyme), Origanum majorana L. (marjoram), and Origanum vulgare L. (oregano) were used to determine whether light modification (plants grown under nets with 40% shaded index or in un-shaded open field) could improve the quantity and quality of essential oils (EOs) and antioxidant activity. The yield of EOs of thyme, marjoram, and oregano obtained after 120 min of hydrodistillation was 2.32, 1.51, and 0.27 mL/100 g of plant material, respectively. At the same time under shading conditions plants synthetized more EOs (2.57, 1.68, and 0.32 mL/100 g of plant material). GC/MS and GC/FID analyses were applied for essential oils determinations. The main components of the thyme essential oil are thymol (8.05–9.35%); γ-terpinene (3.49–4.04%); p-cymene (2.80–3.60%) and caryophyllene oxide (1.54–2.15%). Marjoram main components were terpinene 4-ol (7.44–7.63%), γ-terpinene (2.82–2.86%) and linalool (2.04–2.65%) while oregano essential oil consisted of the following components: caryophyllene oxide (3.1–1.93%); germacrene D (1.17–2.0%) and (E)-caryophyllene (1.48–1.1%). The essential oil from thyme grown under shading (EC₅₀ value after 20 min of incubation) have shown the highest antioxidant activity – 0.85 mg mL⁻¹ in comparison to marjoram and oregano (shaded plants EC₅₀ 19.97 mg mL⁻¹ and 7.02 mg mL⁻¹ and unshaded, control plants EC₅₀ 54.01 mg mL⁻¹ and 7.45 mg mL⁻¹, respectively). The medicinal plants are a good source of natural antioxidants with potential application in the food and pharmaceutical industries. For production practice, it can be recommended to grow medicinal plants in shading conditions to achieve optimal quality parameters.     

Volatile compounds from some wild growing aromatic herbs of the Lamiaceae from southern France

Abstract

The composition of the volatile fraction in selected aromatic plants of the Lamiaceae from garrigue sites in southern France is described. Calamintha nepeta appeared heterogeneous. The oil was dominated by piperitone oxide, and piperitenone oxide or by pulegone and menthone. In Nepeta nepetella, nepetalactone, almost exclusively the (4a-α, 7α, 7a-β)-isomer, made up more than 85% of the essential oil. Dichloromethane extracts from Teucrium polium contained germacrene D or sabinene as main components, α-pinene, β-pinene and β-caryophyllene in varying proportions as further important constituents, and various minor components depending on the origin.     

Leaf essential oil composition of 10 species of Ocotea (Lauraceae) from Monteverde,Costa Rica

The leaf essential oils of 10 species of Ocotea (Lauraceae) from Monteverde, Costa Rica (Ocotea floribunda, Ocotea holdridgeana, Ocotea meziana, Ocotea sinuata, Ocotea tonduzii, Ocotea valeriana, Ocotea veraguensis, Ocotea whitei, and two undescribed species, Ocotea new species “los llanos”, and Ocotea new species “small leaf”) have been obtained by hydrodistillation and analyzed by GC–MS in order to discern the differences and similarities between the volatile chemical compositions of these species. The principal common constituents of the 10 species of Ocotea were α-pinene, β-pinene, β-caryophyllene, and germacrene-D.     

Laurus novocanariensis essential oil: Seasonal variation and valorization

We investigated the qualitative and quantitative seasonal variation of the leaf and fruit oils of the Macaronesian endemism Laurus novocanariensis and their plant defensive potential. The monoterpene fraction dominated the leaf (74%) and berry essential oils (73–44%, ripe–unripe). The insect antifeedant effects of these oils were species- and season-dependent against the aphids (Myzus persicae and Rhopalosiphum padi). Overall, the biological effects of these oils correlated with the oxygenated terpene fraction. Among the pure components tested, β-caryophyllene and its oxide were strong antifeedants to Leptinotarsa decemlineata and Spodoptera littoralis. The aphids responded to β-ocimene, β-pinene, 1,8-cineole, linalool (antifeedants) and linalool oxide (attractive to M. persicae). The antifungal effects of the leaf oils on Fusarium spp. were season-dependent. β-Caryophyllene oxide proved to be a strong antifungal. L. novocanariensis oils inhibited Lactuca sativa germination and radicle elongation, the leaves being more effective. Linalool also inhibited seed germination.     

Chemotaxonomic significance of volatile compounds in Thymus samius and its related species Thymus atticus and Thymus parnassicus

Thymus samius, a rare species endemic to the island of Samos (East Aegean, Greece), has been considered to be of possible hybrid origin, with Thymus cilicicus, Thymus parnassicus or Thymus zygioides as putative parents. Morphologically it also resembles Thymus atticus. In order to evaluate any possible chemotaxonomic relationships indicated by the qualitative and/or quantitative differentiation of volatile compounds, the essential oils of T. samius, T. parnassicus and T. atticus were analyzed and the oils of T. cilicicus and T. zygioides were used for comparison. T. atticus presents considerable variation in chemical constituents, with all Greek populations being poor in thymol/carvacrol and rich in (E)-nerolidol, germacrene D, (E)-caryophyllene, caryophyllene oxide, 1,8-cineole, α-pinene and camphene, depending on the sample. T. parnassicus shows remarkable qualitative stability in its volatile constituents, and all its populations have a similar profile with (E)-caryophyllene being the most prominent compound. T. samius is characterized by the presence of germacrene D and β-bisabolene, which constitute almost half its oil percentage. This species is also characterized by a low amount of monoterpenes; the latter exist in a considerable percentage in the related species. Our results indicate that T. samius does not show similarity or intermediacy in chemical compounds with any given couple of T. atticus, T. parnassicus, T. cilicicus, or T. zygioides.     

Survival in different habitats: Extreme ultramafic and calcareous soils affect Stachys recta essential oils composition

Two populations of Stachys recta growing in Italy on ultramafic and calcareous soils have been studied for their essential oils. Although the yields were comparable, the composition of the essential oils differed significantly. Plants growing on ultramafic soil produced mainly non-terpene derivatives (55.7%), of which the most abundant ones were 1-octen-3-ol (38.2%) and (E)-3-hexen-1-ol (5.9%); the terpenes α-cadinol (6.1%) and δ-cadinene (5.6%) were also significantly represented. In contrast, the populations living on calcareous soil produced an essential oil dominated by terpenes (93.8%), with germacrene D (18.8%), β-caryophyllene (17.7%), 1,8-cineole (15.9%) and α-pinene (14.2%) among the main components.     

Phenological variations of secondary metabolites from Hypericum triquetrifolium Turra

The essential oils and phenolic constituents from the aerial parts of Hypericum triquetrifolium Turra, were analyzed at three developmental stages (vegetative, flowering and fruiting stages). The highest content of oil (0.12% w/w) was obtained at full flowering. Whatever the analyzed stage, n-octane, α-pinene, β-caryophyllene, 2-methyloctane, n-nonane, α-longipinene, caryophyllene oxide and β-pinene were found to be the main compounds. However, their percentages varied with the phenological cycle. Analysis by RP-HPLC-DAD of the methanolic extracts enabled us to identify 14 phenolic components and rutin, hyperoside, quercitrin and quercetin were reported as the main components. With the exception of chlorogenic acid, kaempferol and amentoflavone, the content of the remaining identified phenolic components varied with the phonological cycle.     

Relationship between volatile compounds of Picea likiangensis var. linzhiensis cone and host selection of Dioryctria abietella

This study aimed to determine the relationship between volatile compounds of Picea likiangensis var. linzhiensis cone and host selection of Dioryctria abietella. During the infestation of P. likiangensis var. linzhiensis by D. abietella, their cones and branches emitted volatile compounds, which were extracted using CH₂Cl₂ extraction and XAD₂ adsorption methods, and were analyzed using gas chromatography–mass spectrometry. Before and after overwintering, D. abietella larva preferred annually infested cones and their extracts, and adult D. abietella preferred to lay eggs on annually infested cones and healthy cones of the year, and the oviposition rate of adult D. abietella was 72% on branches with healthy cones of the year, and no egg was laid on branches with annually healthy cones or branches without cones. The volatile compounds after infestation, α- and β-pinene, were significantly higher in cones than those in other tissues; however, myrcene in cones was significantly lower than those in other tissues. The annually infested cones produced β-caryophyllene and (1S)-(-)-β-pinene, while the annually healthy cones and branches produced myrcene and 3-carene. The annually infested cones and their extracts attracted D. abietella larvae, while that of healthy cones and annually infested cones attracted the adults, indicating that the terpene compounds: α-pinene, β-pinene, (1S)-(-)-β-pinene, limonene, and β-caryophyllene are attractive to D. abietella, and the terpene compounds—myrcene and 3-carene—from the branch tissues may be repulsive to D. abietella.     

Essential oil composition of Achyrocline flaccida (Weinm.) DC. (Asteraceae) from different locations of Argentina

The qualitative and quantitative composition of the essential oils obtained from the inflorescences of Achyrocline flaccida (Asteraceae) has been investigated for the first time. Plant material was collected from eleven locations in Argentina. The essential oils were obtained by hydrodistillation (0.1–0.8% v/w, dried material) and analyzed by GC–FID–MS. Eighty-three compounds were identified representing more than the 90% of the oils. The major components were α-pinene and β-caryophyllene. Statistical analysis was performed in order to evaluate the variability of the essential oils analyzed. Two groups were formed reflecting only quantitative differences in the content of major compounds. The chemical pattern of essential oils observed for A. flaccida is similar to other Achyrocline species studied, except Achyrocline hyperchlora.     

Chemical compositions and larvicidal effectiveness of Rhododendron ponticum essential oil on Neodiprion sertifer larvae

In many countries throughout the world, the European pine sawfly, Neodiprion sertifer (Geoffroy, 1785) (Hymenoptera: Diprionidae) is known as a significant forest pest that damages pine needles. As a result of the insect damage, young pine trees, especially, might dry up totally. Mechanical, biotechnical, biological, and chemical approaches are applied in research to keep it under control. Due to the increasing danger of chemical contamination associated with the use of synthetic pesticides to control insects, alternative control strategies have been sought, and studies on essential oils have been prioritized. In this research, in addition to determining the chemical analysis of Rhododendron ponticum L. (Ericales; Ericaceae) essential oil by GC–MS, the larvicidal effects of R. ponticum on N. setifer in the six larval stages were also investigated. The research was conducted in the Artvin Çoruh University Central Laboratory under laboratory settings (25 ± 1 °C, 65 ± 5% RH, and 14L:10D h photoperiods) during 2020–21. 1-Methyl-2-pyrrolidone (38.41%), Phenylethy alcohol (10.07%), Linalool (8.01%), Myrtenol 5.68%), β-Pinene (4.26%), Citronellol (4.05%), α-Pinene (3.02%) were found to be the major components of R. ponticum oil. The administration of R. ponticum essential oil at 10, 15, and 20 μL/Petri doses, as well as controls at the 24th, 48th, 72nd, and 96th hours, produced various rates of death (19.6–100%) on six larval stages of N. sertifer. According to LD₅₀ and LD₉₀ values, the highest toxicity was determined as L₁ (0.58 μL/larva) and the lowest toxicity was as L₆ (10.44 μL/larva). In conclusion, R. ponticum essential oil showed high toxicity against L₁ and L₂ larval stages of N. sertifer.     

Bioactivity of essential oil of Litsea cubeba from China and its main compounds against two stored product insects

During our screening program for agrochemicals from Chinese medicinal herbs and wild plants, the essential oil of Litsea cubeba fruits was found to possess strong contact toxicity against the cigarette beetle Lasioderma serricorne adults and the booklouse Liposcelis bostrychophila, with LD₅₀ values of 27.33 μg/adult and 71.56 μg/cm², respectively, and also showed strong fumigant toxicity against the two stored product insects with LC₅₀ values of 22.97 and 0.73 mg/L, respectively. The essential oil obtained by hydrodistillation was investigated by GC MS. The main components of the essential oil were identified to be E-citral (geranial) (27.49%), Z-citral (neral) (23.57%) and d-limonene (18.82%) followed by β-thujene (3.34%), β-pinene (2.85%), α-pinene (2.57%), 6-methyl-5-hepten-2-one (2.40%) and linalool (2.36%). Citral (Z/E-citral), d-limonene, β-pinene, α-pinene and linalool were separated and purified by silica gel column chromatography and preparative thin layer chromatography, and further identified by means of physicochemical and spectrometric analysis. Citral and linalool showed strong contact toxicity against L. serricorne and L. bostrychophila (LD₅₀ = 11.76, 12.74 μg/adult and 20.15, 99.97 μg/cm², respectively) and fumigant toxicity against L. serricorne and L. bostrychophila (16.54, 18.04 mg/L air and 0.14, 0.71 mg/L air, respectively). Otherwise, citral, d-limonene and linalool were strongly repellent against the cigarette beetle L. serricorne as the essential oil whereas β-pinene and α-pinene exhibited weaker repellency against the cigarette beetle compared with the positive control, DEET. Moreover, except α-pinene and linalool, the other three compounds as well as the essential oil exhibited comparable repellency against the booklouse relative to DEET.     

Effect of a low oxygen and high carbon dioxide modified atmosphere on the mortality of different life stages of Carpophilus hemipterus

Carpophilus hemipterus is an important cosmopolitan pest species that causes high economic losses in fruits before and after harvest. In this study, 0–2 d old eggs, 12 d old mature larvae and 1 week old adults of C. hemipterus were exposed to a modified atmosphere with low oxygen and high carbon dioxide content (2.1% O₂ + 90% CO₂ + 7.9% N₂) for 48–120 h at 20 °C and 75 ± 5% relative humidity. Time-mortality responses were subjected to probit analysis, and the difference between lethal exposure times (LTs) for the different life stages were compared using a lethal dose ratio test. LT₉₅ values were recorded as 221.83 h, 82.79 h and 65.31 h for egg, larval and adult stages, respectively. The statistical difference between LT₉₅ values was significant and egg stage was found to be more tolerant than the other two life stages. In addition, the larvae were found to be more tolerant than adults. According to the results of this study, a long time was needed to control the eggs of C. hemipterus.     

Variation in essential oil composition of Leonotis leonurus,an important medicinal plant in South Africa

Leonotis leonurus widely used by traditional healers in southern Africa for treatment of various ailments, is well known for its reported psychoactive properties. The present study was undertaken to investigate the variation in essential oil composition between geographically distinct populations of L. leonurus in South Africa using gas chromatography. Plant material (n = 50) was collected from three provinces of South Africa. Essential oils of the aerial parts were obtained by hydrodistillation and analysed using one and two dimensional gas chromatography. Twenty-six compounds accounted for more than 80% of the total composition of the oil. Eight major constituents in the oil, representing about 50% of the total oil composition, were identified by both GC–MS–FID and GCxGC–ToF–MS. These major compounds were trans-β-ocimene (0.1–5.0%), cis-β-ocimene (0.1–31.5%), β-caryophyllene (0.3–15.0%), caryophyllene oxide (0.1–5.0%), α-humulene (0.4–18.2%), γ-elemene (0.4–10.6%), α-cubebene (0.2–12.0%) and germacrene D (0.1–22.1%). Marked similarities exist in the essential oil composition between populations; differences are mostly quantitative when determined by GC–MS–FID, while GCxGC–ToF–MS data reveals both quantitative and qualitative differences.Untargeted multivariate analysis was performed using SIMCA-P + 14.0 PCA and OPLS-DA methods, identifying two distinct clusters, inland and coastal populations.