Chemical Variability and In Vitro Anti-Inflammatory Activity of Leaf Essential Oil from Ivorian Isolona dewevrei (De Wild. & T. Durand) Engl. & Diels

The chemical variability and the in vitro anti-inflammatory activity of the leaf essential oil from Ivorian Isolona dewevrei were investigated for the first time. Forty-seven oil samples were analyzed using a combination of CC, GC(RI), GC-MS and 13C-NMR, thus leading to the identification of 113 constituents (90.8-98.9%). As the main components varied drastically from sample to sample, the 47 oil compositions were submitted to hierarchical cluster and principal components analyses. Three distinct groups, each divided into two subgroups, were evidenced. Subgroup I-A was dominated by (Z)-β-ocimene, β-eudesmol, germacrene D and (E)-β-ocimene, while (10βH)-1β,8β-oxido-cadina-4-ene, santalenone, trans-α-bergamotene and trans-β-bergamotene were the main compounds of Subgroup I-B. The prevalent constituents of Subgroup II-A were germacrene B, (E)-β-caryophyllene, (5αH,10βMe)-6,12-oxido-elema-1,3,6,11(12)-tetraene and γ-elemene. Subgroup II-B displayed germacrene B, germacrene D and (Z)-β-ocimene as the majority compounds. Germacrene D was the most abundant constituent of Group III, followed in Subgroup III-A by (E)-β-caryophyllene, (10βH)-1β,8β-oxido-cadina-4-ene, germacrene D-8-one, and then in Subgroup III-B by (Z)-β-ocimene and (E)-β-ocimene. The observed qualitative and quantitative chemical variability was probably due to combined factors, mostly phenology and season, then harvest site to a lesser extent. The lipoxygenase inhibition by a leaf oil sample was also evaluated. The oil IC50 (0.020 ± 0.005 mg/mL) was slightly higher than the non-competitive lipoxygenase inhibitor NDGA IC50 (0.013 ± 0.003 mg/mL), suggesting a significant in vitro anti-inflammatory potential.

Chemical composition of root and stem bark essential oils from Ivorian Isolona dewevrei: structural elucidation of a new natural germacrone

The root and stem bark essential oils from Isolona dewevrei (Annonaceae), growing wild in Côte d'Ivoire, were investigated for the first time, using a combination of chromatographic [CC, GC(RI)] and spectroscopic [MS, ¹³C-NMR] techniques. A new natural germacrone was isolated by repetitive column chromatography carried out on a stem bark oil sample. Its structure was elucidated as germacra-1(10),4(15),5-trien-8-one by 1 D, 2 D-NMR and QTOF-MS. Ninety-six components accounting for 95.5 ± 0.8% and 95.8 ± 1.0%, respectively, for the root and stem bark essential oil samples were identified. The major compounds of root oil were cyperene (19.7 ± 1.6%) and camphene (10.1 ± 2.1%), followed by 5-isopentenylindole (6.4 ± 2.4%), β-elemene (3.9 ± 0.3%), (Z)-α-bisabolene (3.2 ± 1.2%) and γ-gurjunene (3.2 ± 0.3%). The stem bark oil was also dominated by cyperene (29.2 ± 4.1%), followed by β-elemene (6.2 ± 1.1%), (Z)-α-bisabolene (3.8 ± 1.0%), (E)-β-caryophyllene (3.3 ± 0.7%) and α-copaene (2.8 ± 1.1%).

New Natural Oxygenated Sesquiterpenes and Chemical Composition of Leaf Essential Oil from Ivoirian Isolona dewevrei (De Wild. & T. Durand) Engl. & Diels

This study aimed to investigate the chemical composition of the leaf essential oil from Ivoirian Isolona dewevrei. A combination of chromatographic and spectroscopic techniques (GC(RI), GC-MS and 13C-NMR) was used to analyze two oil samples (S1 and S2). Detailed analysis by repetitive column chromatography (CC) of essential oil sample S2 was performed, leading to the isolation of four compounds. Their structures were elucidated by QTOF-MS, 1D and 2D-NMR as (10βH)-1β,8β-oxido-cadin-4-ene (38), 4-methylene-(7αH)-germacra-1(10),5-dien-8β-ol (cis-germacrene D-8-ol) (52), 4-methylene-(7αH)-germacra-1(10),5-dien-8α-ol (trans-germacrene D-8-ol) (53) and cadina-1(10),4-dien-8β-ol (56). Compounds 38, 52 and 53 are new, whereas NMR data of 56 are reported for the first time. Lastly, 57 constituents accounting for 95.5% (S1) and 97.1% (S2) of the whole compositions were identified. Samples S1 and S2 were dominated by germacrene D (23.6 and 20.5%, respectively), followed by germacrene D-8-one (8.9 and 8.7%), (10βH)-1β,8β-oxido-cadin-4-ene (7.3 and 8.7), 4-methylene-(7αH)-germacra-1(10),5-dien-8β-ol (7.8 and 7.4%) and cadina-1(10),4-dien-8β-ol (7.6 and 7.2%). Leaves from I. dewevrei produced sesquiterpene-rich essential oil with an original chemical composition, involving various compounds reported for the first time among the main components. Integrated analysis by GC(RI), GC-MS and 13C-NMR appeared fruitful for the knowledge of such a complex essential oil.

Composition and Intraspecific Chemical Variability of Leaf Essential Oil of Laggera pterodonta from Côte d'Ivoire

The chemical composition of 44 leaf oil samples of Laggera pterodonta (DC.) Sch.Bip. ex Oliv. (Asteraceae) from Côte d'Ivoire was investigated, using combination of chromatographic (GC-FID) and spectroscopic (GC/MS, ¹³ C-NMR) techniques. Two oil samples chosen according to their chromatographic profiles were submitted to column chromatography and all fractions of CC were analyzed by GC-FID, GC/MS and ¹³ C-NMR. In total, 83 components accounting for 96.5 to 99.4 % of the whole chemical composition were identified. Significant variations were observed within terpene classes: monoterpene hydrocarbons (0.4-22.7 %), oxygenated monoterpenes (32.9-54.9 %), sesquiterpene hydrocarbons (18.6-38.3 %) and oxygenated sesquiterpenes (3.5-38.4 %). Thus, the 44 compositions were subjected to hierarchical cluster analysis (HCA) and principal component analysis (PCA). Two groups were differentiated according to their composition. All the samples contained 2,5-dimethoxy-p-cymene, α-humulene and (E)-β-caryophyllene among the main components. Other components were present at appreciable contents and allowed differentiation of two groups: sabinene and germacrene D for Group I; 10-epi-γ-eudesmol and eudesm-7(11)-en-4α-ol for Group II. All the samples collected in Eastern Côte d'Ivoire constituted Group I, while samples collected in the Central area of the country constituted Group II.

Two new eudesman-4α-ol epoxides from the stem essential oil of Laggera pterodonta from Côte d'Ivoire

The investigation of the stem essential oil of Laggera pterodonta (DC.) Sch. Bip. ex Oliv. (Asteraceae) from Côte d'Ivoire was carried out, using a combination of chromatographic (GC-RI, CC, pc-GC) and spectroscopic (GC-MS, ¹³C NMR) techniques. This study led to the identification of fifty constituents of which two new natural compounds 7β,11β-epoxy-eudesman-4α-ol and 7α,11α-epoxy-eudesman-4α-ol. Their structures were elucidated by 1 D and 2 D NMR spectroscopy after pc-GC purifying. Finally, 98.9% of the whole composition of the oil was identified with a high amount of 2,5-dimethoxy-p-cymene (78.9%). The other significant components were α-humulene (6.2%), (E)-β-caryophyllene (1.7%), thymyl methyl oxide (1.7%), α-phellandrene (1.5%), p-cymene (1.2%), (3αH,4βH,6αH,1αMe)-1,6-epoxy-3-hydroxycarvotanacetone angelic acid ester (1.1%) and 10-epi-γ-eudesmol (1.0%).

New trans-β-bergamotene derivatives in the root and the flower essential oils of Cyanthillium cinereum (L.) H. Rob. from Côte d'Ivoire

Root and flower essential oils of Cyanthillium cinereum (L.) H. Rob. (Synonym Vernonia cinerea (L.) Less.) (Asteraceae) collected in Southern Côte d'Ivoire was investigated using a combination of chromatographic and spectroscopic techniques. The root oil composition was dominated by trans-β-bergamotene (20.7%), β-elemene (19.0%), cyperene (10.6%), germacrene A (7.1%) and β-pinene (3.8%), whereas γ-humulene (31.0%), (E)-β-caryophyllene (17.0%), trans-β-bergamotene (7.7%), β-pinene (7.5%) and (E)-β-farnesene (6.0%) were the major components of flower oil. Two new compounds bearing the trans-β-bergamotene framework were identified: trans-β-bergamotenone and (E)-trans-β-bergamotenol.

Composition and Chemical Variability of Ivoirian Polyalthia oliveri Leaf Oil

The chemical composition of 45 essential oil samples isolated from the leaves of Polyalthia oliveri harvested in three Ivoirian forests was investigated by GC-FID (retention indices measured on two columns of different polarities), and by (13) C-NMR, following a method developed in our laboratory. In total, 41 components were identified. The content of the main components varied drastically from sample to sample: (E)-β-caryophyllene (1.2 - 50.8%), α-humulene (0.6 - 47.7%), isoguaiene (0 - 27.9%), alloaromadendrene (0 - 24.7%), germacrene B (0 - 18.3%), δ-cadinene (0.4 - 19.3%), and β-selinene (0.2 - 18.5%). The analysis of six oil samples selected in function of their chromatographic profiles is reported in detail. The 45 oil compositions were submitted to hierarchical cluster and principal components analysis, which allowed the distinction of three groups within the oil samples. The compositions of the oils from group I (15 samples) and II (12 samples) were dominated by (E)-β-caryophyllene and α-humulene, respectively. Oil samples of group III (18 samples) needed to be partitioned into four subgroups III.1-III.4 whose compositions were dominated by alloaromadenrene, isoguaiene, germacrene B, and δ-cadinene, respectively.

Chemical Variability of Ivoirian Xylopia rubescens Leaf Oil

Forty-two essential oil samples were isolated from leaves of Xylopia rubescens harvested in three forests of Southern Ivory Coast. All the samples have been submitted to GC-FID and the retention indices (RIs) of individual components have been measured on two capillary columns of different polarity. In addition, 20 oil samples, selected on the basis of their chromatographic profile, were also analyzed by ¹³ C-NMR and 24 components (78.0 - 92.4% of the whole compositions) have been identified. The content of the main components varied drastically from sample to sample: furanoguaia-1,4-diene (5.7 - 54.1%), furanoguaia-1,3-diene (1.1 - 10.5%), (8Z,11Z,14Z)-heptadeca-8,11,14-trien-2-one (4.3 - 16.0%), and (E)-β-caryophyllene (1.7 - 17.3%). Hierarchical cluster and principal components analysis of the 42 oil compositions allowed the distinction of two well-differentiated groups of unequal importance within the oil samples. Oil samples of the main group (Group II) contained mainly furanoguaia-1,4-diene (mean [M] = 43.1%; standard deviation [SD] = 3.2%) while furanoguaia-1,3-diene (M = 8.4%; SD = 0.9%) and (8Z,11Z,14Z)-heptadeca-8,11,14-trien-2-one (M = 7.1%; SD = 1.5%) were present at appreciable contents. The composition of Group I was dominated by furanoguaia-1,4-diene (M = 17.0%; SD = 8.5%), (8Z,11Z,14Z)-heptadeca-8,11,14-trien-2-one (M = 10.2%; SD = 2.4%) and (E)-β-caryophyllene (M = 9.5%; SD = 5.3%).

Composition and Chemical Variability of Cleistopholis patens Trunk Bark Oil from Côte d'Ivoire

The chemical composition of trunk bark oil from Cleistopholis patens (Benth.) Engl. & Diels, growing wild in Côte d'Ivoire, has been investigated by GC (FID) in combination with retention indices, GC/MS and ¹³ C-NMR. Moreover, one oil sample has been subjected to CC and all the fractions analyzed by GC (RI) and ¹³ C-NMR. In total, 61 components have been identified, including various sesquiterpene esters scarcely found in essential oils. ¹³ C-NMR was particularly efficient for the identification of a component not eluted on GC and for the quantification of heat-sensitive compounds. Then, 36 oil samples, isolated from trunk bark harvested in six Ivoirian forests have been analyzed. The content of the main components varied drastically from sample to sample: (E)-β-caryophyllene (0.4 - 69.1%), β-pinene (0 - 57%), α-phellandrene (0 - 33.2%), α-pinene (0.1 - 30.6%), β-elemol (0.1 - 29.9%), germacrene D (0 - 25.4%), juvenile hormone III (0 - 22.9%), germacrene B (0 - 20.6%) and sabinene (tr-20.3%). Statistical analysis, hierarchical clustering and principal components analysis, carried out on the 36 compositions evidenced a fair chemical variability of the stem bark oil of this species. Indeed, three clusters have been distinguished: the composition of group I (ten samples) was dominated by β-pinene and α-pinene, group II (nine samples) was represented by α-phellandrene and p-cymene and group III (16 samples) by β-elemol. A sample displayed an atypical composition dominated by (E)-β-caryophyllene.

Composition and Chemical Variability of Ivoirian Xylopia staudtii Leaf Oil

The chemical composition of a leaf oil sample from Ivoirian Xylopia staudtii Engler & Diels (Annonaceae) has been investigated by a combination of chromatographic [GC(RI)] and spectroscopic (GC-MS, 13C NMR) techniques. Thirty-five components that accounted for 91.8% of the whole composition have been identified. The oil composition was dominated by the furanoguaiadienes furanoguaia-1,4-diene (39.0%) and furanoguaia-1,3-diene (7.5%), and by germacrene D (17.5%). The composition of twelve other leaf oil samples demonstrated qualitative homogeneity, but quantitative variability. Indeed, the contents of the major components varied substantially: furanoguaia-1,4-diene (24.7–51.7%) and germacrene D (5.9–24.8%). The composition of X. staudtii leaf oil is close to that of X. rubescens leaf oil but varied drastically from those of the essential oils isolated from other Xylopia species. 13C NMR spectroscopy appeared as a powerful and complementary tool for analysis of sesquiterpene-rich essential oils.

Combined Analysis of the Root Bark Oil of Cleistopholis glauca by Chromatographic and Spectroscopic Techniques

The composition of root bark oil from Cleistopholis glauca Pierre ex Engler & Diels growing wild in Ivory Coast was investigated by GC (in combination with retention indices) and 13C NMR spectroscopy after partition of hydrocarbons and oxygenated compounds on silica gel. Thirty-one compounds have been identified. C. glauca produces a sesquiterpene-rich oil, patchoulenone (33.5%), cyperene (9.5%) and germacrene D (6.6%) being the main components. Special attention was paid to the identification and quantification of germacrene C (a heat-sensitive compound) and δ-elemene, which were achieved by a combination of GC(FID) and 13C NMR spectroscopy. The composition of C. glauca root bark and leaf oils differed drastically.

Combined analysis of the root bark oil of Cleistopholis glauca by chromatographic and spectroscopic techniques

The composition of root bark oil from Cleistopholis glauca Pierre ex Engler & Diels growing wild in Ivory Coast was investigated by GC (in combination with retention indices) and "3C NMR spectroscopy after partition o f hydrocarbons a nd oxygenated compounds on silica g el. Thirty-one compounds havebeen identified. C. glauca produces a sesquiterpene-rich oil, patchoulenone (33.5%), cyperene (9.5%) and germacrene D (6.6%) being the main components. Special attention was paid to the identification and quantification ofgermacrene C (a heat-sensitive compound) and &-elemene, which were achieved by a combination of GC(FID) and 13C NMR spectroscopy. The composition of C. glauca root bark and leaf oils differed drastically.

Analysis of Cleistopholis patens leaf and trunk bark oils using combined GC- flame ionisation detection, GC-retention index, GC-MS and (13) C-NMR

INTRODUCTION

Germacrenes A-C are secondary metabolites produced by various plants. They are sesquiterpene hydrocarbons bearing the (E,E)-1,5-cyclodecadiene structure known to undergo thermal rearrangement through a [3.3]-sigmatropic reaction. Such a rearrangement was evidenced by comparing the contents of a given germacrene and the corresponding elemene calculated by GC-flame ionisation detection (FID) with the relative intensities of the signals of both molecules in the (13) C-NMR spectrum of the mixture, recorded at room temperature.

OBJECTIVE

To develop a protocol to identify and quantify germacrenes A, B and C and in parallel the corresponding elemenes, using a combination of GC-FID and (13) C-NMR and then provide a correct analysis of Cleistopholis patens essential oils.

METHODS

The essential oil was submitted to GC-FID, GC-retention index, GC-MS and (13) C-NMR analyses. The relative percentages of every couple of germacrene and elemene measured by GC-FID were summed. Then, the relative ratio of the mean intensities of the signals of the protonated carbons of a given germacrene and the corresponding elemene was calculated. The contents of both compounds were obtained by combining GC-FID and (13) C-NMR data.

RESULTS

The true content of germacrene A/β-elemene, germacrene B/γ-elemene and germacrene C/δ-elemene in leaf and root oils from C. patens was evaluated by combination of GC-FID and (13) C-NMR data. Correct analysis of the essential oils was provided.

CONCLUSION

Combined analysis of essential oil including (13) C-NMR without isolation of the components, appeared really efficient to identify and quantify germacrene isomers and in parallel elemene isomers in essential oils.

Three new natural compounds from the root bark essential oil from Xylopia aethiopica

INTRODUCTION

In the course of on-going work on the characterisation of aromatic plants from the Ivory Coast we investigated the composition of the root oil from Xylopia aethiopica.

OBJECTIVES

The aim of this work was to investigate the chemical composition of X. aethiopica root oil and elucidate the structure of two new compounds.

METHODOLOGY

Analysis of the essential oil was carried out using a combination of chromatographic (CC, GC with retention indices) and spectroscopic techniques (MS, (13)C-NMR, 2D-NMR).

RESULTS

Twenty seven components, accounting for 95.6% of the whole composition, were identified including various compounds for which spectroscopic data were absent on commercial computerised MS libraries. Three compounds are reported for the first time as natural compounds and the structure of two new compounds, 4,4-dimethyl-2-vinylcyclohexene and endo-5-methoxy-3-patchoulene, has been elucidated using extensive two-dimensional NMR spectroscopy.

CONCLUSION

The composition of X. aethiopica root oil is dominated by two dimethylvinylcyclohexene isomers. It differs drastically from the composition of leaf and fruit oils of the same plant. The combination of analytical techniques appeared crucial for a fruitful analysis.

Isothymol in Ajowan essential oil

Ajowan is a popular spice that is used in folk medicine in Algeria. Most studies reported that thymol is the main component of the seed oil. Isothymol was reported to be a constituent of essential oil isolated from aerial parts. Using plants harvested in five different locations in north western Algeria, every two weeks during the flowering stage, we demonstrated that isothymol was the major component when the plant was collected near the sea at low altitude and at the beginning of the flowering stage. In other cases, thymol is the predominant constituent.

Isothymol in Ajowan Essential Oil

Ajowan is a popular spice that is used in folk medicine in Algeria. Most studies reported that thymol is the main component of the seed oil. Isothymol was reported to be a constituent of essential oil isolated from aerial parts. Using plants harvested in five different locations in north western Algeria, every two weeks during the flowering stage, we demonstrated that isothymol was the major component when the plant was collected near the sea at low altitude and at the beginning of the flowering stage. In other cases, thymol is the predominant constituent.

Composition of the leaf, stem bark and root bark oils of Isolona cooperi investigated by GC (retention index), GC-MS and 13C-NMR spectroscopy

The leaf, stem bark and root bark oils of Isolona cooperi Hutchinson & Dalziel from the Ivory Coast have been analysed by GC (retention index), GC-MS and 13C-NMR spectroscopy. Two types of essential oil were produced by the plant. The leaf and stem bark oils were monoterpene-rich, containing principally (Z)-beta-ocimene and gamma-terpinene and three lactones, 5-[(E and Z)-hexylidene]-5H-furan-2-ones and massoia lactone, were present in appreciable amounts. Conversely, the root bark oil was dominated by 5-isopentenylindole and (E)-beta-caryophyllene. The strategy for the analysis of each oil was adapted according to the nature of the components.