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

An evaluation of qH NMR: A complementary approach to GC-FID for quantification of Thymol and trans-Anethole in essential oils and supplements

Sweet fennel (Foeniculum vulgare Mill. var. dulce) and thyme (Zataria multiflora Boiss.) are regarded as the important supplies for pharmaceutical, food, cosmetic, and perfume industries. The major components trans-anethole and thymol are represented in fennel and thyme, respectively. The essential oils (EOs) content and the value of their related constituents should be given in strict quality control due to the storage conditions, source, and adulterations. In this study, we compared the validation of quantitative ¹H NMR (qH NMR) method with the gas chromatography with flame ionization detection (GC-FID) to quantify the trans-anethole and thymol in fennel and thyme EOs and their related supplements. The current results showed that the quantification of trans-anethole and thymol by qH NMR method was successfully achieved from their EOs and supplements. All the validation parameters including linearity, robustness, repeatability, and stability were authenticated for thymol and trans-anethole quantification. Similar results were obtained in both qH NMR and conventional GC-FID methods. Therefore, according to the measured values, the qH NMR method was adequate to determine the constituents of the EOs, with the results being roughly comparable to those obtained by GC-FID, with the advantage of being simple, repeatable, rapid (8-10 min, while for GC-FID 55 min) and essential for quality control of commercial samples.

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 Leaf Essential Oil of Piper umbellatum and Aerial Part Essential Oil of Piper guineense From Côte d’Ivoire

The combination of 13C nuclear magnetic resonance (NMR) spectroscopy, gas chromatography (GC) (retention index), and gas chromatography-mass spectrometry was used to determine the chemical composition of essential oils of Piper guineense and Piper umbellatum from Côte d’Ivoire. Thus, 54 components, accounting for 91.5% to 97.6%, were identified in the essential oil from aerial parts of P. guineense. In P. umbellatum leaf oil, 49 compounds accounting for 92.8% to 98.7% were identified. Both plants oils were dominated by monoterpenes and sesquiterpenes, with α-phellandrene, (2 E,6 E)-farnesol, and linalool as major compounds of P. guineense, whereas the most abundant components of P. umbellatum were linalool and ( E)-β-caryophyllene. (2 E,6 E)-Farnesol, identified for the first time in the essential oil from aerial parts of P. guineense, induced a new chemical composition.

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 Root Bark oil from Ivoirian Cleistopholis patens

The chemical composition of root bark oil of Cleistopholis patens (Benth.) Engl. & Diels from Côte d'Ivoire was determined by GC (in combination with retention indices), GC-MS and 13C NMR. The contents of the major compounds varied drastically from sample to sample: patchoulenone (0–70.5%), β-pinene (0–51.9%), bornyl acetate (0.5–31.2%), α-pinene (0.2–25.7%), juvenile hormone III (0.3–22.2%) and β-elemol (0–18.8%). Three chemical compositions may be differentiated, dominated by i) patchoulenone, ii) β-pinene and α-pinene, iii) juvenile hormone III, accompanied by bornyl acetate or β-elemol. 13C NMR data of patchoulenol (3-patchoulen-5- exo-ol) are reported.

Composition and Variability of Leaf Oil fromMonodora Crispata-13C NMR Identification of Heat-sensitive Compounds

The composition of four samples of essential oil isolated from the leaves of individual Monodora crispata trees growing wild in an Ivorian forest (Adiopodoumé) were investigated by a combination of chromatographic (GC(RI)) and spectrometric (GC-MS,13C NMR) techniques. In total, fifty-seven compounds accounting for 92.3–98.7% of the whole composition were identified. These oils were characterized by the preeminence of sesquiterpene hydrocarbons and the content of the main components varied substantially from sample to sample. Two samples were largely dominated by germacrene D (67.3% and 76.3%, respectively), a third sample was represented by germacrene D (28.3%), germacrene C (14.3%), δ-elemene (12.1%) and β-elemene (9.3%) and the fourth sample was characterized by 3-dimethylallylindole (15.1%), germacrene D (12.0%) and cyperene (7.8%).13C NMR spectroscopy was particularly efficient for the identification of heat-sensitive compounds.

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.

Integrated Analysis of the Wood Oil from Xanthocyparis vietnamensis Farjon & Hiep. by Chromatographic and Spectroscopic Techniques

In order to get better knowledge about the volatiles produced by Xanthocyparis vietnamensis, a species recently discovered in Vietnam, its wood oil has been analyzed by a combination of chromatographic (GC, CC) and spectroscopic (GC-MS, (13)C-NMR) techniques. Forty components that accounted for 87.9% of the oil composition have been identified. The composition is dominated by nootkatene (20.7%), 11,12,13-tri-nor-eremophil-1(10)-en-7-one (17.2%), γ-eudesmol (5.1%), nootkatone (4.7%), valencene (3.5%) and 13-nor-eremophil-1(10)-en-11-one (2.6%). The structure of two new compounds-10-epi-nor-γ-eudesmen-11-one and 12-hydroxy-isodihydroagarofuran-has been elucidated, while 11,12,13-tri-nor-eremophil-1(10)-en-7-ol is reported as a natural product for the first time. The composition of X. vietnamensis wood oil varied drastically from those of leaf oils, dominated by hedycaryol (34.4%), phyllocladene (37.8%) or by pimara-6(14)-15-diene (19.4%).

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.