Neuropeltis acuminata (P. Beauv.): Investigation of the Chemical Variability and In Vitro Anti-inflammatory Activity of the Leaf Essential Oil from the Ivorian Species.

The variability of chemical composition of the leaf essential oil (EO) from Neuropeltis acuminata, a climbing liana growing wild in Ivory Coast, was investigated for the first time. The in vitro anti-inflammatory activity was also evaluated. Thirty oil samples were isolated from leaves collected in three forests of the country and analyzed using a combination of Column Chromatography (CC), Gas Chromatography with Retention Indices (GC(FID)), Gas Chromatography-Mass Spectrometry (GC-MS), and 13Carbon-Nuclear Magnetic Resonance (13C-NMR). Fractionation by CC led to the first-time isolation from natural source of δ-cadinen-11-ol, whose structural elucidation by one dimension (1D) and 2D-NMR spectroscopy is reported here. Finally, 103 constituents accounting for 95.7 to 99.6% of the samples' compositions were identified. As significant variations of the major constituents were observed, the 30 oil compositions were submitted to hierarchical cluster and principal components analyses. Five distinct groups were evidenced: Group I, dominated by (E)-ß-caryophyllene, kessane, and δ-cadinene, while the main constituents of Group II were germacrene B, ledol, α-humulene, (E)-γ-bisabolen-12-ol, and γ-elemene. Group III exhibited guaiol, germacrene D, atractylone, (E)-γ-bisabolen-12-ol, δ-cadinene and bulnesol as main compounds. Group IV was dominated by (E)-nerolidol, guaiol, selina-4(15),7(11)-diene and bulnesol, whereas (E)-ß-caryophyllene, α-humulene and α-muurolene were the prevalent compounds of Group V. As the harvest took place in the same dry season in the three forests, the observed chemical variability could be related to harvest sites, which includes climatic and pedologic factors, although genetic factors could not be excluded. The leaf oil sample S24 behaved as a high inhibitor of LipOXygenase (LOX) activity (half maximum Inhibitory Concentration, IC50: 0.059 ± 0.001 mg mL-1), suggesting an anti-inflammatory potential.

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)-ß-ocimene, ß-eudesmol, germacrene D and (E)-ß-ocimene, while (10ßH)-1ß,8ß-oxido-cadina-4-ene, santalenone, trans-α-bergamotene and trans-ß-bergamotene were the main compounds of Subgroup I-B. The prevalent constituents of Subgroup II-A were germacrene B, (E)-ß-caryophyllene, (5αH,10ßMe)-6,12-oxido-elema-1,3,6,11(12)-tetraene and γ-elemene. Subgroup II-B displayed germacrene B, germacrene D and (Z)-ß-ocimene as the majority compounds. Germacrene D was the most abundant constituent of Group III, followed in Subgroup III-A by (E)-ß-caryophyllene, (10ßH)-1ß,8ß-oxido-cadina-4-ene, germacrene D-8-one, and then in Subgroup III-B by (Z)-ß-ocimene and (E)-ß-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.

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)-ß-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.

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 (10ßH)-1ß,8ß-oxido-cadin-4-ene (38), 4-methylene-(7αH)-germacra-1(10),5-dien-8ß-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-8ß-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%), (10ßH)-1ß,8ß-oxido-cadin-4-ene (7.3 and 8.7), 4-methylene-(7αH)-germacra-1(10),5-dien-8ß-ol (7.8 and 7.4%) and cadina-1(10),4-dien-8ß-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, Seasonal Variation, and Biological Activities of Lantana camara Essential Oils from Côte d'Ivoire.

This work aims to study the variations in the composition of Lantana camara leaf, flower, and stem essential oils over two years. L. camara organs were harvested in Bregbo (East Côte d'Ivoire) each month from June 2015 to June 2017. The essential oils were obtained by hydrodistillation and characterized by GC-MS and 13C NMR. Eighty-four compounds accounting for 84.4-99.1% of the essential oils have been identified. The essential oils hydrodistillated from L. camara are dominated by sesquiterpenes such as (E)-ß-caryophyllene and α-humulene, which were found in all samples. Some monoterpenes such as thymol, sabinene, and α-pinene were also present. Statistical analysis (principal component analysis and clustering) revealed a high variability in essential oil composition between the different organs and also within the studied periods, as the thymol proportion was higher during flowering and fruiting months. In addition, the stem, flower, and fruit essential oils were more concentrated in thymol than the leaf essential oils. The proportions of (E)-ß-caryophyllene and α-humulene were strictly inverted with the thymol proportion throughout the harvest period or vegetative cycle. The antioxidant, anti-inflammatory and insecticidal activities of leaves and flowers essential oils were also studied. Results showed that L. camara leaf and flower essential oils displayed high antioxidant, anti-inflammatory and insecticidal activities.

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%), ß-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 ß-elemene (6.2 ± 1.1%), (Z)-α-bisabolene (3.8 ± 1.0%), (E)-ß-caryophyllene (3.3 ± 0.7%) and α-copaene (2.8 ± 1.1%).

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 7ß,11ß-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)-ß-caryophyllene (1.7%), thymyl methyl oxide (1.7%), α-phellandrene (1.5%), p-cymene (1.2%), (3αH,4ßH,6αH,1αMe)-1,6-epoxy-3-hydroxycarvotanacetone angelic acid ester (1.1%) and 10-epi-γ-eudesmol (1.0%).