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)-ß-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)-ß-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)-ß-caryophyllene (0.4 - 69.1%), ß-pinene (0 - 57%), α-phellandrene (0 - 33.2%), α-pinene (0.1 - 30.6%), ß-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 ß-pinene and α-pinene, group II (nine samples) was represented by α-phellandrene and p-cymene and group III (16 samples) by ß-elemol. A sample displayed an atypical composition dominated by (E)-ß-caryophyllene.

Triterpene glycosides from the aerial parts of Gouania longipetala.

Six previously undescribed triterpenoid saponins, gouaniaside I-VI, were isolated from the aerial parts of Gouania longipetala Hemsl. (Rhamnaceae), in addition to four known triterpenes. The structure elucidation of these compounds was based on analyses of spectroscopic data including 1D- and 2D-NMR and HR-ESI-MS techniques. The inhibitory activity of isolated compounds against promyelocytic leukemia HL60 and human erythromyeloblastoid leukemia K562 cell lines was evaluated and jujuboside I exhibited moderate cytotoxicity, with IC50 values of 13.5 and 21.0 µM, respectively. Among the isolated triterpenes, alphitolic acid exhibited moderate antibacterial activity against Staphylococcus aureus, Enterococcus faecalis and Escherichia coli (MICs 32, 64 and 128 µg/mL, respectively).

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)-ß-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 ß-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)-ß-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 Xylopia quintasii Engl. & Diels leaf oil from Côte d'Ivoire.

The chemical composition of 42 essential-oil samples isolated from the leaves of Xylopia quintasii harvested in three Ivoirian forests was investigated by GC-FID, including the determination of retention indices (RIs), and by (13) C-NMR analyses. In total, 36 components accounting for 91.9-92.6% of the oil composition were identified. The content of the main components varied drastically from sample to sample: (E)-ß-caryophyllene (0.9-56.9%), (Z)-ß-ocimene (0.3-54.6%), ß-pinene (0.8-27.9%), α-pinene (0.1-22.8%), and furanoguaia-1,4-diene (0.0-17.6%). The 42 oil compositions were submitted to hierarchical cluster and principal components analysis, which allowed the distinction of three groups within the oil samples. The composition of the oils of the major group (22 samples) was dominated by (E)-ß-caryophyllene. The oils of the second group (12 samples) contained ß-pinene and α-pinene as the principal compounds, while the oils of the third group (8 samples) were dominated by (Z)-ß-ocimene, germacrene D, (E)-ß-ocimene, and furanoguaia-1,4-diene. The oil samples of Group I and II came from clay-soil forests, while the oil samples belonging to Group III were isolated from leaves harvested in a sandy-soil forest.

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.

Chemical variability of the leaf essential oil of Xylopia aethiopica (Dunal) A.Rich. from Côte d'Ivoire.

The chemical composition of 48 essential-oil samples isolated from the leaves of Xylopia aethiopica harvested in six Ivoirian forests was investigated by GC-FID and (13) C-NMR analyses. In total, 23 components accounting for 82.5-96.1% of the oil composition were identified. The composition was dominated by the monoterpene hydrocarbons ß-pinene (up to 61.1%) and α-pinene (up to 18.6%) and the sesquiterpene hydrocarbon germacrene D (up to 28.7%). Hierarchical cluster and principal component analyses allowed the distinction of two groups on the basis of the ß-pinene and germacrene D contents. The chemical composition of the oils of Group I (38 oil samples) was clearly dominated by ß-pinene, while those of Group II (10 samples) were characterized by the association of ß-pinene and germacrene D. The leaves collected in the four inland forests produced ß-pinene-rich oils (Group I), while the oil samples belonging to Group II were isolated from leaves harvested in forests located near the littoral.