Chemical Variability ofCleistopholis patens(Benth.)Engl.etDielsLeaf Oil from Ivory Coast

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 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.

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.

Understanding the thermal [1s,5s] hydrogen shift isomerization of ocimene

α-Ocimene, β-ocimenes and alloocimenes are isomeric monoterpenes occurring naturally as oils within several plants and fruits. These thermally unstable compounds are employed in the pharmaceutical and fine-chemicals industries due to their natural plant defense properties and pleasant odors. In this work, and in the context of a recent revival in attention on the subject, we provide new theoretical insights concerning the nature of the electronic reorganization driving the decomposition of cis-β-ocimene to alloocimene. Our findings support the experimental proposal of a rearrangement via a six-membered cyclic transition state in a one-step concerted and highly synchronic process.