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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 13 C-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 13 C-NMR appeared fruitful for the knowledge of such a complex essential oil.

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.

This work is a contribution to the characterization of aromatic and medicinal plants from Côte d'Ivoire. To date, no phytochemical investigation was reported on Isolona dewevrei. Thus, the aim of this study was to investigate for the first time, the chemical composition of the leaf essential oil from I dewevrei. Two essential oil samples (S1, S2) were analysed by combination of chromatographic [GC(FID) and GC(RI)] and spectroscopic [MS, 13C‐NMR] techniques. As several compounds remained unidentified, particularly in sample S1, this oil was fractionated on silica gel column, leading to the isolation and structural elucidation of four new natural compounds by QTOF‐MS, 1D and 2D‐NMR analyses. These new natural sesquiterpenes were identified as (5αH,10βMe)‐6,12‐oxido‐elema‐1,3,6,11(12)‐tetraene, 6,12‐oxido‐germacra‐1(10),4,6,11(12)‐tetraene, (1βH,5βH)‐6,12‐oxido‐guaia‐6,10(14),11(12)‐trien‐4α‐ol and germacra‐1(10),4,7(11)‐trien‐6,12‐γ‐lactone. Finally, sixty‐eight constituents were identified in both investigated essential oil samples. They accounted for 96.1 and 97.3%, respectively, of the whole chemical composition of S1 and S2. Leaf essential oil from Idewevrei is very rich in sesquiterpenes. Indeed, its majority compounds were germacrene B (20.8 and 24.8%), (5αH,10βMe)‐6,12‐oxido‐elema‐1,3,6,11(12)‐tetraene (10.3 and 0.3%, new compound), germacrene D (7.5 and 17.8%), (Z)‐β‐ocimene (7.8 and 9.7%),γ‐elemene (6.9 and 7.5%) and (E)‐β‐caryophyllene (6.8 and 3.5%). The contents of thermolabile components were assessed by combination of GC(FID) and 13C‐NMR. [ABSTRACT FROM AUTHOR]

The chemical composition of 35 leaf oil samples from Polyalthia longifolia (Sonnerat) Thwait., growing in five districts in Abidjan and its suburbs, has been investigated by GC(FID) in combination with retention indices, GC-MS and 13C-NMR. In total, 30 individual components have been identified, mostly sesquiterpenes. The contents of the main components varied substantially from sample to sample: (E)-β-caryophyllene (18.9-31.4%), α-zingiberene (6.1-22.1%), allo-aromadendrene (12.4-17.3%) and α-humulene (6.4-11.0%). However, PCA was unable to differentiate groups within the 35 compositions. The chemical composition of Ivorian P. longifolia leaf oils may be summarized as follow: (E)-β-caryophyllene (M = 25.3%; SD = 1.2), allo-aromadendrene (M = 15.2%; SD = 0.5), α-zingiberene (M = 13.6%; SD = 3.6) and α-humulene (M = 8.4%; SD = 0.2). [ABSTRACT FROM AUTHOR]

ABSTRACT Polyalthia longifolia produces sesquiterpene-rich essential oils (EOs) whose compositions varied substantially from sample to sample depending on the origin of the plant (Nigeria and Vietnam). Nothing is known about the phytochemistry of Ivoirian P. longifolia. The aim of the present study was to characterize Ivoirian P. longifolia through the chemical composition of the leaf oil and to develop a strategy that allows the identification of minor oxygenated sesquiterpenes whose MS data are not compiled in commercial or laboratory-constructed MS libraries. The EO was submitted to gas chromatography (GC) retention index (RI), GC-mass spectrometry (MS) and 13C nuclear magnetic resonance (NMR) analysis. Then hydrocarbons and oxygenated components were separated and the oxygenated fraction was chromatographed on silica gel. The fractions were analysed by GC(RI) and 13C NMR. Seventy compounds accounting for 91.8% of the EO were identified. Sesquiterpene hydrocarbons, (E)-β-caryophyllene (27.8%), α-zingiberene (20.0%) and allo-aromadendrene (15.0%), were the major components. Various oxygenated sesquiterpenes whose MS data were not compiled in commercial and laboratory-made MS libraries were identified by comparison of their chemical shift values in the spectrum of the fraction of CC with those reported in the literature and compiled in a laboratory-constructed 13C NMR data library. The composition of the investigated Ivoirian P. longifolia oil sample presented similarities and differences with Nigerian and Vietnamese oils. Combined analysis of Ivoirian P. longifolia EO by chromatographic and spectroscopic techniques including 13C NMR without isolation of the components, appeared particularly efficient to identify minor components of EOs, whose MS spectra are insufficiently differentiated or MS data are not compiled in commercial and lab-constructed MS libraries. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]