Extinction Risk Assessment and Chemical Composition of Aerial Parts Essential Oils from Two Endangered Endemic Malagasy Salvia Species.

Seven essential oil samples of two endemic species of Malagasy sage, Salvia sessilifolia Baker and Salvia leucodermis Baker, were investigated via GC(RI), GC-MS and 13C NMR spectrometry. In total, 81compounds were identified accounting for 93.5% to 98.7% of the total composition. The main constituents for the both species were (E)-ß-caryophyllene (29.2% to 60.1%), myrcene (1.2% to 21.7%), α-humulene (5.2% to 19.7%), (E)-nerolidol (0.8% to 15.5%) and caryophyllene oxide (1.4% to 10.8%). Ethnobotanical survey of 46 informants revealed that decoctions of leafy twigs and chewed leaves were usually used. Due to the repeated fires, over-harvesting and grazing, the populations of S. sessilifolia and S. leucodermis are drastically fragmented. These risk factors led to threats to the habitats of the target species. Salvia sessilifolia Baker and Salvia leucodermis Baker are proposed to be classified as endangered species.

Chemical Composition of Aerial Parts Essential Oils from Six Endemic Malagasy Helichrysum Species.

The essential oils of six endemic Malagasy Helichrysum species were investigated by GC (RI), GC-MS and 13C NMR spectrometry. In total, 153 compounds were identified accounting for 90.8% to 99.9% of the total composition. The main constituents were α-pinene for H. benthamii, 1,8-cineole for H. dubardii, (E)-ß-caryophyllene for H. indutum, and H. bojerianum. H. diotoides essential oil was characterized by the presence of two lilac alcohols and four lilac acetates whereas H. hirtum essential oil exhibited an atypical composition with 7ß-H-silphiperfol-5-ene, 7-epi-subergorgiol, and 7-epi-silphiperfol-5-en-13-oic acid as major components.

Essential oil of the malagasy grass Elionurus tristis Hack. contains several undescribed sesquiterpenoids.

Essential oils (EOs) obtained from aerial parts and roots of Elionurus tristis were investigated by GC, GC-MS, pc-GC and NMR. Both aerial parts and roots EOs contained common molecules such as α-pinene, camphene, trans-α-bergamotene and calarene. Moreover, we identified several unusual sesquiterpenes and four undescribed compounds, 7-epi-khusian-2-ol, 4,8-di-epi-acorone, 2-epi-ziza-5-en-2-ol and antsorenone. The last one exhibits an undescribed natural sesquiterpene skeleton. All undescribed compounds were isolated and fully characterized by MS, 1D and 2D-NMR. Furthermore, the formation pathway of the Antsorane skeleton is discussed.

Chemical composition of the essential oils from the aerial parts of two Malagasy endemic species (Apiaceae): Billburttia capensoides Sales & Hedge and Billburttia vaginoides Sales & Hedge.

The chemical composition of twenty-five essential oil samples from the aerial parts of two Malagasy endemic species Billburttia capensoides Sales & Hedge and B. vaginoides Sales & Hedge, were investigated for the first time. Based on chromatographic profiles, three selected samples were investigated using GC(RI), GC-MS and 13C NMR. The content of the main components varied drastically from sample to sample: p-mentha-1,3,8-triene (0.2-52.7%), terpinolene (2.8-40.7%) and dill apiole (0.0-22.2%). Statistical analysis of the 25 oil compositions allowed the distinction of two well-differentiated groups. Samples of group I contained mainly p-mentha-1,3,8-triene while the Group II was dominated by terpinolene and dill apiole.

Chemical composition of Melicope belahe (Baill.) T. G. Hartley (Rutaceae) leaf essential oil from Madagascar.

Melicope belahe (Baill.) T.G. Hartley (Rutaceae) is an endemic species to Madagascar. The chemical composition of leaf essential oil is reported for the first time. A sample was extracted by hydrodistillation and analysis was carried out by combination of chromatographic (GC), spectroscopic and spectrometric (MS, 13C NMR) techniques. In total, 56 compounds have been identified. The chemical composition was dominated by α-pinene (42.6%) followed by linalool (6.2%) and (E)-ß-caryophyllene (5.2%).

Chemical composition of the essential oil from Croton kimosorum, an endemic species to Madagascar.

Croton kimosorum Leandri is an endemic species to Madagascar. The chemical composition of aerial parts, leaf and stem oils is reported for the first time. Analysis was carried out by combination of chromatographic (CC, GC), spectroscopic and spectrometric (MS, 13C NMR) techniques. In total, 76 compounds have been identified. Essential oil isolated from aerial parts contained mainly linalool (21.6%), sabinene (10.4%), 1,8-cineole (6.3%), beta-pinene (6.2%), (E)-beta-caryophyllene (5.9%), terpinen-4-ol (4.8%), geraniol (4,5%) and germacrene D (2.3%). In comparison with the first sample, the composition of leaf and stem oils varied slightly, while essential oil isolated by vapor distillation from a semi-industrial still exhibited similar composition.

Leaf oil from Vepris madagascarica (Rutaceae), source of (E)-anethole.

The volatile components isolated from leaves of Vepris madagascarica (Baillon) H. Perier (Rutaceae), an endemic species of north-eastern, sub-humid forests of Madagascar, were investigated by GC (Retention Indices), GC-MS and 13C NMR spectroscopy. Oil samples obtained on laboratory and industrial scales exhibited similar composition, dominated by phenylpropanoids. (E)-anethole (78.2% and 78.6%) was the major component followed by estragole (15.6% and 15.4%). In addition, trunk bark oil also contained (E)-anethole as its major component (84.6%), as well as various sesquiterpenes in low contents.