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 C-13 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)-beta-caryophyllene (29.2% to 60.1%), myrcene (1.2% to 21.7%), a-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.