This study investigated the chemical composition of Solidago virga-aurea var. asiatica Nakai essential oils collected using different extraction methods. The essential oils obtained by simultaneous steam distillation extraction (SDE) and hydrodistillation extraction (HDE) methods from the aerial parts of Solidago virga-aurea var. asiatica Nakai were analyzed by GC and GC-MS. Ninety-nine volatile flavor compounds were identified in the essential oil produced from Solidago virga-aurea var. asiatica Nakai using the SDE method. These compounds were classified into eight categories in terms of chemical functionality: 26 hydrocarbons, 8 aldehydes, 36 alcohols, 7 ketones, 12 esters, 5 oxides and epixides, 4 acids, and a miscellaneous one. Spathulenol (15.66%) was the most abundant compound. Ninety-eight compounds including of 35 hydrocarbons, 6 aldehydes, 29 alcohols, 6 ketones, 10 esters, 4 oxides and epixides, 7 acids, and a miscellaneous one were identified in the essential oil from the plant using the HDE method. Hexadecanoic acid (24.74%) was the most abundant compound. The chemical composition of Solidago virga-aurea var. asiatica Nakai essential oils extracted by SDE and HDE methods are characterized by high content of sesquiterpene alcohols and acids, respectively. The extraction methods may be influenced in the chemical composition of natural plant essential oils.

This study investigated the chemical composition of Artemisia princeps var. orientalis (Pampan) Hara (ssuk in Korea) essential oil and the quantitative changes of major terpene compounds according to the time of harvest. The essential oils obtained by hydrodistillation extraction from the aerial parts of ssuk were analyzed by GC and GC-MS. The essential oil composition of ssuk was characterized by higher contents of mono- and sesqui- terpene compounds. Ninety-nine volatile flavor compounds were identified in the essential oil from ssuk harvested in 2010, with camphor (11.9%), β-caryophyllene (9.11%), dehydrocarveol (8.51%), and borneol (7.72%) being the most abundant compounds. Eighty-three compounds were identified in the essential oil from the plant harvested in 2011, with borneol (12.36%), caryophyllene oxide (12.29%), β -caryophyllene (10.24%), camphor (9.13%), and thujone (8.4%) being the most abundant compounds. Eighty-four compounds were identified in the essential oil from the plant harvested in 2012, with β-caryophyllene (20.25%), caryophyllene oxide (14.63%), and thujone (11.55%) being the major compounds. Eighty-nine compounds were identified in the essential oil from the plant harvested in 2013, with thujone (23.11%), alloaromadendrene oxide (12.3%), and β-caryophyllene (11.48%) being the most abundant compounds. Thujone and aromadendrene oxide contents increased significantly from 2010 to 2013, while camphor and dehydrocarveol contents decreased significantly during those 4 years. The quantitative changes in these 4 compounds according to the time of harvest can served as a quality index for ssuk essential oil. The ecological responses to recent climate changes may be reflected in the chemical components of natural plant essential oils.

This study investigates the chemical compositions of Aster koraiensis Nakai essential oils and the quantitative changes of major terpene compounds according to various harvesting times. The essential oils obtained by hydrodistillation from the aerial parts of Aster koraiensis Nakai are being analyzed by GC and GC-MS. The essential oil compositions of Aster koraiensis Nakai are characterized byhigher contents of sesquiterpene compounds. Ninety-seven volatile flavor compounds are being identified in the essential oils from Aster koraiensis Nakai harvested in 2010, and caryophyllene oxide (8.38%), aristolene (7.08%), epiglobulol (5.57%), and ethyl furanone (4.73%) are the most abundant compounds. Ninety-five compounds are identified in the essential oils from the plants harvested in 2011, and aristolene (11.56%), calarene (9.33%), phytol (8.28%), ethyl furanone (7.63%), and epiglobulol (7.18%) are the most abundant compounds. Ninety-five compounds are being identified in the essential oils from the plants harvested in 2012, and calarene (15.3%), aristolene (14.24%), ethyl furanone (7.21%), phytol (6.98%) are the major compounds. The contents of aristolene, α-caryophyllene, α-muurolene, α-calacorene, aromadendrene oxide, and calarene increase significantly from 2010 to 2012. The contents of α-cubebene, isocaryophyllene, and diepi-α-cedrene epoxide decrease significantly from 2010 to 2012. The quantitative changes of aristolene and calarene according to harvesting time can be served as a quality index of the Aster koraiensis Nakai essential oils.