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Of the 57 species of the economically important genus Hypericum (St. John's Wort; Clusiaceae) occurring in China, only a small percentage have been previously phytochemically investigated. As part of our continuing research on the phytochemistry of Hypericum, the chemical compositions of volatiles isolated from 12 Chinese species were determined. Volatile constituents were isolated by microdistillation of dried and ground aerial material from flowering plants and subsequently analyzed by GC/MS. The major component(s) were identified as follows: ar-curcumene (12.6%) and β-selinene (16.3%) in H. acmosepalum; γ-muurolene (11.3%), β-selinene (16.3%) and caryophyllene oxide (18.7%) in H. beanii; α-terpineol (11.5%) and β-pinene (29.2%) in H. calycinum; cis-eudesma-6,11-diene (11.4%) in H. choisyanum; α-pinene (10.4%) and caryophyllene oxide (12.7%) in H. forrestii; cis-β-guiaene (10.7%) and γ-muurolene (12.4%) in H. kouytchense; β-selinene (11.4%) and eudesmadienone (10.8%) in H. lancasteri; cuparene (24.8%) and γ-muurolene (16.8%) in H. leschenaultii; tricosane (13.3%) and myrcene (10.4%) in H. monogynum; β-selinene (14.7%) in H. patulum; β-selinene (18.5%) in H. pseudohenryi; and γ-muurolene (10.7%) and δ-cadinene (10.2%) in H. X moserianum. [ABSTRACT FROM AUTHOR]

The essential oil of fresh aerial parts of Senecio giganteus Desf. (Asteraceae), obtained by hydrodistillation in a Clevenger-type apparatus, is analyzed by GC-MS. Eighteen compounds are characterized representing 82.8% of the essential oil with α-pinene (19.4%), 6,10,14-trimethyl-2-pentadecanone (19.1%), pentacosane (16.9%), and tricosane (11.9%) as the main components. [ABSTRACT FROM AUTHOR]

The essential oils of bracts and inflorescences of cultivated Tilia tomentosa and T. cordata from Greece and Romania, respectively, were investigated. Essential oils were obtained by hydrodistilation and analyzed using GC and GC/MS. The oils of from the inflorescences of T. tomentosa and T. cordata were characterized by a high percentage of hydrocarbons (32.3% and 60.4%, respectively) with tricosane being the main component (21.5% and 31.3%). Isocyclocitral (15.3%) and hotrienol (11.5%) were characterized as the main oxygenated monoterpenes of T. tomentosa and T. cordata inflorescences oils, respectively. Linalool (13.1%) and hexahydrofarnesyl acetone (17.7%) were the major constituents in bract oil of T. tomentosa, whereas the bract oil of T. cordata was characterized by the predominance of hydrocarbons (87.4%) with tricosane (32.2%) being the main constituent. [ABSTRACT FROM AUTHOR]

The essential oil, isolated by hydrodistillation from fresh flowers of Spartium junceum L., was investigated by GC and GC/MS. The 24 main constituents of the samples were identified; the main components of the oil were kairomonal compounds, tricosane (22.9%), tetracosane (8.9%) and pentacosane (16.1%), constituting altogether almost 48% of total composition. These hydrocarbons constitute an important aspect governing the sensitivity of the insects in plant host selection. [ABSTRACT FROM AUTHOR]

The essential oils of the inflorescences of Orchis italica and Orchis quadripunctata were analyzed by GC and GC/MS. Thirty-two compounds were identified and the major components were linear hydrocarbons (mainly tricosane and pentacosane) and linear aldehydes (mainly nonanal). [ABSTRACT FROM AUTHOR]