Active Components On Rhododendron Dauricum L.

The study showed that the insecticidal activities of the extracts from leaves of Rhododendron dauricum L. were studied by the determination methods of bioactivity; and chemical components, chemical structures and relative contents of the extracts from leaves of Rhododendron dauricum L. were determined by GC-MS; and total flavonoid contents and stability of extracts from Rhododendron dauricum L. were determined by UV-VIS; and chemical components, chemical structures and relative contents of the essential oils from the leaves of Rhododendron dauricum L. were determined by GC-MS; and the farrerol content in Rhododendron dauricum L. were determined by HPLC.Insecticidal activities of the extracts from leaves of Rhododendron dauricum L.. The active components in leaves of Rhododendron dauricum L. were extracted by95%alcohol, and then the extracts were separated by petroleum ether, chloroform, ethyl acetate and n-butyl alcohol in turn. The results of insecticidal activities test showed that the chloroform parts, ethyl acetate parts,95%alcohol extracts had insecticidal activities on Lymantria dispar, and the insecticidal activities of the chloroform parts and the alcohol extracts showed more efficient than the ethyl acetate parts of the extracts.Chemical components, chemical structures and relative contents of the extracts from leaves of Rhododendron dauricum L. were determined by GC-MS. Results showed that the major active components in the95%alcohol extracts were:4,5-Dihydro-5-oxo-3-(p-tolyl)isoxazole,7-methoxy-2,2-dimethyl-2H-1-Benzopyran,5-methyl-2-(3,7,11-trimethyl-2,6,10-dodecatrienyl),(E,E)-1,3-Benzenediol; and the major active components in the chloroform parts were:2-ethyl-1,4-dimethyl-Benzene, Ethyl benzene,1,2-Benzenedicarboxylic acid, bis(2-methylpropyl) ester,3-(2-hydroxyphenyl)-1-(2,4-dihydroxy-6-methoxyphenyl)-2-Propen-1-one; and the major active components in the ethyl acetate parts were:(8.alpha.,10.alpha.)-Pregn-4-ene-3,20-dione,5-Fluoro-4-chloro-2-dimethyl amino pyrimidine,3,5-Dihydroxytoluene.Total flavonoid from leaves and stems of Rhodendron dauricum L. were obtained by ultrasonic extraction process, and the total flavonoid content was determined by ultraviolet-visible spectrophotometry. Effects of temperature and light intensity on stability of the extracts from Rhodendron dauricum L. were studied in terms of degradation rate of total flavonoid. Results showed that total flavonoid contents were48.0mg·g-1for leaves,40.2mg·g-1for stems. The degradation rate of total flavonoid increased and the stability of the extracts decreased with increasing temperature or increasing light intensity.The volatile components of the essential oils from the leaves of Rhododendron dauricum L. were extracted by steam distillation and vacuum distillation, respectively, and chemical components, chemical structures and relative contents of the essential oils from the leaves of Rhododendron dauricum L. were determined by GC-MS. The major volatile components which were extracted by steam distillation were:eduesmol, β-guaiene, longifolenaldehyde,(-)-humulene epoxide Ⅱ,1,5,9,9-tetramethyl-1,4,7-cycloundecatriene, germacrone, caryophyllene. While the major volatile components which were extracted by vacuum distillation were: eduesmol, longifolenaldehyde, β-guaiene, germacrone, alpha-ionol, santalol, agarospirol.Farrerol from leaves of Rhodendron dauricum L. were obtained by ultrasonic extraction process, and HPLC was used for determining the farrerol content from leaves of Rhodendron dauricum L., results showed that the farrerol content was0.9356mg·g-1.