Studies On The Chemical Constituents Of Tibetan Medicine Rhododendron Primulaeflorum BUR.ET Franch

Rhododendron primulaeflorum (Ericaceae) is a shrub mainly growing in the sout-hwestern China, especially in Tibet, Yunnan, and Sichuan. For more than a thousand years, its leaves and sprouts have been used in traditional Tibetan medicines for trea-ting chronic tracheitis, suppressing cough, and controlling asthma. The thesis studied t-he chemical constituents of Rhododendron primulaeflorum Bur.et Franch. for the first time, and provided a scientific evidence for the deep exploration and usage of it.The volatile oils of Rhododendron primulaeflorum Bur.et Franch. were extracted by water steam distillation and its chemical constituents were separated and identified by GC-MS. Sixty five peaks were separated and fifty nine components were identifi-ed, which constituted about 97.50% of the total essential oils. The main compounds areβ-pipene(13.81%), a-pipene(12.86%), limonene(8.18%), (β-caryophyllene(7.55%), m-yrcene(6.36%), naphthalene(4.63%). (+)-ledol(4.44%), y-terpipene (4.23%), (+)-aromad-endrene(3.94%) and a-terpineol(2.74%).The constituents were separated and purified with chromatographic methods and their structures were elucidated by spectroscopic methods and chemical analyses. Tw-enty four compounds have been isolated from Rhododendron primulaeflorum. They were identified as:cannabichromeorcinic acid(1),β-sitosterol(2), ursolic acid(3). methyl orsellinate(4), orsellinic acid(5),2-hydroxy-3-oxopentanedioic acid(6), quercetin(7). trans-taxifolin-3-O-a-L-arabinopyranoside(8), taxifolin(9),(-)-epicatechin(10), myricetin(11). fr-axetin(12), dihydromyricetin(13), myricetin-3'-O-β-D-xyloside(14).3,4-dihydroxyl-5-meth-oxyl-phenylpropanol(15), gossypetin-3-O-β-D-galacoside(16), orcinol-O-β-D-glucopyranos-ide(17),2,6-dimethoxy-4-hydroxyphenyl-1-O-β-D-glucopyranoside(18), lyoniside(19),4-hydroxyl-5-methoxyl-phenylpropanol-3-O-β-D-glucopyranoside(20), hyperoside(21),4,6-dihydroxy-2-O-(β-D-glucopyranosyl)acetophenone(22),3.5-dihydroxy-4-O-((3-D-glucopyr-anosyl)acetophenone(23), quercetin-3-O-β-D-robinobioside-7-O-β-D-glucosides(24). Comp-ound 20 is a new phenylpropanol glycoside. Excerpt compounds 4,7 and 8. the oth-er compounds were isolated from the plant for the first time. The structure types we-re involving with flavonoid, phenol, triterpene and coumarin.