Studies On Chemical Constituents Of Rhododendron Seniavinii Maxim

Rhododendron seniavinii Maxim is a medicinal plant mainly distributed in Jiangxi, Fujian, Hunan, Guizhou and other provinces in south China. The leaves of the plant are used as folk remedies for the treatment of acute and chronic bronchitis. In order to perform comprehensive exploitation and ultilization on R. seniavinii Maxim and provide good services for Chinese Traditional Patent Medicine, the chemical constituents of leaves extract from R. seniavinii Maxim were investigated. Twenty-six compounds were isolated from the water extract of this plant. By spectroscopic and chemical methods as well as physical and chemical properties, the structures of24compounds were determined as:5-methoxydehydroconiferyl alcohol (RS-1), dehydroconiferyl alcohol (RS-2),(-)-syringaresinol (RS-3),(-)-lyoniresinol (RS-4),(+)-lyonires-inol3α-O-β-D-glucopyranoside (RS-5),(-)-lyoniresinol3α-O-β-D-glucopyranoside (RS-6), nudiposide (RS-7),(-)-5’-methoxyisolariciresinol3α-O-β-D-glucopyranoside (RS-8),(+)-5’-methoxyis-olariciresinol-9’-O-β-D-xylopyranoside (RS-9),(+)-isolariciresinol3α-O-β-D-gluco-pyranoside (RS-10),(-)-isolariciresinol3α-O-β-D-glucopyranoside (RS-11), threo-2,3-bis-(4-hydroxy-3-methoxyphenyl)-3-ethoxypropan-l-ol (RS-12), ciwujia-tong(RS-13),3’,4-dihydroxy-4,6,2’,4’-tetramethoxy-2,9’-epoxy-1’,7-cyclolignan-9-ol (RS-14),3,4,5-trimetho-xyphenol (RS-15),3,4,5-trimethoxyphenyl-1-O-β-D-glu-copyranoside (RS-16), nikoenoside (RS-17),3,5,7-trihydroxychromone-3-O-α-L-rhamnopyranoside (RS-18), scopoletin (RS-19), scopolin (RS-20), quercitrin (RS-21),5,7,3’-trimethoxy-3,4’-dihydroxyflavone-3-O-β-D-glucopyranoside (RS-22),5,7,3’-trimethoxy-3,4’-dihydroxyflavone (RS-23), and3’,4-dihydroxy-4,6,2’,-4’-tetr-amethoxy-2,9’-epoxy-1’,7-cyclolignan-9-O-β-D-glucopyranoside (RS-24).Among them, RS-22and RS-24are new compounds, RS-23is a new natural product, twenty compounds from RS-1to RS-20were isolated from this plant for the first time.