Gesneriaceae Medicinal Plants In The Chemical Composition And Chemical Systematics

The family Gesneriaceae is an important group of Scrophularials, it is represented by 54 genera and 438 species which are widly spread over south China regions. Many Gesneriaceae species are used in folk medicine. According to Burtt, the family is divided into two subfamily, Gesnerioideae and Cytandroideae, the former being divided into four tribes, Didymocarpeae , Trichosporeae, Cyrtandreae and Klugieae.This doctoral dissertation deals with the study on the chemical constituents of Lysiono-tus pauciflorus Maxim. (Gesneriaceae, Trichosporeae) and of Hemiboea henryi clark. (Gesneriaceae , Didymocarpeae) as well as the chemosystematics of the two genera.Twenty — two natural products were isolated from the EtOH extract of the aerial part of L. pauciflorus. On the basis of physicochemical properties and spectroscopic analyses, LD — 1, LD—2, LD—3, LD—4, LD—5 were determined to be five new compounds. Their structures were elucidated as 5 — hydroxy — 4' , 6, 8 — trimethoxy flavone — 7 — α — L — rhmnopyranosyl — (1→6)— β—D—glucopyranoside(lysioside A, LD—1), 5-hydroxy — 4' ,6,8—trimethoxy flavone—7—0—β-D—glucopyranoside (lysioside B, LD—2),7—hydroxy— 4' ,6,8—trimethoxy flavone—5—O—β—D—glucopyranoside (Lysioside C, LD— 3), 7—hydroxy—4' ,6,8—trimethoxy flavone—5—O—β—D—glucopyranosyl— (1→6) — β—D—glucopyranoside (lysioside D, LD—4). 5,7,3' ,4' — tetrahydroxy—6—mthoxy—8 —C— (6"— acetyl)—β—D—glucopyranoside (lysioside F, LD—5).Among of them, Lysioside A — D are all the new flavone glycosides of aglycone nevadensin, this is the first time to report the aglycone nevadensin existed in nature as gly-cosidation form. Lysioside F is acylated C—glycosylflavone, the aglycone 6—methoxy lute-olin is also the first report be the aglycone of C—glycosylflavone.Eleven known compounds were obtained from the EtOH extract of the whole plant of H. henryi, among of them, vitcxin and 2" — O—rhamnosyl vitexin were isolated from the Gesneriaceae for the first time.In the course of structural elucidation of the new compounds, techniques such as 2DN-...