Phytochemical Investigations On Two Medical Plants And Its Chemotaxonomical Significance

This thesis is composed of five chapters. The first chapter is a review about the advances of prenylflavonoids. The second and third chapters described the phytochemical investigation of two medicial plants, Craibiodendron yunnanense and Epimedium Koreanum. The fourth chapter discussed the chemotaxonomic significance of grayanane diterpenoids in Ericaceae. The last Chapter was a summary of this thesis.The genus Epimedium (Berberidaceae) comprises57species throughout the world, and China possesses about47species, China is the distributing center of Epimedium in northern hemisphere, which is highly possible the original center of Epimedium. Many researches about the bioactivities of Epimedium plants have been reported, including anti-tumor, anti-aging, anti-oxidation, anti-depressant, anti-osteoporosis and so on. By all kinds of chromatographic materials, twenty-five compounds were isolated from E. brevicornum, and fourteen of them were identificated, including six new prenylflavonoids and one flavonoid glycoside. The new compounds were identified by extensive1D and2D NMR spectral analysis, they were:5,7-dihydroxy-4’-methoxy-8-(12,13-dihydroxy-isoprene-11-en)-flavonol3-0-a-L-rhamnose (1),5,7,4’-trihydroxyl-8-(13-hydroxy-7,12-epoxy-isoprene-11-en)-flavonol3-O-α-L-rhamnose (2),5,7,4’-trihydroxy-8-(13-methoxy-7,12-epoxy-isoprene-11-en)-flavonol3-O-α-L-rhamnose (3),5,7,4’,5’-tetrahydroxy-3’-(11,13-dihydeoxy-4’,12-epoxy-isopentane)-flavone (4),5,7,4’-trihydroxy-8-(7,12-epoxy-ethyl-11-en)-flavonol3-O-a-L-rhamnose (5),5,7-dihydroxy-4’-methxoxy-8-(11-methoxy-13-hydroxy-7,12-epoxy-isopropyl)-flavonol3-O-α-L-rhamnose (6), and5,7-dihydroxy-4’-methoxy-8-(12-hydroxy-13-methyl-13-butenyl)-flavonol3-O-α-L-rhamnose (9), Others seven known compouds was identified as:Apigenin (10), Afzelin (11), Quercitrin (12), Crysin (13), Morelosin (14), Quercrtin (15), and Luteolin (16).Craibiodendron yunnanense belonging to the genus of Craibiodendron Eriaceae, are mainly distributed in Yunnan province, where is the modern distributing center of Craibiodendron. In folk medicine, the leaves of C. yunnanense were used to treat wind-cold, gastralgia, rheumatic, traumatic injury and so on. Fifteen known compouds were obtained from the75%acetone/warter extract of the leaves of C. yunnanense, including flavonoids, flavonoid glycosides, diterpenoids, diterpenoid glucosides, triterpenoids and so on. These fifteen known compounds were elucidated as: Quercetin3-O-β-D-Glucopyranoside (1), Craibiodendronin A (2),(-)-Epicatechin (3), luteolin-7-O-α-L-rhamnoside (4),2a-hydroxy-ursolic acid (5),2α,3β,11α,23-tetrahydroxyurs-12-en-28-oic acid (6),3-epi-ternstroamic acid lactone (7), α-amyrin (8), Grayanotoxin-Ⅱ (9), Rhodomollein Ⅱ (10), Craiobiotoxin-Ⅰ (11), Grayanoside C (12), Craiobioside A (13),3,4-dihydroxyphenylethanol3-O-glucoside (14), and β-sitosterol (15)。Moreover, in the fouth chapter of this dissertation, the chemotaxonomic significance of grayanane diterpenoids in Eriaceae was discussed.According to our phytochemical investigation on the toxic and non-toxic plants of the family Ericaceae and literatures, we may state the following conclusions:(1) All well-defined taxa consist of species of the family Ericaceae consistently have maxima in the diterpene and flavanone components. Thus, the isolation of diterpenoids and their glycosides, flavanones and their glycosides indicates that these compounds could be chemotaxonomic markers for the family Ericaceae.(2) Grayanane diterpenoids can be a useful taxonomic tool for the classification of toxic and non-toxic species of the family Ericaceae. Besides, the toxic of plants could be estimated by the content of grayanane diterpenoids and the oxidizability of grayananes (eg.2,3-epoxy and acylated at C-6,14). Flavanones, e.g. quercetin, quercetin derivatives and quercetin nucleoside, were mainly got from the non-toxic plants, such as R. spiciferum, R. alutaceum, R. spinuliferum, and R. delavayi.(3) Higher level phylogenetic analyses of Ericaceae based on both nuclear and chloroplast DNA support the existence of a clade comprising of four groups, and the presumed order of divergence was:(1) Oxydendrum,(2) Lyonia group (incl. Agarista, Craibiodendron, Lyonia, and Pieris)(3) Gaultheria group, and (4) Vaccinieae).Owing to the closely relationship between the genus Craibiodendron and Lyonia, and the existence of highly oxidized grayanane diterpenoids in L. ovalifolia, from he view of evolution, it comes to the conclusion that L. ovalifolia is more evolutionary than C. yannanense.