Studies On The Chemical Constituents Of Two Toxic Medicinal Plants From Andromededoideae

The dissertation is composed of four chapters. In the first chapter, the rencent advances on the chemical constituents and bioactivities of diterpeniods in the subfamily Andromededoideae was summarized. The chapters 2 and 3 dealed with the isolation and identification of the chemical constitutes from two medicinal plants, Pieris formosa D.Don and Craibiodendron yunnanense W.W.Smith. In the last chapter, conclusion of this dissertation was reported.In the natural non-alkaloid toxins, diterpenoids derived from the subfamily Andromededoideae were very compelling. Phytochemical researches on this subfamily had resulted in the discovery of a series of diterpenoids, most of which were found to possess a 5/7/6/5 ring system. As early as 1950s, phytochemical investigation on the flowers and seeds of Rhododendron moll G. Don had been done in China, so that some grayanane diterpenoids had been isolated and identified. Pharmacological experiments demonstrated that most of the grayanane diterpenoids exhibited obvious bioactivities, such as lowering blood pressure, dilating vessels, muscle spindle stimulant, decreasing heart rate and growth inhibitory. In order to investigation the components of the subfamily Andromededoideae and search for bioactive natural products, systemic chemical and preliminary biologic studies on the leaves of Pieris formosa and Craibiodendron yunnanense were carried out in this dissertation.By the means of silica gel, Sephadex LH-20, RP-18 column, MCI column and spectroscopic evidences,30 compounds were isolated and identified from above two Andromededoideae plants, including diterpenoids, triterpenoids, flavonoids, aromatic compounds and steroids.17 compounds were isotated and identified from Pieris formosa, including one new compound, pierisformosin E (1). The known compounds were identified as pierisformosin M (2), pierisformosin L (3), grayanotoxin-ⅩⅧ(4), grayanotoxin-Ⅱ(5), ursolic acid (6), betulinic acid (7),2',4-dihydroxy -4'-methoxy-6'-O-β-glucopyranoside dihydrochalcone (8), phloridzin (9), phloretin (10),3-hydroxy-phloridzin (11), catechin (12), epicatechin (13), epicatechin-(2/β→O→7,4β→8)-ent-epicatechin (14), bis-8, 8'-catechiny-lmethane (15),β-sitoserol (16), daucosterol (17). Compounds 1,5-12, 14 and 15 were obtained from this plant for the first time.Meanwhile,13 known compounds were isolated and identified from Craibiodendron yunnanense:grayanotoxinⅢ(1), rhodomolleinⅡ(2), asebotoxinⅢ(3), asebotoxinⅠ(4), grayanotoxinⅩⅧ(5), pierisformosin A (6), grayanotoxinⅡ(7), arichannatoxinⅠ(8),4-hydroxybenzeneethanol (9), (Z)-p-hydroxy cinamic acid (10), (E)-p-hydroxy cinamic acid (11),β-sitoserol (12) and daucosterol (13).Compounds 1,2,4, and 6-9 were obtained from this plant for the first time.