Tangli Study The Chemical Composition Of Foliage

The studies on the chemical constituents and bioactivities of Pyrus have demonstrated that the main compounds in this genus were polyphenols, phenolic acid esters, lupine alcohol esters, triterpenoids, sterols and polysaccharides, which exhibited antioxidant, anti-inflammatory, anti-cancer and many other medicinal effects. Pyrus pashia (Pyrus) is a kind of deciduous trees, mainly used for cultivating artificially rootstock of pears. Pyrus pashia is also used as nectariferous and medicinal plant. In1971, eight compounds were reported from branches and bark of this paint. In2011,21compounds were isolated from the flowers of Pyrus pashia by our research group. According to our studies on chemical constituents from the branches and leaves of Pyrus pashia in this dissertation, some natural small cyclopeptides were founded. This kind of compounds has never been reported from Pyrus.This dissertation consists of two chapters. In the first chapter, the research progress on the structures and bioactivities of plant cyclopeptides were summarized. In the second chapter, twenty-five compounds were isolated from the ethyl acetate extracts of the branches and leaves of Pyrus pashia. On the basis of IR, ESI-MS, and NMR technologies, their structures were identified as pashinin A (1), pashinin B (2), pashinin C (3), gastrodin-7-O-crs-caffeoyl ester (4), gastrodin-7-O-trans-caffeoyl ester (5), gastrodin-7-O-p-hydroxybenzoyl ester (6), kaempferol-3-O-β-D-(6"-O-cis-p-coumaroyl) glucopyranoside (7), kaempferol-3-O-β-D-(6"-O-trans-β-coumaroyl)glucopyranoside (8), apigenin-4’-O-β-D-glucopyranoside (9), quercetin-3-O-β-D-glucopyranoside (10),2R,3R-dihydyoquercetin (11), luteolin-4’-O-β-D-glucopyranoside (12),5,7,4’-trihydroxyisoflavone-7-O-β-D-glucopyranoside (13), arbutin (14), robustaside B (15), genistein (16),2-(3’,4’-dihydroxy benzene)-1,3-benzodioxide-5-aldehyde (17),2a,3a-Dihydroxy-12-en-28-Oleanolic acid (18), tormentic acid (19), euscaphic acid (20), caffeic acid (21),β-sitosterol (22), daucosterol (23), glucose (1â†'2) tartaric acid (24), glucose (25). Among them,1-4were new compounds,5was a new natural compound, whose NMR data were reported for the first time,6-20were isolated from this plant for the first time. Compounds1～4,8showed no cytotoxic effects on tumor cell (IC50>40μM).1and8exhibited weak anti-HIV-1activities.