| This PhD dissertation focused on an investigation of main iridoids and minor constituents with specific UV absorption bands of the more polar fractions from a water extract of the flower buds of Lonicerajaponica collected from Henan province.By using various chromatographic techniques,31 compounds were isolated,and their structures were elucidated by spectroscopic and chemical methods.Their chemical names and structures are listed in Table 1 and Figure 1,including 23 iridoids(1*～12* and 15～25), 2 nicotinic acid N-glycosides(13* and 14*),3 nucleosides(29～31),chiorogenic acid (26),caffeic acid(27),and syringin(28).Among them,1*～14* were new,and 18 and 28～30 were isolated from L.japonica for the first time.Compounds 1*～4* are based on a novel carbon skeleton derived from a N-substituted nicotinic acid nucleus coupled through C-5 with C-7 of a secoiridoid.5*～8* possesses another novel carbon skeleton derived from a N-substituted pyridine nucleus coupled through C-5 with C-7 of a secoiridoid.9* and 10* are unusual secoiridoids coupling withβ-hydroxy amino acids, and 11* and 12* are two homosecoiridoids with two and three additional carbons in their skeleton,respectively.13* and 14* are the first natural examples of N-β-D-glucopyranosyl nicotinic acid derivatives.1*～8*,13* and 14* were obtained as their inner salt forms.In addition,9* and 10*,which can not be hydrolyzed byβ-glucosidase from almonds, as well as their epimers and anologues(S2*,S4*,S5,and S6) were stereoselectively semi-synthesized by condensation of 17 or 21 withβ-hydroxy- orβ-thiol- amino acids. By using several glucosidases includingβ-glucosidase from almonds,hesperidinase from Aspergillus niger and heloxpomatiase,enzymatic hydrolysic properties of 1*,5*,S1*～S4*,S5,and S6 were investigated.S1*(9*),S3*(10*),S4*,and S5 were completely resisitant toβ-glucosidase and hesperidinase while S2*,S6,1*,and 5* were partially resistant to them.However,they were readily hydrolyzed by heloxpomatiase.The isolates,and semi-synthetic products were assayed on several pharmacological models.3*,4*,7*,8*,10*,16～24 and 26 showed inhibitory activities against the release of glucuronidase in rat polymorphonuclear leukocytes(PMNs) induced by platelet-activating factor(PAF) with inhibition rates of 50.5%～88.2%at 10-5 M.5*, 22 and 23 were active against the release of PGE2 in mouse peritoneal macrophages induced by lipopolysaccharide(LPS),with inhibition rates of 62.3%～65.4%at 10-5 M. 10*,S4*,S5,and S6 exhibited protective activities against serum deprivation-induced PC12 cell apoptosis with cell survival rates of 76.3%～79.0%at 10-5 M.26 showed DPPH free radical scavenging acticity with an inhibition rate of 92%at 10-3 M.S2*,S4*, S5,and S6 showed protective activities against hepatocyte(WB-F344) damage caused by DL-GalN with cell survival rates of 42%～49%at 10 10-5 M.Moreover,biological activities of the extracts,isolates,and semi-synthetic products were evaluated on human cancer cell lines(BGC-823,A2780,A549,HCT-8,and Be17402),a potassium channel regulation model,and etc.,but they were inactive at 10-4～10-6M.
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