Abstract
Rhus semialata var roxburghii is defoliate tree (Rhus L., Anacardiaceae) and is distributed all over the Taiwan and world. Rhus chinensis Mill is formed as a gall by the period when Melaphis chinensis lives in the R. semialata. R. chinensis Mill is a folk medicine using for heat cleansing effect, antidotal action, anti-inflammation and detumescene. Some of these effects may be related to immune regulation and anti-tumor in some literatures. To investigate the effective components from Rhus chinensis Mill is our first aim of this thesis by various chromatographic techniques. Bioassay-directed fractionations and derivative reactions led to twelve pure compounds: one hydrolyzable tannin: 1,2,3,4,6-penta-O- galloyl-β-D-glucose ( 1 ); two monomeric flavonoids: quercetin ( 2 ), quercetin-3,7,3’,4’-tetra-methyl ether ( 3 ); three organic acids: gallic acid ( 4 ), methyl gallate ( 5 ), p-anisic acid ( 6 ); four triterpenoids: lupeol ( 7 ), betulonic acid ( 8 ), moronic acid ( 9 ), semimoronic acid ( 10 ); one steroids:β-sitosterol ( 11 ); one aromatic compound: bis-(2-methylhexyl) phthalate ( 12 ). All above twelve pure compounds were isolated from R. chinensis. To further study the structures and activities relationships (SAR), we took 1,4-naphthoquinones with different regiochemistric hydroxy substitutions as starting materials to prepare three derivatives : 2-acetoxy-1,4- naphthquinone ( 13 ), 5-acetoxy-1,4 naphthquinone ( 14 ), and 2-benzoxy-1,4-naphthoquinone ( 15 ). Structures of all acquired compounds were confirmed by spectral elucidations including NMR, MS, FT-IR etc. Bioassay data revealed that compound 2, 13, 14, 15 exhibited cytotoxic effects against cancer cells ( KB, and HeLa cell lines); moreover, we found that compound 1 ( 1,2,3,4,6-pneta-O-galloy-β-D-glucose, 5GG ) showed some biologically inhibitory effects, such as inhibiting the activation of peripheral blood mononuclear cells (PBMCs), and production of reactive oxygen species (ROS) from neutrophils and mononuclear cells. And it might probably regulate cell cycle of KB cells. Quercetin and three 1,4- naphthoquinone derivatives were further investigated their anticancer mechanism by using DNA Hypoploidy analysis with flow cytometry and catalytic DNA topoisomerase I inhibition assay. We inferred that both synthetic 1,4- naphthoquinone analogues and quercetin had inhibition against DNA topoisomerase I activity and might induce apoptosis through mediating cell cycle of KB cells.