Investigation Of The Chemical Constituents And Biological Activities Of Rubus Chingii Hu

Rubus chingii Hu,commonly known as "Fu-pen-zi" in Chinese,is widely distributed in China that has been used as a traditional medicine to treat kidney enuresis,nocturnal emission,premature ejaculation and other diseases in clinical.The leaves of R.chingii have been used as a functional tea for the treatment of mild diarrhea for long history.Recently,R.chingii have raised considerable interests for their potential health-promoting properties and the broad range of fascinating bioactivities.The extracts of R.chingii have been provided possessing anticancer,antithrombotic,hepatoprotective,immunomodulatory,anti-oxidant,anti-inflammatory and anti-osteoporotic effects.In this thesis,as a continue exploring the bioactive metabolites from Chinese traditional medicine,we have investigated the ethanol extracts of the whole plant of R.chingii collected from Xinchang,Jiangsu province.As a result,the following results were obtained:(1)six compounds were isolated by various chromatographic techniques,including silica gel column,sephadex LH-20 gelatin column,prepared TLC,recrystallization and HPLC.These structures were elucidated as:ent-kaurane-16α,17-diol-2-one(75),17-O-β-D-gluc-oside-ent-kaurane-16α,17-diol-2-one(76),esculetine(77),3,3’-di-O-methylellagic acid 4-(5"-acetyl)-α-L-arabinofuranoside(78).ethyl-β-D-glucoside(79)and quercilicoside A(80)on the basis of extensively spectroscopic analysis,including 1D(1H NMR,13C NMR,DEPT)and 2D NMR(1H-1H COSY,HSQC,HMBC,NOESY),IR,HRMS and by comparison of their NMR data with those of the literature data.Among them,compounds 75 and 76 are the rare new ent-kaurane diterpenes isolated from genus Rubus,and compounds 77,78 and 80 were the first time isolated from R.chingii.(2)Compounds 77-80 were selected to evaluate the free radical scavenging activity and the Ferric reduction capacity by DPPH,FRAP assays,respectively.And compounds 77 and 78 exhibited potential antioxidant activity with IC50 of 0.76 and 2.00 mM for DPPH free radicals and 0.034 and 0.28 mM for the ferric ion reducing activity,respectively.(3)In addition,we investigated the antibacterial activity of compounds 78 and 80,and the results showed that compound 78 significantly inhibited the growth of Gram-negative bacteria E.coli with a MIC of 30 mg/mL.Unfortunately,during the in vitro cytotoxicity activity evalu-ation against human gastric cancer cell line(SGC7901)for the two new compounds 75 and 76,none of them exhibited cytotoxicity activity at 50 μM.