Study On Isolation Active Components From Wedelia Chinensis (Osbeck.) Merr. And Their Bacteriostatic Action

Wedelia chinensis (Osbeck.) Merr. is a Chinese herbal medicine which is an abundant resource in China and is widely used in folk.Wedelia trilobata(L.) Hitchc. is a South Americ- an plant which was introduced into China as a sprigging operation plant.The antibacterial acti- on of the water extracts,95% alcohol extracts,the extracts of alcoholpetroleum ether,chorofo- rm,ethyl acetate,n-butanol from Wedelia chinensis (Osbeck.) Merr. and Wedelia trilobata(L.) Hitchc. on Escherichia coli,Staphyloccocus aureus Rosenbach,Staphylococcus,Bacillussubti- lis,Yersinia enterocolitica,V.anguillarum,Aeromonas hydrophila,Salmonella,Micrococci was studied.Exploitations and prospects of Wedelia chinensis (Osbeck.) Merr. and Wedelia trilo- bata(L.) Hitchc. as antibacterial agent were discussed.The main contents were as follows:1 Preparation of Wedelia chinensis (Osbeck.) Merr. and Wedelia trilobata(L.) Hitchc.,s extracts and the preliminary examination of their chemical compositionObjective: To prepare extracts for our research and get the initial message of the active ingre- dients.Methodology:the conventional method was used to prepare their water extracts and 95% alcohol extracts.Petroleum ether,chloroform,Ethyl acetate, and N-butanol were choosed as the extracting solvents to separate and purify the chemical constituents in correct order.The system of preliminary examination was applied to study their chemical compositions.Results: The examinations showed the water extracts of Wedelia chinensis (Osbeck.) Merr. and Wedel- ia trilobata(L.) Hitchc. contain a variety of ingredients:steroids or triterpenes,volatile oil and esters,alkaloid,iridoid glycoside,terpenoid lactone,cardiac glycoside,phenols,tannin,amino ac- id,peptides,proteins, polysaccharides and amylose,etc; the 95% alcohol extracts contain a var- iety of ingredients:steroids or triterpenes,volatile oil and esters,alkaloid,flavonoid,quinine,iri- doid glycoside,terpenoid lactone,cardiac glycoside,phenols,tannin,organic acid, polysacchari- des and amylose,steroidal saponin etc.Conclusion:Wedelia chinensis (Osbeck.) Merr. and W- edelia trilobata(L.) Hitchc. contain many chief chemical compositions, although they are sibling, they are not homogeneity,so there are some differences between them.2 The the components identification of the volatile oils from Wedelia chinensis (Osbeck.) Merr. and Wedelia trilobata(L.) Hitchc.Objective: To define the chemical compositions of Wedelia chinensis (Osbeck.) Merr. and Wedelia trilobata(L.) Hitchc.,s volatile oils and compare with the differences between them. Methodology: The method of GS-MS was applied to isolate and analyze the components of extraeted Wedelia chinensis (Osbeck.) Merr. and Wedelia trilobata(L.) Hitchc.,s volatile oils. Results: 52 components were detected from Wedelia chinensis (Osbeck.) Merr. ,s volatile oi- ls,48 components were detected from Wedelia trilobata(L.) Hitchc.,s volatile oils. Among th- em,the main ingredients are terpenes,aliphatic compounds and other compounds are less.Con- clusion:There are only 17 components in common between the volatile oils of Wedelia chine- nsis (Osbeck.) Merr. and Wedelia trilobata(L.) Hitchc.,still have two-thirds of the ingredients are different.3 Researches of antibacterial activityObjective: To study the antibacterial actions and MIC,MBC of extracts from Wedelia chinen- sis (Osbeck.) Merr. and Wedelia trilobata(L.) Hitchc. on Escherichia coli,Staphyloccocus aur- eus Rosenbach,Staphylococcus,Bacillus subtilis,Yersinia enterocolitica,V.anguillarum, Aerom- onas hydrophila,Salmonella,Micrococci.Methodology:the filter paper diffusion method was applied to study the antibacterial actions of extracts from Wedelia chinensis (Osbeck.) Merr. and Wedelia trilobata(L.) Hitchc. on all bacterias,and the dilution method was applied to stud- y the MIC and MBC of them. Results:The volatile oils,petroleum ether extracts and ethyl ac- etate extracts of Wedelia chinensis (Osbeck.) Merr. and Wedelia trilobata(L.) Hitchc. had rel- atively strong antimicrobial effect,the effect of the 95%ethanol extracts,chloroform extracts a- nd butanol extracts was weaked.The inhibitory effect of water extracts was weakest relatively, and the inhibitory effect on Staphyloccocus aureus Rosenbach, Aeromonas hydrophila and S- almonella wasn,t obvious.Conclusion: In addition to the water extract,the volatile oils,95% ethanol extracts,petroleum ether extracts,chloroform extracts, ethyl acetate extracts,butanol extracts of Wedelia chinensis (Osbeck.) Merr. and Wedelia trilobata(L.) Hitchc. had a broad spectrum of antibacterial activity.The difference of antimicrobial effect between Wedelia chine- nsis (Osbeck.) Merr. and Wedelia trilobata(L.) Hitchc. wasn,t significant (P>0.05).4 Study on antibacterial mechanism through Transmission Electron Microscopy (hearafter: TEM)Objective:To study the Wedelia chinensis (Osbeck.) Merr. and Wedelia trilobata(L.) Hitchc.,s antibacterial mechanism on Escherichia coli and Staphyloccocus aureus Rosenbach.Method- ology:TEM was applied to observe the changes of the two kinds of bacteria's structure and characteristics after 2h or 6h by dealing with the volatile oils and 95% ethanol extracts of We- delia chinensis (Osbeck.) Merr. and Wedelia trilobata(L.) Hitchc..Results:After initiation of the volatile oils in 50mg/mL and 95% ethanol extracts in 200mg/mL of Wedelia chinensis (Osbeck.) Merr. and Wedelia trilobata(L.) Hitchc.,the structures and characteristics of the two sorts of bacteria under TEM showed significant differences with the normal one.Some cell w- alls were defected,there was a leakage of contents, and some showed a cavity in the bacteria, etc.Conclusion:The volatile oils and 95% ethanol extracts of Wedelia chinensis (Osbeck.) M- err. and Wedelia trilobata(L.) Hitchc. had great influence on the structures and characterristi- cs of Escherichia coli and Staphyloccocus aureus Rosenbach.