Ralationships Between Structure And Antibacterial Activity Of Neochamaejasmine B Ⅲ

There are three strategies to research and develop natural products.Firstly,the rude extracts are used as drugs.Secondly,the active compound is isolated and its derivatives are synthesized.Thirdly,the active compound is used as lead compound to synthesize and screen the new advanced compound.Here we take the second strategy,and study on Neochamaejasmine B which has strong biological activity.Through determination and evaluation antibacterial activity of series of neochamaejasmine B derivatives,the relationship between functional groups and antibacterial activity of neochamaejasmine B was disclosed.Use acetic anhydride as acetylation reagent,compounds A,B,C,D were prepared. Through reaction between neochamaejasmine B and Me₂SO₄,compounds E,F,G,H,were prepared.The single or double carbonyl reduction derivative was prepared Use NaBH₄ as the reductan.Compounds L and M were synthesized through reaction between neochamaejasmine B and NH₂OH.HCL.Based on their spectral data(ESI-MSH,¹N MR and ¹³C NMR),HPLC,mp value and Rf value the compounds were identified as follows:7″-acetoxy-7,4′,4′″,5,5″-pentahydroxy-3,3″-biflavanone,(A),7,7″-diacetoxy-4′,4′″,5,5″-tetrahydroxy-3,3″-biflavanone,(B)7,7″,4′-triacetoxy-4′″,5,5″-trihydroxy-3,3″-biflavanone,(C)7,7″,4′,4′″-tetracetoxy-5,5″-dihydroxy-3,3″-biflavanone(D),7″-methoxy-7,4′,4′″,5,5″-pentahydroxy-3,3″-biflavanone(E),7,7″-dimethoxy-4′,4′″,5,5″-tetrahydroxy-3,3″-biflavanone(F),7,7″,4′-trime-thoxy-4′″,5,5″-trihydroxy-3,3″-biflavanone and7,7″,4′″-trimethoxy-4′,5,5″-trihydroxy-3,3″-biflavanone(G),7,7″,4′,4′″-tetramethoxy-5,5″-dihydroxy-3,3″-biflavanone(H),4-deoxyneochamaejasmine B(J),4-deoxyneochamaejasmine B or 4,4″-double deoxyneochamaejasmine B(K),4-neochamaejasmine B oxime or 4′-neochamaejasmine B oxime(L),4,4″-double neochamaejasmine B oxime(M),7,7″,4′,4′″-tetrbenzoyl-5,5″-dihydroxy-3, 3″-biflavanone(W).We choose Vibrio anguillarum,AeromonasPunctat fintestinalis,Aeromonas hydrophila, Staphylococcus aureas and Escherichia coli as tested bacteria;choose penicillin Na and Ceftriaxone Sodium as controls.The antibacterial activity was tested by double dilution method in vitro against tested bacteria.Compared with antibacterial activity of neochamaejasmine B and its derivatives,it was concluded that 7-OH,7″-OH,4′-OH and 4′″-OH of neochamaejasmine B were the main active groups;7-OH and 7″-OH of neochamaejasmine B are closely related to against G^- bacteria(AeromonasPunctat fintestinalis);4-OH and 4″-OH of neochamaejasmine B are important for against G⁺ bacteria; 5-OH and 5″-OH of neochamaejasmine B have little effect for antibacterial activity;the carbonyl group of neochamaejasmine B shows no biological activity,and the contribution of phenolic hydroxyl for neochamaejasmine B inhibition bacterial is various for diffirent bacteria.