Study On Structure Modification Of Neochamejasmin B And Relationship Of Structure-Antibacterial Activity

The pop field in natural product research and exploiture is mainly about searching and filtrating active material from natural product, meanwhile, using the monomer compound which has good activity as the template and study on systemic structure rebuild and modification, then its SAR.In this dissertation, we studied on neochamaejasmin B which was a new antibacterial activity material separated from the root of Stellera chamaejasme. Former experimental results showed neochamaejasmin B had many advantages such as low toxicity, weightly antibacterial activity and broad antibacterial spectrum. As a result, neochamaejasmin B was viewed as an nature active lead compound which had high potential value of exploitation.We selected the method of acetic anhydride/sodium ethoxide to modify the phenolic hydroxyl of neochamaejasmin B, and then synthesized and separated four acetate derivatives of M1,M4-1,R2-1 and R4. The other two product B1 and B2 were obtained from neochamaejasmin B by using BrCH2COOH as the carboxymethyl etherification reagent. Based on spectral analysis (UV, IR, CI-MS or ESI-MS, 1H NMR, 13C NMR). The structure of six derivatives were elucidated as followed.M1 (4', 4''', 7, 7''-tetraacetoxy-5, 5''-dihydroxy-3, 3''-biflavanone); M4-1 (4', 7, 7''-triacetoxy-4''', 5, 5''-trihydroxy-3, 3''-biflavanone); R2-1 (4', 7-diacetoxy-4''', 7'', 5, 5''-tetrahydroxy-3, 3''-biflavanone); R4 might be the mixture of7''-acetoxy-7, 4', 4''', 5, 5''-pentahydroxy-3, 3''-biflavanone and 7-acetoxy-7'', 4', 4''', 5, 5''-pentahydroxy-3, 3''-biflavanone, now we initially inferred that 7''-acetoxy-7, 4', 4''', 5, 5''-pentahydroxy-3, 3''-biflavanone was the main product; B2 (7- carboxymethyl -7'', 4', 4''', 5, 5''- pentahydroxy-3, 3''-biflavanone); B1 (4'- carboxymethyl -7'', 4', 4''', 5, 5''- pentahydroxy-3, 3''-biflavanone or 7''- carboxymethyl -7, 4', 4''', 5, 5''- pentahydroxy-3, 3''-biflavanone).The antibacterial activity of neochamaejasmin B and its six derivatives, penicillin Na and Ceftriaxone Sodium were tested with dish diffusion of Neo-Sensitab in vitro against S. aureas, S. uberis, S. dysagalactiae, Samonellal and E. coli. The results showed that the antibacterial activity of neochamaejasmin B and derivatives against five bacteria tested all gradually lowered or disappeared in company with the sample concentration declining. The antibacterial...