Study On Synthesis And Biological Activity Of Curcumin Derivatives

Curcumin is a main chemical components of the Curcuma Longa. It has been showed to have many pharmacological activities, such as antioxidant,anti-tumor and antimicrobial activity,et al.α,β-unsaturated carbonyl is an effective group for antimicrobial activity. In this paper new compounds containing the structure of curcumin and N-monoalkyl fumarates were synthesized to obtain compounds having antioxidant and antibacterial activities. The optimum process was obtained by orthogonal experiments, and the antioxidant activity and the antibacterial activity has been studied. Research results are as follows:1,N-monoalkyl fumarates were synthesized from maleic anhydride and alkanol.The optimum conditions of monomethyl fumarate are isomerization catalyst HCl, esterification time 2.0 h, esterification temperature 60℃,isomerization time 2.5h and isomerization temperature 70℃.The yield of monomethyl fumarate was 85.8%.The optimum conditions of monoethyl fumarate are esterification temperature 60℃, esterification time 2.5 h, isomerization temperature 90℃, isomerization time 2.5 h and catalyst dosage 2.5 g/mol. The yield of monoethyl fumarate was 91.3%.The optimum conditions of mono-butyl fumarate are esterification time 3.0 h, esterification temperature 55℃, isomerization time 3.5 h, isomerization temperature 110℃and catalyst dosage 2.5 g/mol.The yield of mono-butyl fumarate was 65.6%.The optimum conditions of Monopentyl fumarate are esterification time 2.5h, esterification temperature 65℃, isomerization time 3.5 h, isomerization temperature 105℃and catalyst dosage 2.5 g/mol. The yield of monopentyl fumarate was 69.42%2,Curcumin-fumarate were synthesized.The optimum conditions of the monoalkyl fumarates chloride are acylating agent SOCl2, material ratio n (SOCl2):n (monoalkyl fumarate)=3:1, reaction time 60 min, and reaction temperature 100℃. the yield of the n-monoalkyl fumarates chloride 80.5 %,83.7%,81.2%,85.4%, respectively.The optimum conditions of the Curcumin-monoethyl fumarate:material ratio n (curcumin):n (monoalkyl fumarates chloride)=1:2.5, reaction temperature 80℃, reaction time 100 min and catalyst dosage n (pyridine):n (curcumin)=1:3, the yield of the Curcumin-fumarate 80.5%,83.7%,81.2%,85.4%, respectively.The structure of Curcumin-fumarates was confirmed by IR, 1H-NMR and 13C-NMR4,The antioxidant activity of curcumin and curcumin derivatives were studied.Curcumin and curcumin derivatives can scavenge DPPH radical. IC50 values of scavenging DPPH radical of curcumin were 36.22μg/mL,164.14μg/mL,166.98μg/ mL,171.97μg/mL,175.10μg/mL, respectively, and the sequence of DPPH radical scavenging ability was curcumin> curcumin-monomethyl fumarate> curcumin-monoethyl fumarate> curcumin-mono-butylfumarate> curcumin-monopentyl fumarate.The results show that the phenolic hydroxyl structure has an important impact on antioxidant activity.The antioxidant activity decreased for the esterification of phenolic hydroxyl.5,The antibacterial activity of curcumin derivatives were studied.The MIC index of the Curcumin-fumarate for four bacteria:staphylococcus aureus,escherichia coli, aspergilluse niger, penicillium sp were 1.5,1.5,0.5,1.0 g/L;1.5,1.5,0.5,1.0 g/L;0.5,0.5,0.25,1.0 g/L;1.0,1.0,0.25,1.0 g/L,respectively.The results show that the new compounds have a strong antibacteria activity;the antibacteria activity of the compounds in trans configuration is better than the compounds in Cis-configuration as a result of the steric effect;with the extension of alkyl chains of the coumpouds, its antibacterial activity increased to some extent.