Synthesis, Antioxidant, and Antiacetylcholinesterase Activities of Sulfonamide Derivatives of Dopamine-Related Compounds

A series of sulfonamides were synthesized from dopamine derivatives. The reactions of amines with methanesulfonyl chloride followed by O-demethylation with BBr3 afforded phenolic sulfonamides. The antioxidant activities of the synthesized phenolic sulfonamides were investigated by thiocyanate method, 2,2-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS(center dot+)), 1,1-diphenyl-2-picryl-hydrazyl (DPPH center dot), N,N-dimethyl-p-phenylenediamine (DMPD center dot+), and superoxide anion (O-2(center dot-)) radical scavenging, reducing power, and ferrous ion (Fe2+) chelating assays. Sulfonamides 13-16 showed around 75-85% inhibition on linoleic acid peroxidation. On the other hand, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), -tocopherol, and trolox indicated an inhibition of 90.0%, 85.73%, 73.33%, and 85.73% on peroxidation, respectively, in the same system at the same concentration (10 mu g/mL). Also, the inhibition effects of the synthesized compounds on acetylcholinesterase (AChE) activity were evaluated. AChE was effectively inhibited by sulfanomides 13-16, with K-i values in the range of 33.04 +/- 4.3 to 131.68 +/- 8.8nM.