Novel semicarbazide-sensitive amine oxidase inhibitor screening from anti-obesity drugs using HPLC-MS based technique

Semicarbazide-sensitive amine oxidase (SSAO) has been considered to be associated with the metabolism of glucose and fat, and elevated SSAO activity was observed in obese patients. In the present study, an in vitro SSAO activity-based method was developed to screen inhibitors from 15 anti-obesity drugs. Among the fifteen anti-obesity drugs, four drugs including caffeine, fenfluramine, bumetanide and amfebutamone inhibited SSAO activity, and caffeine was the most effective one. When the concentration of caffeine was 1.4 mmol/L, the inhibition ratio was 31.9% and 18.8% in rabbit serum and rat adipose tissue, respectively. Inhibition of SSAO activity by caffeine was also confirmed in the in vivo study, showing the inhibition ratio of 15.6% on serum SSAO. Caffeine provides a natural source of inhibition of SSAO activity and may be a promising inhibitor for the study of SSAO.