High throughput Screening to Identify Natural Human Monoamine Oxidase B Inhibitors

Age‐related increase in monoamine oxidase B (MAO‐B) may contribute to CNS neurodegenerative diseases. Moreover, MAO‐B inhibitors are used in the treatment of idiopathic Parkinson disease as preliminary monotherapy or adjunct therapy with L‐dopa. To date, meager natural sources of MAO‐B inhibitors have been identified, and the relative strength, potency and rank of many plants relative to standard drugs such as Selegiline (L‐deprenyl,Eldepryl) are not known. In this work, we developed and utilized a high throughput enzyme microarray format to screen and evaluate 905 natural product extracts (0.025‐.7 mg/ml) to inhibit human MAO‐B derived from BTI‐TN‐5B1‐4 cells infected with recombinant baculovirus. The protein sequence of purified enzyme was confirmed using 1D gel electrophoresis‐matrix assisted laser desorption ionization ‐time‐of‐flight‐tandem mass spectroscopy, and enzyme activity was confirmed by [1] substrate conversion (3‐mM benzylamine) to H202 and [2] benzaldehyde. Of the 905 natural extracts tested, the lowest IC50s [