In-vitro evaluation of Bacopa monniera extract and individual constituents on human recombinant Monoamine oxidase enzymes

Abstract

Bacopa monniera (BM) is a traditional Ayurvedic medicinal plant that has been used worldwide for its nootropic action. Chemically standardized extract of BM is now available as over the counter herbal remedy to enhance memory in children and adults. Considering the nootropic action of BM, we evaluated the effect of clinically available BM extract and six of BM constituents (bacoside A3, bacopaside I, bacopaside II, bacosaponin C, bacosine and bacoside A mixture) on recombinant human monoamine oxidase enzymes. Effect of BM extract and individual constituents on human recombinant MAO-A and MAO-B enzymes were evaluated using MAO-GloTM assay kit (Promega corporation,USA), following the instructional manual. IC50 and mode of inhibition was measured for MAO enzymes. Bacopaside I and bacoside A mix inhibited the MAO-A and MAO-B enzymes. Bacopaside I exhibited mixed mode of inhibition with IC50 and Ki value of 17.08 ± 1.64 and 42.5 ± 3.53 µg/mL, respectively for MAO-A enzyme. Bacopaside I is the major constituent of BM that inhibited the MAO-A enzyme selectively.