In vitro and in silico studies of secang wood (Caesalpinia sappan L.) extracts and Brazilin as natural phosphodiesterase-1 (PDE1) inhibitor for herbal cognitive enhancer development

Secang (Caesalpinia sappan L.) (CS) is one of the plants widely found in Indonesia and known to have a various biological activities. However, there is no scientific evidence regarding its cognitive enhancing activity through the inhibition of Phosphodisesterase-1 (PDE1). PDE1 is recently discovered as a promising molecular target for the development of cognitive enhancer agents to combat cognitive diseases. This study aimed to identify in vitro PDE1-inhibition activity of n-hexane, chloroform and ethanol extracts of CS wood and its major constituent, brazilin, with Cyclic Nucleotide Phosphodiesterase Assay Kit and in silico interaction of brazilin with PDE1 used Molecular Operating Environment (MOE) ver. 2016.01. This study demonstrates that the ethanol extract was the most active PDE1-inhibition activity compared to the other extracts with the inhibition of 52.7 at concentration of 100µg/mL. Interestingly, brazilin at concentration of 11.45µg/mL inhibited PDE1 activity (30.6) equal to the positive control, vinpocetine (14.02 µg/mL). In conclusion, the ethanol extract of CS wood and its major constituent, brazilin, inhibited PDE1 activity and could be develop as cognitive enhancer. © 2020 Elsevier B.V., All rights reserved.