Excavating Precursors from Herb Pairs Polygala tenuifolia and Acori tatarinowii: Synthesis and Anticonvulsant Activity Evaluation of 3,4,5-Trimethoxycinnamic Acid (TMCA) Piperazine Amide Derivatives

<b>Background</b>: Epilepsy is a cluster of central nervous system (CNS) disorders identified by recurrent seizures, which affects about 60 million people around the world. In this research, a total of 40 types of 3,4,5-trimethoxycinnamic acid (TMCA) piperazine amide derivatives were designed and synthesized, inspired by the traditional Chinese medicine (TCM) herb pair drugs <i>Polygala tenuifolia</i> and <i>Acori tatarinowii</i>, followed by determination of their anticonvulsant potency. <b>Methods</b>: All the TMCA analogues were tested for their anticonvulsant potential through two acute models of seizures induced in mice: the maximal electroshock (MES) and sc-pentylenetetrazole (PTZ) models. In addition, the lactate dehydrogenase (LDH) inhibitory activity was determined in vitro. <b>Results</b>: The results showed that compounds <b>A3</b>, <b>A9</b>, <b>A12</b>, <b>A14</b>, <b>B9</b>, and <b>B12</b> exhibited preferable anticonvulsant activity in the primary evaluation. In addition, the molecular docking results predicted good interactions of screened analogues with the LDH. Molecular dynamic simulation was used to reveal the consensual binding affinity between the most promising compound (<b>B9</b>) and active site interactions with LDH. Electroencephalogram (EEG) analysis and silver and immunofluorescence staining were performed to illustrate the anti-epilepsy potential of compound <b>B9</b>. <b>Conclusions</b>: Novel derivatives in this study provide new cores for the further design and optimization inspired by TCM herb pair drugs <i>P. tenuifolia</i> and <i>A. tatarinowii</i>, with the aim to explore new anticonvulsant agents.