Tiliroside from Lagopsis supina Ameliorates Myocardial Ischemia Injury in Zebrafish by Activating the kdr-Mediated PI3K-Akt and MAPK Signaling Pathways

<i>Lagopsis supina</i> (Steph. ex. Willd.) Ikonn.-Gal., an ancient Chinese herbal medicine, is traditionally used to treat blood stasis diseases such as myocardial ischemia (MI). However, its pharmacodynamics substances of the anti-MI effect and their potential mechanisms remain unclear. This study aims to elucidate the pharmacodynamics effects of <i>L. supina</i> against MI and reveal their underlying mechanisms in zebrafish. LSD fraction was screened out for anti-MI active fraction from <i>L. supina</i> by isoprenaline hydrochloride (ISO)-induced zebrafish. It could increase the stroke volume, ejection fraction, and ventricular short-axis systolic rate in the zebrafish model. A total of 30 compounds (Nos. <b>1</b>-<b>30</b>) were isolated and identified from LSD by various chromatographic techniques and nuclear magnetic resonance spectroscopy. Among them, six compounds, including three lignin compounds (Nos. <b>15</b>, <b>16</b>, and <b>18</b>) and three flavonoid glycosides (Nos. <b>14</b>, <b>25</b>, and <b>26</b>), showed noticeable anti-MI activities, and tiliroside (No. <b>25</b>) was more active. Molecular docking indicated that tiliroside has a strong binding ability with the proteins KDR, PI3K, Akt, Erk, p38, Bcl-2, Bax, and Caspase3. In the end, the results of RT-qPCR manifested that tiliroside markedly upregulated expression levels of genes <i>kdr</i>, <i>pik3cb</i>, <i>akt2</i>, <i>mapk1</i>, <i>mapk11</i>, <i>mapk14</i>, and <i>bcl-2b</i> and prominently downregulated expression levels of genes <i>bax</i> and <i>caspase3</i>. According to the above results, tiliroside activated the <i>kdr</i>-mediated PI3K-Akt and MAPK signaling pathways to exert the anti-MI activity. These discoveries give a scientific basis for applying <i>L. supina</i> in MI treatment and suggest new avenues for developing tiliroside as a candidate for MI therapy.