Neolignane and Monoterpene Glycosides Isolated from <i>Cupressus torulosa</i> D. Don and Their Cytotoxicity Evaluation in HepG2 Cell Lines

<i>Cupressus torulosa</i>, known as the Himalayan cypress or Surai, is native to the foothills of the northern Himalaya. Phytochemical analysis of the hot acetone extract of <i>C. torulosa</i> leaves was performed under the guidance of LC/MS and HPLC fingerprint methods. As a result, one previously undescribed neolignane glycoside <b>(16)</b> and two undescribed monoterpene glycosides (<b>21</b> and <b>22</b>), together with twenty-six known compounds belonging to diterpenoids, flavonoids (flavone and biflavones), phenylpropanoid glycosides, neolignane glycosides, and ionones, were isolated. The structures of the new and known compounds were established by using 1D and 2D NMR, IR, and HR-ESI-MS. Their absolute configurations were established by chemical reactions and examination of circular dichroism spectra, and previously reported literature data further confirmed the known compounds. This study also reports 12 compounds, <b>11-15</b>, <b>17-20</b>, <b>23</b>, <b>24</b>, and <b>28</b>, for the first time from this species. The isolated compounds <b>1</b>, <b>4-10</b>, <b>13-16</b>, <b>18, 19</b>, and <b>21-24</b> were evaluated for their cytotoxicity against human liver cancer cell lines HepG2. The compound <b>15</b> showed a significant decrease in cell viability with increasing concentration, with 50% viability at 37.54 μM. Compound <b>15</b> exhibited its antitumor effects by inducing oxidative stress, inhibiting proliferation and migration, arresting the cell cycle in the S-phase, and promoting apoptosis, highlighting its potential as a therapeutic candidate against hepatocellular carcinoma.