New Sesquiterpenoids from <i>Eugenia jambolana</i> Seeds and Their Anti-microbial Activities

Twenty four sesquiterpenoids, <b>1</b>–<b>24</b>, including 11 new sesquiterpenoids, jambolanins A–K, and two new norsesquiterpenoids, jambolanes A and B, along with six known triterpenoids, were isolated from the seeds of <i>Eugenia jambolana</i> fruit. Their structures were elucidated on the basis of NMR and MS spectrometry data analysis. Among the isolates, compound <b>13</b> possessed a rare 6,7-<i>seco</i>-guaiene skeleton, and compounds <b>14</b> and <b>15</b> were norsesquiterpenoids containing a spiro[4.4]­nonane skeleton. Antimicrobial assay evaluation revealed that sesquiterpenoids, <b>4</b>, <b>5</b>/<b>6</b>, <b>17</b>, <b>19</b>, <b>21</b>, <b>23</b>, and <b>24</b> inhibited the growth of the Gram-positive bacterium, <i>Staphylococcus aureus</i>. The current study advances scientific knowledge of <i>E. jambolana</i> phytochemicals and suggests that its sesquiterpenoids may contribute, in part, to the anti-infective effects attributed to the edible fruit of this plant