<p>The comet assay-guided fractionation of the twigs of <i>Manglietia hookeri</i> resulted in the isolation of three sesquiterpene-neolignans, including a new one 5-allyl-2-(4-allyl-phenoxy)-3-[7-(1-hydroxy-1-methyl-ethyl)-1, 4a-dimethyl-decahydro-naphthalen-1-yloxy]-phenol (<b>1</b>), and eudesobovatol A (<b>2</b>) and eudesobovatol B (<b>3</b>), together with three lignans, obovatol (<b>4</b>), honokiol (<b>5</b>) and magnolol (<b>6</b>). Their structures were elucidated on the basis of spectral analysis and by comparison with related literature data. Compounds <b>1</b>, <b>4</b>–<b>6</b> showed a protective effect on UV inductive DNA damage in mice lymphocyte cells, while compound <b>1</b> indicated the smallest Olive Tail Moment 7.34 ± 2.09 at 6 × 10<sup>−6</sup> μM.</p
