<i>In vitro</i> evaluation on the antioxidant and skin photo protection effects of lignans from the olive (<i>Olea europaea</i>) seed

The antioxidant and skin protectant-guided isolation of ethyl ­acetate soluble fraction from olive seed led to the elucidating of three phenolic lignans and one phenolic aldehyde for the first time. Compounds (<b>3</b>) and (<b>4</b>) were reported in the <i>oleaceae</i> family for the first time. Their structures were characterised using NMR and HR-MS analysis as pinoresinol (<b>1</b>), olivil (<b>2</b>), 3,4,5-trimethoxybenzaldehyde (<b>3</b>) and medioresinol (<b>4</b>). All isolated compounds were investigated for antioxidant and skin photo protection activities on NHDF cells. Among them, compound (<b>1)</b> exhibited inhibition of UVB radiation of 300 mJ/cm² on NHDF cells in a dose- dependent manner without any cytotoxic effect. Moreover, the capability of compound (<b>1</b>) to inhibit UVB-induced NHDF cell damage correlated to its potent DPPH radical scavenger (IC₅₀ = 37.47 ± 2.2 µg/mL). This study highlights compound (<b>1)</b> offers a possible bioactive compound for natural skin photo protection in the future.