In vitro evaluation on the antioxidant and skin photo protection effects of lignans from the olive (Olea europaea) 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 (3) and (4) were reported in the oleaceae family for the first time. Their structures were characterised using NMR and HR-MS analysis as pinoresinol (1), olivil (2), 3,4,5-trimethoxybenzaldehyde (3) and medioresinol (4). All isolated compounds were investigated for antioxidant and skin photo protection activities on NHDF cells. Among them, compound (1) 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 (1) 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 (1) offers a possible bioactive compound for natural skin photo protection in the future.