Protective properties of geniposide against UV-B-induced photooxidative stress in human dermal fibroblasts

Context: Geniposide (genipin-1-O-β-d-glucoside) is a major bioactive ingredient in the fruits of gardenia [Gardenia jasminoides J. Ellis (Rubiaceae)], a traditional herbal medicine in Asian countries. Objective: This work assesses the skin anti-photoaging potential of geniposide in human dermal fibroblasts under UV-B irradiation. Materials and methods: The anti-photoaging property of geniposide, at varying concentrations (5, 12 and 30 μM) treated for 30 min prior to UV-B irradiation, was evaluated by analysing reactive oxygen species (ROS), promatrix metalloproteinase-2 (proMMP-2), glutathione (GSH), superoxide dismutase (SOD), nuclear factor erythroid 2-related factor 2 (Nrf2) and cellular viability. Results: Geniposide suppressed the ROS elevation under UV-B irradiation, which was revealed using three ROS-sensitive fluorescent dyes. The use of 2′,7′-dichlorodihydrofluorescein diacetate (DCFH-DA), dihydroethidium (DHE) and dihydrorhodamine 123 (DHR-123) elicited the IC(50) values of 10.5, 9.8 and 21.0 μM, respectively. Geniposide attenuated proMMP-2 at activity and protein levels that were elevated under UV-B-irradiation. Geniposide at 5, 12 and 30 μM augmented the UV-B-reduced total GSH content to 1.9 ± 0.1-, 2.2 ± 0.2- and 4.1 ± 0.2-fold, respectively. Geniposide at 5, 12 and 30 μM upregulated total SOD activity to 2.3 ± 0.1-, 2.5 ± 0.3- and 3.3 ± 0.3-fold, respectively, under UV-B irradiation. The UV-B-reduced Nrf2 levels were also upregulated by geniposide treatment. Geniposide, at the concentrations used, was unable to interfere with cellular viabilities under UV-B irradiation. Discussion and conclusions: After the skin anti-photoaging potential of geniposide may be further verified, it can be utilized as a safer resource in the manufacture of effective anti-aging cosmetics.