Paeonia delavayi seed oil rich in oleic acid and linolenic acid alleviates UVB-induced inflammation and oxidative stress in keratinocytes through inhibition of PI3K/Akt and NF-κB pathways.

Excessive exposure to UVB can induce inflammatory responses and oxidative stress, leading to skin damage. Peony seed oil is rich in unsaturated fatty acids and has been reported to possess anti-inflammatory and antioxidant properties. This study investigated the protective effects and underlying mechanisms of Paeonia delavayi seed oil (PDSO) against UVB-induced damage in human keratinocytes. PDSO at 30-120 μg/mL attenuated UVB-induced inflammation by reducing the mRNA expression of TNF, IL6, CXCL8, and PTGS2 and suppressing the secretion of IL-6 and IL-8. PDSO also inhibited UVB-induced activation of NF-κB signaling. Regarding oxidative stress, 120 μg/mL PDSO reduced intracellular ROS production, decreased MDA levels by approximately 29.4%, and increased SOD activity by approximately 122.0% compared with the UVB group. PDSO also increased the mRNA expression of antioxidant-related genes, including NFE2L2, HMOX1, SOD1, CAT, GCLC, and GCLM. In addition, PDSO alleviated the UVB-induced reduction in keratinocyte viability and attenuated photoaging-related changes. Transcriptomic analysis identified PI3K/Akt signaling as a candidate pathway associated with PDSO treatment, and western blotting further showed that PDSO inhibited UVB-induced PI3K/Akt signaling. Pharmacological intervention with the PI3K activator 740YP partially reversed the anti-inflammatory effects of PDSO, whereas LY294002 exerted anti-inflammatory effects and further enhanced those of PDSO. Moreover, oleic acid and linolenic acid alleviated UVB-induced inflammation and oxidative stress. Collectively, PDSO protects keratinocytes against UVB-induced damage, with PI3K/Akt and NF-κB signaling contributing to its protective effects.