The skin hydration and anti‐ageing benefits of Ectoine, achieved through enhanced Src‐ERK‐mediated HAS‐2 and JNK‐driven AQP‐3 expression in human keratinocytes, along with the inhibition of MMP‐1‐induced collagen‐I degradation in human fibroblasts, both with and without UVB irradiation

OBJECTIVE: ) exposure. METHODS: We incorporated various experimental techniques, including MTT assay (cell viability), small interfering RNA (siRNA) transfection, and immunoblotting analysis, to assess the molecular mechanisms of skin hydration and anti-ageing efficacies of Ectoine. RESULTS: The findings exhibited that Ectoine improved cell viability in the presence or absence of UVB exposure in HaCaT cells. Ectoine upregulated Src and HAS-2 expression in the presence or absence of UVB irradiation in HaCaT cells. Src knockdown reduced Ectoine-increased HAS-2 expression, implying that Ectoine provoked Src-mediated HAS-2 expression in the presence of or without UVB irradiation in HaCaT cells. Ectoine enhanced phosphorylated-ERK expression in a time- and dose-dependent manner in HaCaT cells. In addition, Ectoine increased phosphorylated-ERK expression in UVB-irradiated HaCaT cells. The ERK inhibitor (PD98059) remarkably decreased Ectoine-provoked HAS-2 expression, suggesting that Ectoine triggered ERK-mediated HAS-2 expression in HaCaT cells. Furthermore, Ectoine amplified JNK and AQP-3 levels in the presence or lack of UVB exposure in HaCaT cells. The JNK inhibitor (SP600125) significantly reduced Ectoine-triggered AQP-3 expression, suggesting that Ectoine provoked JNK-mediated AQP-3 expression in HaCaT cells. Ectoine increased collagen-I expression in the presence or lack of UVB irradiation in HaCaT cells. Notably, Ectoine enhanced collagen-I expression and inhibited MMP-1 expression in a dose-dependent manner in fibroblast (Hs68) cells. CONCLUSION: We demonstrated that Ectoine exerts skin hydration effects without or with UVB exposure in human skin keratinocyte (HaCaT) cells and anti-ageing in fibroblast (Hs68) cells. Therefore, Ectoine could serve as a potential natural compound in cosmetic preparations for skin hydration and anti-ageing.