Phalaenopsis orchid flower extract attenuates high glucose-induced senescence via Nrf2/HO-1 activation and promotes wound healing in human dermal fibroblasts

Skin aging in diabetic patients is closely associated with delayed wound healing and oxidative stress-mediated fibroblast dysfunction. This study investigated the protective and regenerative effects of a water extract of Phalaenopsis orchid flower (WEPF), an ornamental plant endemic to Taiwan, on high glucose (HG)-induced cellular senescence in human dermal fibroblasts (CCD-966SK), with a focus on the Nrf2/HO-1 antioxidant pathway. Cytotoxicity, cellular senescence, and ROS production were respectively assessed using MTT assay, senescence-associated β-galactosidase (SA-β-gal) staining, and DCFDA-cellular reactive oxygen species assay. Western blotting and ELISA were used to analyze the cellular senescence-related proteins. Fibroblasts treated with WEPF under HG conditions exhibited reduced senescence-associated β-galactosidase (SA-β-gal) activity, lower ROS levels, and attenuated cell cycle arrest. Protein expression profiling revealed suppression of the p53/p21Waf1, and p16INK4a/Rb pathways and decreased matrix metalloproteinase-1 (MMP-1) expression. Mechanistically, WEPF exerted its effects by activating the Nrf2/HO-1 axis and restoring the expression of senescence marker protein-30 (SMP30), thereby promoting fibroblast repair and reducing pro-inflammatory signaling. These findings support the potential of WEPF as a botanical therapeutic agent for diabetic wound healing and age-related skin deterioration.