Rhizoma Paridis saponins attenuate Gram‐negative bacteria‐induced inflammatory acne by binding to KEAP1 and modulating Nrf2 and MAPK pathways

Acne vulgaris represents a chronic inflammatory condition, the pathogenesis of which is closely associated with the altered skin microbiome. Recent studies have implicated a profound role of Gram‐negative bacteria in acne development, but there is a lack of antiacne agents targeting these bacteria. Polyphyllins are major components of Rhizoma Paridis with great anti‐inflammatory potential. In this study, we aimed to evaluate the antiacne effects and the underlying mechanisms of PPH and a PPH‐enriched Rhizoma Paridis extract (RPE) in treating the Gram‐negative bacteria‐induced acne. PPH and RPE treatments significantly suppressed the mRNA and protein expressions of interleukin (IL)‐1β and IL‐6 in lipopolysaccharide (LPS)‐induced RAW 264.7 and HaCaT cells, along with the intracellular reactive oxygen species (ROS) generation. Furthermore, PPH and RPE inhibited the nuclear translocation of nuclear factor kappa‐B (NF‐κB) P65 in LPS‐induced RAW 264.7 cells. Based on molecular docking, PPH could bind to kelch‐like ECH‐associated protein 1 (KEAP1) protein. PPH and RPE treatments could activate nuclear factor erythroid 2‐related factor 2 (NRF2) and upregulate haem oxygenase‐1 (HO‐1). Moreover, RPE suppressed the mitogen‐activated protein kinase (MAPK) pathway. Therefore, PPH‐enriched RPE showed anti‐inflammatory and antioxidative effects in vitro, which is promising for alternative antiacne therapeutic.