Phytochemical characterization of Paenarthrobacter nicotinovorans YYH-1 from Epimedium rhizosphere and its antioxidant-mediated in vitro activity against premature ovarian failure

The aim of this study was to isolate and identify a nicotine-degrading Paenarthrobacter nicotinovorans strain from the Epimedium rhizosphere, characterize its secondary metabolites, and evaluate its potential antioxidant activity against premature ovarian failure (POF). By exploring the bioactive properties of this rhizosphere microorganism, the research sought to uncover new insights into the functional roles of plant-associated microbes and discover potential natural agents for treating oxidative stress-related diseases. A strain designated YYH-1 was isolated from the E. rhizosphere and identified through morphological observations and 16S rRNA gene sequencing. Ultra-performance liquid chromatography-high resolution mass spectrometry (UPLC-HRMS) combined with GNPS molecular networking was employed to profile the chemical components of the ethyl acetate extract from YYH-1 fermentation broth. In vitro experiments utilized the human ovarian granulosa cell line (KGN) to assess the extract’s effect on D-galactose-induced cellular senescence, measuring the activity of superoxide dismutase (SOD) as an indicator of antioxidant capacity. Additionally, molecular docking was performed to elucidate the interaction mechanisms between key compounds and the Nrf2 signaling pathway. The isolate was confirmed as P. nicotinovorans YYH-1. Chemical profiling identified 21 secondary metabolites, including flavonoids, phenylpropanoids, alkaloids, fatty acids, and amino acid derivatives. In vitro studies demonstrated that the YYH-1 extract significantly mitigated D-galactose-induced cellular senescence in KGN cells and effectively upregulated superoxide dismutase (SOD) activity, which increased by 50.94%, 48.27%, and 38.01% respectively compared with that in the Model group.. Molecular docking analysis revealed that 8-prenylnaringenin, a major compound in the extract, could activate the Nrf2 signaling pathway by stably binding to Keap1 and Nrf2 receptors. This study represents the first report of P. nicotinovorans in the E. rhizosphere. The strain exhibits the potential to produce diverse bioactive secondary metabolites, and its extract demonstrates antioxidant activity against POF through the activation of the Nrf2 pathway. These findings expand our understanding of rhizosphere microbial functions and provide a basis for the development of natural anti-aging therapies targeting oxidative stress-related disorders.