Investigation of DNA Protective Activities and Antimicrobial Effects of Spinach (Spinacia oleracea L.) Plant Extracts on Stenotrophomonas maltophilia

Abstract

Spinach (Spinacia oleracea L.) is a nutrient-dense leafy vegetable known for its rich phytochemical profile, including flavonoids, carotenoids, and phenolic compounds, which contribute to its significant antioxidant and antimicrobial potential. In this study, the DNA protective effects and antibacterial activities of spinach extracts were evaluated, particularly against the multidrug-resistant bacterium Stenotrophomonas maltophilia. Methanolic and aqueous extracts were prepared and analyzed for total phenolic and flavonoid contents, followed by antioxidant activity assessment through DPPH and FRAP assays. The ability of these extracts to protect plasmid DNA from oxidative damage was investigated using an in vitro hydroxyl radical-induced DNA fragmentation model. The antimicrobial activity was tested using the agar diffusion method and MIC determination. The findings indicated that spinach extracts exhibit high antioxidant activity, closely linked to their phytochemical richness, and significantly protect against DNA strand breaks caused by reactive oxygen species (Kaur & Kapoor, 2020; Patel et al., 2018). Furthermore, the methanolic extract showed inhibitory effects on S. maltophilia, suggesting the presence of antibacterial phytoconstituents (Ali et al., 2019; Lee et al., 2021). These results support the traditional use of spinach in health maintenance and its potential application in developing natural antimicrobial and DNA-protective agents, particularly relevant in the era of increasing antibiotic resistance (Singh & Verma, 2017).