Antimicrobial, Anti‐Biofilm Activity and Antioxidants of Phenolic Compounds Isolated From <i>Hypericum perforatum</i> on Periodontal Pathogenic Oral Bacteria

Wild plants are a rich source of phenolic compounds with antimicrobial and antioxidant properties. This study extracted and analyzed <i>Hypericum perforatum</i> leaf fractions for their phenolic profile, antioxidant capacity, and activity against antibiotic-resistant oral bacteria. Phenolic compounds were identified using column chromatography, TLC, and HPLC. Four different fractions, two from ethyl acetate extraction and two from ethanolic extraction, were obtained and evaluated further. The antimicrobial activity of each fraction was assessed against two Gram-negative bacteria that cause gum disease, <i>Morococcus cerebrosus</i> and <i>Eikenella corrodens</i>, using the disc-diffusion assay. Fraction I exhibited the most potent antimicrobial activity against <i>E. corrodens</i> and <i>M. cerebrosus</i>, with 20-25 mm inhibition zones at lower concentrations. Fraction II showed limited activity, primarily at 100 and 200 μg/mL, while Fractions III and IV had moderate effects, with some concentrations effective against <i>E. corrodens</i>. Regarding biofilm formation, Fraction I showed the most significant reduction Fraction I showed the most significant reduction in biofilm formation for both <i>E. corrodens</i> and <i>M. cerebrosus</i> at 50 and 200 μg/mL concentrations. Fraction II demonstrated variable effects, with an increase in biofilm formation at 200 μg/mL for <i>E. corrodens</i>. At the same time, Fractions III and IV had moderate reductions in biofilm formation across most concentrations. The antioxidant activity of <i>H. perforatum</i> fractions, assessed via DPPH, surpassed Vitamin C at lower concentrations, with Fraction II showing the highest activity (83.98% at 500 ppm). These findings highlight <i>H. perforatum</i> as a promising natural source of phenolics with potential applications in managing periodontal infections.