Halimeda gracilis as a bioactive resource: exploring its antioxidant, antibiofilm, anti-inflammatory, and antibacterial potential for dental applications.

Abstract

Aim: This study aimed to evaluate the antibacterial, antibiofilm, antioxidant and anti-inflammatory properties and of Halimeda gracilis extracts.

Materials and methods: The H. gracilis sample was washed and extracted using methanol. The mixture was homogenized using a blender and centrifuged at high speed (10,000 × g) for 2 min, then stirred at room temperature for 30 min using magnetic stirrer, to ensure thorough extraction. Afterward, it was centrifuged at 5,000 × g for 10 min to separate the dissolved components from undissolved debris. Following this antioxidant activity was assessed using DPHH assay, the antimicrobial effects were tested against Streptococcus mutans, Escherichia coli, Enterococcus faecalis and Shigella sonnei using Kirby-Bauer disk diffusion, biofilm inhibition assay was done to assess biofilm inhibition against S. mutans, E. coli, E. faecalis and S. sonnei. Finally, the anti-inflammatory activities of the H. gracilis were determined using a modified version of the BSA assay.

Results: When tested against S. mutans, E. coli, E. faecalis, and S. sonnei strains, the antimicrobial evaluation revealed that the extract successfully inhibited biofilm formation when tested against the same organism, and it also demonstrated increased activity with increasing concentration. The zone of inhibition progressively expanded with increasing concentration, reaching a maximum of 17 mm ± 0.1 for 100 µg/mL. In terms of antioxidant activity, the H. gracilis metholic extract gradually increased from 10 µg/mL to a higher activity at 40 µg/mL in comparison to the control and blank, and then decreased at a dose of 50 µg/mL. At different doses, the anti-inflammatory action of H. gracilis extracts successfully inhibited BSA denaturation, which causes inflammation; the maximum activity has been observed.

Conclusion: This comprehensive analysis highlights H. gracilis as a valuable natural resource with multifaceted biological activities, supporting its further investigation for therapeutic applications in dentistry.