Biological and Safety Evaluation of Green-Synthesized Calcium Oxide Nanoparticles Using Hedyotis diffusa

Background

Dental caries and periodontal diseases are among the most prevalent oral disorders worldwide, necessitating the development of safe and effective therapeutic approaches. Green-synthesized nanoparticles derived from medicinal plants offer enhanced biocompatibility and therapeutic potential. Hedyotis diffusa, a traditional medicinal herb with established antimicrobial and anti-inflammatory properties, represents a promising candidate for nanoparticle synthesis.

Objectives

This study aimed to formulate a dental varnish containing Hedyotis diffusa-mediated Calcium Oxide Nanoparticles (CaONPs) and evaluate its antibacterial, anti-inflammatory, cytotoxic, and embryonic safety profiles for potential oral healthcare applications.

Materials and Methods

CaONPs were synthesized using Hedyotis diffusa extract and incorporated into a resin-based dental varnish. Antibacterial activity was assessed using agar well diffusion and time-kill kinetic assays. Anti-inflammatory activity was evaluated through albumin denaturation and membrane stabilization assays. Cytotoxicity was determined using the brine shrimp lethality assay, while embryonic safety was investigated using Artemia cysts and zebrafish embryo models.

Results

The CaONP-based dental varnish exhibited significant antibacterial activity, demonstrating notable zones of inhibition and rapid microbial reduction. Anti-inflammatory studies revealed dose-dependent inhibition, reaching 86.7±1.7%. Cytotoxicity analysis indicated low toxicity within the tested concentration range. Embryonic toxicity assessments showed normal hatching, survival, and development of both Artemia cysts and zebrafish embryos, confirming favorable biocompatibility.

Conclusion

The Hedyotis diffusa-mediated CaONP dental varnish demonstrated promising antibacterial and anti-inflammatory properties with minimal cytotoxicity and acceptable embryonic safety. These findings support its potential as a sustainable nanoformulation for oral disease management, warranting further in vivo and clinical investigations.