“ANTI-INFLAMMATORY EFFICACY AND EMBRYOTOXICITY ASSESSMENT OF A NOVEL AZADIRACHTA INDICA–LIGNOCAINE GEL USING IN VITRO AND ZEBRAFISH MODELS FOR WOUND MANAGEMENT”

Abstract

Background: Effective wound healing requires a balance of inflammation and oxidative stress control. Conventional wound-healing agents are often limited by cytotoxicity and teratogenicity, underscoring the need for safer alternatives. Azadirachta indica (neem) possesses antimicrobial and anti-inflammatory properties, while lignocaine provides local analgesia and anti-inflammatory effects. This study evaluated the anti-inflammatory efficacy and embryotoxic safety of a novel neem–lignocaine gel.

Methods: Neem extract was prepared and formulated with lignocaine into a gel. Anti-inflammatory activity was assessed in vitro using bovine serum albumin and egg albumin denaturation assays, along with human erythrocyte membrane stabilization, at concentrations of 10–50 µg/mL. Embryotoxicity was evaluated in zebrafish (Danio rerio) embryos exposed to 5–80 µg/mL, with survival, hatching, and morphological outcomes recorded. Cytotoxicity was preliminarily screened using the brine shrimp lethality assay.

Results: The neem–lignocaine gel exhibited significant dose-dependent inhibition of protein denaturation, reaching maximal effect at 50 µg/mL, and was comparable to standard anti-inflammatory agents. Membrane stabilization also matched the reference drug at higher concentrations. Brine shrimp lethality was minimal except at 80 µg/mL, indicating an acceptable safety margin. In zebrafish embryos, low concentrations (≤5 µg/mL) maintained >75% hatching and viability with normal development. However, higher concentrations (>40 µg/mL) produced reduced hatching rates (<40%) and morphological abnormalities, establishing a distinct therapeutic versus toxic dose range.

Conclusion: Neem–lignocaine gel demonstrated potent anti-inflammatory activity with acceptable safety at lower concentrations. Dose optimization is crucial, as embryotoxicity becomes significant at higher levels, supporting its therapeutic potential in wound healing.