Synergistic effect of flavonoids combined with antivenom on neutralisation of Naja naja venom

Abstract

Objective: To evaluate the neutralizing effects of flavonoids on snake venom toxicity by stand-alone and combinatorial approaches. Methods: Synthetic flavonoids were assessed, either individually or in combination with antivenom, for their neutralization of phospholipase A2(PLA2), protease, antioxidant (DPPH) assay and hemotoxic activity. Molecular docking studies were performed to understand possible binding of flavonoids with Naja naja venom PLA2. In vivo studies were carried out to confirm the neutralisation effects using a mouse model. Moreover, inhibition of PLA2was monitored using combinatorial approaches. Results: Among the flavonoids used, quercetin and naringenin inhibited PLA2(56% and 45%), protease (71% and 64%), DPPH scavenging (69.0% and 77.5%) and hemotoxic (70%) activities. Molecular docking studies indicated that the flavonoids bind to the substrate-binding site of PLA2(Cys44 and Tyr63). In vivo studies showed a reduction in the venom toxicity level in the presence of naringenin. Additionally, combinatorial studies using the mixture of flavonoid and anti-venom revealed the possibility of synergistic effect (up to 32% enhancement) in neutralising the venom enzymes. Conclusions: These flavonoids can be used as additives for the treatment of snake bites, which may exert synergistic effects in combination with antivenom and decrease the post-therapeutic effects caused by excessive use of antivenom.