Inhibitory potential of important phytochemicals from Pergularia daemia (Forsk.) chiov., on snake venom (Naja naja)

Pergularia daemia (Forsk.) chiov., is a milk weed of Asclepiadaceae family. In the present study β-sitosterol, β-amyrin, α-amyrin and lupeol were identified in the leaf by GC-MS. Molecular docking studies were performed to evaluate their activities on phospholipase A2 (PLA2) and l-amino acid oxidase enzymes which constituted a rich source in snake venoms (Naja naja). Snake venom Phospholipase A2 with PDB code 1A3D devoid of co-crystallized ligand was extracted from Protein Data Bank. Using Molegro Virtual Docker two cavities are formed by cocrystallization. l-Amino acid oxidase (PDB code 4E0V) was a receptor model with a co-crystallized ligand FAD. Among the phytochemicals analysed, β-sitosterol displayed high affinity of binding to the active site regions of phospholipase A2 and l-amino acid oxidase, respectively. The affinity of binding was −125.939 and −157.521 kcal/mole identified by gold scores. α-Amyrin and β-amyrin had two hydrogen bond interactions with PLA2. Hence this study suggests that β-sitosterol identified in P. daemia can antagonize PLA2 and LAAO activities and forms a theoretical basis for the folk use of the plant against snake venom.