Pharmacological Screening of Aqueous Extract of Parkia biglobosa Leaves: In Vitro Inhibitory Activity against Key Snake Venom Enzymes

Natural products constitute an invaluable source of bioactive compounds with promising therapeutic potential for the treatment and management of various diseases and disorders. Among such challenges, snake envenomation represents a major health concern due to the complex mixture of biologically active proteins and enzymes in snake venom, which contribute to its potent toxic, inflammatory, and cytotoxic effects. This study investigated the phytochemical composition and enzyme-inhibitory potential of aqueous leaf extract of Parkia biglobosa against key venom enzymes [phospholipase A₂ (PLA ₂ ), hyaluronidase, acetylcholinesterase (AChE), and L-amino acid oxidase (LAAO)] of Naja nigricollis (cobra). Phytochemical analyses were performed using standard procedures, while enzyme inhibition assays were conducted in vitro employing spectrophotometric techniques. The phytochemical screening revealed the presence of alkaloids, flavonoids, tannins, phenols, terpenoids, steroids, and saponins. The extract exhibited concentration-dependent inhibitory activity against PLA₂, with an IC₅₀ of 62.83 µg/ml. It also demonstrated significant inhibition of hyaluronidase (IC₅₀ = 101.3 µg/ml), an enzyme responsible for venom dissemination through degradation of extracellular matrix components. The extract inhibited AChE (IC₅₀ = 67.93 µg/ml), suggesting possible neuroprotective effects against venom-induced neurotoxicity. Furthermore, moderate inhibition was observed against LAAO (IC₅₀ = 115.3 µg/ml), indicating potential attenuation of oxidative stress and cytotoxicity. Conclusively, the collective inhibition of these enzymes highlights the extract’s potential as a natural, multi-target antivenom agent. The results not only substantiate its traditional application in snakebite management but also open avenues for developing phytochemical-based adjunct therapies against envenomation.