Neutralization of Inflammation by Inhibiting In vitro and In vivo Secretory Phospholipase A2 by Ethanol Extract of Boerhaavia diffusa L.

Background: Inflammation is a normal and necessary prerequisite to healing of the injured tissues. Inflammation contributes to all disease process including immunity, vascular pathology, trauma, sepsis, chemical, and metabolic injuries. The secretory phospholipase A₂ (sPLA₂) is a key enzyme in the production of pro‑inflammatory mediators in chronic inflammatory disorders such as rheumatoid arthritis, coronary heart disease, diabetes, and asthma. The sPLA₂ also contribute to neuroinflammatory disorders such as Parkinson’s, Alzheimer’s, and Crohn’s disease. Aims: The present study aims to investigate the inhibition of human sPLA₂ by a popular medicinal herb Boerhaavia diffusa Linn. as a function of anti‑inflammatory activity. Materials and Methods: The aqueous and different organic solvents extracts of B. diffusa were prepared and evaluated for human synovial fluid, human pleural fluid, as well as Vipera russelli and Naja naja venom sPLA₂ enzyme inhibition. Results: Among the extracts, the ethanol extract of B. diffusa (EEBD) showed the highest sPLA₂ inhibition and IC₅₀ values ranging from 17.8 to 27.5 μg. Further, antioxidant and lipid peroxidation activities of B. diffusa extract were checked using 2,2‑diphenyl‑1‑picrylhydrazyl radical, thiobarbituric acid, and rat liver homogenate. The antioxidant activity of EEBD was more or less directly proportional to in vitro sPLA₂ inhibition. Eventually, the extract was subjected to neutralize sPLA₂‑induced mouse paw edema and indirect hemolytic activity. The EEBD showed similar potency in both the cases. Conclusions: The findings suggest that the bioactive molecule/s from the EEBD is/are potentially responsible for the observed in vitro and in vivo sPLA₂ inhibition and antioxidant activity.