Assessment of antimicrobial, free radical scavenging, and anti-inflammatory activities of <i>Holarrhena pubescens</i> (Buch.-Ham.) Wall. seeds using <i>in vitro</i> methods and evaluation of antiarthritic potential using an <i>in vivo</i> method

Introduction: Holarrhena pubescens is used traditionally for treating several infectious and inflammatory disorders with no scientific evidence. The present study was designed to evaluate the antimicrobial and free radical scavenging properties of different fractions of ethanolic extract of H. pubescens seeds. Furthermore, the potential of the fractions of the plant extract in treating acute and chronic inflammation through in vitro and in vivo experiments was also evaluated. Methods: The successive fractions of ethanolic extract of H. pubescens seeds, including petroleum ether (HPF), chloroform (HCF), and methanol (HMF) fractions were subjected to in vitro study to evaluate the properties to eradicate the microorganisms using disc diffusion method and to scavenge oxidants in the DPPH method. The HCF was further used in an anti-inflammatory activity study by inhibition of bovine serum albumin denaturation assay and an in vivo study to evaluate the effect of the drug in a chronic inflammatory condition by adjuvant-induced arthritis in a rats’ model. Results: HCF showed the most potent effect among all the test drugs. The fraction showed a broad-spectrum antimicrobial effect and 80.35 ± 0.46% free radical scavenging effect (IC50 value = 28.41 ± 0.33 µg/mL) in the antioxidant study. Further, HCF showed an anti-inflammatory effect with 68.37 ± 1.11% inhibition of denaturation of albumin and 75.16% (0.38 ± 0.16 mL, P&lt;0.05) inhibition of rat paw edema in the in vivo study. Conclusion: The study exhibited the antimicrobial, antioxidant and anti-inflammatory potentials of the fractions of ethanolic extract of H. pubescens seeds.