In vitro antioxidant activity of bark extracts of Oroxylum indicum (L) vent

Abstract

Objectives: The aim of the present work is to screen the antioxidant potentiality of the bark extract of Oroxylum indicum (L) Vent, ethnomedicinally prescribed plant as hepatoprotective. Methods: Bark extracts were prepared using soxhlet apparatus. Total phenol, flavonoid, and total alkaloid were analyzed using Folin–Ciocalteu assay, aluminum chloride colorimetric assay, atropine standard, respectively. Antioxidant capacity and free radical scavenging potentialities were done by several in vitro methods, viz.; 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydrogen peroxide scavenging activity, reducing power assay, metal chelating activity, ferric reducing ability of plasma (FRAP) assay, and thiobarbituric acid (TBA) method. Result: Total phenol, flavonoid, and alkaloid were found to be highest in methanolic extract of O. indicum (L) Vent. Methanolic extract of the bark showed very low inhibitory concentration (IC50) and effective concentration values for DPPH assay and reducing power assay compared to another extract. In hydrogen peroxide scavenging activity assay, the lowest IC50 value was recorded in methanolic extract with 153.45±0.06 µg/ml. The FRAP assay for O. indicum methanolic extract showed the highest activity at 940.09±0.07 µg/mL of ascorbic acid equivalent. The ferric reducing capacity and TBA values of the plant extracts confirmed the presence antioxidant principles in the bark of the said plant. Conclusion: These underused plants may be used for mitigating the detrimental effect of oxidative stress and reactive oxygen species-mediated disease and thus justifies its use in folklore medicines.