Total Phenolics, Total Flavonoids Contents and In Vitro Antioxidant Activity of Methanol Extract and Solvent Fractions of Desmodium ramosissimum G. Don

Oxidative stress poses a risk to human health and has been linked to the pathogenicity of a myriad of diseases. This study investigated the total phenolics content (TPC) and total flavonoids content (TFC) of Desmodium ramosissimum methanol extract and its solvent fractions (n-hexane, ethyl acetate, n-butanol, and aqueous) using Folin-Ciocalteu and aluminum chloride assays respectively. Furthermore, the extract and solvent fractions were appraised for their in vitro antioxidant capacity using relevant assays: total antioxidant capacity (TAC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and ferric reducing antioxidant power (FRAP) methods all at varying concentrations of 25, 50, 100, 200, 250 and 300 µg/ml. Results revealed that ethyl acetate and n-butanol fractions possess higher levels of TPC and TFC when compared to other solvent fractions and extract in a concentration-dependent manner. The ethyl acetate fraction had the highest TPC (532.36 mgGAE/g of plant extract), TFC (2843.33 mgQE/g of plant extract) and exhibited the highest ferric reducing potential (56.70 mgGAE/g of plant extract) at 300 µg/ml. Also, at 300 µg/ml, the TAC (77.33 mgAAE/g of plant extract) of the n-butanol fraction and its DPPH radical scavenging ability (86.04%) were higher. As shown in this study, organic solvents with different chemical natures are capable of extracting chemical constituents with antioxidant components of different polarities. The study also demonstrates that D. ramosissimum may be considered a rich source of natural antioxidants justifying its pharmacological use in traditional medicine for ameliorating diseases.