Assessment of Antioxidant Activity of Ethanol Extracts of Vigna spp.

Abstract

Plants of Vigna Savi genus are widely used in the world as food and medicinal plants. Most investigations propagated the biochemical composition and biological activity of seeds of these plants due to the high content of proteins but fewer studies about the above-ground plant part. The aim of this study focused on the investigation of the antioxidant activity of Vigna spp. The plant raw of Vigna angularis (Willd.) Ohwi & H. Ohashi, V. mungo (L.) Hepper, V. radiata (L.) Wilczek, V. unguiculata (L.) Walp. was collected from the M.M. Gryshko National Botanical Garden of the National Academy of Sciences of Ukraine experimental collection at the start of the vegetation and flowering stage. At the start of vegetation was determined 45.27–77.21 mg GAE.g^-1 (gallic acid equivalent) of total polyphenol compounds (TPC), 8.67–20.48 mg CAE.g^-1 (caffeic acid equivalent) of total phenolic acids (TPAC), 31.84–47.97 mg QE.g^-1 (quercetin equivalent) of total flavonoids content (TFC), 6.97–8.14 mg TE.g^-1 (Trolox equivalent) of antioxidant activity by DPPH method, and 110.52 to 142.61 mg TE.g^-1 of AA by phosphomolybdenum method. At the flowering stage found the following results: 27.16–78.11 mg GAE.g^-1 of polyphenol compounds, 4.97–17.16 mg CAE.g^-1 of phenolic acids, 18.27–54.26 mg QE.g^-1 of flavonoids, 4.6–6.69 mg TE.g^-1 of AA by DPPH method, and 45.16–110.27 mg TE.g^-1 of antioxidant activity by phosphomolybdenum method. A very strong correlation found between antioxidant activity by phosphomolybdenum method and TPAC (r = 0.883), TPC (r = 0.858), and TFC (r = 0.843) at the flowering stage. These results can be used for further biochemical and pharmacological investigations of these plants.