Determination of the Phytochemicals and Antioxidant Properties of Ethanol and Water Extracts Respectively from Leaves and Flowers of Silybum marianum L.

Abstract

This study aims to determine and compare the total phenolic (TPC), flavonoids (TFC) components and antioxidant activities, upon extraction using two different polar solutions: ethanol and boiling water respectively for the extraction of Silybum marianum L. leaves and flowers used maceration method. The TPC and TFC were evaluated using Folin–Ciocalteu reagent and aluminum chloride colorimetric method, respectively; while antioxidant activities were determined by DPPH radical scavenging and reducing power activity. These various antioxidant activities were compared with standard antioxidants as ascorbic acid. The highest TPC was determined in the ethanol extract of leaves (88.53 ± 0.57 mg GAE/g ext.), followed by aqueous extract of flowers (81.39 ± 1.13 mg GAE/g ext.), while, ethanol flowers and aqueous leaves extracts were (72.34 ± 1.16 mg GAE/g ext.) and (71.92 ± 0.73 mg GAE/g ext.) respectively. The highest TFC was found in ethanol extract of leaves (61.61 ± 0.52 mg QUE/g ext.), followed by ethanol extract of flowers (37.79 ± 0.12 mg QUE/g ext.), while extracted with hot water was (18.86 ± 0.13 mg QUE/g ext.) for leaves, and (27.54 ± 0.62 mg QUE/g ext.) for flowers. The extracts of S. marianum showed Average strength antioxidant activity. where the antioxidant activity assessed by DPPH radical scavenging assay was the highest in aqueous flowers extract (IC₅₀ = 189.63 µg ASC.acid/ml), and lowest in aqueous leave extracts (IC₅₀ = 401.61 µg ASC.acid/ml). While the antioxidant activity assessed by reducing power was the highest in ethanol leaves extract (IC₅₀ = 318.90 µg Fe²⁺/mL), and the lowest was in aqueous leaves extract (IC₅₀ = 433.74 Fe²⁺/mL). The present study enumerates the total phenols, total flavonoid and antioxidant activity of the S. marianum, which may help the researchers to set their minds for approaching the utility and efficacy of the plant extracts.