Study of phenolic content and urease and alpha-amylase inhibitory activities of methanolic extract of Rumex acetosella roots and its sub-fractions in different solvents.

The present study aimed to establish relationship between urease and alpha-amylase inhibitory activities on the one hand and on the other between anti-enzymatic activities and total phenolic contents of the methanolic extract of roots of Rumex acetosella and its fractions in various solvents. The methanolic extract and its fractions in chloroform, ethyl acetate, n-butanol and water showed remarkable inhibitory activities against both urease and alpha-amylase, there was a close correspondence between urease and alpha-amylase inhibitory activities of the plant samples. The n-butanol fraction which had the highest total phenolic content (252.19 ± 2.32 µg of Gallic Acid Equivalents/mg of dry mass of the sample) showed prominent activity against both urease and alpha-amylase indicating a possible role of phenolics in inhibiting the activities of these enzymes. The samples displayed enzyme inhibitory activities in a dose dependent manner and their effectiveness was comparable with that of the standards, thiourea (for urease) and acarbose (for alpha-amylase). The samples were manifold more effective against urease than alpha-amylase; 2.8 mg/mL of MeOH extract produced about 81% inhibition in alpha-amylase activity, while only 10 µg/mL of the extract was required to create the same inhibition in urease activity. The IC50 values of methanolic, chloroform, ethyl acetate, n-butanolic, aqueous and standard solutions were 1.29, 1.31, 1.90, 1.38, 0.85 and 1.20 (mg/mL) respectively against alpha-amylase and 0.99, 3.89, 1.76, 0.91, 0.85 and 0.97 (μg/mL) respectively against urease. The total phenolic content in MeOH, hexane, chloroform, ethyl acetate, n-butanol and water fractions was 108.88 ± 2.65, 43.70 ± 1.90, 34.44 ± 2.30, 230.71 ± 1.78, 252.19 ± 2.32 and 94.07 ± 2.25 respectively.