Study of alpha-amylase and urease inhibitory activities of Melilotus indicus [Linn.] All

Melilotus indicus [Linn.] All. is a small herb distributed throughout Pakistan and has a number of ethnomedicinal uses. It is also consumed as a vegetable. In the present work, we are reporting the alpha-amylase and urease inhibitory activities of methanolic extract of M. indicus and its sub-fractions in different solvents. Both the methanolic extract and its fractions in chloroform, ethyl acetate, n-butanol and water showed remarkable inhibitory activities against alpha-amylase with the IC[50] values being 1.29, 1.45, 1.07, 1.45 and 2.10 mg/mL respectively. The efficacy of the methanolic extract was comparable with that of acarbose [1.20 mg/mL], while the ethyl acetate fraction was more potent. The urease inhibitory activities of methanolic extract and chloroform, ethyl acetate, n-butanol and water fractions were more prominent with IC[50] values being 0.95, 0.89, 1.53, 0.98 and 4.90 microg/mL respectively. The activity of methanolic extract was slightly higher than that of thiourea [0.97 microg/mL] which in turn was slightly higher than that of n-butanolic fraction. The chloroform fraction showed the highest anti-urease activity. All the plant samples showed enzyme inhibitory activity in a dose-dependent manner. Moreover, they were manifold more effective against urease than alpha-amylase. The combination of the plant extract with acarbose considerably increased the potency of the latter. The findings suggest that enzyme inhibitory activities of the vegetable M. indicus may have pharmacological significance against diabetes mellitus and gastrointestinal ulcers.

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 micro g 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 alphaamylase]. 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 micro g/mL of the extract was required to create the same inhibition in urease activity. The IC[50] 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 [micro g/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