4.5.1. Urease Enzyme Inhibition Assay

The anti-urease potential of methanolic crude extract and different fractions of V. officinalis were evaluated by using the reported method [41]. A mixture of 20 µL of urease solution (0.025%) prepared in phosphate buffer (1 M, pH 7.0) and 20 μL of extract sample was added in a microtiter plate and then kept for incubation for 15 min at room temperature. Then 60 µL of aqueous urea solution (2.25%) was mixed with the resultant reaction mixture and kept for incubation for 15 min at room temperature and absorbance was recorded at 630 nm (pre-read). Then 60 µL of phenol reagent and 100 µL of solution of sodium hypochlorite (prepared in alkali) were added to the above reaction mixture which was then incubated at room temperature for 30 min. The absorbance was noted at 630 nm (after read). For positive control, hydroxy urea and for negative control phosphate buffer was used. The % inhibition of the urease enzyme was determined using the following Equation (1).

A_sample—absorbance of sample; A_control—absorbance of control.