pylori activity with MIC value of 10 μg/ml. However C1, C13, and C24 have not shown anti-H. pylori activity while, remaining CDs showed MIC in the range of 20–40 μg/ml. From the

overall result it can be stated that the anti-H. pylori activity of the selected CDs is closely related with the degree and substitution of hydroxyl groups. However the methyl group substitution in combination with hydroxyl group has both positive as well as negative influence on the activity of the selected CDs. More specifically it was observed that the presence of 4-, 5-, 6- and/or 7-hydroxyl groups seems to be essential for display of higher BTK inhibitor order anti-H. pylori activity. In the previous work carried out using molecular modelling simulations and high-throughput virtual screening, new derivatives of coumarin have been shown to bind in the active site of GDC-0449 datasheet urease. 22 While describing the structure–activity relationship studies, it has been described in the earlier investigation that the presence of hydroxyl group at 4, 5, 6 and/or 7 and the presence of methyl group at C4 position enhanced the anti-H. pylori activity. 15 Our findings are in agreement with above

described hydroxyl substitutions, as it was observed that the 7-hydroxyl substituted and CDs like C5, C12, C15, C16, C17 and 4-methyl substituted CDs like C12, C15, C16 have demonstrated significant anti-H. pylori activity as compared to other test CDs. The results of the urease inhibition using selected CDs are summarized in Table 2. Amongst the tested CDs the compounds crotamiton like C3, C10, C11, C12, C13, C14, C20, C21, C22 and C23 showed considerable

urease inhibition activity. However the CDs like C20, C23, C10, C21, and C22 have shown significant urease inhibition activity with IC50 values of 48.90, 47.80, 54.63, 53.88 and 55.34 μM respectively. The results were compared with a reference urease inhibitor acetohydroxamic acid (IC50 – 44.64 μM). It was observed from the present result that the presence of 4-, 5-, 7- and/or 8-hydroxyl substituted and 4-phenyl group seems to be a pharmacophore for the manifestation of significant anti-H. pylori urease activity. An attempt was made to unravel the possible structure–activity relationship of the selected CDs and the urease inhibition using molecular docking studies (ArgusLab 4.0.1). The selected CDs were docked onto the ligand (acetohydroxamic acid) binding site of the H. pylori urease (PDB ID-1E9Y) and the docking scores (release of internal energy, kcal/mol) were calculated. The more the amount of internal energy released is attributed with stressful binding of the ligand, while the release of minimum amount of internal energy has relevance with structurally compatible binding of the ligand onto the ligand binding site of the receptor. The results of the docking scores of the selected CDs are shown in Table 3.