Urease inhibitory activities of β-boswellic acid derivatives

4 pentacyclic triterpenoid acids were isolated from Boswellia carterii and identified by NMR and Mass spectroscopic analysis (compounds 1, 3-O-acetyl-9,11-dehydro-β-boswellic acid; 2, 3-O-acetyl-11-hydroxy-β-boswellic acid; 3. 3-O- acetyl-11-keto-β-boswellic acid and 4, 11-keto-β-boswellic acid. Their inhibitory activity on Jack bean urease were evaluated. Docking and pharmacophore analysis using AutoDock 4.2 and Ligandscout 3.03 programs were also performed to explain possible mechanism of interaction between isolated compounds and urease enzyme.It was found that compound 1 has the strongest inhibitory activity against Jack bean urease (IC50？=？6.27？±？0.03 μM), compared with thiourea as a standard inhibitor (IC50？=？21.1？±？0.3 μM).The inhibition potency is probably due to the formation of appropriate hydrogen bonds and hydrophobic interactions between the investigated compounds and urease enzyme active site and confirms its traditional usage.Inhibition of enzymes by natural products which are proven to be the source of therapeutic agents, have increasingly attracted the interests of scientists as a valuable strategy in drug discovery. Boswellia carterii is widely distributed in the Indian subcontinent and Africa. The gum exudates of Boswellia spp. comprise of several pentacyclic triterpenoid acids, which are known as boswellic acids (BA’s) and reported to have different biological activities. Their ability to induce apoptosis choose them as potent compounds in treatment of colon, prostate and breast cancers [1-7] and a broad range of neurodegenerative conditions such as Alzheimer’s and Parkinson’s disease [8-11]. Also their inhibitory effect through topoisomerase I and II has been reported [12].In addition, a number of extracted organic acids of this plant show other biological activities such as inhibition of peptic ulcer formation, probably by increasing the gastric mucosal resistance which its exact molecular mechanism is still not clear. In the recent report, it