Novel thiobarbiturates as potent urease inhibitors with potential antibacterial activity: Design, synthesis, radiolabeling and biodistribution study.

Urease enzyme is a virulence factor that helps in colonization and maintenance of highly pathogenic bacteria in human. Hence, the inhibition of urease enzymes is well-established to be a promising approach for preventing deleterious effects of ureolytic bacterial infections. In this work, novel thiobarbiturate derivatives were synthesized and evaluated for their urease inhibitory activity. All tested compounds effectively inhibited the activity of urease enzyme. Compounds 1, 2a, 2b, 4 and 9 displayed remarkable anti-urease activity (IC50 = 8.21-16.95 µM) superior to that of thiourea reference standard (IC50 = 20.04 µM). Moreover, compounds 3a, 3g, 5 and 8 were equipotent to thiourea. Among the tested compounds, morpholine derivative 4 (IC50 = 8.21 µM) was the most potent one, showing 2.5 folds the activity of thiourea. In addition, the antibacterial activity of the synthesized compounds was estimated against both standard strains and clinical isolates of urease producing bacteria. Compound 4 explored the highest potency exceeding that of cephalexin reference drug. Moreover, biodistribution study using radiolabeling approach revealed a remarked uptake of 99mTc-compound 4 into infection induced in mice. Furthermore, a molecular docking analysis revealed proper orientation of title compounds into the urease active site rationalizing their potent anti-urease activity.

Utility of anthranilic acid and diethylacetylenedicarboxylate for the synthesis of nitrogenous organo/organometallic compounds as urease inhibitors.

Fumarate diester 3 was synthesized upon reacting anthranilic acid with diethylacetylenedicarboxylate. Compound 3 was reacted with different nucleophiles in mild reaction conditions. Selected reaction routes that afforded products 6, 9, 10, 11, and 12 were explained. The estimated mechanism for the reaction of 3 with ethylenediamine to afford 9 was proved by X-ray single-crystal and retro-synthetic reaction. Acetyl anthranilic acid was utilized with zinc and copper to afford the organometallic compounds 14a and 14b, respectively. Three single crystals were afforded for 3, 9 and the organocopper complex 14b. Target compounds were screened for their inhibitory potential against urease enzyme. Most compounds were more potent than thiourea as standard inhibitor, considering that oxopiperazine 9 exhibited double the activity: IC50 = 8.16 ± 0.65 µM (thiourea IC50 = 20.04 ± 0.33 µM). Docking studies were in agreement with the in vitro enzyme assay.

Chemopreventive effect of sulindac in combination with epigallocatechin gallate or kaempferol against 1,2-dimethyl hydrazine-induced preneoplastic lesions in rats: A Comparative Study.

A systematic investigation of the chemopreventive effect of sulindac (SL) in combination with either epigallocatechin gallate (EGCG) or kaempferol similar (KMP) has been carried out 1,2-dimethyl hydrazine-treated rats (DMH). Those SL combinations with KMP and EGCG have enhanced the SL activity producing greater antioxidant, anti-inflammatory, antiproliferating, and apoptotic activities in both combinations than SL alone. The chemopreventive effects of SL with both EGCG and KMP were demonstrated by a decrease in thiobaribituric acid reactive substances level, tissue nitric oxide (NO), serum, and tissue ß-catenin as well as a reduction in the multiplicity of aberrant crypt foci (ACF) with alleviation in the dysplastic changes that resulted from DMH administration. Down-regulation of proliferating cell nuclear antigen (PCNA) and cyclooxygenase-2 (COX-2) were also confirmed by immunohistochemical staining. The current study paves the way for the use of sulindac combination with kaempferol or EGCG as potential chemopreventive agents against colon cancer with more effect in combination with EGCG.