Potential anti-tubercular and in vitro anti-inflammatory agents: 9-substituted 1,8-dioxo-octahydroxanthenes through cascade/domino reaction by citric fruit juices

A series of 9-substituted 1,8-dioxo-octahydroxanthenes, 3a-k were synthesized and evaluated for their anti-tubercular and in vitro anti-inflammatory potential. Compounds 3b, 3d, 3e, 3f, 3g, and 3k demonstrated their potential anti-tubercular activity at 0.4 mu g/ml comparable to streptomycin and pyrazinamide (standard drugs) screened by Microplate Alamar Blue assay against Mycobacterium tuberculosis H37 Ra. Compounds 3j, 3e, 3f, and 3c showed good in vitro anti-inflammatory activity by the inhibition of enzyme MMP-2 75, 65, 70, and 60 % and inhibition of enzyme MMP-9 by 90, 70, 60, and 60 %, respectively by gelatin zymography on gel electrophoresis. Standard drug tetracycline (300 mu g/ml) is used as positive control which showed 90 % inhibition. The percentage inhibition was determined by a gel documentation system. DMSO was used as solvent control which did not show any inhibition.