Biologically active carbazole alkaloids from Murraya koenigii

The bioassay guided fractionation of the acetone extract of the fresh leaves of Murraya koenigii resulted in the isolation of three bioactive carbazole alkaloids, mahanimbine (1), murrayanol (2), and mahanine (3), as confirmed from their (1)H and (13)C NMR spectral data. Compound 2 showed an IC(50) of 109 microg/mL against hPGHS-1 and an IC(50) of 218 microg/mL against hPGHS-2 in antiinflammatory assays, while compound 1 displayed antioxidant activity at 33.1 microg/mL. All three compounds were mosquitocidal and antimicrobial and exhibited topoisomerase I and II inhibition activities.