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A series of new azoalkyl ether imidazo[2,1- b ]benzothiazoles were developed via a convenient synthetic procedure. The antimicrobial assays showed that a good number of the prepared derivatives exhibited significant inhibitory properties against most of the tested strains. Especially 2-methyl-5-nitroimidazole derivative 5a presented superior inhibit activity against MRSA and B. typhi with MIC = 4 μg/mL and MIC = 1 μg/mL, respectively. The highly active compound 5a showed low toxicity against mammalian cells without obvious triggering of the development of bacterial resistance, and it also possessed rapid bactericidal efficacy. Molecular docking study exposed that the active molecule 5a could interact with the active site of S. aureus gyrase through hydrogen bond. Quantum chemical studies were also performed to explain the high antibacterial activity. Further investigation revealed that compound 5a could significantly associate with gyrase–DNA complex by mean of hydrogen bonds and could efficiently intercalate into MRSA DNA to form 5a –DNA supramolecular complex, which impart potent bioactivity. [ABSTRACT FROM AUTHOR]

Eight new lindenane sesquiterpenoid dimers, chlojapolides A–H ( 1 – 8 ), along with 11 known analogues were isolated from the whole plant of Chloranthus japonicus . Their structures including absolute configurations were elucidated by spectral and chemical methods. All the compounds were examined for their inhibitory effects on the nitric oxide (NO) production induced by lipopolysaccharide (LPS) in RAW 264.7 macrophages, and compounds 1 , 11 , 13 , and 17 exhibited pronounced inhibition with IC 50 values in the range of 6.91–15.75 μM, being more active than the positive control, quercetin (IC 50 = 15.90 μM). [ABSTRACT FROM AUTHOR]