Search

Investigation of the crude extract obtained from the aerial parts of Canthium multiflorum led to the isolation of a new iridoid (1) together with twelve known compounds. The structures of these compounds were elucidated by interpretation of 1D and 2D NMR spectroscopic data, accurate mass measurements and comparison with analytical data of previously known analogues. Most of the isolated compounds have been reported for the first time from C. multiflorium. The antimicrobial activities of the isolated compounds were evaluated on five different bacterial strains using agar diffusion technique. The Gram-positive bacterium Staphylococcus aureus subsp. aureus (DSM 799), and the Gram-negative bacteria Actinobacter calco-aceticus (DSM 30006), Serratia plymuthica (DSM 4540), Pseudomonas stutzeri (DSM 4166) and Escherichia coli (DSM 1116) were employed for this purpose. The new iridoid, named 6-oxo-genipin (1), demonstrated significant inhibitory activity against all microbial strains tested, especially the pathogen Staphylococcus aureus. In addition, the compounds 3, 4 and 9 exhibited antiplasmodial activity against Plasmodium falciparum strain K1 and weak cytotoxicity against L6 cell lines., (© 2013 Elsevier B.V. All rights reserved.)

Bioassay guided fractionation of Hypericum riparium leaves extract has resulted in the isolation and characterization of three new compounds namely chipericumin E ( 1 ), hyperenone C ( 3 ), and hyperixanthone ( 5 ), together with twenty known compounds. Their structures were elucidated based on comprehensive interpretation of spectroscopic and spectrometric data. Compounds 1 – 4 , and 6 – 8 displayed moderate antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA) and cytotoxic effects on the human gastric cell line BGC-823 with IC 50 values ranging from 6.54 to 18.50 μM. [ABSTRACT FROM AUTHOR]