5162-01-6Relevant academic research and scientific papers
Antimicrobial activities of naphthazarins from Arnebia euchroma
Shen, Chien-Chang,Syu, Wan-Jr,Li, Shyh-Yuan,Lin, Chia-Hung,Lee, Gum-Hee,Sun, Chang-Ming
, p. 1857 - 1862 (2007/10/03)
Bioassay-directed fractionation of extract of Arnebia euchroma led to the isolation of alkannin (1), shikonin (2), and their derivatives (3-8) as the active principles against methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE). The stereochemistry of α-methylbutyryl alkannin (8) is revealed for the first time, and the antimicrobial activity of 8 was compared with its corresponding diastereomer (9). The derivatives 3-9 showed stronger anti-MRSA activity [minimum inhibitory concentrations (MICs) ranged from 1.56 to 3.13 μg/mL] than alkannin or shikonin (MIC = 6.25 μg/mL). Anti-MRSA activity of derivatives was bactericidal with minimum bactericidal concentration (MBC)/ MIC ≤ 2. In a time-kill assay, the bactericidal activity against MRSA was achieved as rapidly as 2 h. The derivatives 3-9 were also active against vancomycin-resistant Enterococcus faecium (F935) and vancomycin-resistant Enterococcus faecalis (CKU-17) with MICs similar to those with MRSA. Aromatic ester derivatives were also synthesized for antimicrobial activity comparison. None of these compounds were active against Gram-negative bacteria tested. Their cytotoxicity was also evaluated on selected cancer cell lines, and they expressed their activity in the range 0.6-5.4 μg/mL (CD50). Our results indicate that the ester derivatives of alkannin are potential candidates of anti-MRSA and anti-VRE agents with antitumor activity.
