| Title: | Antimicrobial activities of naphthazarins from Arnebia euchroma |
| Authors: | Shen C.C.;Syu W.J.;Li S.Y.;Lin C.H.;Lee G.H.;Sun C.M. |
| Contributors: | 化學系 |
| Date: | 2002 |
| Issue Date: | 2009-12-04 15:44:21 (UTC+8) |
| Abstract: | 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 alpha-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 mug/mL] than alkannin or shikonin (MIC = 6.25 mug/mL). Anti-MRSA activity of derivatives was bactericidal with minimum bactericidal concentration (MBC)/ MIC less than or equal to 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 mug/mL (CD50). Our results indicate that the ester derivatives of alkannin are potential candidates of anti-MRSA and anti-VRE agents with antitumor activity. |
| Relation: | JOURNAL OF NATURAL PRODUCTS Volume: 65 Issue: 12 Pages: 1857-1862 |
| Appears in Collections: | [Department of Chemistry & Graduate Institute of Applied Chemistry ] journal articles
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