Abstract
A survey of crude plant extracts for DNA polymerase β inhibitors resulted in the identification of a methyl ethyl ketone extract prepared from Knema elegans that strongly inhibited the enzyme. Subsequent bioassay-guided fractionation of the extract, using an assay to monitor the activity of DNA polymerase β, led to the isolation of two potent inhibitors, (+)-myristinins A (1) and D (2), which are known flavans having unusual structures. (+)-Myristinins A and D exhibited IC50 values of 12 and 4.3 μM, respectively, as inhibitors of DNA polymerase β in the presence of bovine serum albumin (BSA), and 2.7 and 1.2 μM in the absence of BSA. As such, they are the most potent DNA polymerase β inhibitors reported to date. Compounds 1 and 2 potentiated the cytotoxicity of bleomycin toward cultured P388D1 cells, reducing the number of viable cells by at least 30% when employed at 9 μM concentration for 6 h in the presence of an otherwise nontoxic concentration of bleomycin (75 nM). Principles 1 and 2 also induced strong Cu2+-dependent DNA strand scission in a DNA cleavage assay. Accordingly, 1 and 2 exhibit two activities, namely, DNA polymerase β inhibition and DNA damage.
Original language | English (US) |
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Pages (from-to) | 1625-1628 |
Number of pages | 4 |
Journal | Journal of Natural Products |
Volume | 68 |
Issue number | 11 |
DOIs | |
State | Published - Nov 2005 |
Externally published | Yes |
ASJC Scopus subject areas
- Analytical Chemistry
- Molecular Medicine
- Pharmacology
- Pharmaceutical Science
- Drug Discovery
- Complementary and alternative medicine
- Organic Chemistry