Natural compounds from plants – phytochemicals – provide a variety of health benefits, including anticancer activity. The human topoisomerases, enzymes that “detangle” DNA, are important targets for plant-derived anticancer drugs.
To discover novel phytochemicals with anticancer activity, Kendra Vann, Neil Osheroff, Ph.D., and colleagues screened a library of 341 Mediterranean plant extracts for activity against human topoisomerase II-alpha. They found that an extract from Phillyrea latifolia L., a member of the Oleaceae family of olive trees, enhanced DNA cleavage by topoisomerase II-alpha.
The investigators identified and tested several olive metabolites and demonstrated that three of them enhanced DNA cleavage and acted as covalent topoisomerase II poisons. Extracts from other olive tree species, as well as a commercial olive leaf supplement and extra virgin olive oils also enhanced DNA cleavage by topoisomerase II-alpha.
The findings, reported in the journal Biochemistry, show that olive metabolites act as topoisomerase II poisons. This activity may contribute to the cancer preventive properties attributed to the Mediterranean diet.
This research was supported by the National Institutes of Health (grant GM033944), ICA in Israel, the Deutsche Forschungsgemeinschaft, and the Richard H. Holzer Foundation.
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