South African knobwood yields cancer-killing compound that converts during lab processing
Millan PMM, Riveiro ME, Zhu W, Naidoo-Maharaj D, Maharaj V.
Medicinal Plants
Native prickly ash, planted by eastern gardeners for zebra swallowtail caterpillar habitat, belongs to the same genus as this South African medicinal tree, whose alkaloids proved potent enough to kill prostate cancer cells in the lab.
Researchers screened dozens of South African medicinal plants to find ones that could kill prostate cancer cells. One tree, small knobwood, contains a compound so potent it halted cancer cell growth at very low doses. The study also caught something unexpected: when scientists processed this compound using certain lab solvents, it transformed into a weaker version of itself, which means earlier studies may have unknowingly tested the wrong molecule.
Key Findings
Chelerythrine from small knobwood killed three prostate cancer cell lines with IC50 values of 1.3-2.5 μM, indicating strong potency at low concentrations
Chelerythrine converts to the less active derivative dihydrochelerythrine when processed in acidic acetonitrile solvents, but remains stable in methanol
Prefractionating crude plant extracts before screening improved identification of which specific compounds drove cancer-cell killing activity
chevron_right Technical Summary
Scientists screened dozens of South African medicinal plants against prostate cancer cells and found that small knobwood contains a natural compound, chelerythrine, that kills cancer cells at very low doses. They also discovered that this compound quietly converts into a weaker form when processed with certain lab solvents, which may help explain inconsistencies in earlier studies on similar plant compounds.
Abstract Preview
Original paper
Characterisation of anti-prostate cancer metabolites from a prefractionated south African medicinal plant library reveals a bioactive metabolite conversion.
Natural products remain important sources of structurally diverse metabolites with anticancer potential, but biological screening of crude plant extracts can obscure active constituents. In this st...
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