ABSTRACT The genus Cryptocarya is commonly found in Southeast Asia, Southern Africa and South America. The genus includes over 350 species, many of which are used in traditional medicine. Phytochemicals from the tree species Cryptocarya kurzii Hook.f. have been rarely studied. A group of four 10-membered lactones, designated kurziflavolactones A-to-D, has been identified 30 years ago from this species. Two related compounds, kurzichalcolactones A and B, have been isolated from other Cryptocarya species. We investigated the interaction of these 6 little-known compounds with tubulin, using a molecular docking approach based on the crystal structure of the α/β-tubulin dimer (PDB: 5FNV). The flavonoids cryptoconones A-E also issued from Cryptocarya species have been tested also, but their α-tubulin binding potential was found to be limited. The modeling analysis suggests that kurziflavolactone A can fit very well into the pironetin site of α-tubulin. The compound anchors deeply into the binding cavity, providing a large array H-bonds and van der Waals contacts to stabilize the drug-protein complex. Kurziflavolactone B and C are slightly less prone to bind to α-tubulin pironetin-site compared to kurziflavolactone A. The binding of the two kurzichalcolactones is even less favored, as it is the case with kurziflavolactone D. Nevertheless, in all cases the docking is significant and all 6 compounds could be considered as potential α-tubulin binders. Structure-binding relationships are discussed. Altogether, the computational analysis provides a new vision on the possible mechanism of action of these neglected natural products. With no doubt, kurziflavolactone A warrants further investigation as an anticancer modulator of microtubule dynamic.
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