Molecular modelling and competition binding study of Br-noscapine and colchicine provide insight into noscapinoid-tubulin binding site

► Reported here that noscapinoids bind onto tubulin at or near the colchicine binding site. ► Br-noscapine inhibits binding of colchicine onto tubulin in a concentration dependent fashion. ► In silico molecular docking studies of Br-noscapine and noscapine revealed similar binding modes to that of the experimental bound colchicine. ► The calculated binding affinity of Br-noscapine and noscapine using MM-GB/SA is in agreement with the experimental binding affinity. ► These lines of investigation constitute the first evidence for the binding site of noscapinoids onto tubulin.