Abstract
Computation analysis of bisphophonates (BPs) and BP/Ca complexes were performed by using personal computer. Molecular mechanics (MM) calculations and molecular orbital (MO) calculations were performed. Six kinds of BPs, etidronate, clodronate, pamidronate, alendronate, risedronate, zoledronate, were studied.
The three-dimensional structure with the lowest steric energy of BPs and BP/Ca complexes were obtained by MM calculation. Steric energies of BP/Ca complexes were higher than those of BPs. Correlation between ΔE (energy differences of BP/Ca complex and BP) and presumed temporary activity index of BPs was found.
The energies of highest occupied MO (HOMO) and lowest unoccupied MO (LUMO) were obtained by MO calculations. A slight correlation was found between ΔE'(energy differences between LUMO of Ca ion and HOMO of BPs) and presumed temporary activity index of BPs.
It revealed that ΔE and ΔE' will play a significant role in the activity of BPs. MM and MO calculations will be one of the useful tools which analyze and understand the role of BPs or other biological compounds.
