Shiva Joohari and Majid Monajjemi

pp. 327 - 343

Abstract

Vincristine is a biological active alkaloid that has been used clinically against a variety of neoplasms. In the current
study we have theoretically investigated the magnetic properties of titled compound to predict physical and chemical properties of vincristine as a biological inhibitor. Ab initio computation using HF and B3LYP with 3-21G(d) and 6-31G(d) level of
theory have been performed and then magnetic shielding tensor (σ, ppm), shielding asymmetry (μ), magnetic shielding anisotropy (σ_aniso, ppm), the skew of a tensor (K), chemical shift anisotropy (Δσ) and chemical shift (δ) were calculated to indicate
the details of the interaction mechanism between microtubules and vincristine. Moreover, E_HOMO, E_LUMO and E_bg were
evaluated. The maximum and minimum values of E_bg were found in HF/3-21g and B3LYP/3-21g respectively. It was also
uggested that O₂₄, O₃₇, O₄₉ and O₅₅ with minimum values of σ_iso, are active sites of titled compound. Furthermore the
calculated chemical shifts were compared with experimental data in DMSO and CDCl₃
 solvents.