Spectroscopy, Thermodynamics and Molecular Docking of Fraxinellone with DNA.

Abstract

Fraxinellone is an important botanical lactone compound andhas been demonstrated to have insecticidal activity. To provide theoretical support tothe assessment on the safetyof utilizingfraxinellone as a natural insecticidal agent, the interactions between fraxinellone and armyworm DNA, salmon sperm DNA and calf thymus DNA were investigated using UV-Vis absorption spectroscopy, isothermal titration calorimetry, and molecular docking. Results showed that there were two types of combinations between fraxinellone and three kinds of DNA. Type I combination had an equilibrium constant of combination (Ka1) of about 105 and binding sites (n1) of 0.40-0.70, while type II combination had an equilibrium constant of combination (Ka2) of 103 and binding sites (n2) of 1.35-3.15. Results of molecular docking showed that there werenon-classical embedding type interactions between fraxinellone and three kinds of DNA, with the reaction taking place in small groove areas of the DNA structure, resulting in relatively weak interactive forces.