Tab. 3.

π–π Interaction energies of intercalating antitumor agents and caffeine.

Compounds	Evac (kcal/mol)a	Eaq (kcal/mol)b
Caffeine + Berberine	−19.34	−12.60
Caffeine + Camptothecin	−18.04	−13.05
Caffeine + Chelerythrine	−20.54	−14.12
Caffeine + Doxorubicin	−19.16	−15.86
Caffeine + Ellipticine	−16.83	−11.02
Caffeine + Sanguinarine	−21.60	−16.47

^aCalculated interaction energies in the gas phase.

^bCalculated interaction energies using an aqueous solvation model (SM5.4 [41]).