Obacunone and limonin could bound to the same active site residue Trp447 through different types of bonds (pi–pi stacked and H-bonds, respectively), creating a more stable protein structure to assist in maintaining the position of limonin within NOS3, suggesting the synergistic effects against NOS3 associated with hyperuricemia between limonin and obacunone [12]. The gene discussed is NOS3; the disease is hyperuricemia.