Quassin is a quassinoid that has been found in Q. amara and has diverse biological activities.^1,2,3 It is active against chloroquine-sensitive and -resistant strains of P. falciparum (IC50 = 0.15 µM for both).¹ Quassin has antifeedant and insecticidal activity against the diamondback moth (P. xylostella) when applied to dietary cabbage leaf discs at 16, 31.9, or 63.7 µg/cm2.2 It increases viability of SH-SY5Y cells in a model of hydrogen peroxide-induced neuronal injury when used at concentrations of 25, 50, or 100 µM.³