N nHO nHO2 nLS nSR M(1)IC50(i)/M(i)IC50(1)           CloneD10 CloneK1 14 1.00 0.45 1.24 2.69 2.1× 10−2 4.4× 10−2 15 1.00 0.45 1.24 2.69 1.7× 10−2 − 16 1.00 0.45 1.24 2.69 4.8× 10−2 5.1× 10−2 17 1.00 0.45 1.24 2.69 1.9× 10−3 − 18 0 0 2 2.00 2.9× 10−2 6.0× 10−2 19 0 0 2 2.00 5.7× 10−2 3.1× 10−2 20 0 0 2 2.00 1.5× 10−1 1.6× 10−1 21 0 0 2 2.00 7.3× 10−3 − 22 0 0 2 2.00 1.1× 10−2 1.9× 10−2 23 0 0 2 2.00 7.2× 10−3 − 24 0 0 2 2.00 4.0× 10−2 7.7× 10−2 25 0 0 2 2.00 1.5× 10−3 − 26 0 0 2 2.00 1.1× 10−3 8.4× 10−3 27 0 0.40 0.60 1.00 2.4× 10−3 − 28 0 0.40 0.60 1.00 2.2× 10−3 −

Table 3: Comparison of the antimalarial activity of endoperoxides 1428 (M(1)IC50(i)/M(i)IC50(1)) (43) with the number of free radicals, which are formed due to their intramolecular oxidation (44).