Fig. 8
Pairs of natural products with in vitro antiplasmodial activities that represent activity cliffs. Panels a and b show the structures, the value of structural similarity (similarity), activity (IC50) of each compound (Activity 1 and Activity 2), difference in activity (Delta activity) and structure–activity landscape index (SALI). The major structural differences between the compounds are highlighted with red circles. On Panel a, the hydroxyl group and methoxy group highlighted on Structure 1 and Structure 2 seem to make the difference between the antiplasmodial activities. This structural-activity landscape analysis provides valuable information about structural features in NAA required for antiplasmodial activity