To focus on structural features of the central scaffolds of these natural products, all existing carbohydrate moieties were removed by substructure filtering using DataWarrior software (www.openmolecules.org/datawarrior/, 5.0.0) ; 2931 molecules were retained. To assess pairwise similarities, all molecules were represented as bit vectors according to the Morgan fingerprint algorithm . Morgan fingerprints numerically encode the presence of radial molecular fragments (length = 2048, radius = 2) as implemented in RDKit (version 2018.03). Molecule 1 was randomly selected from the dataset. The four most similar molecules according to their Tanimoto similarity (Tanimoto coefficient, TC) to molecule 1 were chosen from MEGx (TC 0.78 to 0.82). Based on molecule 1, the MaxMinPick algorithm, as implemented in RDKit (LazyBitVectorPick), was used to select a subset of four dissimilar natural products (TC = 0.04 to TC = 0.10).