Fig. 4

Examples of fragments shared by natural compounds and drugs in the absence of high global similarity. The two examples shown here illustrate how a fragment-based approach can automatically detect commonalities between molecules that are globally different. Panel (a) shows a tetracyclic fragment present both in a natural compound and in an anti-cancer agent (Paclitaxel). In spite of the common core shared by the two molecules, the Tanimoto similarity between the drug and the natural compound is relatively low (0.56). In panel (b), the beta-lactam ring is detected (which a small variation) in both an approved antibiotic (tazobactam) and a natural compound (SN0240101). However, the Tanimoto similarity between the natural compound and tazobactam is low (0.49)