The second approach was based on a study of Peter Ertl who previously extracted the ring systems from the molecules in ChEMBL (version not specified) and associated them with their reported bioactivity in ChEMBL against the following biological target families: G protein-coupled receptor (GPCR), kinase, protease, nuclear receptor, ion channel, transporters, and epigenetic. For LANaPDB, it was determined which compounds contain these bioactive ring systems reported by Ertl. It was found that 31.51% of the LANaPDB compounds (4,279 molecules) have bioactive ring systems. Chart 1 shows the twenty most abundant ring systems found in the LANaPDB compounds, the most abundant ring system agrees with the most abundant pathway found in LANaPDB (Figure ) as it pertains to bioactive sesquiterpenic lactones. It is important to take in account that the remaining percentage of compounds (68.49%) without bioactive ring systems, are not necessarily inactive compounds, they may be active but against other biological targets different from the ones that reported Ertl. Take into account that the currently known scaffold space is far from being fully explored. This is exemplified by the fact that in 2024, Ertl published a database of four million medicinal chemistryrelevant scaffolds that are not included in ChEMBL and PubChem. 50