A quantum chemical and chemometric study of sesquiterpene lactones with cytotoxicity against tumor cells

The semi‐empirical molecular orbital method PM6 was employed to calculate a set of molecular descriptors of 20 sesquiterpene lactones (SQLs) with cytotoxicity against HL‐60 (leukemia) tumor cells. The principal component analysis (PCA) and hierarchical cluster analysis (HCA) methods were used to obtain possible relationships between the calculated descriptors and the biological activity of the lactones. Four descriptors were identified as responsible for the separation between the active and inactive compounds: EHOMO (highest occupied molecular orbital energy); Q11 (net atomic charge on C11); Q12 (net atomic charge on C12) and Q13 (net atomic charge on C13). These results indicated that the presence of the α‐methylene‐γ‐lactone group has a significant role in the mechanism by which SQLs exert their biological activities.In order to deepen our knowledge about the structure–activity relationship of sesquiterpene lactones (SQLs), a quantum chemical and chemometric study of sesquiterpene lactones with cytotoxicity was performed against HL‐60 (leukemia) tumor cells. The analysis of the molecular descriptors identified as responsible for the separation between the active and inactive compounds indicated that the presence of the α‐methylene‐γ‐lactone functionality has a significant role in the mechanism by which SQLs exert their biological activities.