Analytical Procedures

Antiprotozoal Compounds from Urolepis hecatantha (Asteraceae)

“…The differences in activity between T. cruzi and L. infantum for compound 4 compared to compound 3 are remarkable. Both are germacranolides with the same molecular formula (C 22 H 28 O 8 ) but differ in the stereochemistry of the C4–C5 double bond: lactone 3 is a germacrolide (a trans, trans -germacranolide) while lactone 4 is a heliangolide (a trans , cis -germacranolide) [ 22 ]; they also differ in the location of the acetyl group which in lactone 3 esterifies the hydroxyl group of the 4,5-dihydroxytigloyloxy ester residue at C-8, while, in lactone 4, it esterifies the hydroxyl group at C-3 of the heliangolide skeleton. These differences should be expected to strongly affect conformation, electronic distribution, and hydrogen bonding interactions.…”

The potential role of sesquiterpene lactones isolated from medicinal plants in the treatment of the metabolic syndrome – A review

“…Based on their carbocyclic skeleton, SLns are mainly classified in four major groups: germacranolides (10-membered ring), eudesmanolides (6–6 bicyclic compounds), guaianolides and pseudoguaianolides (5–7 bicyclic compounds) and many subtypes of SLns according to their skeletal arrangement ( Adekenov, 2017 ; Padilla-Gonzalez et al., 2016 ). In many cases, the γ-lactone ring contains an exocyclic double bond conjugated to the carbonyl group (α-methylene-γ-lactone) but in some cases the exocyclic methylene is reduced or the double bond can be endocyclic ( Martínez et al., 2012 ; Padilla-Gonzalez et al., 2016 ; Sülsen et al., 2018 ). It has been well documented that biological activity of the most common types of SLns is mainly attributed to formation of covalent union between the α,β-unsaturated group in the exo -methylene-γ-lactone and nucleophilic biological targets ( e.g.…”

“…Another structural influences on the biological effects are the molecular size, hydrophobicity, chemical environment and the presence of other functional groups ( e.g. , epoxy groups, hydroxyls or hydroxyls esterified with acetate, propionate, isobutyrate, angelate, epoxyangelate, and benzoate) ( Chaturvedi, 2011 ; Ivanescu et al., 2015 ; Padilla-Gonzalez et al., 2016 ; Sülsen et al., 2018 ).…”

Antibacterial Sesquiterpene Lactones from Kaunia lasiophthalma

“…For example, the antibacterial activity shown by the guaianolide dehydroleucodine, isolated for the first time from Artemisia douglasiana and also from Kaunia lasiophthalma, stands out, being active against six clinical isolates of Helicobacter pylori with MIC values of 1 to 8 μg/mL. [12] Staphylococcus aureus and Klebsiella sp. are human pathogens that cause hospital-acquired infections, [13,14] while Escherichia coli causes intestinal diseases.…”