Maja Karnaš

The pursuit of biologically active compounds has led many researchers to synthesize different heterocyclic hybrids with prominent activity. Both coumarin and 1,2,4-triazole are very potent scaffolds whose hybrids have improved biological activities. : This study synthesized twenty-one new coumarin-1,2,4-triazole hybrids in a one-step reaction using choline chloride : urea deep eutectic solvent. The green approach to this synthesis has led to shorter reaction times, higher yields, and purity of final compounds. : The title compounds were characterized and screened for drug-likeness parameters to evaluate their viability as potential drug candidates and for their in vitro acetylcholinesterase inhibitory activity. All tested compounds complied with the drug-likeness rules. However, they exhibited only weak to moderate inhibitory activity against acetylcholinesterase. : Molecular docking analysis revealed that title compounds mostly bind to the peripheral anionic region of the acetylcholinesterase active site, therefore hindering, but not completely obstructing, substrate from entering the enzyme catalytic site.

Coumarins are secondary plant metabolites widely distributed in higher plants, bacteria, fungi, and sponges. This great structural diversity of these natural compounds and their synthesized derivatives enables their wide range of pharmacological activities, such as antioxidant; antibacterial; antifungal; anti-human immunodeficiency infection; anti-tubercular; and anti-cancer activities, which were very well reviewed previously. There are also many reports about their effectiveness against plant pathogenic pests (phytopathogenic fungi, bacteria, nematodes, and insects). These secondary metabolites protect environmental enemies and competing plants. However, there is still limited literature on coumarins’ practical applications in agriculture, as well as their effects on beneficial populations of soil organisms. This review summarizes recent knowledge about the effects of natural and synthesized coumarins on phytopathogens and beneficial populations of soil organisms. A separate section is dedicated to poorly reviewed computer-aided molecular design (CAMD) methods of agrochemicals. It also reviewed CAMD techniques to develop low-toxicity and environmentally safe pesticides. Despite the many positive effects of coumarins related to plant protection, they do possess properties harmful to the environment and health. These properties are described in the last section. Prediction of coumarin hazardous properties using a quantitative structure-activity relationship (QSAR) approach was also reviewed.

Leaf removal (LR) treatments improve the photosynthetic capacity of the remaining leaves and induce flavonoid synthesis as a stress response in the common grapevine ( Vitis vinifera L.). However, excessive exposure of grape berries to UV‐B radiation as a result of cultural practices in the Mediterranean climate may have negative effects on berry composition. This 2‐year study determined the effects of defoliation on the autochthonous red grape variety ‘Babica’ in a Mediterranean climate (wine‐growing region Dalmatia, Croatia). Six leaves were removed before flowering (FLR) and at the end of véraison (the onset of grape ripening; VerLR) and were compared to the untreated control. Yield parameters, sugar content, grape must pH, total polyphenols (TP), total anthocyanin (TA) content, and individual anthocyanin compounds were measured in grape skin extracts and wines. However, the greater mean daily temperature during the vegetation period and lesser rainfall before harvest in 2018 increased yield per vine, average cluster weights, density, and total acidity, compared to 2017. Both defoliation treatments significantly reduced TP in grape extracts, but these differences were not observed in wine. Compared to the control (NLR), VerLR treatment significantly reduced TA in grape skin extracts and wine. Significantly lesser TP concentrations, in grape skin extracts and wine, as well as TA were noticed during the 2017 season. VerLR treatment reduced the concentration of nine individual anthocyanins compared to the control in grape skin extracts, while this effect was not observed in wine. Season year was a statistically significant source of variability of the individual anthocyanin contents in wine. Under specific environmental conditions LR can decrease polyphenols, especially anthocyanins, and negatively impact grape and wine quality.