Study On The Calculation And Effect Of Supramolecular Association Between Terpenoid Mosquito Repellents And Attractants

Using repellent is one of the most important methods for mosquito control.Our previous study found that there is a supramolecular association between repellents and attractants during the use of repellents.In order to understand the true nature of this association and its effects,in this study,22 self-made terpenoid repellents from our research team and two major human attractants(L-lactic acid,ammonia)were selected as research objects.The mainstream repellent DEET was used as a comparison.Quantum chemical calculations on the repellent monomer and complexes derived from the supermolecule association between repellents and attractants were performed by using Gaussian software,and supermolecule associations between repellents and attractants were analyzed from the perspective of quantum chemical;Using Aedes albopictus,an important vector of mosquitoes in China,as the test insect,the effects of repellent monomers and its supramolecular associations on Aedes albopictus were determined through the human repellent activity experiments and electroantennographic experiments;The structural descriptors of the repellent monomers and its supramolecular associations were calculated by using the Codessa software,and the quantitative structure-activity relationship model between the structure descriptors and the repellent activity was constructed,in order to obtain a comprehensive understanding of the repellent mechanism of the supramolecule association between repellent and attractant.The main findings are as follows:1)The main form of the supramolecular association between terpenoid repellent and L-lactic acid,ammonia is hydrogen bonding,and its strength belongs to medium-strong hydrogen bonds.The association process of the repellents with the attractants is an exothermic process that tends to be ordered.The calculation results of association distance,association angle,and association energy all indicate that the addition of ammonia molecules can promote the supramolecule association between repellents and L-lactic acid.2)There are several types of compounds in the six-membered ring and bridged ring terpenoid derivatives that have good repellent activity.Both bimolecular association(repellent + L-lactic acid)and trimolecular association(repellent + L-lactic acid + ammonia)can enhance the repellent activity,and it has certain universality.The trimolecular association has the effect of continuously enhancing the repellent activity on the basis of the bimolecular association,and also has a certain degree of universality.3)There are several types of compounds in the six-membered ring and bridged ring terpenoid derivatives,the relative value of electroantennogram response of them increase as the concentration increases.The relative values of electroantennogram response of terpenoid repellent monomers,bimolecular associations and trimolecular associations are gradually increased with increasing concentration,and have a good repeatability.Terpenoid repellents 1,7,17 and 21 keep increasing in all three cases.At the intermediate concentration of each concentration gradient,the compounds that showed significant decrease in the relative value of electroantennogram response also have a good repeatability,including terpenoid repellents 10 and 15.4)The surface charge distribution,bonding conditions,polarity and size of the terpenoid repellents have a great influence on their repellent activity;the effects of the bimolecular association are closely related to the surface charge distribution and molecular size of the repellents,and at the same time they are closely related to the charge distribution in the association region;The trimolecular association is mainly in the form of hydrogen bond interactions,in which the donor and acceptor of hydrogen bond are closely related to the effects exerted by the associations.The factors affecting the hydrogen bond donor and acceptor acceptability may be related to the electrophilic reactivity of the oxygen atoms and the nucleophilic reactivity of the carbon atoms in the donor/acceptor structure.At the same time,it is related to the surface charge distribution of the repellents before the association and the distribution of the charge in the association region after the association.As a conclusion,supramolecular association between terpenoid repellents and attractants did exist,the main form of the association is hydrogen bonding,and this association has a significant effect on the repellent activity and the electroantennogram of Aedes albopictus.The factors that influence the association are mainly Including the surface charge distribution,bonding conditions,polarity and size of the terpenoid repellents,the electrophilic reactivity of the oxygen atoms and the nucleophilic reactivity of the carbon atoms in the donor/acceptor structure and the distribution of the charge in the association region.