Molecular properties as descriptors of octanol-water partition coefficients of herbicides

Reddy, Krishna N.; Locke, Martin A.

doi:10.1007/bf00279169

Cited by 22 publications

(6 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Moreover, differences in grade of toxicity can be associated with solubility of herbicides in lipids; it is well known that lipid-soluble substances easily pass into cells through the cell wall (Tang et al, 1998) and, that the sorption of the herbicide to algal cells is a prerequisite for its action at the chloroplast membrane. Isoproturon (log Kow 2.25) can be considered a moderately lipophilic compound, but the triazine terbutryn (log Kow 3.49) could be rapidly taken up, as a passive uptake, from the medium by C. vulgaris cells due to affinity of this molecule to the algal cell ( Reddy and Locke, 1996). This hypothesis will agree with the results obtained in the present work.…”

Section: Discussionsupporting

confidence: 92%

Physiological response of freshwater microalga (Chlorella vulgaris) to triazine and phenylurea herbicides

et al. 2002

View full text Add to dashboard Cite

The effects of two herbicides used wide-spread, isoproturon (phenylurea) and terbutryn (triazine), on growth, dry weight, elemental composition, photosynthetic pigments and protein content, and cell volume assayed by flow cytometry in the freshwater microalgae Chlorella vulgaris were studied. Different parameters for algal activity show widely different sensitivities to these aquatic pollutants. After 96 h of herbicide exposure, terbutryn was the strongest inhibitor of growth, giving an EC50 value for growth twice lower than that for isoproturon cultures (EC50 terbutryn=0.097 microM; EC50 isoproturon=0.199 microM). However, lower concentrations of the triazine herbicide provoked an increase in the cellular density and growth rate of this microalga, not observed in the phenylurea-treated cultures. Cellular volume and dry weight of C. vulgaris cells were increased strongly in the presence of isoproturon and terbutryn. Other cellular parameters, such as pigment and protein content, were stimulated with both herbicides at higher concentrations.

show abstract

Section: Discussionsupporting

confidence: 92%

Physiological response of freshwater microalga (Chlorella vulgaris) to triazine and phenylurea herbicides

et al. 2002

View full text Add to dashboard Cite

show abstract

“…It is calculated by the sum over all orbitals of the ratio between orbital densities and the corresponding orbital energies. The superdelocalizability of the HOMO (S HOMO ) and of the LUMO (S LUMO ), and the electrophilic (SE) and nucleophilic superdelocalizabilities (SN) can also be calculated (Reddy and Locke, 1996). The SE has been designed to quantify the susceptibility of a molecule for an electrophilic attack (Tehan et al, 2002b).…”

Section: Quantum-chemical Descriptorsmentioning

confidence: 99%

“…For 50 aromatic hydrocarbons, 300 pharmaceutical compounds and 14 phthalates, the K OW were correlated to E-state indices (Gombar and Enslein, 1996;Huuskonen et al, 1999;Thomsen et al, 1999), but these indices cannot account for 3D and conformational effects, which may play a major role for solubility properties of chemical compounds. The polarizability α was combined with μ to predict the K OW of 22 PCDPS (Shi et al, 2012); with μ and the superdelocalizability of the highest unoccupied molecular orbital (S HOMO ) to predict the K OW of 17 ureas (Reddy and Locke, 1996); with μ, E LUMO and the largest negative net atomic charge on an atom (q − ) for 28 alkyl (1-phenylsulfonyl) cycloalkanecarboxylates (Chen et al, 1996a); with E HOMO and E LUMO for 209 PCB (Zhou et al, 2005); and with the partial atomic charge on nitrogen (q 2 N) and the partial atomic charge on oxygen (q 2 O) to predict the K OW of 592 miscellaneous compounds (Xing and Glen, 2002). As indicated before, the bigger the α, the more hydrophobic the molecule is predicted to be: molecules which require a bigger cavity are predisposed to move into the octanol layer.…”

Section: Octanol-water Partition Coefficientmentioning

confidence: 99%

Prediction of the Fate of Organic Compounds in the Environment From Their Molecular Properties: A Review

Mamy¹,

Patureau²,

Barriuso³

et al. 2014

Critical Reviews in Environmental Science and Technology

124

View full text Add to dashboard Cite

A comprehensive review of quantitative structure-activity relationships (QSAR) allowing the prediction of the fate of organic compounds in the environment from their molecular properties was done. The considered processes were water dissolution, dissociation, volatilization, retention on soils and sediments (mainly adsorption and desorption), degradation (biotic and abiotic), and absorption by plants. A total of 790 equations involving 686 structural molecular descriptors are reported to estimate 90 environmental parameters related to these processes. A significant number of equations was found for dissociation process (pKa), water dissolution or hydrophobic behavior (especially through the KOW parameter), adsorption to soils and biodegradation. A lack of QSAR was observed to estimate desorption or potential of transfer to water. Among the 686 molecular descriptors, five were found to be dominant in the 790 collected equations and the most generic ones: four quantum-chemical descriptors, the energy of the highest occupied molecular orbital (EHOMO) and the energy of the lowest unoccupied molecular orbital (ELUMO), polarizability (α) and dipole moment (μ), and one constitutional descriptor, the molecular weight. Keeping in mind that the combination of descriptors belonging to different categories (constitutional, topological, quantum-chemical) led to improve QSAR performances, these descriptors should be considered for the development of new QSAR, for further predictions of environmental parameters. This review also allows finding of the relevant QSAR equations to predict the fate of a wide diversity of compounds in the environment.

show abstract

“…This difference in toxicity - as read from an integrative endpoint such as biomass yield - between substances designed to have an efficient herbicidal action should result from the interplay between intake suitability, the metabolic pathway affected and the meaning of the impairment for the overall physiological performance of the organism. Terbuthylazine has a higher Kow than nicosulfuron (3.4 vs. 0.61 at 20 °C and pH = 7 32 ), meaning that the former is much more lipid-soluble thus of easier internalization through cell membranes 41 . However, L. minor is a rooted macrophyte, and the translocation of substances absorbed through the roots should compensate for a lower direct intake of nicosulfuron via inner frond surface contact compared to terbuthylazine (see Cedergreen and Madsen 42 for a revision on chemical’s absorption in Lemna ).…”

Section: Resultsmentioning

confidence: 99%

Mixture toxicity assisting the design of eco-friendlier plant protection products: a case-study using a commercial herbicide combining nicosulfuron and terbuthylazine

Queirós¹,

Vidal²,

Nogueira³

et al. 2018

Sci Rep

View full text Add to dashboard Cite

The development of environmentally friendly plant protection products (PPPs), including pesticides, is a challenge nowadays. A commercial herbicide combining terbuthylazine and nicosulfuron as active substances (a.s.) was selected as a model PPP. The suitability of manipulating the ratio between a.s. towards alternative formulations with reduced impacts in a non-target indicator (Lemna minor) was assessed. The efficacy of such eco-friendlier a.s. ratios was then assessed using a target weed, Portulaca oleracea. Single and mixture toxicity testing with L. minor revealed an antagonistic joint action of the a.s., suggesting an environmentally protective effect of the combination compared to single dosing of a.s. The efficacy testing against the target weed of single and combined treatments of the a.s. showed that (i) the a.s. behave antagonistically throughout the whole P. oleracea response surface; (ii) there were no environmentally safe a.s. combinations ensuring target-efficacy; (iii) terbuthylazine alone was effective in controlling P. oleracea with no environmental hazardous potential, dosed at concentrations 10-fold lower than those involved in commercially recommended application doses. Overall, this case-study suggests that modelling tools widely used in the field of environmental risk assessment of PPPs may also have application in PPP design stages for a more efficient meeting of efficacy and environmental friendliness requirements.

show abstract

Molecular properties as descriptors of octanol-water partition coefficients of herbicides

Cited by 22 publications

References 24 publications

Physiological response of freshwater microalga (Chlorella vulgaris) to triazine and phenylurea herbicides

Physiological response of freshwater microalga (Chlorella vulgaris) to triazine and phenylurea herbicides

Prediction of the Fate of Organic Compounds in the Environment From Their Molecular Properties: A Review

Mixture toxicity assisting the design of eco-friendlier plant protection products: a case-study using a commercial herbicide combining nicosulfuron and terbuthylazine

Contact Info

Product

Resources

About