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Adaptive Neuro-Fuzzy Inference System Applied QSAR with Quantum Chemical Descriptors for Predicting Radical Scavenging Activities of Carotenoids.

Jhin C, Hwang KT - PLoS ONE (2015)

Bottom Line: Ionisation energies of neutral and monovalent cationic carotenoids and the product of chemical potentials of neutral and monovalent cationic carotenoids were significantly correlated with the radical scavenging activities, and consequently these descriptors were used as independent variables for the QSAR study.The R-square values of the developed QSAR models with the variables calculated by PM6 and PM7 methods were 0.921 and 0.902, respectively.The results of this study demonstrated reliabilities of the selected quantum chemical descriptors and the significance of QSAR models.

View Article: PubMed Central - PubMed

Affiliation: Department of Food and Nutrition, Research Institute of Human Ecology, Seoul National University, Seoul, Korea.

ABSTRACT
One of the physiological characteristics of carotenoids is their radical scavenging activity. In this study, the relationship between radical scavenging activities and quantum chemical descriptors of carotenoids was determined. Adaptive neuro-fuzzy inference system (ANFIS) applied quantitative structure-activity relationship models (QSAR) were also developed for predicting and comparing radical scavenging activities of carotenoids. Semi-empirical PM6 and PM7 quantum chemical calculations were done by MOPAC. Ionisation energies of neutral and monovalent cationic carotenoids and the product of chemical potentials of neutral and monovalent cationic carotenoids were significantly correlated with the radical scavenging activities, and consequently these descriptors were used as independent variables for the QSAR study. The ANFIS applied QSAR models were developed with two triangular-shaped input membership functions made for each of the independent variables and optimised by a backpropagation method. High prediction efficiencies were achieved by the ANFIS applied QSAR. The R-square values of the developed QSAR models with the variables calculated by PM6 and PM7 methods were 0.921 and 0.902, respectively. The results of this study demonstrated reliabilities of the selected quantum chemical descriptors and the significance of QSAR models.

No MeSH data available.


Scatter plot between the experimental EC50 of carotenoids reported by Jiménez-Escrig et al. [20] and the predicted TEAC based on the quantum chemical descriptors calculated by PM6 (A) and PM7 (B) methods.
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pone.0140154.g005: Scatter plot between the experimental EC50 of carotenoids reported by Jiménez-Escrig et al. [20] and the predicted TEAC based on the quantum chemical descriptors calculated by PM6 (A) and PM7 (B) methods.

Mentions: To verify the reliabilities of the selected quantum chemical properties (i.e., I, Icat, and μcross) and the design of developed QSAR models, QSAR models were developed with radical scavenging activity data sets from other previous studies. The TEAC values of 8 carotenoid species were adapted from Miller et al. [5] and the EC50 data of 6 carotenoid species were adapted from Jiménez-Escrig et al. [28]. The results from correlation analysis of these data sets are presented in Table 4. The I, Icat, and μcross of carotenoids calculated by both of the PM6 and PM7 were significantly correlated with the TEAC values from Miller et al. at p-value below 0.001. Although statistical significances were low on the correlation between experimental EC50 and quantum chemical properties of carotenoids due to a small sample size of the data set by Jiménez-Escrig et al. (n = 6), positive correlations were observed between EC50 and selected quantum chemical properties of carotenoids. A previous QSAR study regarding on radical scavenging activities of carotenoids by Soffers et al. [15] reported a positive relationship between the ionisation energies and the TEAC values using single data set constituted of 9 carotenoids. In addition to the previous study, this positive tendency was also verified using several number of data sets in this study. Kleinová et al. [16] also constructed a QSAR model for electrochemical redox potentials of carotenoids using polarizability as an independent variable. Since the polarizability was closely correlated with ionisation energy [43], the use of polarizability as an independent variable seemed adequate. However, based on electrochemical properties of carotenoids, the results from the previous study could not be directly interpreted to radical scavenging activities of carotenoids. In the present study, the reliabilities of selected quantum chemical properties for predicting radical scavenging activities and the prediction efficiency of ANFIS applied QSAR models were confirmed by applying various data sets (Figs 4 and 5).


Adaptive Neuro-Fuzzy Inference System Applied QSAR with Quantum Chemical Descriptors for Predicting Radical Scavenging Activities of Carotenoids.

Jhin C, Hwang KT - PLoS ONE (2015)

Scatter plot between the experimental EC50 of carotenoids reported by Jiménez-Escrig et al. [20] and the predicted TEAC based on the quantum chemical descriptors calculated by PM6 (A) and PM7 (B) methods.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4608816&req=5

pone.0140154.g005: Scatter plot between the experimental EC50 of carotenoids reported by Jiménez-Escrig et al. [20] and the predicted TEAC based on the quantum chemical descriptors calculated by PM6 (A) and PM7 (B) methods.
Mentions: To verify the reliabilities of the selected quantum chemical properties (i.e., I, Icat, and μcross) and the design of developed QSAR models, QSAR models were developed with radical scavenging activity data sets from other previous studies. The TEAC values of 8 carotenoid species were adapted from Miller et al. [5] and the EC50 data of 6 carotenoid species were adapted from Jiménez-Escrig et al. [28]. The results from correlation analysis of these data sets are presented in Table 4. The I, Icat, and μcross of carotenoids calculated by both of the PM6 and PM7 were significantly correlated with the TEAC values from Miller et al. at p-value below 0.001. Although statistical significances were low on the correlation between experimental EC50 and quantum chemical properties of carotenoids due to a small sample size of the data set by Jiménez-Escrig et al. (n = 6), positive correlations were observed between EC50 and selected quantum chemical properties of carotenoids. A previous QSAR study regarding on radical scavenging activities of carotenoids by Soffers et al. [15] reported a positive relationship between the ionisation energies and the TEAC values using single data set constituted of 9 carotenoids. In addition to the previous study, this positive tendency was also verified using several number of data sets in this study. Kleinová et al. [16] also constructed a QSAR model for electrochemical redox potentials of carotenoids using polarizability as an independent variable. Since the polarizability was closely correlated with ionisation energy [43], the use of polarizability as an independent variable seemed adequate. However, based on electrochemical properties of carotenoids, the results from the previous study could not be directly interpreted to radical scavenging activities of carotenoids. In the present study, the reliabilities of selected quantum chemical properties for predicting radical scavenging activities and the prediction efficiency of ANFIS applied QSAR models were confirmed by applying various data sets (Figs 4 and 5).

Bottom Line: Ionisation energies of neutral and monovalent cationic carotenoids and the product of chemical potentials of neutral and monovalent cationic carotenoids were significantly correlated with the radical scavenging activities, and consequently these descriptors were used as independent variables for the QSAR study.The R-square values of the developed QSAR models with the variables calculated by PM6 and PM7 methods were 0.921 and 0.902, respectively.The results of this study demonstrated reliabilities of the selected quantum chemical descriptors and the significance of QSAR models.

View Article: PubMed Central - PubMed

Affiliation: Department of Food and Nutrition, Research Institute of Human Ecology, Seoul National University, Seoul, Korea.

ABSTRACT
One of the physiological characteristics of carotenoids is their radical scavenging activity. In this study, the relationship between radical scavenging activities and quantum chemical descriptors of carotenoids was determined. Adaptive neuro-fuzzy inference system (ANFIS) applied quantitative structure-activity relationship models (QSAR) were also developed for predicting and comparing radical scavenging activities of carotenoids. Semi-empirical PM6 and PM7 quantum chemical calculations were done by MOPAC. Ionisation energies of neutral and monovalent cationic carotenoids and the product of chemical potentials of neutral and monovalent cationic carotenoids were significantly correlated with the radical scavenging activities, and consequently these descriptors were used as independent variables for the QSAR study. The ANFIS applied QSAR models were developed with two triangular-shaped input membership functions made for each of the independent variables and optimised by a backpropagation method. High prediction efficiencies were achieved by the ANFIS applied QSAR. The R-square values of the developed QSAR models with the variables calculated by PM6 and PM7 methods were 0.921 and 0.902, respectively. The results of this study demonstrated reliabilities of the selected quantum chemical descriptors and the significance of QSAR models.

No MeSH data available.