Novel quantitative structure activity relationship models for predicting hexadecane/air partition coefficients of organic compounds

Predicting the logarithm of hexadecane/air partition coefficient (L) for organic compounds is crucial for understanding the environmental behavior and fate of organic compounds and developing prediction models with polyparameter linear free energy relationships. Herein, two quantitative structure activity relationship (QSAR) models were developed with 1272 L values for the organic compounds by using multiple linear regression (MLR) and support vector machine (SVM) algorithms. On the basis of the OECD principles, the goodness of fit, robustness and predictive ability for the developed models were evaluated. The SVM model was first developed, and the predictive capability for the SVM model is slightly better than that for the MLR model. The applicability domain (AD) of these two models has been extended to include more kinds of emerging pollutants, i.e., oraganosilicon compounds. The developed QSAR models can be used for predicting L values of various organic compounds. The van der Waals interactions between the organic compound and the hexadecane have a significant effect on the L value of the compound. These in silico models developed in current study can provide an alternative to experimental method for high-throughput obtaining L values of organic compounds.

Whitening effect of L-ascorbate-2-phosphate trisodium salt on solar lentigos

Little is known about the anti-pigmenting effects of whitening agents on solar lentigos (SLs), which comprise ~ 60% of hyperpigmented facial lesions of Asian subjects. Lotions with or without 6% L-ascorbate-2-phosphate trisodium salt (APS) [test lotion (TL) and placebo lotion (PL), respectively] were applied twice daily for 24 weeks in a double-blind half-face study of 27 Japanese females with SLs on both sides of their faces. Pigmentation scores were evaluated using a photo-scale and the skin colors were assessed using a color difference meter and a mexameter for SLs and the non-lesional surrounding skin (NLS). Although the pigmentation scores were not significantly different between the TL and PL-treated SLs after 24 weeks, the L values of TL-treated SLs and NLS increased significantly with a significantly higher △L value in SLs than in NLS. In contrast, the L values of PL-treated SLs and NLS remained unchanged after the treatment. The number of subjects with > 2.0 △L was 7 of 27 (TL) and 0 of 27 (PL) in SLs and 3 of 27 (TL) and 0 of 27 (PS) in NLS. In contrast, the melanin index in TL-treated SLs and NLS significantly decreased with a significantly higher △melanin index in SLs than in NLS. Similarly, the melanin index of PL-treated SLs and NLS were significantly decreased with a significantly higher △melanin index in SLs than in NLS. These findings strongly indicate that APS has a weak but significant anti-pigmenting effect on SLs and a significant whitening effect even on normally pigmented healthy skin.