No abstract

No abstract

Lipophilicity has, for a long time, been recognized as a meaningful parameter in structure-activity relationships. It is also the single most informative physicochemical property that reveals a wealth of information on intermolecular forces, intramolecular interactions, and molecular structure in the broadest sense. In this paper, a total of 14 chromatographic measures of lipophilicity (thin-layer chromatography and high-performance liquid chromatography) and 11 computationally estimated logP-s for 21 newly synthesized 3-(4substituted benzyl)-cycloalkylspiro-5-hidantoin derivatives have been investigated. Similarities among the investigated compounds as well as lipophilicity measures were examined by the multivariate exploratory analysis, principal component analysis, hierarchical cluster analysis, and sum of ranking differences. These chemometric approaches reveal the arrangement of investigated compounds into clusters according to lipophilicity. Chemometric consideration of lipophilicity renders principal component scores as entirely unsuitable lipophilicity measures. Furthermore, the logP values estimated from calibration graph by using a set of standard reference compounds were equivalent to the corresponding chromatographic descriptors of hydantoins extrapolated from linear relationship between retention parameters and mobile phase composition. Comparison of the 2 chromatographic techniques places high-performance liquid chromatography lipophilicity indices slightly ahead of thin-layer chromatography.

The application of chemometric approaches in the comparison of the activity and the chemical composition of essential oils of 10 aromatic Lamiaceae species (Melissa officinalis, Mentha piperita, Mentha aquatica, Mentha longifolia, Ocimum basilicum, Origanum vulgare, Rosmarinus officinalis, Salvia officinalis, Salvia nemorosa, and Thymus vulgaris) is reported in this paper. The standard methodology of principal component analysis needs too many principal components (PCs) to effectively describe the relationships between studied samples. PC1 explains only 47.58% of the total variance reflecting the most significant differences between essential oils of S. nemorosa and Or. vulgare. PC2 explains 19.77% of the total variance and shows the most significant differences between the essential oils of M. aquatica compared with those of S. nemorosa, S. officinalis and Or. vulgare. Efficient compression of the data was possible by hierarchical clustering analysis (HCA) complemented with a color map. HCA shows that essential oils of both investigated representatives of genus Salvia are characterized by a high content of oxygenated sesquiterpenes and remarkable antifungal activities, but low antibacterial and antioxidant activity, particularly for the S. officinalis. Unlike sage, the essential oils of oregano and thyme have high content of aromatic oxygenated monoterpenes and low antifungal but pronounced antibacterial activity. Peppermint, basil, rosemary, and lemon balm are characterized by high content of oxygenated monoterpenes and aliphatic components as well as by high antioxidant 2,2-diphenyl-1-picrylhydrazil activity of essential oils.

No abstract