Quantitative structure-chromatographic retention relationship of synthesized peptides (HGRFG, NPNPT) and their derivatives.

Carapax Trionycis extract peptides (HGRFG, NPNPT) are able to protect against CCl4-induced liver fibrosis. Therefore, this study applies to deal with chromatographic lipophilicity determination of synthesized peptides (HGRFG, NPNPT) and their derivatives using reversed-phase high performance liquid chromatography (RP-HPLC) combined with methanol-water mobile phase and two reversed-phase chromatographic columns (COSMOISL 5C18-MS-II and SHIMADZU-C18). The chromatographic lipophilicity of the analyzed compounds was expressed as logkw constant and correlated with lipophilicity descriptors. Quantitative structure-retention relationships (QSRR) analysis was performed to imitate chromatographic lipophilicity behavior using molecular descriptors. Modeling was performed using linear regression (LR) and multiple linear regression (MLR) methods with the help of principal component analysis (PCA) and hierarchical cluster analysis (HCA). The most influential molecular descriptors were lipophilicity descriptors, which are important for molecules ability to pass through biological membranes. All established QSRR models were statistically validated by standards, cross- and external validation parameters. According to these statistical validation parameters, MLR models (R2 > 0.856) were better for chromatographic lipophilicity prediction of peptide compounds. It can be concluded that chromatographic systems with COSMOISL 5C18-MS-II column were better for modeling of logkw than systems with SHIMADZU-C18 column. Modeling was performed in order to obtain lipophilicity profiles of investigated compounds as future drug candidates.

A Highly Selective and Sensitive Colorimetric Probe for Cu2+ Determination in Aqueous Media Based on Derivative of Tryptanthrin.

A new colorimetric probe, based on tryptanthrin derivative (TR-A), has been successfully synthesized. The probe shows good selectivity and sensitivity for Cu2+ over 12 competing metal ions in a 10 mM Tris-HCl buffer solution (pH 5.5). A significant peak at 623nm appears in the UV-Vis absorption of TR-A-Cu2+, and a noteworthy color change is observed with the naked eye from aquamarine blue to light orange. The interaction of TR-A and Cu2+ are proven to form a 1:1 binding stoichiometry; this identifying is expected to be completed within 1 min. The probe with a limit of detection (16 nM, R2 = 0.9934) shows excellent potential to determine Cu2+ in analysis systems.