Evaluation of the antitrypanosoma activity and SAR study of novel LINS03 derivatives

Chagas' disease is a parasitic infection caused by Trypanosoma cruzi that is still treated by old and toxic drugs. In the search for novel alternatives, natural sources are an important source for new drug prototypes against T. cruzi to further structural exploitation. A set of natural-based compounds (LINS03) was designed, showing promising antitrypanosoma activity and low cytotoxicity to host cells. In this paper, nine novel LINS03 derivatives were evaluated against T. cruzi trypomastigotes and amastigotes. The selectivity was assessed through cytotoxicity assays using NCTC mammalian cells and calculating the CC₅₀/IC₅₀ ratio. The results showed that compounds 2d and 4c are noteworthy, due their high activity against amastigotes (IC₅₀ 13.9 and 5.8 µM) and low cytotoxicity (CC₅₀ 107.7 µM and >200 µM, respectively). These compounds did not showed alteration on plasma membrane permeability in a Sytox green model. SAR analysis suggested an ideal balance between hydrosolubility and lipophilicity is necessary to improve the activity, and that insertion of a meta-substituent is detrimental to the activity of the amine derivatives but not to the neutral derivatives, suggesting different mechanisms of actions. The results presented herein are valuable for designing novel compounds with improved activity and selectivity to be applied in future studies.

Effects of hydrophilic monomers on sorptive properties of divinylbenzene-based reversed phase sorbents

Solid phase extraction (SPE) has been extensively used as a pretreatment method. In SPE methods, commercially available reversed phase type sorbents, which consist of macroporus styrene-divinylbenzene or copolymers including divinylbenzene (DVB) and hydrophilic monomers, have been applied to a variety of samples. The later sorbents are called hydrophilic lipophilic balanced (HLB) type sorbents. Hydrophilic monomers in hydrophilic lipophilic balanced type sorbents contribute to the increase in retention of polar compounds, because hydrophilic monomers improve the wettability and increase the interaction with polar compounds as analytes. In this study, three different methacrylate monomers (ethylene glycol dimethacrylate (EGDMA), glycerol dimethacrylate (GDMA) and trimethylolpropane trimethacrylate (TMPTMA)), which are expected to improve the retention of polar compounds, were chosen, and DVB-based copolymetric sorbents including the three monomers were newly synthesized. Among them, the sorbents including GDMA or TMPTMA gave higher recoveries to polar compounds such as uridine and adenine than that including EGDMA. The optimization studies of hydrophilic lipophilic balance, inert diluent and the purity of DVB improved the sorptive abilities of the sorbents. The developed sorbents have higher recoveries for variety of polar compounds (cytosine, uracil, cytidine, uridine, 2'-deoxycytidine, 2'-deoxyguanosine, adenine, thymidine, adenosine and 2'-deoxyadenosine) than commercially available hydrophilic lipophilic balanced type sorbents, while the recoveries for theophylline were comparable between the proposed sorbents and the commercial sorbents.