Anti-colon cancer activity tracking isolation of peptide from ginseng leaves and potential mechanisms evaluation in vitro and in vivo

Improved performance of proteomic characterization for Panax ginseng by strong cation exchange extraction and liquid chromatography-mass spectrometry analysis

Panax ginseng is a precious and ancient medicinal plant. The completion of its genome sequencing has laid the foundation for the study of proteome and peptidome. However, the high abundance of secondary metabolites in ginseng reduces the identification efficiency of proteins and peptides in mass spectrometry. In this report, strong cation exchange pretreatment was carried out to eliminate the interference of impurities. Based on the charge separation of proteolytic peptides and metabolites, the sensitivity of mass spectrometry detection was greatly improved. After pretreatment, 2322 and 2685 proteins were identified from the root and stem leaf extract. Further, the ginseng peptidome was analyzed based on this optimized strategy, where 970 and 653 endogenous peptides were identified from root and stem leaf extract, respectively. Functional analysis of proteins and endogenous peptides provided valuable information on the biological activities, metabolic processes, and ginsenoside biosynthesis pathways of ginseng.

A bioimaging system combining human cultured reporter cells and planar chromatography to identify novel bioactive molecules

For the first time, a human cancer cell line was shown to grow and be functionally active on the particulate porous adsorbent surface of separated sample mixtures. This allowed the novel combination of chromatographic separations with human cells as biological detector. As exemplary screening for cancer treatment drugs, cytotoxic substances were directly discovered in Saussurea costus and ginseng samples using the Cytotox CALUX® osteosarcoma cells (with luciferase expressing reporter gene) as detector. In addition, rosiglitazone and pioglitazone were detected as luminescent zones upon binding to the PPARγ receptor expressed in the respective CALUX cell line that was grown on the surface of the adsorbent. This demonstrates the ability to address receptor-mediated signaling with this method, and opens the perspective to use our novel bioimaging method to identify bioactive molecules targeting a wide range of pathways with toxicological, pharmaceutical and nutraceutical relevance. The new bioimaging directly pointed to individual effective compounds in multi-component mixtures. Furthermore, discovered effective compounds were directly characterized by online elution to high-resolution mass spectrometry and fragmentation.

DIC/Oxyma-based accelerated synthesis and oxidative folding studies of centipede toxin RhTx

Coupling reagents play crucial roles in the iterative construction of amide bonds for the synthesis of peptides and peptide-based derivatives. The novel DIC/Oxyma condensation system featured with the low risk of explosion displayed remarkable abilities to inhibit racemization, along with efficient coupling efficiency in both manual and automated syntheses. Nevertheless, an ideal reaction molar ratio in DIC/Oxyma condensation system and the moderate reaction temperature by manual synthesis remain to be further investigated. Herein, the synthetic efficiencies of different reaction ratios between DIC and Oxyma under moderate reaction temperature were systematically evaluated. The robustness and efficiency of DIC/Oxyma condensation system are validated by the rapid synthesis of linear centipede toxin RhTx. Different folding strategies were applied for the construction of disulfide bridges in RhTx, which was further confirmed in assays of circular dichroism and patch-clamp electrophysiology evaluation. This work establishes the DIC/Oxyma-based accelerated synthesis of peptides under moderate condensation conditions, which is especially useful for the manual synthesis of peptides. Besides, the strategy presented here provides robust technical supports for the large-scale synthesis and oxidative folding of RhTx.