Elucidation of the Mechanisms and Effective Substances of Paeoniae Radix Rubra Against Toxic Heat and Blood Stasis Syndrome With a Stage-Oriented Strategy

In the clinical practice of traditional Chinese medicine, toxic heat and blood stasis syndrome (THBSS) is a common syndrome observed in various critical diseases. Paeoniae Radix Rubra (PRR) has known therapeutic effects on THBSS. However, its pharmacodynamic mechanisms and effective substances in the treatment of THBSS still need further elucidation. Our previous study indicated that THBSS had three stages of progression, and the abnormal biochemical indices of each stage were different. Therefore, this study aimed to elucidate the pharmacodynamic mechanisms and effective substances of PRR for the treatment of THBSS with a stage-oriented strategy. Specifically, research was performed separately in two stable stages of THBSS: the excessive heat and little blood stasis (EHLBS) and blood stasis (BS) stages. THBSS model rats, at different time periods after syndrome initiation (first 5 h for EHLBS and 24 h later for BS), were used to conduct the two-stage investigation. Targeted metabonomics analysis was performed to elucidate the pharmacodynamic mechanisms of PRR in the treatment of EHLBS or BS. Based on the relationship between the individual differences in blood drug concentrations and pharmacodynamic effects, partial least squares regression analysis was employed to screen for the effective substances from the original constituents and metabolites of PRR. We found that PRR could upregulate primary bile acid biosynthesis, glycerophospholipid metabolism, ether lipid metabolism, and five amino acid metabolic pathways (e.g., arginine and proline metabolism) to treat EHLBS. Meanwhile, PRR alleviated BS by upregulating primary bile acid biosynthesis and downregulating glycerophospholipid metabolism. But PRR had no obvious effects on ether lipid metabolism and amino acid metabolism in this stage. In total, 17 and 9 potential effective substances were found in the EHLBS and BS stages, respectively, among which there were only five common compounds between the two stages. To our knowledge, sixteen compounds were regarded as potential effective substances of PRR for the first time. Therefore, the pharmacodynamic mechanisms and effective substances of PRR in the treatment of EHLBS and BS were partly different. Overall, this stage-oriented strategy provides a new way to study the pharmacodynamic mechanisms and effective substances of traditional Chinese drugs.

Metabolomics-based molecular signatures reveal the toxic effect of co-exposure to nitrosamines in drinking water

Nitrosamines, a group of emerging nitrogenous pollutants, are ubiquitously found in the drinking water system. However, less is known about how systemic biological responses resist or tolerate nitrosamines, especially long-term co-exposure at low concentrations. In this study, untargeted metabolomics was used to investigate the metabolic perturbations in human esophageal epithelial Het-1A cells induced by a mixture of nine common nitrosamines in drinking water at environmentally relevant, human-internal-exposure, and genotoxic concentrations. Generally, the disrupted metabolic spectrum became complicated with nitrosamines dose increasing. Notably, two inflammation-associated pathways, namely, cysteine (Cys) and methionine (MET) metabolism, and nicotinate and nicotinamide metabolism, changed significantly under the action of nitrosamines, even at the environmentally relevant level. Furthermore, targeted metabolomics and molecular biology indicators in cells were identified in mice synchronously. For one thing, the up-regulated Cys and MET metabolism provided methyl donors for histone methylation in the context of pro-inflammatory response. For another, the down-regulated NAD⁺/NADH ratio inhibited the deacetylation of NF-кB p65 and eventually activated the NF-кB signaling pathway. Taken collectively, the metabolomics molecular signatures were important indicative markers for nitrosamines-induced inflammation. The potential crosstalk between the inflammatory cascade and metabolic regulation also requires further studies. These findings suggest that more attention should be paid to long-term co-exposure at low concentrations in the control of nitrosamines pollution in drinking water. Additionally, this study also highlights a good prospect of the combined metabolomic-molecular biology approach in environmental toxicology.