Metabolic study of bioactive compounds that undergo a dynamic and sequential process of metabolism is still a great challenge. Salidroside, one of the most active ingredients of Rhodiola crenulata, can be metabolized in different sites before being absorbed into the systemic blood stream. This study proposed an approach for describing the sequential biotransformation process of salidroside based on comparative analysis. In vitro incubation, in situ closed-loop and in vivo blood sampling were used to determine the relative contribution of each site to the total metabolism of salidroside. The results showed that salidroside was stable in digestive juice, and it was metabolized primarily by the liver and the intestinal flora and to a lesser extent by the gut wall. The sequential metabolism method described in this study could be a general approach to characterizing the metabolic routes in the digestive system for natural products.

Chimeric antigen receptor T (CAR-T) cell targeting CD19 antigen has achieved exhilarative clinical efficacy in B-cell malignancies. However, challenges still remain for the currently approved anti-CD19 CAR-T therapies, including high recurrence rates, side effects and resistance. Herein, we aim to explore combinatorial therapy by use of anti-CD19 CAR-T immunotherapy and gallic acid (GA, an immunomodulatory natural product) for improving treatment efficacy. We assessed the combinatorial effect of anti-CD19 CAR-T immunotherapy with GA in cell models and a tumor-bearing mice model. Then, the underlying mechanism of GA on CAR-T cells were investigated by integrating network pharmacology, RNA-seq analysis and experimental validation. Furthermore, the potential direct targets of GA on CAR-T cells were explored by integrating molecular docking analysis with surface plasmon resonance (SPR) assay. The results showed that GA significantly enhanced the anti-tumor effects, cytokine production as well as the expansion of anti-CD19 CAR-T cells, which may be mainly through the activation of IL4/JAK3-STAT3 signaling pathway. Furthermore, GA may directly target and activate STAT3, which may, at least in part, contribute to STAT3 activation. Overall, the findings reported here suggested that the combination of anti-CD19 CAR-T immunotherapy with GA would be a promising approach to increase the anti-lymphoma efficacy.

Areca catechu L. nut, a well-known toxic traditional herbal medicine, has been widely used to treat various diseases in China and many other Asian countries for centuries. However, to date the in vivo absorption and metabolism of its multiple bioactive or toxic components still remain unclear. In this study, liquid chromatography coupled with tandem mass spectrometry was used to analyze the major components and their metabolites in rat plasma and urine after oral administration of Areca catechu L. nut extract (ACNE). A total of 12 compounds, including 6 alkaloids, 3 tannins and 3 amino acids, were confirmed or tentatively identified from ACNE. In vivo, 40 constituents, including 8 prototypes and 32 metabolites were identified in rat plasma and urine samples. In summary, this study showed an insight into the metabolism of ACNE in vivo, which may provide helpful chemical information for better understanding of the toxicological and pharmacological profiles of ACNE.