Tissue Distribution, Excretion, and Metabolic Profile of Dihydromyricetin, a Flavonoid from Vine Tea (Ampelopsis grossedentata) after Oral Administration in Rats

Uptake and Transport Mechanism of Dihydromyricetin Across Human Intestinal Caco-2 Cells

A variety of beneficial pharmacological activities have been reported for dihydromyricetin (DMY), however, its oral bioavailability is poor and the intestinal absorption profiles of DMY remains unknown. The aim of this study was to investigate the uptake and transport mechanism of DMY in human intestinal Caco-2 cells. DMY was detected using a liquid chromatography-tandem mass spectrometry method. Several factors including time, concentration, pH, temperature and efflux transporters were systematically evaluated. DMY was poorly absorbed by a passive diffusion mechanism. The uptake and transport of DMY were time and concentration dependent. Interestingly, decreasing the pH from 8.0 to 6.0 markedly enhanced the DMY uptake, but didn't significantly affect its bidirectional transport. Efflux transporters, multidrug resistance protein 2 and breast cancer resistance protein also influenced the DMY uptake and transport processes. This work details the uptake and transport characteristics of DMY and provides basis for future study.

PRACTICAL APPLICATION

This study elucidated the uptake and transport characteristics of dihydromyricetin (DMY). DMY was poorly absorbed by a passive diffusion mechanism. The uptake and transport of DMY were time and concentration dependent. Interestingly, pH affected DMY uptake but not its bidirectional transport. MRP2 and BCRP were involved in the uptake and transport of DMY, which hindered the absorption of DMY in the intestinal. Thus, the present study may provide useful information for designing DMY delivery systems and avoiding DMY-drug interactions.

Interactions of Dihydromyricetin, a Flavonoid from Vine Tea (Ampelopsis grossedentata) with Gut Microbiota

Dihydromyricetin (DMY) is the main bioactive constituent in vine tea (Ampelopsis grossedentata), which was predominantly distributed in the gastrointestinal tract and showed poor oral bioavailability. Our aim was to systematically investigate the interactions of DMY with gut microbiota. Through the metabolism study of DMY by fecal microflora in vitro, it was found that DMY could be metabolized into three metabolites by fecal microflora via reduction and dehydroxylation pathways, and the dehydroxylation metabolite was the dominant one. Meanwhile, in order to consider the influence of gut microbiota metabolism on the pharmacokinetics of DMY, the pharmacokinetics of DMY in control and pseudo-germ-free rats were compared. It was shown that area under the curve (AUC) could only slightly increase, however, peak concentration (C_max ) could significantly increase in the pseudo-germ-free rats compared with the control rats, which indicated the gut microbiota metabolism played an important role in the pharmacokinetics of DMY. In addition, the long-term influence of DMY on gut microbiota composition by using 16S rRNA pyrosequencing was further investigated. And it was found that DMY could markedly alter the richness and diversity of the gut microbiota and modulate the gut microbiota composition. The present findings will be helpful for the future development and clinical application of DMY.

PRACTICAL APPLICATION

The gut microbiota plays an important role in the pharmacokinetics of flavonoids. As well, the long-term supplements of flavonoids could alter the gut microbiota composition in turn. The study aims to clarify the mutual interaction of DMY with gut microbiota, which may lead to new information with respect to the mechanism study and clinical application of DMY.

Systems pharmacology approach reveals the antiinflammatory effects of Ampelopsis grossedentata on dextran sodium sulfate-induced colitis

AIM

To investigate the protective effects of Ampelopsis grossedentata (AMP) on dextran sulfate sodium (DSS)-induced colitis in mice based on systems pharmacology approach.

METHODS

Systems pharmacology approach was used to predict the active ingredients, candidate targets and the efficacy of AMP on ulcerative colitis (UC) using a holistic process of active compound screening, target fishing, network construction and analysis. A DSS-induced colitis model in C57BL/6 mice (n = 10/group) was constructed and treated with 5-aminosalicylic acid (100 mg/kg/d) and AMP (400 mg/kg/d) to confirm the underlying mechanisms and effects of AMP on UC with western blot analyses, polymerase chain reaction, histological staining and immunohistochemistry.

RESULTS

The therapeutic effects of AMP against DSS-induced colitis were determined in the beginning, and the results showed that AMP significantly improved the disease in general observations and histopathology analysis. Subsequent systems pharmacology predicted 89 corresponding targets for the four candidate compounds of AMP, as well as 123 candidate targets of UC, and protein-protein interaction networks were constructed for the interaction of putative targets of AMP against UC. Enrichment analyses on TNF-α and RANKL/RANK, a receptor activator of NF-κB signaling pathways, were then carried out. Experimental validation revealed that inflammation-related signaling pathways were activated in the DSS group, and AMP significantly suppressed DSS-induced high expression of IRAK1, TRAF6, IκB and NF-κB, and inhibited the elevated expression levels of TNF-α, IL-1β, IL-6 and IL-8.

CONCLUSION

AMP could exert protective effects on UC via suppressing the IRAK1/TRAF6/NF-κB-mediated inflammatory signaling pathways.