Diversity of urinary excretion patterns of main ellagitannins' colonic metabolites after ingestion of tropical highland blackberry (Rubus adenotrichus) juice

- Blackberry may cause urinary excretion of urolithin A or B up to 4 days after ingestion.
- Quantitative inter-individual variability of urolithin excretion is high.
- Two excretion patterns could be evidenced, “predominant UA and UB excreters”.
- Urolithin excretion pattern appears to be stable for a same individual.
- The solubility of specific protein fractions is influenced by wine pH.

Tropical highland blackberries are a rich source of ellagitannins (ETs), which are metabolized by gut microbiota to yield urolithin, a potentially bioactive compound excreted in urine up to 7 days after ingestion. Following the ingestion of 250 mL of tropical highland blackberry juice, a spot of urine from 26 volunteers collected at 51 ± 4 h was analyzed for urolithin A and B main derivatives (aglycones and glucuronated forms). Three main groups, “no or low urolithin excreters,” “predominantly UA derivatives excreters” and “predominantly UB derivatives excreters,” were observed. These categories were also unambiguously observed from 9 individuals following the total excretion of ETs' main metabolites over a 4-day period after ingesting one shot of blackberry juice. Although relatively high inter- and intra-individual variabilities were observed, individuals preserved their status during different intervention periods with different amounts of ETs ingested. Accurate UPLC-DAD/ESI-Q-TOF/MS2 allowed the tentative assignment of an identity to 15 other ET metabolites in urine, but profiling did not allow the discrimination of any other compounds aside from UA or UB derivatives. The results highlight the importance of the interaction of gut microbiota composition and the host endogenous excretery system, which may play a major role in the observed inter-individual variability.