Abstract: In this study, we determined the contents of the heavy metals Cd, Pb and Cr in dried wild bolete (white-, black-, red- and yellow-colored bolete) from the major production areas of Yunnan (Chuxiong, Qujing, Dali and Pu’er) and analyzed the bioaccessible/bioavailable concentrations of the heavy metals by in vitro simulated gastrointestinal digestion as well as using a Caco-2 cell model. Meanwhile, the health risk associated with the consumption of bolete with high contents of heavy metals was assessed by determining the effect of the centrifugal supernatants of bolete subjected to sequential simulated gastric/intestinal fluids digestion on the expression of the interleukin-8 (IL-8) gene in Caco-2 cells. The results showed that the average content of Cd in dried bolete was about 20 times the national food safety standard limit for food pollutants (GB 2762-2017). The bioaccessibility of Cr, Cd and Pb in the gastric phase was 18.2%, 3.1% and 17.0%, respectively, and decreased to 15.3%, 0.6% and 5.5% in the intestinal phase, respectively, while only Cd was absorbed by Caco-2 cells and detected at 1.10 μg/mg protein. The estimated daily intake (EDI) calculated based on the total heavy metal content showed a great human health risk, while the data calculated based separately on bioaccessible/bioavailable concentrations showed little health risks. Besides, we also found that the digestion products of wild bolete with high heavy metal contents did not up-regulate IL-8 mRNA expression in Caco-2 cells. In conclusion, the health risk of heavy metals in bolete may be overestimated by the risk assessment model based on the total content of heavy metals, but accurately estimated according to the bioavailability.

Key words: dried bolete; heavy metals; in vitro simulated gastrointestinal digestion; Caco-2 cell; health risk