Simulated gastrointestinal digestion/Caco-2 cell transport: Effects on biological activities and toxicity of a Brazilian propolis

The objective was to assess the effect of gastrointestinal digestion/Caco-2 cell transport on biological activities and toxicity of the ethanolic extract of organic propolis from southern Brazil (EEOP1). As principal results, the EEOP1 deactivated the ROO center dot, HOCl and O2 center dot- reactive oxygen species, attenuated NF-xB transcription factor activation, and decreased the release of TNF-alpha and IL-6 in macrophages after Caco-2 cell transport, while CXCL2/ MIP-2 release was reduced after gastrointestinal digestion. Furthermore, the phytochemical profile monitored by HPLC-ESI-QTOF-MS changed, especially for lignans, lignan-precursors and phenolic acids. Conversely, the antimicrobial activity was observed only in the non-digested EEOP1. The EEOP1 lethal dose to kill 50 % of the Galleria mellonella larvae was 1.1 g/kg, and its digested fraction had no toxic effect. Hence, there is indication that some phytochemicals present in the EEOP1 are resistant to the gastrointestinal tract and maintain their biological activities, as expected for a functional food ingredient.

Automated summary

This study aimed to investigate the impact of gastrointestinal digestion/Caco-2 cell transport on the biological activities and toxicity of ethanolic extract of organic propolis from southern Brazil (EEOP1). The results demonstrated that EEOP1 deactivated reactive oxygen species and attenuated the activation of transcription factors, while also reducing the release of pro-inflammatory cytokines. Additionally, the phytochemical profile of EEOP1 changed after digestion, and antimicrobial activity was only observed in the non-digested form.