NIZO: progress update on the health benefit substantiation of olive leaf extracts

At NIZO we have been working on the optimization of our in vitro technologies for the assessment of potential health benefits of plant extracts. In parallel, a small number of olive leaf extracts and pure polyphenols have already been tested.

We applied our Gut Health Discovery Platform (GHDP), starting with fecal batch fermentations in our MicroColon technology (Figure 1). Effects of extracts on gut microbiota composition and metabolism has been studied, as well as the potential of extracts to inhibit growth of the intestinal pathogen Clostridiodes difficile.

So far, results show that microbial metabolism can be modulated as shown by pH and short-chain fatty acid (SCFA) analysis. Further, microbiota composition can be modulated as assessed by qPCR and microbiome analysis, and extracts/pure polyphenols are being metabolized as determined with our targeted UHPLC-MS/MS method (Figure 2). Notably, growth of the intestinal pathogen C. difficile was shown to be inhibited by the OPA 20% extract, while beneficial bifidobacteria were not affected.

The connection to the host (Figure 1) was made by applying MicroColon spent culture medium (supernatant after microbial fermentation, containing all metabolites) to our in vitro cell culture model (Figure 3). So far, preliminary results showed protective effects of some extracts and pure polyphenols, and of MicroColon spent supernatant, on the recovery of intestinal barrier function.