Indigestible fraction of guava fruit: Phenolic profile, colonic fermentation and effect on HT-29 cells

Abstract

Guava fruit is rich in phenolic compounds (PCs), whose metabolic fate has not been explored. Non-digestible carbohydrates and PCs in whole guava (WG) and seedless guava (SG) were submitted to an in vitro colonic fermentation, followed by evaluation of the anti-proliferative activity of the fermentation extracts in HT-29 cancer cell lines. The main PCs in both samples were (+)-gallocatechin and gallic acid, while procyanidin B was the most abundant one associated with soluble indigestible fraction and quercetin predominated in the insoluble indigestible fraction. The fermentability index at 24 h was 78.84% in WG and 84.74% for SG, near to the value for raffinose used as reference, with butyric acid as the main short chain fatty acids (SCFA) produced. The greatest antiproliferative effects were observed in the SG at 12 h of fermentation and WG at 24 h of fermentation. These results allow to suggest consumption of guava fruit, either with or without seeds, as a feasible way to maintain colonic health.