The Digestibility of Hibiscus sabdariffa L. Polyphenols Using an In Vitro Human Digestion Model and Evaluation of Their Antimicrobial Activity

Abstract

Hibiscus sabdariffa L. (H.s.) is a polyphenolic-rich plant commonly consumed either as a beverage or spice. The aim of the present study was to evaluate the in vitro digestibility of H.s. polyphenols using an in vitro model of digestion which simulates the human stomach and small intestine. The bioaccessible polyphenols released in the digested samples were analyzed by liquid chromatography coupled to photodiode array and mass spectrometry detection. H.s. anthocyanins (cyanidin-3-O-sambubioside and delphinidin-3-O-sambubioside) content drastically dropped during the digestion process from 2.91 ± 0.03 µg g−1 and 8.53 ± 0.08 µg g−1 (w/w) CG (Cyanidin-glucoside) in the raw extract, respectively, to 0.12 ± 0.01 µg g−1 0.12 ± 0.01 µg g−1 (w/w) CG at the end of duodenal digestion. Total polyphenols also have shown a decrease from 1192.65 ± 30.37 µg g−1 (w/w) in the raw extract to 282.24 ± 7.21 µg g−1 (w/w) by the end of gastric digestion, in contrast to their increase by the end of duodenal digestion 372.91 ± 3.97 µg g−1 (w/w). On the other hand, the decrease in certain compounds (e.g., caffeoylquinicandcoumaroylquinic acids) was observed during gastric digestion resulting in an increase of quinic acid in the duodenal aliquots, thus suggesting that this compound was derived from the degradation of the more complex hydroxycinnamic acids. H.s. extract also exhibited a bacteriostatic effect against Staphylococcus aureus ATCC 6538 (MIC of 2.5 mg mL−1) and a bactericidal effect against a food isolate of Listeria monocytogenes (MBC of 2.5 mg mL−1). The undigested polyphenols of H.s. in the upper gastrointestinal tract enters the colon, where they are metabolized by the gut microbiota. The present study results showed that resistance of H.s. polyphenols during gastrointestinal digestion might affect their uptake, resulting in a decrease in their digestibility.

Microencapsulation and Bioaccessibility of Phenolic Compounds of Vaccinium Leaf Extracts

“…Quinic acid production in the intestine can be attributed to the fact that this compound results from the breakdown of hydroxycinnamic acids, such as caffeoylquinic, feruloyl quinic, chlorogenic acids or other similar more complex compounds. A comparable result has also been reported by El Majdoub et al, 2021, where Hibiscus sabdariffa L. (H.s.)…”

“…This study also revealed that the absorption of polyphenols is affected during gastrointestinal digestion, which diminishes their digestibility. In addition, in the course of the reduction of some compounds (e.g., caffeoylquinicandcoumaroylquinic acids), quinic acid was produced in the duodenal aliquots [71].…”

In Vitro Evidence on Bioaccessibility of Flavonols and Cinnamoyl Derivatives of Cruciferous Sprouts

“…This is of special relevance because the biological activity of glycosylated flavonols and cinnamic derivatives, present in cruciferous sprouts, is closely dependent on their bioaccessibility [9]. The decrease in the total content of phenolic compounds after the gastric, intestinal and duodenal phases of action of the digestive process of the plant material, has previously been reported [10,11]. However, the different effect of gastrointestinal digestion on the release and stability of phenolic compounds depends on different factors, such as the physicochemical traits of the food matrix, pH, temperature, or enzymatic activity [12,13].…”

The Effect of In Vitro Digestion on Polyphenolic Compounds and Antioxidant Properties of Sorghum (Sorghum bicolor (L.) Moench) and Sorghum-Enriched Pasta

“…Different findings were obtained by Majdoub et al [ 40 ]. They noted a decrease in certain compounds after in vitro gastric and duodenal digestion.…”