Table 2.

Beneficial effects of polyphenols on dextran sulfate sodium (DSS)-induced colitis in relation to the gut microbiota in murine models.

Reference, Publication Year, Animal Species, Polyphenol(s), and Dosage	Major Physiological Issues Improved	Mode of Action
		Antioxidative and Anti-Inflammatory Action	Gut Microbiota Modulation
[56] 2017 Mice, chlorogenic acid (CA), p.o. with drinking water containing 1 mM CA for 15 days; 2.5% DSS was given during the last 8 days with CA	Ameliorated DSS-induced colitis and improved mucosal damage	Suppressed the active NF-κB signaling pathway in the colon	Decreased the Firmicutes/Bacteroidetes ratio and increased the relative abundance of Akkermansia
[57] 2017 Mice, nanoparticle curcumin (NC), p.o. with diet containing 0.2% NC for 18 days; 3% DSS was given from day 8 to day 18	Ameliorated DSS-induced colitis and improved mucosal permeability	Suppressed NF-κB activation in colonic epithelial cells	Increased the abundance of butyrate-producing bacteria and fecal butyrate levels
[58] 2018 Mice, bronze tomato extract (BTE) rich in anthocyanins, flavonols, and stilbenoids, p.o. with diet containing 1% BTE for 2 weeks; 1% DSS was given from day 14 to day 29	Ameliorated DSS-induced colitis	Suppressed LPS-mediated production of pro-inflammatory cytokines	Decreased the Firmicutes/Bacteroidetes ratio
[59] 2018 Rats, polyphenol-rich Chinese propolis (CP) or Brazilian propolis (BP), p.o. at 300 mg/kg/day for 17 days; 3% DSS was given from day 7 for 1 week	Ameliorated DSS-induced colitis	Alleviated the intestinal oxidative status, and suppressed inflammatory gene expression in the distal colon	Reduced populations of Bacteroides spp.
[60] 2018 Mice, quercetin aglycone (Q) or quercetin aglycone with monoglycosides (Q + MQ), p.o. with diet containing 0.21% Q or 0.35% Q + MQ for 7 days; 3% DSS was given from day 8 for 1 week	Ameliorated DSS-induced colitis	Suppressed oxidative stress indicated by MPO, GSH, and MDA	Ameliorated reduced Firmicutes population and increased Proteobacteria population by DSS
[61] 2019 Mice, rape bee pollen extract rich in polyphenols including kaempferol, sinapic acid, and rosmarinic acid, p.o. at 10.6 and 21.2 g/kg/day for 15 days; 3% DSS was given from day 8 to day 12	Ameliorated DSS-induced colitis	Attenuated oxidative stress and downregulated the expression of inflammatory cytokines such as IL-1β	Reduced the abundance of Allobaculum and Bacteroides, and increased the abundance of Lactobacillus
[62] 2019 Rats, honey polyphenols including caffeic acid, chlorogenic acid, and rutin, p.o. at 10.5 mg/kg twice daily for 7 days; 3% DSS was given from day 0 to day 5	Improved DSS-induced colonic apoptosis and reduced the expression of inflammatory cytokines in the colon	Improved the levels of SOD, GSH-Px, NO, and MPO; downregulated the expression of IL-1β, IL-6, TNF-α, and IFN-γ genes, and upregulated the expression of IκB-α gene	Reduced the population of Bacteroides, Corynebacterium, and Proteus species at the genus level
[63] 2021 Mice, taxifolin, p.o. at 100 mg/kg/day for 7 days; from day 8, mice received 3% DSS for 7 days	Prevented DSS-induced colitis	Inhibited the secretion of proinflammatory cytokines, and increased the secretion of IL-10, secretory IgA, SOD, and immunoglobulins; increased the expression of intestinal tight junction proteins	Restored the microbiota composition in the colon, including the decrease in the abundance of Bacteroidetes and the Bacteroidetes/Firmicutes ratio at the phylum level
[64] 2021 Mice, Exp. I, epigallocatechin-3-gallate (EGCG), p.o. or rectal administration at 50 mg/kg/day for 3 days starting after supplementation with 2.5% DSS for 7 days; Exp. II, EGCG, p.o. at 50 mg/kg/day for 3 weeks with 2.5% DSS for the last 6 days; Exp. III, 2.5% DSS for 7 days followed by FMT for 3 days	Exp. I: oral, but not rectal, EGCG alleviated DSS-induced colitis; Exp. II: oral EGCG prevented DSS-induced colitis; Exp. III: FMT alleviated DSS-induced colitis	Oral, but not rectal, EGCG attenuated oxidative stress, and exerted an anti-inflammatory effect along with enhanced integrity of the colonic barrier; oral EGCG pre-supplementation induced beneficial outcomes similar to those achieved with oral EGCG administration	Attenuation of colitis by oral EGCG suggests an intimate involvement of SCFA-producing bacteria, of the genus Akkermansia.
[65] 2021 Mice, green pea (Pisum sativum L.) hull polyphenol extracts containing quercetin and its derivatives, kaempferol trihexanside, and catechin and its derivatives, p.o. at 100 and 600 mg/kg for 14 days; 3% DSS was given for 7 weeks from day 8	Alleviated DSS induced colitis	Restored oxidative balance, and regulated inflammatory factors along with repaired colonic function	Increased the Firmicutes/Bacteroidetes ratio, promoted the growth of Lactobacillaceae and Lachnospiraceae, and improved the level of SCFAs

p.o., per os; IL-1β, interleukin-1β; SOD, superoxide dismutase; GSH-Px, glutathione peroxidase; NO, nitric oxide; IL-6, interleukin-6; TNF-α, tumor necrosis factor-α; IFN-γ, interferon-γ; IκB-α, NF-κB inhibitor-α; IL-10, interleukin-10; IgA, immunoglobulin A; FMT, fecal microbiota transplantation; SCFA, short-chain fatty acids.