Catechin-7-O-β-D-glucopyranoside isolated from the seed of Phaseolus calcaratus Roxburgh ameliorates experimental colitis in rats

The seeds of Phaseolus calcaratus Roxburgh (PHCR) are common legumes that comprise part of the daily diet in Chinese and Korean culture. Recent findings highlight anti-inflammatory and anti-septic potentials of catechin-7-O-β-D-glucopyranoside (CGP) isolated from PHCR seeds. We investigated the intestinal anti-inflammatory activity and associated mechanisms of CGP using a rat model of trinitrobenzenesulfonic acid (TNBS)-induced colitis. Oral treatment with CGP (10 mg/kg body weight) suppressed body weight loss and intestinal inflammatory damages in TNBS-induced colitic rats. This treatment reduced myeloperoxidase activity and malondialdehyde level, but increased glutathione level in the TNBS colitic rats. CGP treatment also inhibited the TNBS-mediated increases in nitric oxide synthase, cyclooxygenase-2, interleukin-1β, tumor necrosis factor-α, intercellular adhesion molecule-1, and monocyte chemotactic protein-1 proteins or mRNA levels. This inhibition was accompanied by the increased mRNA levels of mucins MUC2 and MUC3. The CGP treatment prevented phosphorylation of p38 mitogen-activated protein kinase, IκB-α, and DNA-nuclear factor-κB binding, all of which were increased in the inflamed colons of TNBS-treated rats. Furthermore, oral administration with a crude PHCR butanol extract (100 mg/kg body weight) which contains 1.5% of CGP showed intestinal anti-inflammatory potentials similar to that of CGP. Collectively, our current findings suggest that CGP or CGP-containing PHCR seeds may have favorable effects on intestinal inflammatory diseases.