Polyphenolic antioxidants inhibit peptide presentation by antigen-presenting cells

Antioxidant effects of liquorice (Glycyrrhiza uralensis) extract during aging of longissimus thoracis muscle in Tan sheep

“…Previous studies paid close attention to glycyrrhizin for its antiphlogosis and ability to relieve asthma (Ram et al, 2006;Toshihiro, 2000), but most flavonoids are discarded in the process of extracting glycyrrhizin to cause economic waste products. Flavonoids exert many physiological actions including those of an antioxidant, because they can scavenge free radials (Cook & Samman, 1996;Formica & Regelson, 1995;Sestili, Guidarelli, Dachà, & Cantoni, 1998), chelate metal ions (Belinky, Aviram, Fuhrman, Rosenblat, & Vaya, 1997), inhibit enzyme activity involved in the formation of free radical (Gong & Chen, 2003;Valdameri et al, 2010), and modulate signal transduction pathways to affect antioxidase expression (Williams, Spencer, & Rice-Evans, 2004). All of these actions can help to improve oxidation resistance.…”

Immunosuppressive Effect of Quercetin on Dendritic Cell Activation and Function

“…In addition, quercetin exerts antimicrobial, antihypertensive, neuroprotective, and chemoprotective effects (16). The immunomodulatory activity of quercetin has been investigated in NK cells (17), macrophages (18), mast cells (19), neutrophils (20), B cells (21), and T cells (22). Although a number of studies have reported the activity of flavonoids in the modulation of DC activation (23)(24)(25)(26)(27), the effect of quercetin on DCs remains unknown.…”

Buckwheat extracts (Fagopyrum tataricum) and rutin attenuate Th2 cytokines production and cellular allergic effects in vitro and in vivo

“…Moreover, PPARc activation also promotes the conversion of CD4 T cells into Foxp3 regulatory T cells (Chung et al, 2003;Lei, Hasegawa, Matsumoto, & Yasukawa, 2010;Wang, Zhu, Zhu, & Ma, 2010). Elevation of PPARc by rutin has been reported (Chuang et al, 2010), and rutin suppresses APCs activation for peptide presentation to exert anti-allergy (Gong & Chen, 2003); in addition, this compound also reduces mast cell activation by IgE induction thereby attenuating histamine production and secretion (Chen, Gong, Liu, & Mohammed, 2000b). These results indicated that rutin has potentials for down-regulating allergy by multi-manners; however, the affects of rutin for T cell and Th cytokine production remains unknown yet.…”

“…A recent study has shown that rutin can inhibit peptide presentation by APCs (Gong & Chen, 2003) as well as suppress histamine secretion from mast cells (Chen et al, 2000a). In addition, the anti-allergic and immunopharmacological activities of buckwheat have been investigated by Koda (1979a, 1979b).…”

“…It has been introduced as a part of human diet in many countries, because the seeds of this herb are healthy and nutritionally important. Rutin has been found to be the major ingredient of buckwheat (Holasova et al, 2002), and has recently been shown to possess anti-allergic activity by inhibiting peptide presentation by the APCs (Gong & Chen, 2003) and suppressing IgE-mediated mast cell activation, thereby reducing histamine production and secretion (Chen et al, 2000a). The findings of these studies, however, did not reveal the effects of rutin on T cells.…”