Tricin Isolated from Enzyme-Treated Zizania latifolia Extract Inhibits IgE-Mediated Allergic Reactions in RBL-2H3 Cells by Targeting the Lyn/Syk Pathway

Abstract

Tricin, a flavone present in rice bran, is confirmed as the major efficacious compound present in the enzyme-treated Zizania latifolia extract (ETZL), which protects against UVB-induced skin-aging. However, the suppressive mechanism of tricin on allergic responses remains unknown. The present study, therefore, aimed to determine the mechanisms of tricin and ETZL on mast cell degranulation in IgE-activated rat basophilic leukemia cell line (RBL-2H3) cells. We investigated the regulatory effects of tricin and ETZL on degranulation, production of cytokines and lipid mediators, and signaling proteins involved in the IgE-bound high-affinity IgE receptor activation, mitogen-activated protein kinase, arachidonic acid and Syk. The production of β–hexosaminidase, tumor necrosis factor-α, interleukin-4, leukotrienes (LT) B4, LTC4 and prostaglandin E2 in IgE-stimulated RBL-2H3 cells were significantly inhibited by exposure to tricin or ETZL. Moreover, tricin and ETZL inhibit the phosphorylation of cytosolic phospholipase A2, 5-lipoxygenase and cyclooxygenase-2. Furthermore, the phosphorylation of Akt, ERK, p38, JNK, protein kinase Cδ and phospholipase Cγ1 were effectively suppressed by both samples. Exposure to tricin or ETZL also significantly decreases the phosphorylation of Lyn and Syk, but has minimal effect on Fyn. Taken together, our data indicate that tricin and ETZL are potential anti-allergic materials that could be applied for the prevention of allergy-related diseases.

Integrated Metabolomic and Transcriptomic Analysis of the Flavonoid Accumulation in the Leaves of Cyclocarya paliurus at Different Altitudes

“…Tricetin is a potential anti-inflammatory and anticancer agent ( Chang et al, 2017 ; Chung et al, 2017 ). Tricin showed anti-allergic ( Lee et al, 2020 ) and anti-cancer ( Li et al, 2021 ) activities. In this study, naringin was mainly found in the leaves collected at high altitude.…”

The interplay between mast cells, pineal gland, and circadian rhythm: Links between histamine, melatonin, and inflammatory mediators

“…Recently, exposure of IgE‐activated RBL‐2H3 MCs to tricin, a flavone in rice bran, suppressed production of TNF‐α, IL‐4, leukotrienes (LT) B 4 , LTC 4 , and prostaglandin E 2 by significantly decreasing the phosphorylation of the tyrosine‐protein kinase (Lyn) and spleen tyrosine kinase (Syk) 137 . This suggested that the Lyn/Syk axis as a new potential target for prevention of IgE‐mediated allergic reactions.…”

Zizania latifolia and Its Major Compound Tricin Regulate Immune Responses in OVA-Treated Mice

“…According to the reports of Mohanlal et al [16], Kwon and Kim [17] and Quan et al [18], the tricin content of Oryza sativa calculated 48.6 mg/kg, 32.9 mg/kg, and 0.55 mg/kg, respectively. Tricin suppressed the arachidonic acid signal, mitogen-activated protein kinase (MAPK), and FcεRI signal of the RBL-2H3 cells and showed anti-allergic effects by suppressing the release of LTB4, LTC4, and PGE2 [19]. Indeed, Jiang et al [20] revealed that tricin has effectively the biological properties by functional groups such as phenolic hydroxyl groups, carbonyl groups, methoxyl groups.…”