ovalbumin and baicalein

Allergic rhinitis (AR) is a common disease that causes severe inflammation and even disabilities. Previous studies have reported baicalein to have an anti-inflammatory effect. However, the pharmacological action of baicalein on anaphylaxis has not been clarified yet. This study assessed the in vivo protective effect of baicalein post-treatment in an ameliorating ovalbumin (OVA)-sensitized AR rat model. Baicalein attenuated histological alterations, aberrant tissue repair and inflammation after OVA-induced AR. Baicalein reduced the frequency of nasal/ear rubs and sneezes in rats, and inhibited generation of several inflammatory cytokines (TNF-α, IL-1β, and IL-6) in both blood and nasal lavage of rats. Infiltrations of eosinophils, lymphocyte, and neutrophils were decreased in baicalein-administered rats. Furthermore, baicalein inhibited the expression of STAT3 phosphorylation in the nasal mucosa. In summary, baicalein attenuated OVA-induced AR and inflammation, which suggests it as a promising therapeutic agent for the alleviation of AR-associated inflammation and pathology.

Topics: Animals; Disease Models, Animal; Eosinophils; Flavanones; Inflammation; Lymphocytes; Male; Nasal Mucosa; Ovalbumin; Rats; Rats, Sprague-Dawley; Rhinitis, Allergic

Topics: Animals; Antioxidants; Asthma; Cell Line; Collagen; Drug Evaluation, Preclinical; Flavanones; Immunoglobulin E; Mice; Mucus; NF-kappa B; Nitric Oxide Synthase Type II; Ovalbumin; Phytotherapy; Plant Extracts; Scutellaria baicalensis; Signal Transduction

The incidence of food allergy, which is triggered by allergen permeation of the gastrointestinal tract followed by a T-helper (Th) 2-mediated immune response, has been increasing annually worldwide. We examined the effects of baicalein (5,6,7-trihydroxyflavone), a flavonoid from Scutellaria baicalensis used in oriental herbal medicine, on regulatory T (Treg) cell induction and intestinal barrier function through the regulation of tight junctions in a mouse model of food allergy. An allergic response was induced by oral challenge with ovalbumin, and the incidence of allergic symptoms and T cell-related activity in the mesenteric lymph nodes were analyzed with and without the presence of baicalein. Our results demonstrated that the administration of baicalein ameliorated the symptoms of food allergy and attenuated serum IgE and effector T cells. However, Treg-related factors were up-regulated by baicalein. Furthermore, baicalein was shown to enhance intestinal barrier function through the regulation of tight junctions. We also found that baicalein treatment induced the differentiation of Treg cells via aryl hydrocarbon receptors (AhRs). Thus, the action of baicalein as an agonist of AhR can induce Treg differentiation and enhance barrier function, suggesting that baicalein might serve as an effective immune regulator derived from foods for the treatment of food allergy.

Topics: Animals; Disease Models, Animal; Female; Flavanones; Food Hypersensitivity; Forkhead Transcription Factors; Intestinal Mucosa; Intestines; Mice, Inbred BALB C; Ovalbumin; Phytotherapy; Plant Extracts; Receptors, Aryl Hydrocarbon; Scutellaria baicalensis; T-Lymphocytes, Regulatory; Tight Junctions

Effects of baicalein on release of slow reacting substance of anaphylaxis (SRS-A) or leukotriene (LT) from the sensitized guinea pig lung after antigen challenge and tonus of guinea pig tracheal muscles were studied. Baicalein inhibited release of SRS-A from sensitized guinea pig lung after antigen challenge. High-performance liquid chromatography (HPLC) analysis revealed that released SRS-A consisted to LTC4 and D4. Baicalein also reduced release of LTC4 and D4 from the sensitized lung after antigen challenge. Baicalein relaxed the isolated guinea pig tracheal smooth muscle contracted by LTD4, carbachol or histamine. However, this compound produced a contraction when the tracheal muscle was contracted by prostaglandin F2 alpha(PGF2 alpha). This contraction by baicalein was abolished by pretreatment with indomethacin, a cyclooxygenase inhibitor. Baicalein elicited a relaxation in the normal non-sensitized preparation but a contraction in the tissue isolated from actively sensitized guinea pig in 4 among 7 cases. Baicalein also produced a contraction in the trachea pretreated with phorbol dibutyrate and contracted by carbachol, which was eliminated after treatment with indomethacin. The results suggest that baicalein exerts action via, at least, two different mechanisms, the inhibition of releasing SRS-A (LTs) and direct relaxing effects on the trachea. Besides, baicalein seems to produce contraction under certain conditions, which may involve stimulation of the cyclooxygenase pathway.

Topics: Animals; Biological Assay; Chromatography, High Pressure Liquid; Cyclooxygenase Inhibitors; Dinoprost; Dose-Response Relationship, Drug; Enzyme Activation; Enzyme Inhibitors; Flavanones; Flavonoids; Guinea Pigs; Ileum; Indomethacin; Lung; Male; Muscle Contraction; Muscle, Smooth; Ovalbumin; Oxytocics; Protein Kinase C; SRS-A; Trachea