The Role of Rhodomyrtus tomentosa (Aiton) Hassk. Fruits in Downregulation of Mast Cells-Mediated Allergic Responses

Enriched-Baicalein Attenuates Allergy in Cells and Mice

Enriched-baicalein (baicalein) from baicalin was prepared by fermentation of an SB extract with mycelium of Laetiporus sulphureus. To investigate the pharmacologic effects of baicalein, its antiallergic effect was measured in vitro and in vivo. Allergy was induced by intraperitoneal injection of ovalbumin (OVA) into Balb/c mice. As a result, baicalein showed antiallergic effects by inhibiting the release of β-hexosaminidase from immunoglobulin E- (IgE-) stimulated rat basophilic leukemia (RBL-2H3) mast cells without cytotoxicity after the methodology. After four weeks, the decrease of OVA-specific IgE level, decrease of histamine and tryptase level in serum, and then the decrease of the levels of T helper type 2 (Th2) cell-derived cytokines interleukin- (IL-) 4 and IL-13 in the splenocyte were observed. In a histological analysis for lung, baicalein excellently reduced eosinophil infiltration with the inhibition of characteristic lesions and inflammation including OVA-induced necrosis, numbers of inflammatory cells, and pulmonary edema. Therefore, these results showed that baicalein had excellent efficacy in the antiallergic activity.

The role of myricetin from Rhodomyrtus tomentosa (Aiton) Hassk fruits on downregulation of FcɛRI-mediated mast cell activation

Rhodomyrtus tomentosa was reported to contain various bioactive metabolites, especially phenolic compounds. In the present study, the suppressive activity of phenolic compound from R. tomentosa fruits on mast cell activation was investigated in vitro. The result showed that myricetin was isolated from R. tomentosa fruits and its characterization was identified by nuclear magnetic resonance spectroscopy. Notably, myricetin was found to be effective in inhibition of mast cell degranulation by attenuating the release of β-hexosaminidase and the elevation of intracellular calcium. Moreover, myricetin exhibited inhibitory effect on the production of IL-4 and Tumor necrosis factor alpha (TNF-α) in a concentration-dependent manner. Furthermore, high antioxidant activity of myricetin due to scavenging 1,1-diphenyl-2-picryl-hydrazyl (DPPH) and ABTS⁺ radicals was also evidenced. Notably, the activation of FcɛRI-mediated signaling molecules including Syk, PLCγ, and NF-κB was also suppressed by myricetin treatment. Accordingly, myricetin from R. tomentosa fruits could be suggested as a functional food for the amelioration of allergic diseases. PRACTICAL APPLICATIONS: Polyphenol have been shown to exert various biological activities and health beneficial effects. Results from the present study revealed that myricetin from R. tomentosa fruits possesses the inhibitory effect on allergic response in mast cells. Therefore, myricetin from R. tomentosa fruits could be developed as a functional ingredient for the amelioration of allergic diseases.