Acute and Chronic Toxicity Tests and Assessment of In Vitro and In Vivo Anti-Allergic Effects of Prabchompoothaweep Remedy

Prabchompoothaweep (PCT) is an anti-allergic remedy on the Thailand National List of Essential Medicines, traditionally used to relieve common colds and allergic reactions in Thai traditional medicine (TTM). However, the anti-allergic activity of PCT and its plant ingredients had not been characterized. We evaluated the acute and chronic oral toxicity of PCT ethanolic extract in rats and assessed its in vitro and in vivo anti-allergic activities. Activity in vitro was measured as inhibition of antigen-induced β-hexosaminidase release in RBL-2H3 cells and in vivo using an ovalbumin (OVA)-induced allergic rhinitis mouse model. The extract produced no mortality or signs of toxicity in either study. Several plant ingredients and the PCT extract inhibited β-hexosaminidase release more effectively than chlorpheniramine. In OVA-induced mice, PCT (75, 150, and 300 mg/kg) did not significantly lower OVA-specific serum IgE or IgG2a (OVA-specific IgG1 was likewise not reduced); however, it reduced inflammatory cell infiltration, goblet cell hyperplasia and mast cell numbers in the nasal mucosa and downregulated the T helper 2 (Th2) cytokines IL-5 and IL-13. These findings support the traditional anti-allergic use of the PCT remedy.