ovalbumin and 7-hydroxycoumarin

The therapeutic effects of umbelliferone (30, 60 and 90 mg/kg), a coumarin isolated from Typha domingensis (Typhaceae) were investigated in a mouse model of bronchial asthma. BALB/c mice were immunized and challenged by nasal administration of ovalbumin. Treatment with umbelliferone (60 and 90 mg/kg) caused a marked reduction of cellularity and eosinophil numbers in bronchoalveolar lavage fluids from asthmatic mice. In addition, a decrease in mucus production and lung inflammation were observed in mice treated with umbelliferone. A reduction of IL-4, IL-5, and IL-13, but not of IFN-gamma, was found in bronchoalveolar lavage fluids of mice treated with umbelliferone, similar to that observed with dexamethasone. The levels of ovalbumin-specific IgE were not significantly altered after treatment with umbelliferone. In conclusion, our results demonstrate that umbelliferone attenuates the alteration characteristics of allergic airway inflammation. The investigation of the mechanisms of action of this molecule may contribute for the development of new drugs for the treatment of asthma.

Topics: Animals; Anti-Asthmatic Agents; Asthma; Bronchoalveolar Lavage Fluid; Disease Models, Animal; Dose-Response Relationship, Drug; Interleukin-13; Interleukin-4; Interleukin-5; Male; Mice; Mice, Inbred BALB C; Molecular Structure; Ovalbumin; Pneumonia; Umbelliferones

7-Hydroxycoumarin (7-HC) was chemically conjugated by diazo coupling to carrier proteins such as bovine serum albumin (BSA), thyroglobulin and ovalbumin. These conjugates were characterised by sodium dodecyl sulphate/polyacrylamide gel electrophoresis (SDS-PAGE) and high-performance liquid chromatography (HPLC). Rabbits were immunised using the 7-HC-BSA conjugate. The highest antibody titre achieved was 1:10,000, as determined by competitive enzyme-linked immunosorbent assay (ELISA). The resulting antibodies were purified by ammonium sulphate precipitation, followed by protein A affinity chromatography. Their purity was assessed by SDS-PAGE and HPLC. These antibodies have been used in the development of a competitive ELISA, an amperometric biosensor and an electrochemical immunoassay. Both the ELISA and amperometric biosensor have been successfully applied to the analysis of 7-HC and its glucuronide conjugate in human urine samples. Each of these antibody-based methods provides a novel approach to the analysis of the main metabolites of coumarin.

Topics: Animals; Antibodies; Antibody Specificity; Antigen-Antibody Reactions; Binding, Competitive; Chromatography, High Pressure Liquid; Coumarins; Electrochemistry; Electrophoresis, Polyacrylamide Gel; Enzyme-Linked Immunosorbent Assay; Humans; Male; Ovalbumin; Rabbits; Serum Albumin, Bovine; Thyroglobulin; Umbelliferones