iridoids and Hypersensitivity

Genipin is a natural compound isolated from the fruit of Gardenia jasminoides with various pharmacological effects. In this study, we investigated whether genipin effectively alleviates allergic responses in a murine model of ovalbumin (OVA)-induced asthma. The mice were administered an intraperitoneal injection of OVA on day 0 and 14 to boost the immune response; genipin was then administered from day 18 to 23 by oral gavage. On days 21 to 23, mice were OVA-challenged using am ultrasonic nebulizer, and airway hyperresponsiveness (AHR) was determined on day 24 by plethysmography. Genipin significantly reduced the inflammatory cell count in bronchoalveolar lavage fluids (BALF) and AHR, which were accompanied by lower interleukin-5 (IL-5), IL-13 and OVA-specific immunoglobulin (Ig) E levels in the BALF or serum from OVA-induced asthmatic mice. In histology, genipin significantly decreased airway inflammation and mucus hypersecretion in OVA-induced asthmatic mice. Additionally, genipin inhibited OVA-induced increases in the expression of inducible nitric oxide synthase and cyclooxygenase-2 proteins. Further, genipin reduced the activity and protein levels of matrix metalloproteinase-9 in lung tissue from OVA induced asthmatic mice. Overall, genipin effectively alleviated the asthmatic inflammatory response in an OVA-induced asthmatic model. Therefore, our results suggest that genipin has therapeutic potential for treating asthma.

Topics: Animals; Anti-Inflammatory Agents; Asthma; Bronchial Hyperreactivity; Bronchoalveolar Lavage Fluid; Disease Models, Animal; Female; Gardenia; Hypersensitivity; Immunoglobulin E; Inflammation; Interleukin-13; Interleukin-5; Iridoids; Lung; Matrix Metalloproteinase 9; Mice; Mice, Inbred BALB C; Nitric Oxide Synthase Type II; Ovalbumin

Allergy-preventive activity of flower buds of Lonicera japonica THUNB. was found in the 35% EtOH extract (LJ) using an in vivo assay, The assay system uses monitoring of a decrease in blood flow (BF) in the tail vein of mice subjected to sensitization with hen-egg white lysozyme (HEL). Bioassay-guided fractionation of the 35% EtOH extract led to isolation of chlorogenic acid (1) and three known iridoid derivatives, loganin (2), secoxyloganin (3) and sweroside (4), all of which inhibited the BF decrease. This suggested that the flower buds of L. japonica and compounds isolated from them have allergy-preventive properties. The structure-activity relationship of iridoid derivatives, morroniside (5), geniposide (6), asperuloside (7), aucubin (8) and catalpol (9), were also tested using the same bioassay method. Compounds 2-5 and 9 having the sp(3) atom at C-8 showed an allergy-preventive effect, while compounds 6, 7 and 8 having a double bond at C-7, C-8 did not.

Topics: Animals; Anti-Allergic Agents; Chickens; Chlorogenic Acid; Female; Flowers; Hypersensitivity; Iridoid Glucosides; Iridoids; Lonicera; Male; Mice; Mice, Inbred Strains; Muramidase; Phytotherapy; Plant Extracts; Structure-Activity Relationship; Veins