Preventive and curative glycoside kaempferol treatments attenuate the TH2-driven allergic airway disease.

Asthma is a chronic respiratory disease characterized by airway inflammation and airway hyperresponsiveness (AHR). One strategy to treat allergic diseases is the development of new drugs. Flavonoids are compounds derived from plants and are known to have antiallergic, anti-inflammatory, and antioxidant properties. To investigate whether the flavonoid kaempferol glycoside 3-O-[beta-d-glycopiranosil-(1-->6)-alpha-l-ramnopiranosil]-7-O-alpha-l-ramnopiranosil-kaempferol (GRRK) would be capable of modulating allergic airway disease (AAD) either as a preventive (GRRK P) or curative (GRRK C) treatment in an experimental model of asthma. At weekly intervals, BALB/c mice were subcutaneously (sc) sensitized twice with ovalbumin (OVA)/alum and challenged twice with OVA administered intranasally. To evaluate any preventive effect, GRRK was administered 1h (hour) before each OVA-sensitization and challenge, while to analyze the curative effect, mice were first sensitized with OVA, followed by GRRK given at day 18 through 21. The onset of AAD was evaluated 24h after the last OVA challenge. Both treatments resulted in a dose-dependent reduction in total leukocyte and eosinophil counts in the bronchoalveolar lavage fluid (BAL). GRRK also decreased CD4(+), B220(+), MHC class II and CD40 molecule expressions in BAL cells. Histology and lung mechanic showed that GRRK suppressed mucus production and ameliorated the AHR induced by OVA challenge. Furthermore, GRRK impaired Th2 cytokine production (IL-5 and IL-13) and did not induce a Th1 pattern of inflammation. These findings demonstrate that GRRK treatment before or after established allergic lung disease down-regulates key asthmatic features. Therefore, GRRK has a potential clinical use for the treatment of allergic asthma.

Anti-allergic effect of bee pollen phenolic extract and myricetin in ovalbumin-sensitized mice.

ETHNOPHARMACOLOGICAL RELEVANCE: The bee pollen is used in folk medicine to alleviate allergic reactions. The bee pollen phenolic extract (BPPE) consists in phenolic compounds (flavonoids) from plants picked by Apis mellifera bee. AIM OF THIS STUDY: Here we evaluated the anti-allergic property of the BPPE and the flavonoid myricetin (MYR) in murine model of ovalbumin (OVA)-induced allergy. MATERIALS AND METHODS: The study focused on the BPPE or myricetin treatment of OVA-sensitized BALB/c mice and their effects on the IgE and IgG1 production, pulmonary cell migration, eosinophil peroxidase (EPO) activity and anaphylactic shock reaction. RESULTS: The BPPE treatment (200mg/kg) showed inhibition of the paw edema, IgE and IgG(1) OVA-specific production, leukocyte migration to the bronchoalveolar lavage (BAL) and EPO activity in lungs. In addition, BPPE treatment showed partial protection on the anaphylactic shock reaction induced by OVA. Treatment with myricetin (5 mg/kg) also inhibited pulmonary cell migration and IgE and IgG(1) OVA-specific production. CONCLUSIONS: These results support the hypothesis the myricetin is one of the flavonoids of BPPE responsible for the anti-allergic effect and a potential tool to treat allergies.