Study of the administration of two plant extracts P. venusta in the treatment of asthma in an animal model

Author(s)

Andiamira Cagnoni Balestra

• Document type: Master's Dissertation
• Press: Ribeirão Preto.
• Institution: Universidade de São Paulo (USP). Faculdade de Medicina de Ribeirão Preto (PCARP/BC)
• Defense date: 2016-11-07

Examining board members

Marcos de Carvalho Borges; Fabio Carmona; Iolanda de Fátima Lopes Calvo Tibério

• Advisor: Marcos de Carvalho Borges

Abstract

Asthma is a chronic inflammatory disease of the airways responsible for considerable morbidity and mortality worldwide. With the currently available treatment, including bronchodilators and corticosteroids, some patients do not reach the recommended control. Furthermore, these drugs have undesirable side effects. Thus, the development of new drugs for the treatment of asthma is needed. P. venusta (KerGahl.) Miers (\"liana-of St. John,\" Bignoniaceae), a widely distributed climbing worldwide and in Brazil mainly in the Brazilian cerrado, has anti-inflammatory and antioxidative activity. To date, there is no study of P. venusta in the treatment of asthma. The aim of the study was to evaluate the effects of administration of two extracts of P. venusta with different doses (100 and 300 mg/kg) in the treatment of asthma in an animal model and the mechanisms involved. Two protocols were conducted with different period of treatment. In protocol 1, Balb/c mice were sensitized twice with ovalbumin (OVA) intraperitoneally (ip) one week apart. After one week, mice were challenged with intranasal OVA for three consecutive days and treated with aqueous extract or hydroethanolic extract of P. venusta (100mg/kg) ip for three consecutive days, during OVA challenges. In protocol 2, Balb/c mice were sensitized ip with OVA twice with an interval of one week and after one week challenged four times with OVA intranasally in alternate days. The animals were treated with the aqueous extract or hydroethanolic extract of P. venusta (300 mg/kg) ip for seven consecutive days. Control mice received saline on the same days. After sensitization and challenge, the animals were ventilated and in vivo measurement of bronchial hyperresponsiveness was performed wiht increasing concentrations of methacholine. After, bronchoalveolar lavage was collected for total and differential cell count. The blood was collected to measure OVA specific IgE and lungs were removed for cytokines quantification in the pulmonary homogenates and histological analysis. In protocol 1, aqueous extract administration significantly reduced total and differential cells number, and bronchial hyperresponsiveness compared to the group that received no treatment. Hydroethanolic extract did not significant reduce airway inflammation. In relation to Protocol 2, the asthmatic group treated with aqueous extract had a significant decrease in total and differential inflammatory cells, lung inflammation, and bronchial hyperresponsiveness. Moreover, aqueous extract administration increased significantly antioxidant capacity. The hydroethanol extract decreased significantly only total cells and eosinophils. The aqueous and hydroethanolic extracts of P. venusta did not reduce the levels of inflammatory cytokines. We conclude that the administration P. venusta aqueous extract at a dose of 300mg/kg attenuated the main features of asthma in an animal model, probably via an antioxidant mechanism. (AU)

• FAPESP's process: 14/07616-0 - Study of asthma treatment with the administration of Pyrostegia venusta extract in a mouse model of allergic asthma
• Grantee: Andiamira Cagnoni Balestra
• Support Opportunities: Scholarships in Brazil - Master