Evaluation of the antioedematogenic, free radical scavenging and antimicrobial activities of aerial parts of Tillandsia streptocarpa Baker -: Bromeliaceae

The crude methanolic extract of the aerial parts of Tillandsia streptocarpa was investigated for their acute toxicity and antioedematogenic, antioxidant and antimicrobial activities. Also, the antioedematogenic activity of the hexane fraction resulting from the partition of the crude methanolic extract was evaluated. The methanolic extract and the hexane fraction showed significant (P < 0.05) inhibition of ear oedema, observed at 2 mg/ear in the croton oil-induced mice ear oedema test. In the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging test, a high reactivity and potent antioxidant effect (IC50 = 0.0056%, w/v) were observed for the methanolic extract. The antimicrobial activity assay showed that the crude methanolic extract was inactive toward Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus subtilis, Candida albicans, C. parapsilosis, C. krusei and C. tropicalis (MIC > 500 mug/ml). The methanolic extract showed no toxic effect on mice at a single dose of 2000 mg/kg (p.o). Common side effects including mild diarrhoea, loss of weight and depression were not recorded. The compounds cycloartenol, 4',5-dihydroxy-3',7-dimethoxyflavanone and a mixture of the steroids stigmasterol, beta-sitosterol and campesterol, were isolated from the hexane fraction and identified by spectroscopic methods. (C) 2004 Elsevier Ireland Ltd. All rights reserved.