Screening of antifungal activity of plants from the northeast of Mexico.

Screening of the antifungal activity of plants from the northeast of Mexico against some of the main etiological agents inducing pulmonary mycoses, Candida albicans, Aspergillus fumigatus, Histoplasma capsulatum, and Coccidioides immitis, was conducted in vitro. We used the M27-A2 and M38-A methods from the National Committee for Clinical Laboratory Standards to screen the antifungal activity. Ten hydroalcoholic extracts from the 15 plants evaluated showed antifungal activity against at least one of these fungi. Following this, a differential extraction was conducted with solvents of different polarities, and 16 extracts showed activity ranging from 16 to 125microg/mL against the different fungi. Toxicity of the extracts was evaluated by means of the test of lethality to Artemia salina, two of which were shown to have toxicity.

Evaluation of the flora of northern Mexico for in vitro antimicrobial and antituberculosis activity.

The aim of the present study was to evaluate the potential antimicrobial activity of 14 plants used in northeast México for the treatment of respiratory diseases, against drug-sensitive and drug-resistant strains of Streptococcus pneumoniae, Staphylococcus aureus, Haemophilus influenzae type b and Mycobacterium tuberculosis. Forty-eight organic and aqueous extracts were tested against these bacterial strains using a broth microdilution test. No aqueous extracts showed antimicrobial activity, whereas most of the organic extracts presented antimicrobial activity against at least one of the drug-resistant microorganisms tested. Methanol-based extracts from the roots and leaves of Leucophyllum frutescens and ethyl ether extract from the roots of Chrysanctinia mexicana showed the greatest antimicrobial activity against the drug-resistant strain of Mycobacterium tuberculosis; the minimal inhibitory concentration (MIC) were 62.5, 125 and 62.5 microg/mL, respectively; methanol-based extract from the leaves of Cordia boissieri showed the best antimicrobial activity against the drug-resistant strain of Staphylococcus aureus (MIC 250 microg/mL); the hexane-based extract from the fruits of Schinus molle showed considerable antimicrobial activity against the drug-resistant strain of Streptococcus pneumoniae (MIC 62.5 microg/mL). This study supports that selecting plants by ethnobotanical criteria enhances the possibility of finding species with activity against resistant microorganisms.