In Vitro Bioactivity of Methanolic Extracts from Amphipterygium adstringens (Schltdl.) Schiede ex Standl., Chenopodium ambrosioides L., Cirsium mexicanum DC., Eryngium carlinae F. Delaroche, and Pithecellobium dulce (Roxb.) Benth. Used in Traditional Medicine in Mexico

Seven out of eight methanolic extracts from five plants native to Mexico were inactive against ten bacterial strains of clinical interest. The fruit extract of Chenopodium ambrosioides inhibited the bacteria Enterococcus faecalis (MIC = 4375 μg/ml), Escherichia coli (MIC = 1094 μg/ml), and Salmonella typhimurium (MIC = 137 μg/ml). The fruit extract of C. ambrosioides was with CC(50) = 45 μg/ml most cytotoxic against the cell-line Caco-2, followed by the leaf extract from Pithecellobium dulce (CC(50) = 126 μg/ml); interestingly, leaves of C. ambrosioides (CC(50) = 563 μg/ml) and bark of P. dulce (CC(50) = 347 μg/ml) extracts were much less cytotoxic. We describe for the first time the cytotoxic effect from extracts of the aerial parts and the flowers of Cirsium mexicanum (CC(50) = 323 μg/ml and CC(50) = 250 μg/ml, resp.). Phytochemical analysis demonstrated for both extracts high tannin and saponin and low flavonoid content, while terpenoids were found in the flowers. For the first time we report a cytotoxicological study on an extract of Eryngium carlinae (CC(50) = 356 μg/ml) and likewise the bark extract from Amphipterygium adstringens (CC(50) = 342 μg/ml). In conclusion the fruit extract of C. ambrosioides is a potential candidate for further biological studies.