Medicinal plants used in South Ecuador for gastrointestinal problems: An evaluation of their antibacterial potential

The present study aimed to identify the main medicinal plants used by people in Ecuador South Andes to treat gastrointestinal problems, and to evaluate their antibacterial effect. Escherichia coli and Salmonella spp., as gram-negative and Staphylococcus aureus as gram-positive bacteria were used as in vivo models for the antibacterial screening. An ethnobotanical survey about gastrointestinal problems was applied to known healers in the study area. Collected information was contrasted to results of interviews to 13 different yachaks from the same area. The antibacterial potential of chloroform and methanol extracts was evaluated by a micro – dilution technique, and IC50 and IC90 values of the bioactive extracts were estimated. Cytotoxicity of bioactive extracts was assessed using MRC-5 SV2 cells. The ethnomedical approach allowed collecting a total of 132 plants used for the treatment of 9 different gastrointestinal problems described by the consulted experts (yachaks). Among collected plants, 82 are native, 38 are introduced, and 3 are endemic of Ecuadorian Andes. Methanol and chloroform extracts of Hypericum laricifolium, Otholobium mexicanum and Peperomia sp. showed activity against S. aureus, while either chloroform or methanol extracts from other 13 plants were also active against the same bacteria. No activity against gram-negative bacteria was detected. The collected information was verified by yachaks and it agrees with previous ethnomedical reports. The results of antibacterial screening and cytotoxicity assays will contribute to a more rational and safer use of medicinal plants.