Antibacterial and Antioxidant Properties of Extracts of Yucca Baccata, a Plant of Northwestern Mexico, against Pathogenic Bacteria.

Introduction: Bacterial agents and oxidative reactions are involved in health and food preservation issues, and Yucca baccata (Y. baccata) can be a source of compounds with practical applications in both areas, but its investigation remains limited. Materials and Methods: Butanolic (YBE) and aqueous (YAE) extracts were obtained from the stem of Y. baccata. The total saponin, phenolic, and flavonoid contents were analyzed in the YBE and YAE. The antioxidant capacity of the extracts was determined by the DPPH, TEAC, FRAP, and ORAC assays. Seven Gram-positive and five Gram-negative pathogenic bacteria strains were used to determine the MIC and MBC. Results: Saponin contents were 30% and 1.81% (w/w) in the YBE and YAE, respectively. The total phenolic and flavonoid contents in the extracts were 29.5 µg GAEmg-1 (2.95%) and 5.58 µg GAEmg-1 (0.56%) in the YBE and 69.92 µg QEmg-1 (7.0%) and 1.65 µg QEmg-1 (0.165%) in the YAE. The antioxidant capacity values of YBE were 29.18 µg TEmg-1, 121.8 µg TEmg-1, 33.41 µg TEmg-1, and 156.84 µg TEmg-1 by the DPPH, TEAC, FRAP, and ORAC assays, respectively. YAE had lower antioxidant values than YBE (P < 0.05). Values of 80 mgmL-1 and 100 mgmL-1 were estimated for MIC and MBC of YBE against the Gram-positive bacteria. Values of 100 mgmL-1 and 120 mgmL-1 for MIC and MBC of YBE were estimated against the Gram-negative bacteria. No MIC and MBC were obtained for YAE. Conclusion: YBE exhibited higher antioxidant activity than YAE. Apparently, antibacterial properties of the YBE tended to be higher than those of the YAE.

Plants from the abandoned Nacozari mine tailings: evaluation of their phytostabilization potential.

Phytostabilization is a remediation technology that uses plants for in-situ stabilization of contamination in soils and mine tailings. The objective of this study was to identify native plant species with potential for phytostabilization of the abandoned mine tailings in Nacozari, Sonora in northern Mexico. A flora of 42 species in 16 families of angiosperms was recorded on the tailings site and the abundance of the most common perennial species was estimated. Four of the five abundant perennial species showed evidence of regeneration: the ability to reproduce and establish new seedlings. A comparison of selected physicochemical properties of the tailings in vegetated patches with adjacent barren areas suggests that pH, electrical conductivity, texture, and concentration of potentially toxic elements do not limit plant distribution. For the most abundant species, the accumulation factor for most metals was <1, with the exception of Zn in two species. A short-term experiment on adaptation revealed limited evidence for the formation of local ecotypes in Prosopis velutina and Amaranthus watsonii. Overall, the results of this study indicate that five native plant species might have potential for phytostabilization of the Nacozari tailings and that seed could be collected locally to revegetate the site. More broadly, this study provides a methodology that can be used to identify native plants and evaluate their phytostabilization potential for similar mine tailings.

Antimycobacterial activity of medicinal plants used by the Mayo people of Sonora, Mexico.

ETHNOPHARMACOLOGICAL RELEVANCE: Tuberculosis (TB) is an infectious disease mainly caused by Mycobacterium tuberculosis (Mtb), which generates 9 million new cases worldwide each year. The Mayo ethnicity of southern Sonora, Mexico is more than 2000 years old, and the Mayos possess extensive knowledge of traditional medicine. AIMS OF THE STUDY: To evaluate the antimycobacterial activity levels of extracts of medicinal plants used by the Mayos against Mtb and Mycobacterium smegmatis (Msm) in the treatment of TB, respiratory diseases and related symptoms. MATERIALS AND METHODS: A total of 34 plant species were collected, and 191 extracts were created with n-hexane, dichloromethane, ethyl acetate (EtOAc), methanol and water. Their minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) were determined against Mtb H37Rv using the microplate alamar blue assay (MABA) and against Msm using the resazurin microplate assay (REMA) at 6 and 2 days of exposure, respectively, and at concentrations of 250-1.9µg/mL (n-hexane extracts) and 1000-7.81µg/mL (extracts obtained with dichloromethane, EtOAc, methanol and water). RESULTS: Rhynchosia precatoria (Willd.) DC. (n-hexane root extract), Euphorbia albomarginata Torr. and A. Gray. (EtOAc shoot extract) and Helianthus annuus L. (n-hexane stem extract) were the most active plants against Mtb H37Rv, with MICs of 15.6, 250, 250µg/mL and MBCs of 31.25, 250, 250µg/mL, respectively. R. precatoria (root) was the only active plant against Msm, with MIC and MBC values of ≥250µg/mL. None of the aqueous extracts were active. CONCLUSIONS: This study validates the medicinal use of certain plants used by the Mayo people in the treatment of TB and related symptoms. R. precatoria, E. albomarginata and H. annuus are promising plant sources of active compounds that act against Mtb H37Rv. To our knowledge, this is the first time that their antimycobacterial activity has been reported. Crude extracts obtained with n-hexane, EtOAc and dichloromethane were the most active against Mtb H37Rv.

An ethnomedicinal study of the Seri people; a group of hunter-gatherers and fishers native to the Sonoran Desert.

BACKGROUND: Worldwide, coastal communities' ethnomedicinal knowledge has been sporadically recorded and poorly understood. Based on the ethnomedicinal knowledge of the Seri people; a hunting-gathering and fishing society of Northwestern Mexico, this study assesses a) the biological richness of Seri ethnomedicinal knowledge, b) the fidelity level of Seri remedies, and c) the association between gender, age, years of formal schooling and Seri ethnomedicinal knowledge. METHODS: To assess the degree of ethnomedicinal knowledge proficiency, we conducted 75 open-ended semi-structured interviews collecting information on ethnomedicinal knowledge of marine and terrestrial organisms and the socio-demographic profile of each collaborator. With the support of primary collaborators, we collected the materials to be used as stimuli along our interviews. A correlation analysis was used to determine the relationship between gender, literacy and age with the ethnomedicinal knowledge proficiency. A paired t-test was used to determine differences in the number of remedies known by gender among members of the Seri community. RESULTS: A total of 28 medicinal specimens were presented as stimuli material. Marine remedies (12 species), were represented by 4 algae, 3 mollusks, 3 echinoderms, on reptile, and one annelid. Terrestrial plants (13 species) were distributed in 12 families. About 40 % of marine preparations used the organism in whole. In contrast, 29 % of of the remedies involving plants made use of leafy branches. Stimuli materials are used against 17 ailments mainly, being diarrhea, colds, menstrual problems, and swelling the ailments against most organisms (44 %) are used for. Marine organisms presented higher fidelity level values overall, suggesting that lower fidelity levels in terrestrial plants reflect a process of continuous and ongoing experimentation with easily accessible biological materials. Highest fidelity level values were recorded for Atriplex barclayana (93.87 %) Batis maritima (84.37 %), and Turbo fluctuosus (84.21 %). Age moderately correlates to ethnomedicinal knowledge proficiency (r = 0.41). Conversely, years of formal schooling show a negative correlation with ethnomedicinal knowledge proficiency (r = -0.49). Significant differences (p <0.05) were observed on ethnomedicinal knowledge proficiency when gender groups were compared under a paired t-test. CONCLUSIONS: This research contributes to describing the complex biodiversity present in the ethnomedicinal systems of coastal non-agricultural societies. In addition, our research improves our understanding of the role that gender plays in the intra-cultural distribution of ethnomedicinal knowledge among Seri. Our results broaden our understanding of human adaptations to coastal and xeric environments. This research can potentially benefit the development of proposals to improve coastal and marine resource management and conservation while strengthening ethnomedicinal knowledge systems in populations, such as the Seri, limited by precarious socio-economic conditions and inadequate health services.