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Ethnopharmacological relevance An extensive ethnopharmacological survey was carried out in the Peruvian Amazonian district of Loreto with informants of various cultural origins from the surroundings of Iquitos (capital city of Loreto) and from 15 isolated riverine Quechua communities of the Pastaza River. A close attention was paid to the medical context and plant therapy, leading to the selection of 35 plant species (45 extracts). The extracts were tested for antiviral activity against HCV with counting of Huh-7 cellular death in case of toxicity, and cytotoxicity was evaluated in HepG2 cells.

Context:Our survey was performed near Iquitos (Peruvian Amazon) and its surroundings and leads us to consider Mestizo ethnomedical practices. The plant species reported here are traditionally used for ailments related to microbial infections. Inhabitants of various ethnic origins were interviewed, and 52 selected plants extracts were evaluated for their antimicrobial properties against a panel of 36 sensitive and multi-resistant bacteria or yeast. The study aimed at providing information on antimicrobial plant extract activities and the ethnomedical context of Mestizo riverine populations from Loreto (Peru).Material and Method:The minimum inhibitory concentrations (MICs) of the plant crude extracts were carried out using the agar dilution method and ranged between 0.075 and 5.0 mg/ml.Results:Of the 40 plants analyzed, 9 species showed MIC ≤0.3 mg/ml (Anacardium occidentale, Couroupita guianensis, Croton lechleri, Davilla rugosa, Erythrina amazonica, Jacaranda copaia subsp. Spectabilis, Oenocarpus bataua, Peperomia macrostachya, and Phyllanthus urinaria) for one or several of the 36 microorganisms and only 6 drug extracts were inactive. Among the 40 plants, 13 were evaluated for the first time for an antibacterial activity.Conclusion:This evaluation of the antimicrobial activity of 40 plants using an approved standard methodology allowed comparing those activities against various microbes to establish antimicrobial spectra of standardized plant extracts, and give support to the traditional use of these plants. It may also help discovering new chemical classes of antimicrobial agents that could serve against multi-resistant bacteria.SUMMARY This study leads us to consider Mestizo ethnomedical practices near Iquitos (Peruvian Amazon) and its surroundings. The plant species reported here are traditionally used for ailments related to microbial infections. 52 selected plants extracts were evaluated for their antimicrobial properties against a panel of 36 sensitive and multi resistant bacteria or yeast. The study aimed at providing information on antimicrobial plant extract activities and the ethnomedical context of Mestizo riverine populations from Loreto.

The Napo River basin, which is situated within the Upper Amazon archaeological region, is one of the most speciose forests in Greater Amazonia. Standard thinking in scholarship and science holds that these forests are essentially pristine because any Indigenous impacts in the past would have been minimal, seedbanks would have been nearby, and natural forests would have reappeared after the humans left, died out, or dispersed. Inventory research in 2019 on three ridgetop forests in Waorani territory inside the Curaray basin (which drains to the right margin of the Napo River) and a comparable inventory on one control site forest along the Nushiño River (also in the Curaray basin) show human impacts from about the late nineteenth century to about 1960; they occurred during the period of wartime among Waorani themselves and between Wao people and outsiders. The human impacts resulted in the high basal-area presence of two long-lived species with important Waorani cultural uses: cacao (Theobroma cacao L.) and ungurahua palm (Oenocarpus bataua Mart.). These species have high frequency and dominance values and do not occur in the control site, which is comparable in terms of elevation above the flood zone of the rivers in the sample. These findings mean that alpha diversity in the right margin sector (or south) of the Napo River basin cannot a priori be explained by reference to traditionally, biologically accepted patterns of ecological succession but may require knowledge of historical patterns of Indigenous land use and secondary landscape transformation over time due to human (specifically Waorani) impacts of the past.

A phytochemical investigation of the ethanolic extract of leaves from Piper pseudoarboreum led to the isolation of 3-chlorosintenpyridone 1, an unprecedented chlorinated piperamide, together with the known compounds 2-12. Their structures were established based on 1D and 2D (COSY, ROESY, HMQC, and HMBC) NMR spectroscopy, in addition to high resolution mass spectrometry. The proposed biosynthetic pathway of compound 1 is discussed. Compounds 1-12 were tested in vitro for their leishmanicidal potential against promastigote stages of Leishmania amazonensis, L braziliensis, L. guyanensis and L. infantum. Two compounds from this series, the alkamide 1 (IC 50 3.4-5.2 μM) and the fatty acid 9 (IC 50 18.7-29.6 μM) displayed higher or similar potency to Miltefosine, used as the reference drug.

Objetivo: Determinar el efecto antibacteriano del extracto de Stevia rebaudiana (S. rebaudiana) frente a Streptococcus sanguinis (S. sanguinis) y Actinomyces viscosus (A. viscosus). Métodos: Se desarrolló la prueba de sensibilidad en placa de agar con discos, para lo cual se cultivaron las cepas de S. sanguinis y A. viscosus en placas de agar tripticasa soya (TSA) y agar sangre respectivamente, incubando a 37 °C por 48 horas a S. sanguinis y por 7 días en condiciones de anaerobiosis a A. viscosus. Las cepas bacterianas fueron estandarizadas a una escala de 0,5 de Mc Farland, y tomando inóculos de 100 μL fueron sembradas en diez placas de agar sangre y TSA, luego sobre cada placa se colocaron los discos de papel secante de 6 mm de diámetro de forma equidistante, cargados con 10 μL de las diferentes concentraciones del extracto, para luego ser incubados. Resultados: Las concentraciones de 15, 30, 50, 60 y 120 mg/ml presentaron un halo de inhibición promedio de 6,8±0,258; 8,2±1,15; 8,2±1,13; 8,3±0,823; 8,1±0,80 mm respectivamente, para las bacterias de S. sanguinis. Las concentraciones de 15, 30, 50, 60 y 120 mg/ml presentaron un halo de inhibición promedio de 7,2±0,75; 9,65±2,15; 9,20±2,03; 7,95±1,09; 8,05±0,96 mm respectivamente, para las bacterias de A. viscosus. La prueba de Kruskal Wallis determinó que existe diferencia estadísticamente significativa con p<0,05 de los promedios entre las concentraciones de A. viscosus. Conclusiones: El extracto de S. rebaudiana no presenta efecto antibacteriano para S. sanguinis, pero si presenta efecto antibacteriano sobre A. viscosus para las concentraciones de 30 y 50 mg/ml.

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