Se probó el efecto del quitosano sobre la producción de metabolitos secundarios de extractos etanólicos de Piper auritum, así como la actividad fungicida in vitro contra Fusarium oxysporum f. sp. vanillae. Las plantas de P. auritum se dividieron en seis parcelas y se añadió quitosano comercial a la mitad de ellas. Se midieron las concentraciones de flavonoides, fenoles, terpenos, alcaloides y ácido salicílico en extractos etanólicos de P. auritum y la actividad antifúngica se midió con la concentración efectiva media (CE50). Las concentraciones totales de flavonoides, fenoles y terpenos fueron más altas con el tratamiento con quitosano (sin quitosano 12.8 versus con quitosano 12.4 ?g equivalente de quercetina por mg, 12.6 versus 2.3 ?g equivalente de ácido tánico por 10 mg y 16.3 versus 11.6 mg equivalente de mentol por 100 mg). Mientras que la concentración de alcaloides disminuyó mediante la adición de quitosano (de 148.2 a 84.5 ?g de equivalente de piperina por mg). La adición de quitosano aumentó la concentración de ácido salicílico (de 1.3 a 2.2 ?g de equivalente de ácido salicílico por mg). La concentración de 4 mg mL-1 de extracto etanólico de P. auritum tratado con quitosano inhibió el 100% del crecimiento micelial. El tratamiento con quitosano generó que la CE50 de P. auritum contra F. oxysporum f. sp. vanillae fuera menor (1.5 mg mL-1) respecto al control (5.1 mg mL-1). Se concluye que la adición de quitosano aumentó la producción de metabolitos secundarios y la actividad antifúngica in vitro en extractos de P. auritum.

Platanus mexicana is a dominant arboreal species of riparian ecosystems. These ecosystems are associated with altitudinal gradients that can generate genetic differences in the species, especially in the extremes of the distribution. However, studies on the altitudinal effect on genetic variation to riparian species are scarce. In Mexico, the population of P. mexicana along the Colipa River (Veracruz State) grows below its reported minimum altitude range, possibly the lowest where this tree grows. This suggests that altitude might be an important factor in population genetics differentiation. We examined the genetic variation and population structuring at four sites with different altitudes (70, 200, 600 and 1700 m a.s.l.) using ten inter-simple sequence repeats (ISSR) markers. The highest value for Shannon index and Nei’s gene diversity was obtained at 1700 m a.s.l. (He = 0.27, Ne = 1.47, I = 0.42) and polymorphism reached the top value at the middle altitude (% p = 88.57). Analysis of molecular variance (AMOVA) and STRUCTURE analysis indicated intrapopulation genetic differentiation. The arithmetic average (UPGMA) dendrogram identified 70 m a.s.l. as the most genetically distant site. The genetic structuring resulted from limited gene flow and genetic drift. This is the first report of genetic variation in populations of P. mexicana in Mexico. This research highlights its importance as a dominant species, and its ecological and evolutionary implications in altitudinal gradients of riparian ecosystems.

Introduction. Mulberry (Morus alba), a plant native to China, is used as a fodder on some farms. Its high protein content stimulates milk production in cattle; however, it is not known whether its flavonoids can be incorporated into goat milk. Objective. To evaluate the effect of a diet enriched with mulberry-enriched, on flavonoids concentration and bromatological parameters of milk from stabled alpine goats. Materials and methods. The experiment was carried out in 2019, with goats from a particular farm located in Veracruz, Mexico. Two groups were formed (A with the treatment and B control) with five Alpine breed goats each, with similar characteristics (stall feeding, three calving, without mastitis, morning and evening hand milking). Group A received forage without mulberry before and after treatment (days 1-10 and 21-31, respectively), and a modified forage diet with mulberry (days 11-20; group B was fed forage without mulberry on all 31 days of experimentation. Additionally, the flavonoid content in mulberry and every three days in milk samples were analyzed, in addition to the bromatological content of protein, fat, lactose, non-fat solids, and density. Results. During the mulberry-modified diet, the flavonoid concentration reached a maximum of 53.45 mg mL-1 EQ in group A at day 20, it decreased gradually during the post-treatment period; however, it maintained 20 % more flavonoids than the control group. A significant increase in protein content was also observed in group A, with no significant difference in the other bromatological parameters of the milk between the two groups. Conclusions. The diets modified with mulberry favored the incorporation of flavonoids and the increase of protein in goat milk, without modifying the other bromatological parameters.

Las especies del género Piper han mostrado potencial como biocidas naturales en diferentes organismos, lo cual es atribuible a la diversidad de metabolitos secundarios que sintetizan. Por lo cual, el objetivo de esta investigación fue evaluar el efecto nematicida contra Caenorhabditis elegans de los extractos hidroacohólicos, etanólicos y metanólicos de cuatro especies del género Piper. Los resultados mostraron que el extracto de P. aduncum fue el que presentó mayor actividad con una concentración letal media (CL₅₀) estimada en 0.650 mg mL⁻¹. Se determinaron perfiles cromatográficos por HPTLC y en GC-EIMS de los extractos de mayor actividad. Los metabolitos identificados fueron alcaloides, flavonoides, terpenos, esteroles, cumarinas y saponinas. En la GC-EIMS se identificaron 67 compuestos potenciales en los extractos etanólicos. Se concluye que el extracto etanólico de Piper aduncum presentó mayor actividad nematicida (CL₅₀ de 0.650 mg mL⁻¹) y el de mayor número de compuestos identificados preliminarmente.

Bacterial resistance to antibiotics has driven the search for new chemical compounds with biological activity derived from plants. An example of these bioactive compounds are piperamides, terpenes, alkaloids, and others found in species of the Piper L genus. Additionally, it has been observed that certain elicitors can modify the production of these bioactive compounds. Therefore, the effect of chitosan on the induction of secondary metabolites and antibacterial activity of extracts from Piper psilorhachis C. DC. was evaluated. Three wild populations of P. psilorhachis were selected, and ten individuals per population were sprayed with a 1 mg/mL chitosan solution. Subsequently, leaves were collected, and ethanolic extracts were made, with the total content of flavonoids, phenols, alkaloids, terpenes, and salicylic acid quantified using spectrophotometry. Additionally, a phytochemical profile was determined by GC-MS. Antibacterial activity was evaluated against Escherichia coli (ATCC 25922), Staphylococcus aureus (ATCC 25923), Enterococcus faecalis (ATCC 29212), and Pseudomonas fluorescens (ATCC 15635) using the plate dilution method, and the Minimum Inhibitory Concentration (MIC) was estimated. Chitosan stimulated the production of flavonoids, phenols, and terpenes in all three populations compared to the control, while alkaloids and salicylic acid only significantly increased in one population. Terpene and amide precursors were tentatively identified by GC-MS. Antibacterial activity was significantly higher in the chitosan-treated extracts, with Escherichia coli being the most sensitive strain.

Se ha reportado que las especies de Annona presentan potencial actividad biológica que pudiera ser modificada gracias al estimulo de algunos elicitores. Por tal motivo, se evaluó el efecto de un autolizado de Saccharomyces cerevisieae como potencial elicitor, su efecto en la producción de metabolitos bioactivos de Annona cherimola y su actividad antibacteriana. Se aplicaron cinco tratamientos de autolizado. Realizando cuatro aspersiones por semana en tratamientos con 5 individuos por tratamiento de A. cherimola. Se colectaron hojas para obtener extractos etanólicos, de los cuales se cuantificaron: fenoles, flavonoides, alcaloides, terpenos totales, así como ácido salicílico. Se evaluó la actividad antibacteriana sobre Escherichia coli, Pseudomonas aureginosa, Pseudomonas fluorescens, Salmonella typhi, Enterococcus faecalis y Staphylococcus aureus. Las pruebas de sensibilidad bacteriana se realizaron con agar Müeller-Hinton. Se probaron cinco concentraciones de los extractos y se determinó la concentración mínima inhibitoria. Se observó que el autolizado de levadura modificó la producción de metabolitos bioactivos en Annona cherimola aumentando la concentración de fenoles, flavonoides, alcaloides, terpenos totales y ácido salicílico. Por último, la aplicación del elicitor generó diferencias significativas entre la actividad antibacteriana de los extractos, algunas cepas bacterianas fueron sensibles.