Angélica Gutiérrez-Sánchez

The genus Fusarium comprises multiple species recognized as plant pathogens in both annual and perennial crops. Some phytopathogenic species of this genus can be transmitted by insect vectors, which introduce them into woody plant species of ecological and agroeconomic importance. Among these species, Fusarium kuroshium stands out, but studies are limited because it is a quarantine pathogen that requires special biosafety measures for its culture. This fungus produces fusaric acid (FA), a virulence factor that is widespread in Fusarium spp. To gain insight into the role of this phytotoxin in virulence, we exposed leaves of four woody host species (Liquidambar styraciflua, Persea americana, Citrus sinensis, and Populus nigra) of F. kuroshium to FA in vitro. The plant tissue exhibited varying degrees of cell death and physiological alterations, including a reduction in biomass, generation of reactive oxygen species (ROS), elevated electrolyte leakage, and loss of photosynthetic pigments. A chemical analysis demonstrated that the flavonoid and isoflavonoid pathways, in addition to linoleic and linolenic acid metabolism, were markedly affected by FA. Following the quantification of phenolic compounds in leaves, 11 metabolites were identified whose concentrations increased in response to FA stress. The findings of this study indicate that phenolic compounds play a significant role in the response to FA stress. Particularly, scopoletin has a protective effect on leaves of Liquidambar styraciflua.

Antecedentes y Objetivos: Las hojas de Bursera simaruba se utilizan tradicionalmente para tratar diversas enfermedades. Sin embargo, existen pocos reportes sobre la descripción de los fitoquímicos potencialmente responsables de tales actividades biológicas. Por lo tanto, este estudio tuvo como objetivo describir el potencial antifúngico, antibacteriano y antidiabético mediante experimentos in vitro, así como contribuir al conocimiento de la composición química de las hojas de B. simaruba. Métodos: Se analizó la actividad antibacteriana, antifúngica y antidiabética de un extracto metanólico (MeOH-Ex) de hojas de B. simaruba, y se detectaron diferentes grupos de metabolitos secundarios mediante ensayos cualitativos. Además, el análisis fitoquímico de MeOH-Ex se determinó con cromatografía líquida de ultra alta resolución acoplada a espectrometría de masas de alta resolución (UHPLC-ESI+-MS-QTOF), y las identificaciones putativas se realizaron utilizando bases de datos espectrales públicas. Resultados clave: El MeOH-Ex de las hojas de B. simaruba contiene cualitativamente alcaloides, terpenos y esteroides, saponinas, taninos, cumarinas y compuestos fenólicos, tales como ácido cafeico, ácido clorogénico, apigenina, kaempferol, florizina, quercitrina, quercetina-glucósido y apigenina-glucósido. Además, se identificaron tentativamente los lignanos burseran y yatein. El MeOH-Ex exhibió una baja actividad antifúngica contra Fusarium solani (16.3% de inhibición del crecimiento micelial) y un alto efecto antidiabético por inhibición in vitro de las enzimas α-amilasa (87.7%) y α-glucosidasa (75.9%). Finalmente, el estándar de ácido clorogénico mostró una inhibición significativa de las enzimas α-amilasa (49.5%) y α-glucosidasa (85.1%). Conclusiones: El MeOH-Ex de las hojas de B. simaruba representa una fuente de metabolitos secundarios con potencial actividad antidiabética. Los compuestos fenólicos tentativamente identificados podrían desempeñar un papel importante en la prevención de trastornos por hiperglucemia posprandial al inhibir las enzimas α-amilasa y α-glucosidasa. Destaca la presencia de ácido clorogénico como uno de los principales compuestos bioactivos potenciales en las hojas de B. simaruba.

Background and Aims: Rhynchostele rossii is an orchid native to Mexico known as gallinitas (little chickens) that is threatened due to overexploitation for ornamental purposes, as a consequence of which it is necessary to realize efforts for its conservation. To date there are no reports of phytochemical studies of this orchid, although it is well known that species of the Orchidaceae family are a good source of bioactive and nutraceutical compounds (e. g. vanillin). Therefore, the main objective of this research was to establish a R. rossii in vitro germination protocol for propagation and determination of phenolic compounds that contribute to its phytochemical knowledge.Methods: A specimen of a wild plant and some seedlings obtained by in vitro culture were dried, milled and their components extracted with MeOH; anti-free radical activity (DPPH), total phenols and flavonoids were determined by spectrophotometric methods, and individual phenolic compounds were identified and quantified by liquid chromatography coupled to mass spectrometry (LC-MS).Key results: The root of the wild plant showed the highest content of total phenols and flavonoids with 121.60 mg GAE g-1 and 108.73 mg CE g-1, respectively, and the best anti-free radical activity with an IC50 53.63 μg ml-1. Extracts from seedlings obtained by in vitro culture also produced phenolic compounds, showing a total phenolic and flavonoid content of 37.35 mg GAE g-1 and 0.16 mg CE g-1, respectively. One coumarin (scopoletin) , three cinnamic acids (4-coumaric acid, ferulic acid and trans-cinnamic acid), three benzoic acids (vanillic acid, vanillin and 4-hydroxybenzoic acid) and three flavonoids (quercetin-3-D-galactoside, quercetin-3-glucoside and kaempferide) were identified and quantified by LC-MS.Conclusions: This study demonstrates that R. rossii is a potential source of antioxidant metabolites that can be obtained by in vitro culture, without harming the wild specimens.