Nutraceutical Quality and Soluble Solids of Cucumis melo Developed in Vermicompost-River Sand Mixtures, Under Shade Mesh Conditions.

<b>Background and Objective:</b> There is ample evidence that the consumption of fruits and vegetables, with a high content of secondary metabolites, favours better human health. In the same sense, the application of organic fertilizers has favoured the content of phenolic compounds and a greater antioxidant capacity in various crops. Factoring that the application of Vermicompost (VC) increases the nutritional quality of plants. This research determined the content of soluble solids, biochemical components and the antioxidant capacity of the melon fruits (<i>Cucumis melo</i> L.) developed under shade net conditions with VC as a source of fertilization. <b>Materials and Methods:</b> During the 2020 spring-summer season, a hybrid melon Honeydew type was grown under five mixtures of VC: River sand (RS), with ratios 0:1, 1:1, 1:2, 1:3 and 1:4. Nutrient Steiner solution was applied only in the first mixture (control) while VC was used as an organic nutrient for all other mixtures. The five formulated mixtures, with five replications, were randomly distributed. The total phenolic content, total flavonoids, antioxidant capacity and the total soluble solids of the melon fruit were determined. Data obtained were statistically analyzed by analysis of variance and means were compared by Tukey 0.05 test. <b>Results:</b> The ANOVA indicates that no statistical differences were registered for any of the variables under study, however, the levels of the parameters were high. <b>Conclusion:</b> VC treatment of melon fruit is proven to be a promising source of nutrients to plants increasing their natural antioxidants and content of soluble solids.

Rizobacterias promotoras del crecimiento vegetal: una alternativa de biofertilización para la agricultura sustentable / Plant growth promoting rhizobacteria: a biofertilization alternative for sustainable agriculture

RESUMEN La agricultura moderna enfrenta nuevos desafíos, integrando enfoques ecológicos y moleculares, para lograr mayores rendimientos de los cultivos y reducir al mínimo los impactos sobre el ambiente. Para generar mayores rendimientos se han incrementado significativamente las dosis de fertilizantes sintéticos por unidad de superficie, los cuales pueden provocar contaminación, daños a la salud y pérdida de la fertilidad de los suelos, convirtiéndose en una de las preocupaciones más importantes en la producción agrícola. Para mejorar la producción sin el uso de fertilizantes de origen sintético, las investigaciones se han orientado hacia el desarrollo de nuevas biotecnologías: provocando que exista un interés creciente en los microorganismos benéficos del suelo ya que éstos pueden promover el crecimiento de las plantas y, en algunos casos, evitar infecciones del tejido vegetal por patógenos. Las interacciones de las rizobacterias promotoras del crecimiento vegetal (RPCV) con el medio biótico - plantas y microorganismos - son muy complejas y utilizan diferentes mecanismos de acción para promover el crecimiento de las plantas. Estos mecanismos se agrupan en: 1) Biofertilización; 2) Fito-estimulación; y 3) Biocontrol. Inocular los cultivos con RPCV reduce sustancialmente el uso de fertilizantes sintéticos y los impactos negativos al suelo, aumenta el rendimiento de los cultivos, contribuyendo a la economía del productor y a la alimentación de la población. Esta revisión describe aspectos básicos inherentes a la interacción entre las RPCV y las especies vegetales, centrándose en los beneficios que aportan las RPCV a la actividad agrícola.

ABSTRACT Modern agriculture faces new challenges, integrating ecological and molecular approaches, to achieve higher crop yields and to minimize negative impacts on the environment. To generate higher yields, the doses of synthetic fertilizers per unit area have been significantly increased, which can cause contamination, damage to the health and loss of soil fertility, making this one of the most important concerns in agricultural production. To improve production without the use of fertilizers of chemical origin, research has been oriented towards the development of new biotechnologies: causing a growing interest in beneficial microorganisms in the soil, as these can promote plant growth and, in some cases, avoid infections of plant tissue by pathogens. The interactions of plant growth promoting rhyzobacteria (PGPR) with the biotic medium - plants and microorganisms - are very complex and use different mechanisms of action to promote plant growth. These mechanisms are grouped into: 1) Biofertilization; 2) Phytostimulation and 3) Biocontrol. Inoculating the crops with PGPR could substantially reduce the use of synthetic fertilizers and the negative impacts to the soil, increase crop yields, contributing to the producer's economy and the population's nutrition. This review describes basic aspects inherent to the interaction between PGPR and plant species, focusing on the benefits of PGPR to the agricultural activity.

Antibacterial activity and phenolic content of propolis extracts obtained by different extraction methods

Introduction: The data available regarding the chemical composition and procedures for the extraction of the propolis are currently inconclusive. In this study the chemical groups present in the extracts of a propolis mixture obtained by different methods were identified. Additionally, their content of polyphenols and flavonoids was determined, and antioxidant and antibacterial activity was studied. Method: The extracts were obtained by maceration and for the ultrasonic and microwave method. Phenolic and flavonoid compounds, as well as the measurement of antioxidant activity, were quantified by spectrophotometric methods. The antibacterial activity was studied from the inhibitory effect of each extract against Escherichia coli, Salmonella typhi, Staphylococcus aureus and Proteus mirabilis, and by the percentage of activity and the Index of Bacterial Susceptibility (IBS). Results: The phytochemical screening evidenced the presence of abundant compounds with important biological activity. It was found a significant difference (p<0.05) in the antioxidant and antimicrobial activity of the extracts of propolis obtained by different methods. Conclusion: The presence of chemical groups of bioactive compounds and their antioxidant and antibacterial activity justifies the use of these extracts in traditional medicine.

Introducción: Los datos disponibles sobre la composición química y los procedimientos para la extracción del propóleo son actualmente inconclusos. En este estudio se identificaron los grupos químicos presentes en los extractos de una mezcla de propóleos obtenidos por diferentes métodos. Además, se determinó su contenido de polifenoles y flavonoides y se estudió su actividad antioxidante y antibacteriana. Método: Los extractos se obtuvieron por maceración, por el método ultrasónico y mediante microondas. Los compuestos fenólicos y flavonoides, así como la medición de la actividad antioxidante, se cuantificaron por métodos espectrofotométricos. La actividad antibacteriana se estudió a partir del efecto inhibitorio de cada extracto contra Escherichia coli, Salmonella typhi, Staphylococcus aureus y Proteus mirabilis, así como por el porcentaje de actividad y el Índice de Susceptibilidad Bacteriana (IBS). Resultados: El tamiz fitoquímico evidenció la presencia de abundantes fitoquímicos biológicamente activos. Se encontró una diferencia significativa (p<0.05) en la actividad antioxidante y antimicrobiana de los extractos de propóleos obtenidos por diferentes métodos. Conclusión: La presencia de grupos químicos de compuestos bioactivos y su actividad antioxidante y antibacteriana justifica el uso de estos extractos en la medicina tradicional.