Phenolic Composition and Biological Properties of Rhus microphylla and Myrtillocactus geometrizans Fruit Extracts.

Plants from arid zones of Mexico are an interesting source of phytochemicals that exhibit a large number of biological properties. In this context, Rhus microphylla (Rm) and Myrtillocactus geometrizans (Mg) fruits have been used as folk remedies and to make traditional foods, respectively; however, studies on their composition and bioactivity are limited. Thus, the objective of this work was to evaluate the yields, phenolic composition, and bioactive properties (scavenging and reducing capacities, antiproliferative, and antifungal) of aqueous and hydroalcohol extracts of Rm and Mg fruits obtained by conventional agitation and ohmic heating (OH). The results showed that the Rm fruit extracts had the highest total phenolic content (TPC) values and the strongest scavenging and reducing capacities compared to those of Mg fruits, being characterized by the presence of gallic acid, while the composition of the Mg extracts varied with respect to the extraction conditions used. Regarding antifungal activity in vitro against two phytopathogenic fungi, Rhizopus stolonifer and Fusarium oxysporum, the hydroalcohol extracts obtained by conventional agitation of both plants (RmH-C and MgH-C) showed the best inhibitory effect, respectively. Interestingly, none of the extracts under study presented cytotoxicity against the noncancerous ARPE-19 cell line, while three extracts of Rm fruit exhibited a moderate antiproliferative activity against HeLa (cancerous) cell line. These findings reveal for the first time the potential of Rm and Mg fruits as a new source of bioactive compounds for future industrial applications.

Use of Chitosan-PVA Hydrogels with Copper Nanoparticles to Improve the Growth of Grafted Watermelon.

Modern agriculture requires alternative practices that improve crop growth without negatively affecting the environment, as resources such as water and arable land grow scarcer while the human population continues to increase. Grafting is a cultivation technique that allows the plant to be more efficient in its utilization of water and nutrients, while nanoscale material engineering provides the opportunity to use much smaller quantities of consumables compared to conventional systems but with similar or superior effects. On those grounds, we evaluated the effects of chitosan-polyvinyl alcohol hydrogel with absorbed copper nanoparticles (Cs-PVA-nCu) on leaf morphology and plant growth when applied to grafted watermelon cultivar 'Jubilee' plants. Stomatal density (SD), stomatal index (SI), stoma length (SL), and width (SW) were evaluated. The primary stem and root length, the stem diameter, specific leaf area, and fresh and dry weights were also recorded. Our results demonstrate that grafting induces modifications to leaf micromorphology that favorably affect plant growth, with grafted plants showing better vegetative growth in spite of their lower SD and SI values. Application of Cs-PVA-nCu was found to increase stoma width, primary stem length, and root length by 7%, 8% and 14%, respectively. These techniques modestly improve plant development and growth.