Zinc oxide nanoparticles have gained attention in the last decades due to their versatile applications; in agriculture, they have been used for their multiple benefits. In this study, the effects of zinc oxide nanoparticles, obtained via chemical and biological synthesis and of 70–80 nm in size, on the germination and seedling growth of Capsicum annuum and Solanum lycopersicum seed were determined. The physiological parameters, photosynthetic pigments, the content of total phenols, total flavonoids, as well as the antioxidant capacity of 2,2-diphenyl-1-picrylhydrazyl (DPPH), and the enzymatic activity of catalase, peroxidase, and polyphenol oxidase were evaluated. The results indicated that treatment with zinc oxide nanoparticles obtained via green synthesis improved seed germination rate, while chemically synthesized nanoparticles at higher concentrations decreased germination percentage. In general, the parameters of enzymatic and nonenzymatic antioxidants in treated plants showed significant differences with respect to the control. However, the treatments with the bionanoparticles resulted in more beneficial parameters. Zinc oxide nanoparticles obtained via green synthesis are more effective in generating bioactive compounds and activating the enzyme defense system due to being more biocompatible.

Background: Pathogens use multiple mechanisms to disrupt cell functioning in their host and allow pathogenesis. These mechanisms involve communication between the pathogen and the host cell through protein-protein interactions. Methods: Protein-protein interactions chains referred to as signal transduction pathways are the processes by which a chemical or physical signal transmits through a cell as series of molecular events so the pathogen needs to intercept these molecular pathways at few positions to induce pathogenesis such as pathogen viability, infection or hypersensitivity. Results: The pathogen nodes of interception are not necessarily the most immunogenic; so that novel immunogenicity-improvement strategies need to be developed thought a chemical conjugation of the pathogen-carrier nodes to develop an efficient immune response in order to block pathogenesis. On the other hand, if pathogen-carriers are immunogens; toleration ought to be induced by this conjugation avoiding hypersensitivity. Thus, this paper addresses the biological plausibility of plant-phenolics as pathogen-carrier immunogenicity modulator haptens. Conclusion: The plant-phenolic compounds have in their structure functional groups such as hydroxyl, carbonyl, carboxyl, ester, or ether, capable of reacting with the amino or carbonyl groups of the amino acids of a pathogen-carrier to form conjugates. Besides, the varied carbon structures these phenolic compounds have; it is possible to alter the pathogen-carrier related factors that determine the immunogenicity: 1) Structural complexity, 2) Molecular size, 3) Structural heterogeneity, 4) Accessibility to antigenic determinants or epitopes, 5) Optical configuration, 6) Physical state, or 7) Molecular rigidity.

Background: Immunization or vaccination is the process of inducing artificial immunity against an antigen taking advantage of the mechanisms of immunological memory. Current vaccines include substances known as adjuvants, which tend to improve the immunogenicity of the antigen, reduce the antigen quantity employed, and boost the immune response in weak responders. Unfortunately, only a few vaccine adjuvants are approved for human use. Objective: Thus, the objective of this study was to investigate the effect of Tannic acid on humoral and cell-mediated immunity against bovine serum albumin (BSA) as a protein antigen in Wistar rats. Method: In order to establish the Tannic acid concentration to test it as an adjuvant, the lethal dose 50 and maximum non-toxic dose were calculated through cytotoxicity and hemolytic assays with J774 A.1 cell line and rat erythrocytes by resazurin reduction method and UV/vis spectrophotometry. Thirty Wistar rats were divided into 5 groups that included two controls without antigen and three treatment groups of adjuvants plus BSA as a protein antigen. The rats were immunized in a 30-day scheme. Blood samples were collected for humoral immunity analysis by means of immunoglobulin quantification, isotyping and antigen-antibody precipitation inhibition analysis. Rat peritoneal macrophages and splenocytes were isolated for cell-mediated immunity analysis by means of nitric oxide quantification from adjuvant stimulated peritoneal macrophages and lymphocytes proliferation assay. Results: Tannic acid was capable of increasing the immunogenicity of the antigen; besides, it was able to stimulate cell-mediated immunity by means of increased lymphocyte proliferation. Moreover, Tannic acid improved the humoral response by means of increased specific antibodies titers. These activities may be attributed to pattern recognition receptors stimulation. Conclusion: Tannic acid was considered biocompatible when tested in vivo because the concentration tested did not show cytotoxicity or hemolytic effect, and there was no detrimental effect observed on the animals’ health. These results show Tannic acid as a promising candidate for vaccine adjuvant.

Background: The world's population is still growing, having an impact on the environment and the economic growth of developing countries; so that, there is a particular interest in the development of new fertility control methods, focused on male contraception.Objective: The objective of this study was to evaluate the effect of methanolic extracts of leaf and fruit of Azadirachta indica on sperm quality and testicular histology of Long Evans rats.Methods: Antifertility effects of a methanolic leaf and fruit extracts of A. indica on 24 male rats were investigated. The animals were randomly divided into two control groups and four treatment groups (n=4). Doses of the leaf and fruit extract were given at concentrations of 100 and 200 μg mL-1.Results: A significant decrease in the viability of sperm cells was observed. The leaf extract at a concentration of 200 μg mL-1 inhibited cell viability compared to the negative control (p< 0.001). The percentage of abnormal cells in leaf extract was shown in 100 and 200 μg mL-1, the conditions at which a higher percentage of morphological irregularities of observed (15% and 16% respectively). The results show that there was cellular detachment in the seminiferous epithelium in the experimental groups treated with methanolic extracts. Sperm death was observed without decreasing the number of sperm.Conclusion: The methanolic extracts of Azadirachta indica have a modulating effect on the spermatogenesis of experimental rats through sperm morphological alterations.

The medicinal plants of the desert can be a potential source of natural bioactive compounds with applications in health and food preservation. This work aimed to investigate the phenolic content and antioxidant potential of twenty-three plants from the arid zone of Viesca, Mexico. The antioxidant potential was determined by three methods (ABTS, FRAP, and DPPH). Two extraction methods and three different concentration levels (1:10 mg/mL, 1:25 mg/mL, and 1:50 mg/mL) were evaluated. According to the results, Turnera diffusa (Damiana), Gutierrezia sarothrae (Hierba de San Nicolas), and Leucophyllum frutescens (Cenizo) present the largest content of phenolic compounds and high antioxidant activity. The highest values of antioxidant activity were achieved using a solid/liquid ratio of 1:50 g/mL for T. diffusa and G. sarothrae and 1:25 mg/mL for L. frutescens. The maceration method was the most suitable for extracting antioxidant compounds from T. diffusa and L. frutescens, while ultrasound-assisted extraction was more efficient for G. sarothrae. The HPLC-MS analysis showed the presence of important phenolic compounds. This study shows for the first time that three plants that naturally grow in Viesca have great potential as a source of natural antioxidant compounds.