Medicinal Plants with Anti-dengue and Immunomodulatory Activity.

Dengue fever is a disease with a high mortality rate around the world, which is an important issue for the health authorities of many countries. As a result of this, the search for new drugs that are effective to combat this disease has become necessary. Medicinal plants have been used since ancient times to treat a wide list of diseases, including dengue fever. In this mini-review, 12 medicinal plants with known pharmacological properties are presented, which have been used in studies to evaluate their antiviral activity in vitro tests. Among the chemical agents involved in the antiviral response, found in the alcoholic extracts of these plants, are flavonoids, terpenes and alkaloids, which within the mechanism of action in blocking viral replication are considered entry inhibitors, fusion inhibitors, translation inhibitors and protease inhibitors. The present work shows whether these plants possess antiviral activity and the chemical compounds involved in this response.

Plant Phenolics as Pathogen-Carrier Immunogenicity Modulator Haptens.

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.