Some viral outbreaks have plagued the world since antiquity, including the most recent COVID-19 pandemic. The continuous spread and emergence of new viral diseases have urged the discovery of novel treatment options that can overcome the limitations of currently marketed antiviral drugs. Chalcones are natural open chain flavonoids that are found in various plants and can be synthesized in labs. Several studies have shown that these small organic molecules exert a number of pharmacological activities, including antiviral, anti-inflammatory, antimicrobial and anticancer. The purpose of this review is to provide a summary of the antiviral activities of chalcones and their derivatives on a set of human viral infections and their potential for targeting the most recent COVID-19 disease. Accordingly, we herein review chalcones activities on the following human viruses: Middle East respiratory syndrome coronavirus, severe acute respiratory syndrome coronavirus, human immunodeficiency, influenza, human rhinovirus, herpes simplex, dengue, human cytomegalovirus, hepatitis B & C, rift valley fever and Venezuelan equine encephalitis. We hope that this review will pave the way for the design and development of potentially potent and broad-spectrum chalcone based antiviral drugs.

Being a developed and promising approach, nanotechnology has attracted a lot of attention in biomedical and pharmaceutical therapy applications. Among nanostructured materials, mesoporous silica nanoparticles (MSNs) are effectively used as nanocarriers for drug delivery systems. MSNs can be tailored-designed by different synthetic techniques. Their morphological characteristics dictate the type of application of such materials. Recently, polymer-based materials have been employed to functionalize the MSNs surface. These modified nanocarriers are loaded with the drug and can unload their “cargo” upon exposure to either endogenous or exogenous types of stimuli. In this study, different targeting concepts, including passive, active, vascular, nuclear, and multistage targeting, are discussed.

The present study describes the synthesis of a series of 22 chalcone analogs. These compounds were evaluated as potential human MAO-A and MAO-B inhibitors. The compounds showed varied selectivity against the two isoforms. The IC₅₀ values were found to be in the micromolar to submicromolar range. The K_i values of compound 16 were determined to be 0.047 and 0.020 μM for the inhibition of MAO-A and MAO-B, respectively. Dialysis of enzyme-inhibitor mixtures indicated a reversible competitive mode of inhibition. Most of the synthesized chalcone analogs showed a better selectivity toward MAO-B. However, introducing of 2,4,6-trimethoxy substituents on ring B shifted the selectivity toward MAO-A. In addition, we investigated the molecular mechanism of MAO-B inhibition by selected chalcone analogs. Our results revealed that these selected chalcone analogs increased dopamine levels in the rat hepatoma (H4IIE) cells and decreased the relative mRNA expression of the MAO-B enzyme.

Parkinson’s disease (PD) is a neurodegenerative disease characterized by the loss of mainly the nigrostriatal dopaminergic neurons, which leads to motor dysfunction. Although, most of the drugs are currently used for symptomatic treatment, there are at least three FDA-approved drugs for the treatment of PD that have been suggested preclinically to have neuroprotective effects. Among these drugs are monoamine oxidase (MAO) type B inhibitors such as selegiline and rasagiline, and non-ergot derivative dopamine agonist, pramipexole. In this review article, we focused on the potential uses of non-selective reversible MAO inhibitor, 2,3,6-trimethyl-1,4-naphthoquinone, from flue-cured tobacco leaves extract and two β- carboline alkaloids (harman and norharman) as potent, reversible and non-selective MAO inhibitors for the treatment of PD. In addition, we discussed the potential uses of farnesol as a potent inhibitor of MAO-B and farnesylacetone as a less potent selective MAO-B inhibitor. Furthermore, adducts of 1,2,3,4-tetrahydroisoquinoline have shown to have competitive inhibitory effects for both MAO-A and MAO-B. These inhibitors have potential neuroprotective effects, which might be mediated at least through nerve growth factor, neurotrophin 3, brain derived neurotrophic factor, and glial-cell-line-derived neurotrophic factor. We suggest here the neuroprotective implication of extracted MAO inhibitors from smoke tobacco; however, it is important to note that there are several existing compounds in tobacco smoke that have toxic effects in the brain, these include and not limited to the induction of neuropathological features observed in individuals suffering from Alzheimer’s disease and dementia.