Jasonia glutinosa (L.) DC., a Traditional Herbal Tea, Exerts Antioxidant and Neuroprotective Properties in Different In Vitro and In Vivo Systems

A Comprehensive Analytical Review of Polyphenols: Evaluating Neuroprotection in Alzheimer's Disease

Alzheimer's Disease (AD), a prevalent neurodegenerative disorder, is the primary cause of dementia. Despite significant advancements in neuroscience, a definitive cure or treatment for this debilitating disease remains elusive. A notable characteristic of AD is oxidative stress, which has been identified as a potential therapeutic target. Polyphenols, secondary metabolites of plant origin, have attracted attention due to their potent antioxidant properties. Epidemiological studies suggest a correlation between the consumption of polyphenol-rich foods and the prevention of chronic diseases, including neurodegenerative disorders, which underscores the potential of polyphenols as a therapeutic strategy in AD management. Hence, this comprehensive review focuses on the diverse roles of polyphenols in AD, with a particular emphasis on neuroprotective potential. Scopus, ScienceDirect, and Google Scholar were used as leading databases for study selection, from 2018 to late March 2024. Analytical chemistry serves as a crucial tool for characterizing polyphenols, with a nuanced exploration of their extraction methods from various sources, often employing chemometric techniques for a holistic interpretation of the advances in this field. Moreover, this review examines current in vitro and in vivo research, aiming to enhance the understanding of polyphenols' role in AD, and providing valuable insights for forthcoming approaches in this context.

Phytochemical Constituents and Biological Activities of Jasonia glutinosa L.: The First Report for the Plant Growing in North Africa

Jasonia glutinosa (rock tea), also known as Chiliadenus glutinosa Cass., is a medicinal plant growing in the Mediterranean Basin. It is used for the treatment of depression, gastrointestinal complaints, inflammations, appendicitis, colds, and respiratory disorders. The current study is the first report for the plant species growing in Libya and aims to investigate the phytochemical constituents, antioxidant, cytotoxic, and antimicrobial activities of the plant’s aqueous ethanolic extract. The phytochemical investigation was conducted by the spectrophotometric quantitative assay and the LC-MS analysis. The analysis revealed the presence of 14.67 and 46.72 mg/g of the total phenolics and flavonoids equivalent to gallic acid and rutin, respectively. A total of thirty compounds of phenolic acids and flavonoids were identified by the LC-MS analysis, with a total relative percentage of 18.69%. The analysis revealed the dominance of methoxylated flavonoids and cinnamic acid derivatives, including caffeoylquinic acids. The in vitro antioxidant assays showed 265.55, 513.32, and 27.10 μM Trolox eq/mg of extract in the ABTS, ORAC, and FRAP assays, respectively. Cancer cell growth inhibitions of 9.23, 11.42, and 34.01% at a concentration of 100 μg/mL against MCF-7, HepG2, and PANC-1 cell lines were obtained, which is considered a weak cytotoxic effect when compared to the standard anticancer agent, doxorubicin (DOX). No antimicrobial activity was noticed for the plant extract against all tested microorganisms, i.e., Escherichia coli, Bacillus subtilis, Staphylococcus aureus, Salmonella typhimurium, Candida albicans, and Saccharomyces cerevisiae. The weak antimicrobial effect of the plant did not support the claim of traditional use of the plant as an antimicrobial agent.

Natural Bioactive Products and Alzheimer’s Disease Pathology: Lessons from Caenorhabditis elegans Transgenic Models

Alzheimer’s disease (AD) is an age-dependent, progressive disorder affecting millions of people. Currently, the therapeutics for AD only treat the symptoms. Although they have been used to discover new products of interest for this disease, mammalian models used to investigate the molecular determinants of this disease are often prohibitively expensive, time-consuming and very complex. On the other hand, cell cultures lack the organism complexity involved in AD. Given the highly conserved neurological pathways between mammals and invertebrates, Caenorhabditis elegans has emerged as a powerful tool for the investigation of the pathophysiology of human AD. Numerous models of both Tau- and Aβ-induced toxicity, the two prime components observed to correlate with AD pathology and the ease of performing RNA interference for any gene in the C. elegans genome, allow for the identification of multiple therapeutic targets. The effects of many natural products in main AD hallmarks using these models suggest promising health-promoting effects. However, the way in which they exert such effects is not entirely clear. One of the reasons is that various possible therapeutic targets have not been evaluated in many studies. The present review aims to explore shared therapeutical targets and the potential of each of them for AD treatment or prevention.

Iron overload and neurodegenerative diseases: What can we learn from Caenorhabditis elegans?

Iron (Fe) is an essential trace element required for several physiological processes. It plays important roles in mitochondrial function, synthesis, and metabolism of the neurotransmitter, as well as oxygen transport. However, excess Fe can cause toxicity. Particularly, Fe overload may result in neurotoxicity, contributing to the development and progression of neurodegenerative diseases, although the molecular mechanisms underlying Fe-induced neurodegeneration have yet to be entirely understood. Alternative (non-rodent) experimental models have been pointed as important approaches to elucidate molecular and physiological events mediating Fe-induced pathology. Among such alternative strategies, an advantageous experimental worm-model system, Caenorhabditis elegans ( C. elegans), has been used to investigate Fe-induced neurotoxicity and neurodegenerative disorders. Its genome has been fully sequenced, corroborating that it shares significant homology with mammalians, and has approximately 40% of human disease-related genes. As part of this review, we discuss studies using the C. elegans model to study molecular mechanisms such as oxidative stress, mitochondrial dysfunction, disturbed homeostasis, and its potential contribution to the study of metal-induced neurodegenerative diseases such as Parkinson’s disease (PD) and Alzheimer’s disease (AD).

Crosstalk Between Intestinal Serotonergic System and Pattern Recognition Receptors on the Microbiota-Gut-Brain Axis

Disruption of the microbiota-gut-brain axis results in a wide range of pathologies that are affected, from the brain to the intestine. Gut hormones released by enteroendocrine cells to the gastrointestinal (GI) tract are important signaling molecules within this axis. In the search for the language that allows microbiota to communicate with the gut and the brain, serotonin seems to be the most important mediator. In recent years, serotonin has emerged as a key neurotransmitter in the gut-brain axis because it largely contributes to both GI and brain physiology. In addition, intestinal microbiota are crucial in serotonin signaling, which gives more relevance to the role of the serotonin as an important mediator in microbiota-host interactions. Despite the numerous investigations focused on the gut-brain axis and the pathologies associated, little is known regarding how serotonin can mediate in the microbiota-gut-brain axis. In this review, we will mainly discuss serotonergic system modulation by microbiota as a pathway of communication between intestinal microbes and the body on the microbiota-gut-brain axis, and we explore novel therapeutic approaches for GI diseases and mental disorders.