Neuroprotective natural products’ regulatory effects on depression via gut–brain axis targeting Tryptophan

Liaqat, Humna (author), Parveen, Amna (author), Kim, Sun Yeou (author)

L-tryptophan (Trp) contributes to regulating bilateral communication of the gut–brain axis. It undergoes three major metabolic pathways, which lead to formation of kynurenine, serotonin (5-HT), and indole derivatives (under the control of the microbiota). Metabolites from the principal Trp pathway, kynurenic acid and quinolinic acid, exhibit neuroprotective activity, while picolinic acid exhibits antioxidant activity, and 5-HT modulates appetite, sleep cycle, and pain. Abnormality in Trp plays crucial roles in diseases, including depression, colitis, ulcer, and gut microbiota-related dysfunctions. To address these diseases, the use of natural products could be a favorable alternative because they are a rich source of compounds that can modulate the activity of Trp and combat various diseases through modulating different signaling pathways, including the gut microbiota, kynurenine pathway, and serotonin pathway. Alterations in the signaling cascade pathways via different phytochemicals may help us explore the deep relationships of the gut–brain axis to study neuroprotection. This review highlights the roles of natural products and their metabolites targeting Trp in different diseases. Additionally, the role of Trp metabolites in the regulation of neuroprotective and gastroprotective activities is discussed. This study compiles the literature on novel, potent neuroprotective agents and their action mechanisms in the gut–brain axis and proposes prospective future studies to identify more pharmaceuticals based on signaling pathways targeting Trp.

• Language: English
• Keywords: L-tryptophan, 5-HT, metabolites, phytochemicals, gut–brain axis, neuroprotective, gastroprotective, signaling pathways
• Work type: Article
• Typology: 1.02 - Review Article
• Organization: BF - Biotechnical Faculty
• Publication status: Published
• Publication version: Version of Record
• Year: 2022
• Number of pages: 40 str.
• Numbering: iss. 16, art. 3270
• PID: 20.500.12556/RUL-142152
• UDC: 616:579
• ISSN on article: 2072-6643
• DOI: 10.3390/nu14163270
• COBISS.SI-ID: 118270723
• Publication date in RUL: 21.10.2022

Record is a part of a journal

• Title: Nutrients
• Shortened title: Nutrients
• Publisher: MDPI
• ISSN: 2072-6643
• COBISS.SI-ID: 2948140

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: medicina, bolezni, os črevesje možgani, črevesna mikrobiota, triptofan