chlorogenic-acid and Cognitive-Dysfunction

Caffeoylquinic acids (CQAs) are specialized plant metabolites we encounter in our daily life. Humans consume CQAs in mg-to-gram quantities through dietary consumption of plant products. CQAs are considered beneficial for human health, mainly due to their anti-inflammatory and antioxidant properties. Recently, new biosynthetic pathways via a peroxidase-type p-coumaric acid 3-hydroxylase enzyme were discovered. More recently, a new GDSL lipase-like enzyme able to transform monoCQAs into diCQA was identified in Ipomoea batatas. CQAs were recently linked to memory improvement; they seem to be strong indirect antioxidants via Nrf2 activation. However, there is a prevalent confusion in the designation and nomenclature of different CQA isomers. Such inconsistencies are critical and complicate bioactivity assessment since different isomers differ in bioactivity and potency. A detailed explanation regarding the origin of such confusion is provided, and a recommendation to unify nomenclature is suggested. Furthermore, for studies on CQA bioactivity, plant-based laboratory animal diets contain CQAs, which makes it difficult to include proper control groups for comparison. Therefore, a synthetic diet free of CQAs is advised to avoid interferences since some CQAs may produce bioactivity even at nanomolar levels. Biotransformation of CQAs by gut microbiota, the discovery of new enzymatic biosynthetic and metabolic pathways, dietary assessment, and assessment of biological properties with potential for drug development are areas of active, ongoing research. This review is focused on the chemistry, biosynthesis, occurrence, analytical challenges, and bioactivity recently reported for mono-, di-, tri-, and tetraCQAs.

Topics: Acyltransferases; Animals; Anti-Inflammatory Agents; Antioxidants; Biosynthetic Pathways; Brachypodium; Cognitive Dysfunction; Dietary Supplements; Humans; Ipomoea batatas; Mixed Function Oxygenases; Neuroprotective Agents; Phytochemicals; Plant Proteins; Plants, Medicinal; Quinic Acid; Terminology as Topic

The accumulation of amyloid β (Aβ) in the brain is a major pathological feature of Alzheimer's disease (AD). In our previous study, we demonstrated that coffee polyphenols (CPP) prevent cognitive dysfunction and Aβ deposition in the brain of an APP/PS2 transgenic mouse AD model. The underlying mechanisms, however, remain to be elucidated. Here, we investigated the effects of the chronic administration of 5-caffeoylquinic acid (5-CQA), the most abundant component of CPP, on cognitive dysfunction in APP/PS2 mice to identify the role of CPP in Aβ elimination. Relative to the untreated controls, the mice fed a 5-CQA-supplemented diet showed significant improvements in their cognitive function assessed by Y-maze and novel object recognition tests. Histochemical analysis revealed that 5-CQA substantially reduced Aβ plaque formation and neuronal loss in the hippocampi. Moreover, 5-CQA upregulated the gene encoding low-density lipoprotein receptor-related protein 1, an Aβ efflux receptor, and normalized the perivascular localization of aquaporin 4, which facilitates Aβ clearance along the paravascular pathway. These results suggest that 5-CQA reduces Aβ deposition in the brain by modulating the Aβ clearance pathways and ameliorating cognitive decline and neuronal loss in APP/PS2 mice. Thus, 5-CQA may be effective in preventing cognitive dysfunction in AD.

Topics: Alzheimer Disease; Amyloid beta-Peptides; Animals; Brain; Coffee; Cognition; Cognitive Dysfunction; Disease Models, Animal; Female; LDL-Receptor Related Proteins; Male; Mice, Transgenic; Phytotherapy; Polyphenols; Quinic Acid

Topics: Alzheimer Disease; Animals; Centella; Cognition; Cognition Disorders; Cognitive Dysfunction; Diet; Disease Models, Animal; Female; Learning; Male; Memory; Mice; Mice, Inbred C57BL; Mice, Transgenic; Plant Extracts; Quinic Acid; Triterpenes

This study was performed to investigate the effects of Artemisia argyi and 4,5-dicaffeyolquinic acid (4,5-diCQA) as a main compound of ethyl acetate fraction from Artemisia argyi (EFAA) on high-fat diet (HFD)-induced cognitive dysfunction. Both EFAA and 4,5-diCQA were effective in improving cognitive function on HFD-induced cognitive dysfunction. In brain tissue analysis, it was confirmed that EFAA and 4,5-diCQA inhibited the reduction of neurotransmitters as well as oxidative stress and mitochondrial dysfunction. In addition, they inhibited amyloid β (Aβ) accumulation by increasing the expression of insulin-degrading enzyme and consequently prevented apoptosis. In conclusion, it is presumed that Artemisia argyi may help to improve the cognitive impairment due to the HFD, and it is considered that this effect is closely related to the physiological activity of 4,5-diCQA. PRACTICAL APPLICATIONS: Artemisia argyi is used in traditional herbal medicine in Asia. Type 2 diabetes mellitus has been proven by a variety of epidemiological studies to be a risk factor for cognitive impairment, such as Alzheimer's disease. This study confirmed that 4,5-diCQA is a bioactive compound of Artemisia argyi on improving HFD-induced cognitive dysfunction. Therefore, this study can provide useful information to the effect of Artemisia argyi and related substance.

Topics: Amyloid beta-Peptides; Apoptosis; Artemisia; Brain; Cognitive Dysfunction; Diet, High-Fat; Insulysin; Oxidative Stress; Phytotherapy; Plant Extracts; Plants, Medicinal; Quinic Acid