Medicinal Potential of the Insoluble Extracted Fibers Isolated from the Fomes fomentarius (Agaricomycetes) Fruiting Bodies: A Review.

The tough, hoof-shaped fruiting bodies of the tinder conk mushroom, Fomes fomentarius (L.) Fr. (Polyporaceae, Agaricomycetes), were traditionally used all over the world as tinder to start fire, for ritual purposes, to make artworks like clothing, frames, ornaments, and also to cure various human diseases (wounds, gastro-intestinal disorders, liver-related problems, inflammations, various cancers, etc.). The first wave of scientific interest in F. fomentarius in Europe dates back to the early 1970s with the discovery of the red-brown pigments of the F. fomentarius external layer. Since then, a number of research papers and reviews have mentioned the history of use, taxonomy, composition and medicinal properties of some F. fomentarius preparations, e.g., soluble extracts and their fractions, isolated cell walls, mycelia and compounds purified from the culture broth. The present review is focused on the composition and benefits of the water-insoluble cell walls obtained from the F. fomentarius fruiting bodies. Isolated cell walls of the tinder mushroom reveal a fibrous hollow structure with an average diameter of 3-5 µm and a wall thickness of 0.2-1.5 µm. Naturally, the fibers are composed of 25-38% glucans, with a majority of ß-glucans, around 30% polyphenols, 6% chitin and less than 2% hemicellulose. The percentage of the main structural compounds can vary either slightly or considerably, depending on the extraction conditions. According to in vitro, in vivo, ex vivo as well as clinical studies, F. fomentarius fibers can modulate the immune system, contribute to intestinal health, accelerate wound healing, absorb heavy metals, organic dyes and radionuclides, normalize kidney and liver function, and provide antibacterial, antiviral, antifungal, anxiolytic, anti-inflammatory and analgesic effects. Multiple action of the insoluble cell walls purified from the F. fomentarius fruiting bodies is particularly effective in the treatment of chronic, recurring, complicated multifactorial diseases. It is certainly worth exploring the medicinal potential and the practical application of these preparations further.

Coupling of cerebral blood flow and functional connectivity is decreased in healthy aging.

Aging leads to cerebral perfusion and functional connectivity changes that have been assessed using various neuroimaging techniques. In addition, a link between these two parameters has been demonstrated in healthy young adults. In this work, we employed arterial spin labeling (ASL) fMRI to measure global and voxel-wise differences in cerebral blood flow (CBF) and intrinsic connectivity contrast (ICC) in the resting state in a group of cognitively normal elderly subjects and a group of cognitively normal young subjects, in order to assess the effects of aging on CBF-ICC coupling, which had not been previously evaluated. Our results showed age-related global and regional CBF decreases in prefrontal mesial areas, lateral frontal regions, insular cortex, lateral parietal areas, precuneus and occipital regions. Subcortically, perfusion was reduced in the medial thalamus and caudate nucleus. ICC was also found reduced with age in prefrontal cortical areas and insular cortex, affecting key nodes of the default mode and salience networks. Areas of ICC and CBF decrease partially overlapped, however, the CBF reduction was more extensive and encompassed more areas. This dissociation was accompanied by a decrease in CBF-ICC coupling. These results suggest that aging leads to a disruption in the relationship between CBF and intrinsic functional connectivity that could be due to neurovascular dysregulation.