Tag: fungus

Inaoside A, a New Antioxidant Derived from Mushrooms

Photo by Marek Piwnicki

Natural products have unique chemical structures and biological activities and can play a pivotal role in advancing pharmaceutical science. In a pioneering study, researchers from Shinshu University discovered Inaoside A, an antioxidant derived from Laetiporus cremeiporus mushrooms. This breakthrough, published in the journal Heliyon, sheds light on the potential of mushrooms as a source of therapeutic bioactive compounds.

The search for novel bioactive compounds from natural sources has gained considerable momentum in recent years due to the need for new therapeutic agents to combat various health challenges. Among a diverse array of natural products, mushrooms have emerged as a rich reservoir of bioactive molecules with potential pharmaceutical and nutraceutical applications. The genus Laetiporus has attracted attention for its extracts exhibiting antimicrobial, antioxidant, and antithrombin bioactivities. The species Laetiporus cremeiporus, spread across East Asia, has also been reported to show antioxidant properties. However, the identification and characterisation of specific antioxidant compounds from this species have not been conducted.

In a groundbreaking study, researchers led by Assistant Professor Atsushi Kawamura from the Department of Biomolecular Innovation, Institute for Biomedical Sciences, Interdisciplinary Cluster for Cutting Edge Research, Shinshu University, along with Hidefumi Makabe from the Department of Agriculture, Graduate School of Science and Technology, Shinshu University, and Akiyoshi Yamada from the Department of Mountain Ecosystem, Institute for Mountain Science, Interdisciplinary Cluster for Cutting Edge Research, Shinshu University, recently discovered the antioxidant compound derived from L. cremeiporus.

The researchers collected fresh fruiting bodies of L. cremeiporus from the Ina campus of Shinshu University. The obtained extracts were concentrated and partitioned between water and ethyl acetate. After this, the extracts were subjected to advanced chromatographic techniques, which led to the successful isolation of Inaoside A, a new antioxidant phenolic compound, along with three other well-characterised bioactive compounds, i.e., 5′-S-methyl-5′-thioadenosine (MTA), nicotinamide, and adenosine.

“Our study marks the pioneering discovery of Inaoside A from an extract of the edible mushroom Laetiporus cremeiporus. To date, there has been only one prior report on the biological function of an extract of L. cremeiporus. We are the first to uncover the isolation of an antioxidant compound from L. cremeiporus,” states Professor Kawamura, highlighting the breakthrough research.

Next, the researchers wanted to determine the structure of the newly found antioxidant compound. For this, they utilised one and two- dimensional NMR and other spectroscopic analyses. The structure of Inaoside A revealed a planar configuration. With a molecular formula of C17H24O7, the compound was found to feature a distinctive ribose moiety, identified as α-ribofuranoside through stereochemical analysis. Subsequent investigation into the absolute stereochemistry confirmed the D-ribose configuration, thereby reinforcing the planar structure of this compound.

The mushroom extracts were then isolated into fractions to determine the antioxidant activities of the four isolated bioactive compounds. These fractions were then examined by DPPH radical scavenging and superoxide dismutase assays. The findings were noteworthy as the DPPH radical scavenging activity exhibited by Inaoside A was significant, showing 80% inhibition at 100μg/mL, indicative of its significant antioxidant properties. The IC50 value of Inaoside A was determined to be 79.9μM, further highlighting its efficacy as an antioxidant agent.

What are the objectives of the researchers following the discovery of Inaoside? Professor Kawamura reveals, “We are now focusing on investigating the chemical compositions and biological properties of natural compounds obtained from mushrooms. Our goal is to uncover the potential of edible mushrooms as functional foods through this discovery.”

The identification of Inaoside A as an antioxidant from Laetiporus cremeiporus marks a significant breakthrough in natural product research, highlighting the potential of mushrooms as a source of therapeutic bioactive compounds. These findings may lead to the development of novel antioxidant-based therapies for various health conditions. Further studies should focus on synthetic research and detailed investigations into the biological activity of Inaoside A, aiming to harness its potential as a pharmaceutical lead compound.

Source: Shinshu University

A Fungus in Certain Foods Slows Intestinal Healing

A study has found that a fungus found in certain foods such as cheese and processed meats can cause intestinal injuries in humans and mice with Crohn’s disease to fester and impeding healing.

These findings, from researchers at Washington University School of Medicine in St. Louis and the Cleveland Clinic, suggest that there is potentially a diet-based way to treat Crohn’s disease.

“We’re not suggesting that people stop eating cheese and processed meat; that would be going far beyond what we know right now,” said first author Umang Jain, PhD, an instructor in pathology & immunology at the School of Medicine. “What we know is that this foodborne fungus gets into inflamed, injured tissue and causes harm. We’re planning to perform a larger study in people to figure out if there’s a correlation between diet and the abundance of this fungus in the intestine. If so, it is possible dietary modulation could lower levels of the fungus and thereby reduce symptoms of Crohn’s disease.”

Crohn’s disease is driven by chronic inflammation in the gastrointestinal tract and immunosuppressive medication is the usual treatment. Crohn’s patients endure flare-ups where digestive tracts are dotted with inflamed, open sores that can persist for up to months.

To understand why intestinal ulcers heal so slowly in some people, the researchers studied mice with injured intestines. By sequencing microbial DNA at the site of injury, they discovered that the fungus Debaryomyces hansenii was abundant in wounds but not in uninjured parts of the intestine. D. hansenii can be found in all kinds of cheeses, as well as sausages, beer, wine and other fermented foods.

Introducing D. hansenii into mice with injured intestines slowed down the healing process, and eliminating the fungus with amphotericin B sped it up. In humans, the researchers discovered  D. hansenii in seven out of seven of people with Crohn’s disease, and another analysis of Crohn’s patients found D. hansenii present but only in sites of injury and inflammation. 

“If you look at stool samples from healthy people, this fungus is highly abundant,” Jain said. “It goes into your body and comes out again. But people with Crohn’s disease have a defect in the intestinal barrier that enables the fungus to get into the tissue and survive there. And then it makes itself at home in ulcers and sites of inflammation and prevents those areas from healing.”

Their results suggest that elimination of the fungus could allow wounds to heal normally again, and minimise flare-ups. In mouse studies, amphotericin B eliminated the fungus but it is of limited use in people since it can only be administered intravenously, therefore an oral antifungal is being researched.

“Crohn’s disease is fundamentally an inflammatory disease, so even if we figured out how to improve wound healing, we wouldn’t be curing the disease,” Jain said. “But in people with Crohn’s, impaired wound healing causes a lot of suffering. If we can show that depleting this fungus in people’s bodies—either by dietary changes or with antifungal medications—could improve wound healing, then it may affect the quality of life in ways that we’ve not been able to do with more traditional approaches.”

Source: Medical Xpress

Journal information: U. Jain et al., “Debaryomyces is enriched in Crohn’s disease intestinal tissue and impairs healing in mice,” Science (2021). science.sciencemag.org/cgi/doi … 1126/science.abd0919