By analyzing extracts from the discarded underground component of wood-decaying mushrooms known as the mycelium, researchers have uncovered a host of compounds with skin-protecting properties, providing some of the first detailed evidence for the anti-aging properties of mushroom mycelia.

The study, published Feb. 23 in Biotechnology Letters, found three categories of compounds in extracts from the mycelia of three species of mushrooms, and then evaluated these extracts for specific skin-protecting effects, including the inhibition of tyrosinase and hyaluronidase, two hormones implicated in skin aging. They also calculated the SPF of the extracts, finding they ranged from around 2 to 9.

"One of the biggest challenges of modern cosmetology is inhibiting or slowing down the aging processes of the skin," said first author Katarzyna Sułkowska-Ziaja, an assistant adjunct professor in the Department of Pharmaceutical Botany of the Jagiellonian University Medical College in Krakow, Poland.

"There are several hundred natural ingredients used in cosmetics technology. These mainly include extracts and oils obtained from plants," Sułkowska-Ziaja told The Academic Times. "However, the cosmetic industry, looking for new solutions, now turns to traditional Chinese and Japanese medicine, which for centuries has been using the kingdom of mushrooms as an antidote to many diseases and as an elixir of youth."

The pharmacological effects of mushrooms have been acknowledged by traditional Chinese medicine for thousands of years, inspiring modern researchers to examine them more closely. For example, "Shen Nong's Herbal Classic," written as early as 100 B.C., described the mushroom species Ganoderma lucidum as increasing lifespan and vitality, effects that have now been quantified in the lab.

Cosmetics companies are beginning to see the commercial value of fungi, and "Preparations containing mushroom extracts with anti-wrinkle, whitening, moisturizing and nourishing properties are appearing on the market," Sułkowska-Ziaja noted.

But much about the specific chemistry of their anti-aging properties, particularly those of the mycelium, still warrants further research.

"Due to the high antioxidant potential, mushroom extracts are used in anti-aging preparations, and due to the content of compounds with anti-inflammatory or antimicrobial properties, they are increasingly used in products for problematic skin," Sułkowska-Ziaja said. "Mushroom extracts also can absorb ultraviolet rays, so they can be used as a natural sunscreen. These valuable properties prompted me to undertake such research topics."

This study focused on three species of xylophagous mushrooms, a catch-all term for any mushroom that feeds on living or dead wood: Ganoderma applanatum and Trametes versicolor, both of which are found worldwide, and Laetiporus sulphureus, found throughout Europe and North America. While they all produce mushrooms, the team used cultures from the mycelium — the vegetative undergrowth of the mushroom that lies mostly invisible under the ground, like the roots of a tree. Using these cultures helped the team get purer samples than would have been possible picking mushrooms from the wild.

Finding anti-aging compounds in the mycelium also presents a new avenue for harvesting these materials and preventing waste, as the mycelium of the fungus is often discarded or left behind when harvesting mushrooms.

As explained by Sułkowska-Ziaja, the compounds the team isolated included sterols, which make skin more flexible; phenolic acids, natural exfoliants that improve skin regeneration; and indoles, which protect against sun damage.

The team, composed of researchers from across the medical college's faculty of pharmacy, also analyzed these compounds for their ability to inhibit the activity of key enzymes associated with skin aging. 

The first, tyrosinase, is involved in the production of melanin, which can contribute to hyperpigmentation spots. The researchers found that extracts from all three species of mushroom inhibited this enzyme due to high levels of kojic acid, a known tyrosinase inhibitor. The paper also states that kojic acid has antibacterial and moisture-retaining properties.

The second enzyme, hyaluronidase, is a known "spreading factor" for skin because it degrades portions of the extracellular matrix that binds it, resulting in drooping, sagging skin. The team found that while all the extracts inhibited tyrosinase, only L. sulphureus, also known as chicken-of-the-woods, inhibited hyaluronidase.

The team is next interested in investigating other properties of the extracts, such as anti-inflammation and antioxidation. The researchers are optimistic that their results will see real-world application in future anti-aging products.

"Mushrooms are still underestimated in Western culture as a medicinal raw material," said Sułkowska-Ziaja. "Studied mycelial cultures can be proposed as a model for researching the accumulation of valuable substances with multidirectional biological properties. The use of this strategy allows us to obtain results potentially of an applied nature in the future."

The study, "Mycelial culture extracts of selected wood-decay mushrooms as a source of skin-protecting factors," published Feb. 23 in Biotechnology Letters, was authored by Katarzyna Sułkowska-Ziaja, Karolina Grabowska, Anna Apola, Agata Kryczyk-Poprawa and Bozena Muszyńska, Jagiellonian University Medical College.