Will the sulphur polypore (laetiporus sulphureus) become a new functional food?

The sulphur shelf (Laetiporus sulphureus Bull.:Fr.) Murrill.), also known as crab-of-the-woods or chicken-of-the-woods, is a saprophyte mushroom from the family Polyporaceae that grow on trees in Europe, Asia and North America. Its fruit bodies have a striking golden-yellow color and grow on tree trunks and branches (Figure 1). Old fruits slowly fade into pale beige or pale gray. L. sulphureus was fi rst described by French mycologist Pierre Bulliard in 1789 as Boletus sulphureus. The current name comes from American mycologist William Murill. The mushroom is used as a food or as a folk medicine. It contains a large number of biologically active substances that have a benefi cial effect on human health. It can therefore be assumed that it could be a new functional food and help with some diseases. Food and/or medicine?


Introduction
The sulphur shelf (Laetiporus sulphureus Bull.:Fr.) Murrill.), also known as crab-of-the-woods or chicken-of-the-woods, is a saprophyte mushroom from the family Polyporaceae that grow on trees in Europe, Asia and North America. Its fruit bodies have a striking golden-yellow color and grow on tree trunks and branches ( Figure 1). Old fruits slowly fade into pale beige or pale gray. L. sulphureus was fi rst described by French mycologist Pierre Bulliard in 1789 as Boletus sulphureus.

The current name comes from American mycologist William
Murill. The mushroom is used as a food or as a folk medicine. It contains a large number of biologically active substances that have a benefi cial effect on human health. It can therefore be assumed that it could be a new functional food and help with some diseases.

Food and/or medicine?
Over the generations, this mushroom has become an integral part of some national cuisines particularly for its taste. Besides, it is used in folk medicine for treatment of coughs, pyretic diseases, gastric cancer and rheumatism. Young fruit bodies are edible and their taste is described like crab or lobster. It is highly regarded in Great Britain, Germany, and North America and it is considered as potential source of natural antioxidants [1]. Some people have severe gastrointestinal adverse reactions after eating [2], including vomiting and fever, but this is now thought to be the result of confusion with morphologically similar species such as L. huroniensis and L. gilbertsonii [3].
The mushroom is remarkable in many respects and is valued as a signifi cant source of numerous biologically active substances with potential use in many fi elds of human activity, but especially in medicine [6]. The presence of substances with favorable effect on human health makes the L. sulphureus a new functional food [7]. Experiments with its cultivation on artifi cial substrates [8], have already begun to be produced in large quantities outside the forest, like, for example button mushroom (Agaricus bisporus) or the oyster mushroom (Pleurotus ostreatus).

Summary
Mushrooms are a rich source of chemical compounds. Such a mushroom is also polypore Laetiporus sulphureus, in which a large number of bioactive substances with cytotoxic, antimicrobial, anticancer, anti-infl ammatory, hypoglycemic, and antioxidant activity have been found. This short review summarizes the results of the most important chemical and biological studies of the fruiting bodies and the mycelial cultures of L. sulphureus. Since the ingredients of this edible mushroom have benefi cial effects on human health, it could become a functional food.

Pharmacology effects
The study of the pharmacological effects of L. sulphureus bioactive substances stems from the fact that this mushroom has been used for many centuries in the traditional folk

Cytotoxic and anticancer efefects
Triterpenoids of lanostan-type isolated from the fruiting bodies demonstrate cytotoxic activity. Eburicoic acid (I, EA) is one of main cytotoxic components isolated from L. sulphureus.

Anti-infl ammatory effect
The anti-infl ammatory effect of L. sulphureus is explained by the presence of exopolysaccharide (EPS) which protects cells from apoptosis by signifi cantly inducing inhibition of pro-infl ammatory mediators in cells such as nitric oxide (NO), prostaglandin E2 (PGE2), and tumor necrosis factor- (TNF-) without signifi cant cytotoxicity [16] and also by presence lanostane triterpenoids which were identifi ed as eburicoic acid derivatives [28]. These triterepenoids inhibited the NO production and supressed the production of pro-infl ammatory cytokines, mainly inducible nitric oxide synthase, cyclooxygenase-2, interleukin (IL)-1, IL-6 and TNF-. Eburicoic acid is the main bioactive metabolite in the L. sulphureus against gastric ulcers in mice model [39].

Hypoglycemic effect
EPS also demonstrated the hypoglycemic effect in rats with single dose streptozotocin induced diabetes and caused an increased proliferation and regeneration of pancreatic islet  cells [13]. Other compound with anti-diabetic potential is dehydrotrametenolic acid (V), also isolated from fruiting bodies. It induces the differentiation of adipocytes in vitro, and and antihyperlipidemic effect and therapeutic potential in the treatment of type 2 diabetes and hyperlipidemia [40][41][42].

Conclusion
In recent years, mushrooms are increasingly being searched for new biologically active substances. Since mushrooms are an important part of the daily diet of people in many countries, their analysis is valuable in terms of natural chemoprevention. This is also the case with L. sulphureus, which contains biologically signifi cant substances and could be considered a functional food. Several secondary metabolites have been discovered in the mushrooms of this fungus and have been shown to be cytotoxic, antitumor, antimicrobial, anti-infl ammatory, and antidiabetic.

Competing interest
I declare that I have no competing fi nancial, professional, or personal interests that might have infl uenced the performance or presentation of the work described in this manuscript.