## 4 Natural Antioxidants and Their Role in Cosmetics
### Fungi-Derived Antioxidants  
In addition to plants, microorganisms and macroorganisms, including actinomycetes, bacteria, cyanobacteria, and fungi with lichens, also serve as sources of antioxidants and other bioactive compounds. This section will explore the medicinal and cosmetic potential of various mushroom species, particularly large-fruited fungi and lichens [164; 165]. Mushrooms such as _Ganoderma lucidum_, _Hericium erinaceus_, _Lentinus edodes_, _Cordyceps sinensis_, _Sclerotinia scleroum_, and _Trametes versicolor_ are widely recognized for their health-promoting properties and are considered functional and nutraceuticalal foods [166]. Numerous studies indicate that fungi exhibit a broad spectrum of biological activity, including immunomododulatory, anticancer, antiviral, antibacterial, antifungal, anti-inflammatory, antioxidant, antidiabetic, neurotonic, hepatoprotective, and cosmeceutical properties. They also help regulate triglyceride and cholesterol levels in the blood and lower blood pressure, among other benefits [166; 167; 121; 122]. The substances responsible for these versatile properties vary in chemical nature and include ergothionine, glutathione, phenols, flavonoids, \(\beta\)-glucans, ergosterol, and \(\beta\)-carotene [167]. The main nutrients found in mushroom fruiting bodies include proteins, carbohydrates, fats, vitamins, and minerals. Both wild and cultivated mushroom fruiting bodies are rich in antioxidants. One of the most extensively studied mushroom species over the years is _Ganoderma lucidum_, known as lingzhi in Chinese and reishi in Japanese [166]. Among the phenolic compounds found in mushrooms, the largest percentage consists of phenolic acids, which are well known for their antioxidant activity. Species with the greatest diversity of phenolic compounds include _Boletus badius_, _Cantharellus cibarius_, and _Pleurotus ostreatus_[166; 168; 169]. Antioxidant properties are also associated with the presence of non-hallucinogenic indole compounds in mushrooms, including L-tryptophan, 5-hydroxy tryptophan, serotonin, melatonin, and tryptamine [125; 170]. Additionally, mushrooms are one of the few natural sources of ergosterol, a precursor of vitamin D\({}_{2}\). The presence of other vitamins in forest mushroom fruiting bodies, such astocopherol, \(\beta\)-carotene, and ascorbic acid, has also been confirmed. These compounds contribute significantly to the antioxidant potential of mushrooms [166]. Antioxidants derived from fungi (species from _Basidiomycota_, _Ascomycota_, _Zygomycota_), such as polysaccharides, pigments, peptides, ergothioneine, ergosterol, phenols, and alkaloids, have potential applications in the food, pharmaceutical, and cosmetic industries [171]. Active compounds extracted from mushrooms are widely used in the production of cosmetic products for hair and skin. Important bioactive ingredients derived from fungi, such as kojic acid (Figure 6), chrysophanol, cytonemin, mycosporine-like amino acids, \(\beta\)-glucans, triterpen (ganoderic acid, ergosterols), ergothioneine, ceramides, and chitosan, play a crucial role in the effectiveness of cosmetic formulations [167]. Beyond their antioxidant properties, mushrooms and their extracts exhibit anti-tyrosine and anti-hyaluuronidase activities, which help control skin discoloration and prevent the breakdown of hyaluronic acid. Additionally, they possess anti-collagenase and anti-elastase properties, which contribute to maintaining skin firmness and elasticity. _Ganoderma lucidum_, _Euplorbia characias_, and _Pistacia atlantica_ subsp. _muntica_ are mushroom species with strong anti-tyrosine native activity, making them valuable ingredients in skin-whitening products. Mushroom extracts and their bioactive metabolites offer excellent antioxidant, anti-wrinkle, anti-aging, moisturizing, and skin-whitening properties, making them ideal multifunctional cosmetic ingredients.