ABSTRACT: The extracellular matrix (ECM) is the largest component of the dermal skin layer, and has a fundamental role in tissue development, differentiation, homeostasis and disease progression. It is continually remodeled by cells in response to environmental factors, such as physical force, hypoxia, trauma and infection. During the aging process, the balance of synthesis and degradation of ECM proteins necessary for skin integrity and tissue regeneration becomes impaired. Elastin, an important structural protein of ECM, is the main component of the elastic fibers that impart resilience and elasticity to elastic tissues, such as skin, lungs, ligaments and arterial walls. Human neutrophil elastase (HNE), a serine protease primarily found in the azurophilic granules of neutrophils, has broad substrate specificity and can cleave not only elastin but also other ECM proteins, such as collagen, fibronectin, laminin and proteoglycan. As the pharmacological inhibition of HNE might prevent the loss of skin elasticity, thus preventing skin sagging during aging, efforts to discover potent HNE inhibitors have increased considerably in the last several years. Mushrooms have been utilized in folk medicine throughout the world since ancient times. They produce various classes of secondary metabolites, many of which possess interesting biological activities and have the potential to be developed as therapeutic agents. Thus, much attention has been paid to the search for specific pharmacologically significant compounds from mushrooms. Phellinus linteus, commonly referred to as Sangwhang in Korea, is a well-known fungus of the genus Phellinus in the family Hymenochaetaceae, which is indigenous mainly to the tropical Americas, Africa, and East Asia. This mushroom has been used as a traditional oriental medicine in Korea, China, Japan and other Asian countries for the treatment of various ailments, including stomachaches, inflammation, oral ulcer, gastroenteric disorders, lymphatic disorders, arthritis of the knee and various cancers. Numerous bioactive substances have been isolated from the fruiting bodies of P. linteus, such as polysaccharides, sterols, proteoglycans, cyclophellitol, furan derivatives, hispidin and hispolon, and their biological activities have been verified in vitro and in vivo. However, there is little information on compounds of the mycelium of P. linteus, with the exception of polysaccharides.
Lee, I.-S., Bae, K., Yoo, J. K., Ryoo, I.-J., Kim, B. Y., Ahn, J. S., Yoo, I.-D. 2012. “Inhibition of human neutrophil elastase by ergosterol deriviatives from the mycelium of Phellinus linteus.” The Journal of Antibiotics. 65,437-440. doi: 10.1038/ja.2012.42.