Recent research and development of Antrodia cinnamomea

Abstract

Medicinal mushrooms have attracted much attention recently owing to their potent therapeutic activity, especially as chemopreventive and immunomodulatory agents. Antrodia cinnamomea is a treasured Taiwanese mushroom that has been used by aboriginal tribes for centuries to treat food intoxication and to enhance liver functions. It was included in Asian folk medicine in the last few decades with remarkable results in treating inflammatory disorders, cancers, hypertension and hepatitis. This myriad of therapeutic activities encouraged several research groups to subject A. cinnamomea to intensive biological and phytochemical investigation, leading to the isolation of different classes of pharmacologically active secondary metabolites. The in vitro and in vivo biological results of the mushroom extracts and its active components revealed their potent cytotoxic, anti-inflammatory and hepatoprotective activities. The aim of this study is to review recent reports on the biological activities of A. cinnamomea extracts and its active components; quality control protocols; synthetic methodologies for the preparation of active components; developed culture techniques; phylogenetic analysis and gene cloning. This study also tackles major challenges facing future expansion of A. cinnamomea production.

Introduction

Fungi form the second largest group of living organisms after insects and it is believed that over 1.5 million fungal species exist in nature (Mueller & Bills, 2004). They have attracted scientists from different disciplines owing to their fascinating nature and capability to survive in hostile environments in the midst of decay at the harshest layer of the ecosystem. This survival mechanism has been evolved over millennia through producing an arsenal of secondary metabolites to fight array of different pathogens in such environments. These secondary metabolites have been utilized in the health care system over the past two centuries with astonishing success in reducing mortality rate and diseases burden (Halpern, 2007). Fungi can be subdivided into two main categories, microfungi and macrofungi or mushrooms. Mushrooms are not a taxonomic group but do include well over 12,000 species possessing macroscopic fruiting-bodies, the mushrooms or sporocarps, which are visible to the naked eye.

Medicinal mushrooms have emerged as integral ingredients of dietary supplements in the last few decades. It is estimated that between 80 and 85% of all medicinal mushrooms products are derived from the fruiting bodies, which have been either artificially cultured or collected from nature. However, due to the increased in market demand, mycelial products are considered the wave of the future (Cheung, 2008). Dietary supplements or functional foods or nutraceuticals are food components which affect one or more identified functions in the body in a positive manner and contain higher doses of food bioactive agents exceeding the levels obtained from normal food (Chang & Miles, 2004). The concept of functional food aroused from the prevailing fact that food and medicine have a common origin. Dietary supplements play a major role in global health system through curtailing health expenditure and offering superior health habits. It is estimated that the global market for dietary supplement reached $187 billion in 2010 (S.-H. Liu et al., 2010). Self-selected dietary supplements offer a unique opportunity for citizens to participate actively in the management of their own health issues instead of being on the passive side accepting whatever treatment the health professional decides to administer (Webb, 2006). Of course the health care team members participating in treatment should be fully aware with the patient's functional food intake to adjust therapeutic regimen and avoid any undesirable interactions. In a recent survey conducted in USA, it was found that 60% of patients who use dietary supplements never informed their physicians fearing of their disapproval or lack of understanding of complementary alternative medicine concept (Morris & Murray, 2006). Moreover, some physicians lack solid knowledge on dietary supplements biological activity and their interactions with prescribed drugs. However, with the proper knowledge from both sides, this sort of democratizing treatment is believed to improve patient compliance and mutual trust between patient and other health care team members.

Currently there are several important medicinal mushrooms used worldwide as dietary supplements including: Antrodia cinnamomea (AC), Cordyceps sinensis, Ganoderma lucidum, Phellinus igniarius, Polystictus versicolori, and Poria cocos (Halpern, 2007). In this review we focus on summarizing the recent milestones in AC research, especially the published work after 2008. We discuss in a chronological order the pharmacological activities of AC purified components and crude extracts as well as the biological effects of AC mycelia and fruiting bodies. We also state the recent findings in AC quality control protocols, synthetic methodologies for the preparation of its active components, developed culture techniques, phylogenetic analysis and gene cloning. For the research published before 2008, the reader is advised to refer to the following reviews (Ao et al., 2009, Chen et al., 2010, Geethangili and Tzeng, 2011, Rios et al., 2012).