Keywords
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Iranian wild mushrooms; Antioxidant activity; Medicinal properties; Molecular identification. |
Introduction
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Over decades, edible mushrooms have been considered one of the most prominent functional foods. They have earned this reputation based on a body of information demonstrating that edible mushrooms are excellent sources of fiber, essential oils, protein (including all the essential amino acids), vitamins, minerals, lectins, and bioactive compounds [1]. However, the current cultivated mushrooms are a very small proportion of the total wild mushrooms, as many of wild mushrooms have not yet been standardized for cultivation [2]. Thus, it is not surprising that the interest in exploring nutritional and medicinal capabilities of wild mushrooms has been increasing. |
At least, three review articles have exclusively focused on a specific area of medicinal properties of mushrooms, including antioxidant [3], anticancer [4], and antibacterial activities [5]. In addition, a number of other review articles have covered a wider range of pharmacological and medicinal properties of edible mushrooms, including antimicrobial, anticancer, antioxidant, antiviral, immunomodulatory, immunosuppressive, anti-allergic, anti-inflammatory, and anticholesterol activities [6]. Among other medicinal properties, the antioxidant activity of edible mushrooms could be directly applicable to daily life, as it may associate to natural prevention of oxidative stress that itself is largely influenced by lifestyle habits [7]. |
Over the past decade, advances have been made in research on antioxidant properties of Iranian wild mushrooms. Therefore, in order to update the existing knowledge, this review will outline efforts on collection, identification and study of medicinal properties of edible mushrooms growing wild in Iran. The main focus of this mini-review is on antioxidant activity, though other important medicinal properties have been mentioned. It may also encourage researchers from other countries (similar to Iran) to develop protocols for collection and cultivation of well-identified wild mushrooms and explore their pharmaceutical properties. |
Oxidative Stress and Natural Antioxidants
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Oxidative stress is a well-known phenomenon caused by an imbalance between formation and removal of reactive micromolecules such as reactive oxygen species (ROS). In a broad spectrum, the term of ROS may refer to both the oxygencentered radicals and non-radical derivatives of O2 (such as hydrogen peroxide, singlet oxygen, and hypochlorous acid) [8]. These reactive molecules may be produced in all mammalian cells in response to exogenous stimuli through normal cellular metabolism or activation of membrane-bound enzymes [8, 9]. Oxidative stress has the potential to damage cells and may eventually lead to cancer, cardiovascular diseases, diabetes, aging, and a vast number of other illnesses and disorders [10]. The human body?s defense system responds to oxidative stress generally through scavenging or lessening ROS formation using endogenous and/or diet-derived molecules [9]. However, the antioxidant defense system needs to be assisted by consumption of antioxidant-containing supplements. Due to carcinogenic risks associated with consuming synthetic antioxidants, there has been increasing interest to replace synthetic antioxidants by natural sources of antioxidants, namely vegetables, herbs, fruits and mushrooms [11]. |
Wild Edible Mushrooms as Sources of Antioxidants
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Up to the present, only around 40 mushroom species have been commercially cultivated. Although recent efforts have been made to standardize cultivation of wild edible mushrooms, the number of cultivated mushrooms is still a very small proportion of the total number of wild mushrooms, as it has been estimated that the number of wild mushrooms could reach around 140,000 [2]. |
A number of studies have reported antioxidant capability of wild or cultivated edible mushroom species, extensively reviewed by Ferreira et al., 2009 [3]. Most of these studies have measured antioxidant activity through in vitro assays including DPPH inhibition, reducing power, ferric chelating, and biochemical assays including lipid peroxidation inhibition. In addition, a number of compounds related to antioxidant activity have been identified, including polyphenols (phenolic acids, phenylpropanoids, lignin, melanins, tannins, and flavonoids), Ã |