Chemical Composition and Biological Properties of Portuguese Wild Mushrooms: A Comprehensive Study LILLIAN BARROS,BRUNA A. VENTURINI,PAULA BAPTISTA, LET ´ ICIA M. ESTEVINHO, AND ISABEL C. F. R. FERREIRA* CIMO/Escola Superior Agra ´ria, Instituto Polite ´cnico de Braganc ¸a, Campus de Santa Apolo ´nia, Apartado 1172, 5301-855 Braganc ¸a, Portugal The chemical composition and biological properties of Portuguese wild mushrooms (Cantharellus cibarius, Hypholoma fasciculare, Lepista nuda, Lycoperdon molle, Lycoperdon perlatum, Ramaria botrytis, Tricholoma acerbum) were evaluated in order to assess these products as sources of nutrients and nutraceuticals. The analyzed mushrooms contain very useful phytochemicals such as phenolics, tocopherols, ascorbic acid, and carotenoids. All of the species proved to have antioxidant activity (measured by four different methods), being more significant for R. botrytis (EC 50 values < 1 mg/ mL). Lycoperdon species were resistant to all of the tested microorganisms, and the other samples revealed antimicrobial activity selectively against Gram-positive bacteria, with very low minimal inhibitory concentration, in some cases, even lower than the standard. The combination of bioactive compounds and rich nutritional composition (high contents in protein and carbohydrates, low content in fat with the precious contribution of unsaturated fatty acids and the absence of trans fatty acids) in the mushroom makes it a very special food. KEYWORDS: Mushrooms; chemical compounds; antioxidant activity; antimicrobial activity INTRODUCTION In recent years oxidative stress, induced by reactive oxygen species (ROS) that are generated by normal metabolic activity as well as lifestyle factors such as smoking, exercise, and diet, have been implicated in the causation and progression of several chronic diseases. Antioxidants that can mitigate the damaging effects of ROS have been the focus of recent research (1). There is convincing scientific evidence in support of the association between diet and chronic diseases such as cancer, cardiovascular disease, diabetes, and osteoporosis. Epidemiological studies have consistently shown an inverse association between the consump- tion of vegetables and fruits and the risk of certain forms of cancer and cardiovascular diseases (2). Although the protective effects have been primarily attributed to the well-known antioxidants, such as vitamin C, vitamin E, and -carotene, plant phenolics may also play a significant role (3). Phenolic compounds exhibit a wide range of biological effects including antibacterial, anti-inflammatory, antiallergic, hepato- protective, antithrombotic, antiviral, anticarcinogenic, and va- sodilatory actions (3); many of these biological functions have been attributed to their free radical scavenging and antioxidant activity. Flavonoids are the most common and widely distributed group of plant phenolics and have been shown to be highly effective scavengers of most types of oxidizing molecules, including singlet oxygen and various free radicals, which are possibly involved in DNA damage and tumor promotion (4). The health benefits of tocopherol as a bioactive compound are well documented. R-Tocopherol, the principal form of vitamin E, is a lipid-soluble antioxidant, and it functions as a chain- breaking antioxidant for lipid peroxidation (LP) in cell mem- branes and also as a scavenger of ROS such as singlet oxygen. It is considered to serve as the first line of defense against LP, and it protects polyunsaturated fatty acids (PUFAs) in cell membranes from free radical attack through its scavenging activity in biomembranes at early stages of LP (5). The antioxidant properties of carotenoids have been suggested as being mainly responsible for their beneficial effects (6). Particularly, -carotene has been found to be inversely associ- ated with cancer risk in epidemiologic studies and showed promising results in laboratory assays. Also, the role of lycopene in the prevention of chronic diseases has been evaluated in epidemiological studies as well as in tissue culture experiments using human cancer cell lines, animal studies, and also human clinical trials (6). The biological properties of mushrooms, namely, antioxidant (7–9) and antimicrobial properties (10–13), have been described and attributed to their high content in antioxidants (14–16) and antibiotics, respectively. Besides their pharmacological char- acteristics, wild mushrooms are becoming more and more important in our diet for their nutritional value, including high protein and low fat/energy contents (17–20). The fatty acid * Author to whom correspondence should be addressed (e-mail iferreira@ipb.pt; telephone +351-273-303219; fax +351-273-325405). 3856 J. Agric. Food Chem. 2008, 56, 3856–3862 10.1021/jf8003114 CCC: $40.75  2008 American Chemical Society Published on Web 04/25/2008