marine drugs Review Phycochemical Constituents and Biological Activities of Fucus spp. Marcelo D. Catarino, Artur M. S. Silva ID and Susana M. Cardoso * ID Department of Chemistry & Organic Chemistry, Natural Products and Food Stuffs Research Unit (QOPNA), University of Aveiro, Aveiro 3810-193, Portugal; [email protected] (M.D.C.); [email protected] (A.M.S.S.) * Correspondence: [email protected]; Tel.: +351-234-370-360; Fax: +351-234-370-084 Received: 27 June 2018; Accepted: 23 July 2018; Published: 27 July 2018 Abstract: Seaweeds are known to be a good supply of key nutrients including carbohydrates, protein, minerals, polyunsaturated lipids, as well as several other health-promoting compounds capable of acting on a wide spectrum of disorders and/or diseases. While these marine macroalgae are deeply rooted in the East Asian culture and dietary habits, their major application in Western countries has been in the phycocolloid industry. This scenario has however been gradually changing, since seaweed consumption is becoming more common worldwide. Among the numerous edible seaweeds, members of the genus Fucus have a high nutritional value and are considered good sources of dietary fibers and minerals, especially iodine. Additionally, their wealth of bioactive compounds such as fucoidan, phlorotannins, fucoxanthin and others make them strong candidates for multiple therapeutic applications (e.g., antioxidant, anti-inflammatory, anti-tumor, anti-obesity, anti-coagulant, anti-diabetes and others). This review presents an overview of the nutritional and phytochemical composition of Fucus spp., and their claimed biological activities, as well as the beneficial effects associated to their consumption. Furthermore, the use of Fucus seaweeds and/or their components as functional ingredients for formulation of novel and enhanced foods is also discussed. Keywords: Fucus spp.; nutritional value; bioactivities; fucoidan; phlorotannins; fucoxanthin 1. Introduction Seaweeds, i.e., marine macroalgae, have a long tradition of usage and applications among the far East populations, either for direct consumption and nutrition or for medicinal purposes, whereas, in Western countries, their industrial utilization has been rather confined to extraction of phycocolloids and, to a lesser extent, certain fine biochemicals [1]. Nevertheless, this panorama is currently shifting as macroalgae are becoming more and more popular since, in addition to not competing with food crops for the use of arable land and fresh water resources, they are claimed to be a good supply of key nutrients including carbohydrates, protein and minerals [2], as well as a rich source of health-promoting compounds capable of acting on a wide spectrum of disorders and/or diseases [3]. Note also that the Japanese have the world’s longest life expectancy, which has been partly associated with their different dietary patterns, and of course, the regular consumption of macroalgae [4]. Based on this evidence, marine macroalgae are presently pointed out as the plant-based food of the future, and their regular consumption among Western population has been trending upward [5]. Indeed, the global functional food market, which was valued at US $168 in 2013 and expected to exceed US $305.4 billion by 2020, is believed to be one of the most important exploiting opportunities where direct applications of seaweeds, crude extracts or purified fractions of seaweeds might hold potential [4]. Fucus, an abundant and widely distributed genus of brown, perennial and edible seaweeds, has earned increasing attention throughout the last years. This genus occupies the cold-temperate waters from the littoral and sublittoral regions along the rocky shorelines of the northern hemisphere Mar. Drugs 2018, 16, 249; doi:10.3390/md16080249 www.mdpi.com/journal/marinedrugs Mar. Drugs 2018,, 16,, x 249 FOR PEER REVIEW 22 of of 33 34 from the littoral and sublittoral regions along the rocky shorelines of the northern hemisphere (Figure 1)(Figure [6], and1)[ is6 comprised], and is comprised of 66 currently of 66 currentlyaccepted taxonomically accepted taxonomically species all speciescharacterized all characterized by a greenish by browna greenish trisected brown thallus, trisected i.e., thallus, a structure i.e., a structure consisting consisting of a ofholdfa a holdfast,st, a small a small stipe stipe and and flattened flattened dichotomously-branched blades blades with with terminal terminal recept receptaclesacles that that swell swell during during the the reproductive reproductive season. season. The blades usually have a central-thickened area called midrib and, in some species, air bladders can be found to keep them floating floating in a vertical position when submerged [[7].7]. F. vesiculosus is the most well-knownwell-known species from Fucus genus, often dominating shallow macroalgae communities.communities. ItIt growsgrows on on the the mid-tide mid-tide zone zone of of high high salinity salinity waters waters forming forming large large belts belts that thathave have an important an important role in role the structurein the structure of the habitats of the habitats that harbor that species-rich harbor species-rich epiphytic andepiphytic epibenthic and epibenthiccommunities communities [8]. Other important[8]. Other speciesimportant from species this genus from this include genusF. spiralisincludeand F. spiralisF. serratus and, F. the serratus former, thegrowing former in growing the upper in intertidalthe upper zone intertidal and the zone latter and in the the latter lower-mid in the lower-mid intertidal zone intertidal [9,10]. zone [9,10]. Figure 1. Geographical distribution of Fucus L. © OpenStreetMap contributors (licensed under Open Figure 1. Geographical distribution of Fucus L. © OpenStreetMap contributors (licensed under Open Data Commons Open Database License); GBIF.org (25 July 2018) GBIF Occurrence Download Data Commons Open Database License); GBIF.org (25 July 2018) GBIF Occurrence Download https: https://doi.org/10.15468/dl.l5mbpr (licensed under CC BY 4.0). //doi.org/10.15468/dl.l5mbpr (licensed under CC BY 4.0). With high content in dietary fiber, minerals and vitamins, and low in fat, seaweeds belonging to this genusWith highhave content an exceptional in dietary combination fiber, minerals of macro- and vitamins, and micronutrients and low in fat, that seaweeds make them belonging very interestingto this genus from have a nutritional an exceptional perspective. combination In fact, of several macro- Fucus and micronutrients spp. have long that been make harvested them veryand usedinteresting as food from sources a nutritional mainly in perspective.far East Asian In countr fact, severalies, butFucus also inspp. some have coastal long countries been harvested of Western and Europeused as and food Alaska sources [11]. mainly In particular, in far East F. Asian spiralis countries, is a popular but alsodelicacy in some in the coastal Azores countries Islands of where Western its swollenEurope andreceptacles Alaska are [11]. very In particular, appreciatedF. spiralisand knownis a popular as sea lupines delicacy [12]. in the Azores Islands where its swollenIn traditional receptacles medicine, are very appreciatedFucus spp. andbecame known very as popular sea lupines mainly [12]. due to their high content in iodine,In which traditional renders medicine, them remarkableFucus spp. therapeutic became very prop popularerties for mainly treating due goiter, to their i.e., highthe swelling content of in thyroidiodine, whichand thyroid-related renders them complications, remarkable therapeutic and obesity properties [13]. Moreover, for treating this goiter,genus i.e.,is also the an swelling excellent of sourcethyroid of and bioactive thyroid-related compounds complications, such as fucoidans, and obesity phlorotannins [13]. Moreover, and fucoxanthin, this genus is which also an have excellent been repeatedlysource of bioactive shown to compounds possess important such as fucoidans,therapeutic phlorotannins properties including and fucoxanthin, the treatment which of have cellulite, been bloodrepeatedly clot formations, shown to possess rheumatoid important arthritis, therapeutic asthma, properties atherosclerosis, including diabetes, the treatment psoriasis of and cellulite, skin diseases,blood clot cancer formations, and other rheumatoid oxidative arthritis, and inflammatory asthma, atherosclerosis, related conditions diabetes, [14–17]. psoriasis Thanks and to skinthe presencediseases, of cancer such andfunctional other oxidativecompounds, and Fucus inflammatory spp. have related been seen conditions as potential [14–17 functional]. Thanks and/or to the activepresence ingredients of such functional with great compounds, interest and Fucusapplicabspp.ility have not beenonly seenin the as cosmetic potential and functional pharmaceutical and/or industriesactive ingredients but also within the great food interest and nutraceutical and applicability industries not only [18]. in Indeed, the cosmetic the development and pharmaceutical of novel andindustries improved but alsofoods in thecontaining food and seaweeds nutraceutical and/or industries seaweed-derived [18]. Indeed, components the development is already of novel a reality and thatimproved is showing foods promising containing results, seaweeds mainly and/or in the seaweed-derived field of dayries components and seafoods is [19–22]. already a reality that is showingIn this promising context, results, the present mainly inmanuscript the field of revi