Prediction scenarios of past, present, and future environmental suitability for the Mediterranean species Arbutus unedo L.

Climate change is a challenge for forests in the coming decades, with a major impact on species adaptation and distribution. The Mediterranean Basin is one of the most vulnerable hotspots for biodiversity conservation under climate change in the world. This research aimed at studying a Mediterranean species well adapted to the region: the Arbutus unedo L. (strawberry tree). The MaxEnt, a presence-only species-distribution software, was used to model A. unedo’s environmental suitability. The current species potential distribution was accessed based on actual occurrences and selected environmental variables and subsequently projected for the Last Glacial Maximum (LGM), the Mid-Holocene (MH), and the years 2050 and 2070, considering the two Representative Concentration Pathways: RCP4.5 and RCP8.5. Results from the LGM projection suggest the presence of refugia in the core of the Mediterranean Basin, in particular the Iberian Peninsula (IP). The projections for the MH indicate increasing climatic suitability for the species and an eastward expansion, relatively to LGM. The predicted future environmental changes will most likely act as a catalyst for suitable habitat loss and a range shift towards the North is likely to occur.

Is the Strawberry Tree, Arbutus unedo (Ericaceae), native to Ireland, or was it brought by the first copper miners?

The Strawberry Tree (Arbutus unedo L.) is often referred to as one of Ireland’s ‘Lusitanian’ species to describe its disjunct distribution, since it is absent from Britain and is mainly found around the Mediterranean Sea and on the Iberian Peninsula. In Ireland, it is regarded as native in the south-west and in Co. Sligo. However, a recent genetic study suggests that it could have been introduced to Ireland directly from northern Spain. This possibility was previously dismissed, since palynological and archaeological evidence showed it to be present in south-west Ireland 4,000 years ago. Here, we examine how an introduction might have occurred prior to this date, by first reviewing what is known of its distribution, ecology and history in Ireland along with archaeological information. Then, combining an updated distribution of A. unedo where it is regarded as native in Ireland with historical accounts, palynological and archaeological records and other information from the literature, we present two online maps, designed to be an ongoing accessible resource. The information has enabled us to propose a means by which A. unedo might have arrived in Ireland with miners who came to work the first known copper mine in north-west Europe, in the Chalcolithic phase of the Late Neolithic, which was at Ross Island on Lough Leane in Co. Kerry. The species’ distribution today suggests that it then spread with subsequent Bronze Age copper mining activity in south-west Ireland, though this is unlikely to account for its arrival in Co. Sligo. Previous suggestions that A. unedo was once much more widely distributed in Ireland and subsequently contracted due to preferential cutting for smelting, are shown to be unfounded.

MOROCCAN STRAWBERRY TREE (Arbutus Unedo L.) LEAVES: COMPARATIVE STUDY OF THE NUTRITIONAL VALUE AND MINERAL COMPOSITION

Strawberry tree (Arbutus Unedo L.) is one of the evergreen trees that grow spontaneously in Moroccan forests. This tall shrub is traditionally used in grazing zones of some Moroccan areas, especially during the dry season, but its value in Morocco has still been underestimated. In this paper, the nutritional composition of A. unedo leaves sample collected from seven Moroccan regions has been assessed. For this, the leaves were dried, crushed, and chemically analyzed for their proximate composition, energetic value, total and reducing sugar, and mineral composition. Results of this study suggested that samples from BniAarouse (BA) region showed the highest contents of essential nutrients such as proteins, dietary fiber, ashes, and fat with average values of 7.53, 17.89, 4.14, and 8.05 g/ 100 g of dry weight, respectively, which positively influences its consumption by small ruminants. Cluster analysis based on surveyed parameters separated the strawberries individuals into four distinct groups, providing a high variability among and within studied locations. That could be related to the diversity of the edaphoclimatic conditions between regions and to the genetic effect. The results of the present study highlighted the potential use of leaves as livestock feed, with intermediate quality, and promotes their optimal cultivation and subsequent domestication in Morocco.

Comparative Study on the Phenolic Fingerprint and Antioxidant Activity of Strawberry Tree (Arbutus unedo L.) Leaves and Fruits

The strawberry tree (Arbutus unedo L., Ericaceae family) is an evergreen Mediterranean shrub whose leaves and fruits are used in traditional medicine due to their antioxidant, antimicrobial, antidiabetic, diuretic, and antiproliferative properties. The health benefits are mainly attributed to the presence of phenolic compounds. The aim of this study was to compare the phenolic profiles, total phenolic content (TPC), and radical scavenging activity (RSA) of A. unedo leaves and fruits collected at two locations in Croatia. Phenolic profiles were identified using an ultra-high-performance liquid chromatograph (UHPLC) coupled with a hybrid mass spectrometer (LTQ Orbitrap MS). TPC was determined by Folin–Ciocalteu’s assay, while RSA was investigated using DPPH reagent. A total of 64 phenolics (60 and 42 compounds in leaves and fruits, respectively) were identified. Hyperoside and flavan-3-ols were predominant compounds in leaves, while gallocatechin and catechin were the major compounds found in fruits. To the authors’ knowledge, 16 and 5 phenolics in leaves and fruits, respectively, were reported for the first time. Principal component analysis (PCA) showed that UHPLC-LTQ Orbitrap MS could be used to identify which phenolics were able to discriminate samples regarding plant tissue and geographical origin. TPC in leaves and fruits were in the ranges of 67.07–104.74 and 16.78–25.86 mg gallic acid equivalents (GAE)/g dried weight (dw), respectively. RSA for leaves and fruits were in the ranges of 408.92–430.98 and 74.30–104.04 μmol Trolox equivalents (TE)/g dw, respectively. The number of identified phenolics was lower in fruits compared to leaves. Such a large number of bioactive phenolics identified and the strong antioxidant activity pointed to A. unedo as a promising health-promoting plant and natural food preservative.

Study of the Phenolic Compound Profile of Arbutus unedo L. Fruits at Different Ripening Stages by HPLC-TQ-MS/MS

Arbutus unedo L. berries have traditionally been used as edible and medicinal fruits in folk medicine for the treatment of some pathologies. Besides their good nutritional properties, these berries are rich in bioactive compounds. Accordingly, a HPLC-triple quadrupole (TQ)-MS/MS method was developed and validated for the first time to characterize the changes produced in the phenolic composition profile of A. unedo L. fruits through three ripening stages. Several hydroxycinnamic and hydroxybenzoic acids were detected, gallic acid being the highest phenolic acid quantified. Quercetin, quercetin-3-β-glucoside, rutin, and kaempferol were found in similar amounts at the different maturity stages. High amounts of (+)-catechin, procyanidin B2, epigallocatechin, and (−)-epigallocatechin gallate were observed in the unripe fruits. Naringin and vitexin were also quantified. Stilbenes, such as trans-resveratrol and trans-piceid, were identified for the first time in these fruits. Total phenolic compounds, total anthocyanin compounds, and radical scavenging activity were also determined in the fruits harvested at different years in several locations of the Iberian Peninsula at different ripening stages. The results confirmed that these fruits are an excellent source of these bioactive compounds (mainly flavanols) with high antioxidant activity, which could be used as a new source for preparation of nutraceutical or functional foods.

An Insight into Phytochemical, Pharmacological, and Nutritional Properties of Arbutus unedo L. from Morocco

Arbutus unedo L. (Ericaceae) is an evergreen shrub widely distributed in the Mediterranean region, particularly through the Moroccan forests. It is an important medicinal plant of great scientific interest due to its nutritional, pharmacological, and chemical properties. The objective of this review is to provide insights into traditional medicinal uses and phytochemical and pharmacological properties of A. unedo from Morocco. In Morocco, the plant has been used as a traditional medicine to treat several pathological conditions. Many phytochemical compounds have been reported in the plant, of which vitamins, carotenoids, flavonoids, polyphenols, tannins, and their derivatives are the most prevalent. Leaves and fruits of A. unedo contain the most significant number of phytochemicals among the species. Furthermore, researchers have demonstrated that A. unedo exhibited antioxidant, anticancer, antibacterial, antidiabetic, antiaggregant, and antihypertensive activities due to the presence of many biochemical compounds with health-promoting properties. According to different toxicity tests, the use of A. unedo is devoid of any significant side effects and/or toxicity. Despite its nutraceutical and health-promoting properties, Moroccan A. unedo remains underexploited mainly, and most of its traditional uses have not yet undergone scientific evidence-based research; therefore, improved knowledge about the potential value of the plant would allow understanding of its biological activity based on its phytochemical compounds that may contribute to the species preservation and valorization.

Moroccan Strawberry Tree (Arbutus unedo L.) Fruits: Nutritional Value and Mineral Composition

The strawberry tree (Arbutus unedo L.), grown throughout the Mediterranean, produces edible fruit; as it is easily bruised, the sweet, reddish fruit is used mostly to prepare jams, marmalades and alcoholic beverages. As the genus is paraphyletic, phytochemical analysis can assist in defining the fruit composition with the species Arbutus unedo L. (A. unedo). Here we report on the carbohydrate, total sugar, protein, fat, fiber, ash, and mineral content of wild fruit, harvested from 45 specimens from five locations. The dominant nutrients were carbohydrates (78.2–84.8 g/100 g), total sugars (52.1–67.2 g/100 g) and dietary fiber (11.0–20.1 g/100 g). Other important nutrients supplied by A. unedo fruit include P, K, and Fe. The fruit was observed to contain health-promoting components providing 42 and 36%, of recommended daily allowance (RDA) for fiber and zinc, respectively, as well as iron and manganese, at levels exceeding minimum RDA. The free-sugar profile revealed high glucose followed by fructose content with minor amounts of sucrose (14, 11, and 6 g/100 g, respectively). Significant differences both between regions and within individuals were observed for several traits. The richness of fruit nutrients in A. unedo confers nutritional value and as such, a promising alternative fruit source.

Identification and Characterization of Arbutus unedo L. Endophytic Bacteria Isolated from Wild and Cultivated Trees for the Biological Control of Phytophthora cinnamomi

Arbutus unedo L. is a resilient tree with a circum-Mediterranean distribution. Besides its ecological relevance, it is vital for local economies as a fruit tree. Several microorganisms are responsible for strawberry tree diseases, leading to production constrictions. Thus, the development of alternative plant protection strategies is necessary, such as bacterial endophytes, which may increase their host’s overall fitness and productivity. As agricultural practices are a driving factor of microbiota, this paper aimed to isolate, identify and characterize endophytic bacteria from strawberry tree leaves from plants growing spontaneously in a natural environment as well as from plants growing in orchards. A total of 62 endophytes were isolated from leaves and identified as Bacillus, Paenibacillus, Pseudomonas, Sphingomonas and Staphylococcus. Although a slightly higher number of species was found in wild plants, no differences in terms of diversity indexes were found. Sixteen isolates were tested in vitro for their antagonistic effect against A. unedo mycopathogens. B. cereus was the most effective antagonist causing a growth reduction of 20% in Glomerella cingulata and 40% in Phytophthora cinnamomi and Mycosphaerella aurantia. Several endophytic isolates also exhibited plant growth-promoting potential. This study provides insights into the diversity of endophytic bacteria in A. unedo leaves and their potential role as growth promoters and pathogen antagonists.