Arbutus unedo Leaf Water is an aqueous solution obtained from the evergreen plant Arbutus unedo L. (Strawberry tree) belonging to the Ericaceae family, which is distributed in the Mediterranean area. The fruits are used for the preparation of jams, infusions and liqueurs. The strawberry tree is also used to produce a bitter-tasting honey. It is a plant that reaches and exceeds a height of 3 metres.

What it is used for and where

Medical

In traditional medical science, the fruits and leaves of Arbutus unedo have been used as diuretics, antiseptics, laxatives and to treat high blood pressure. 

In the phytochemical composition of the fruits we find (1)

• phenolic compounds: gallic acid, protocatechuic acid, gentisic acid, p-hydroxybenzoic acid, vanillic acid, catechin, procyanidin, ellagic acid 
• unsaturated fatty acids: α-linolenic (36%), linoleic (21%) and oleic (21%)
• saturated fatty acids: palmitic acid (8%)
• vitamins: vitamin E, α-, β-, γ- and δ-tocopherol and α-tocotrienol, vitamin C
• sugars: fructose and glucose

In the phytochemical composition of the leaves we find

phenolic compounds: arbutin (hydroquinone β-glucoside), chlorogenic acid, quercitrin, isoquercitrin

• flavanols: catechins
• flavonols: quercetin, kaempferol
• vitamins: α-tocopherol

In the phytochemical composition of the root we find:

• flavanols: catechins
• phenolic compounds: benzoic acid, caffeic acid, gallic acid

Now let us see what properties and contraindications are attributed to this plant by the scientific literature: antioxidant activity in the fruit and leaves, anti-fungal activity in the leaves, anti-inflammatory activity in the leaves, antibacterial activity in the root. However, it should be borne in mind that all these properties are conditioned by important factors that determine their quality and effectiveness: harvest time, climate, possible environmental pollution and more.

Food safety

Arbutin is the phenolic component of the leaves that has shown antioxidant activity and a low potential for DNA damage, but it seems to be understood that excessive doses of this component could somehow have an undesirable effect (2).

Cosmetics

INCI Functions:

Skin conditioning agent. It is the mainstay of topical skin treatment as it has the function of restoring, increasing or improving skin tolerance to external factors, including melanocyte tolerance. The most important function of the conditioning agent is to prevent skin dehydration, but the subject is rather complex and involves emollients and humectants that can be added in the formulation.

Skin conditioning agent - Emollient. Emollients have the characteristic of enhancing the skin barrier through a source of exogenous lipids that adhere to the skin, improving barrier properties by filling gaps in intercorneocyte clusters to improve hydration while protecting against inflammation. In practice, they have the ability to create a barrier that prevents transepidermal water loss.  Emollients are described as degreasing or refreshing additives that improve the lipid content of the upper layers of the skin by preventing degreasing and drying of the skin. The problem with emollients is that many have a strong lipophilic character and are identified as occlusive ingredients; they are oily and fatty materials that remain on the skin surface and reduce transepidermal water loss. In cosmetics, emollients and moisturisers are often considered synonymous with humectants and occlusives.

The antifungal activity of phenolic compounds is useful in cosmetic formulations to prevent fungal formations from attacking the product over time. The antioxidant activity helps with preservation.

CAS     84012-12-4

EC number    281-657-2

Read more:

Arbutus unedo studies

References_____________________________________________________________________

(1) Miguel MG, Faleiro ML, Guerreiro AC, Antunes MD. Arbutus unedo L.: chemical and biological properties. Molecules. 2014 Sep 30;19(10):15799-823. doi: 10.3390/molecules191015799. 

Abstract. Arbutus unedo L. (strawberry tree) has a circum-Mediterranean distribution, being found in western, central and southern Europe, north-eastern Africa (excluding Egypt and Libya) and the Canary Islands and western Asia. Fruits of the strawberry tree are generally used for preparing alcoholic drinks (wines, liqueurs and brandies), jams, jellies and marmalades, and less frequently eaten as fresh fruit, despite their pleasing appearance. An overview of the chemical composition of different parts of the plant, strawberry tree honey and strawberry tree brandy will be presented. The biological properties of the different parts of A. unedo and strawberry tree honey will be also overviewed.

(2) Jurica K, Brčić Karačonji I, Mikolić A, Milojković-Opsenica D, Benković V, Kopjar N. In vitro safety assessment of the strawberry tree (Arbutus unedo L.) water leaf extract and arbutin in human peripheral blood lymphocytes. Cytotechnology. 2018 Aug;70(4):1261-1278. doi: 10.1007/s10616-018-0218-4. 

Abstract. Strawberry tree (Arbutus unedo L.) leaves have long been used in the traditional medicine of the Mediterranean region. One of their most bioactive constituents is the glycoside arbutin, whose presence makes A. unedo suitable as a potential substitute for bearberry [Arctostaphylos uva ursi (L.) Spreng] leaves, an herbal preparation widely used for treating urinary tract infections. The safety and biocompatibility of strawberry tree water leaf extract have not yet been documented well. This study estimated arbutin content in strawberry tree water leaf extract (STE) using high performance liquid chromatography. Furthermore, we performed an in vitro safety assessment of the 24 h exposure to three presumably non-toxic concentrations of standardized STE and arbutin in human peripheral blood lymphocytes using the apoptosis/necrosis assay, the alkaline comet assay, and the cytokinesis-block micronucleus cytome assay. The STE was also tested for total antioxidant capacity and lipid peroxidation. At a concentration corresponding to the maximum allowable daily intake of arbutin, the tested extract was not cytotoxic, had a negligible potential for causing primary DNA damage and even hindered micronuclei formation in lymphocytes. It also showed a valuable antioxidant capacity, and did not exert marked lipid peroxidation. These promising results represent a solid frame for further development of STE-based herbal preparations. Although arbutin generally had a low DNA damaging potential, the slowing down of lymphocyte proliferation observed after 24 h of exposure points to a cytostatic effect, which merits further research.

Jurica K, Benković V, Sikirić S, Brčić Karačonji I, Kopjar N. The effects of strawberry tree (Arbutus unedo L.) water leaf extract and arbutin upon kidney function and primary DNA damage in renal cells of rats. Nat Prod Res. 2020 Aug;34(16):2354-2357. doi: 10.1080/14786419.2018.1534106. 

Abstract. Although strawberry tree (Arbutus unedo L.) leaves have long been used as a herbal remedy, insufficient information is available on their nephrotoxicity. We assessed the safety of strawberry tree water leaf extract and its key component arbutin, administered per os to Lewis rats of both genders at 200 mg/kg b.w./day for 14 and 28 days. The effects of the tested compounds on DNA integrity in renal cells was evaluated using alkaline comet assay, while kidney function was studied using serum creatinine and urea levels. Strawberry tree water leaf extract showed high biocompatibility with kidney tissue. It did not impair DNA integrity of renal cells and kidney function, either in male or female rats. However, exposure to single arbutin affected the levels of primary DNA damage in renal cells which could be related to metabolic conversion of arbutin into hydroquinone, whose nephrotoxicity has previously been proven.