Prunus spinosa L. is a perennial, thorny shrub, highly decorative for landscape and forest edges, belonging to the Rosaceae family, genus Prunus, representing one of the ancestors of P. domestica. Modern phytotherapeutics emphasizes the benefits of consuming parts or products based on the Prunus spinosa L. shrub, as it is considered a plant with functional nutritional and therapeutic properties, remarkable in various pathologies with increasing incidence. Up to now, research has shown that the polyphenols found in large amounts in the fruits of P. spinosa L. are biofunctional compounds. These include anthocyanins, phenolic acids, flavonoids, and coumarin derivatives.
1. Introduction
Studies on the biologically active substances that are found in food are of great relevance in the innovation and certification of functional food products. Thus, at the global level, a great emphasis is placed on the search for plant-based foods as alternative options to prevent chronic inflammation through dietary interventions
[1]. Food manufacturers aim to develop new food products that are attractive to a wide range of potential consumers while also trying to become competitive in the market. Currently, these actions can be divided into two directions, namely a return to natural and traditional products that are minimally processed and the production of functional foods, often using unconventional materials or additives. These directions have been established based on recent studies that prioritize the global effort to find technological methods for food processing that minimize the loss or degradation of biologically active phytocompounds. The fruits of
P. spinosa L. contain high levels of phenolic compounds, which have strong anti-oxidant properties
[2][3][4][5][2,3,4,5]. These compounds have potential applications in the food and phytopharmaceutical sectors
[1][4][6][7][8][9][1,4,6,7,8,9]. The blackthorn can be utilized as an ingredient in various food products such as yogurt
[10], ice cream
[11], jam
[12], wholemeal biscuits with dried fruit, gin and tonic drinks
(the latter being the focus of our research team). Incorporating blackthorn into these food items would enhance their nutritional value, therefore fortifying them and improving their overall quality. The recent study conducted by Özkan (2023)
[13] demonstrated that dried
P. spinosa L. pestles exhibit high bioaccessibility of polyphenols during gastrointestinal digestion. This finding suggests that
P. spinosa L. could be a promising option for producing beverages. The utilization of
P. spinosa L. extracts as novel anthocyanin-based food dyes in confectionery items, such as topping on donuts and in “beijinho”, a Brazilian biscuit product, has resulted in significant changes in nutritional content
[14].
Modern phytotherapeutics emphasizes the benefits of consuming parts or products based on the
Prunus spinosa L. shrub as it is considered a plant with functional nutritional and therapeutic properties, remarkable in various pathologies with increasing incidence. Studies to date have shown that the polyphenols, which are present in significant amounts in the fruits of
P. spinosa L., are biofunctional components, including anthocyanins, phenolic acids, flavonoids, and coumarin derivatives
[4][6][15][16][4,6,19,20].
2. The Bioecology of the P. spinosa L. Shrub
Prunus spinosa L. is a perennial, thorny shrub, highly decorative for landscape and forest edges, belonging to the Rosaceae family, genus Prunus, representing one of the ancestors of
P. domestica [6][17][18][6,23,26].
It is native to Europe (
Figure 1), mainly central and southern Europe, except the lower half of the Iberian Peninsula, extending northwards to the southern part of the Scandinavian Peninsula
[18][19][26,27].
P. spinosa L. is also widespread in western Asia and northwest Africa and is locally present in New Zealand, Tasmania, and eastern North America (USDA NRCS, The PLANTS database, 2015)
[20][28], the Pacific Northwest and New England in the U.S. (
Figure 1). Some authors believe that it originates in the northernmost tip of the European continent, in Scotland
[21][29], and is commonly found in Europe, around deciduous forests, and in the temperate areas of Asia, especially in central, northern, western, and southern Anatolia. Towards the east, it reaches Asia Minor, the Caucasus, and the Caspian Sea
[22][30]. Isolated populations have been found in Tunisia and Algeria. It is widespread in the Southern Alps, Switzerland, at altitudes up to 1600 m
[23][31].
Species of
P. spinosa L. are also found on the slopes of wild, uncultivated areas in several regions of Bosnia and Herzegovina
[24][32]. It is commonly found at forest edges and openings, on sunny, rocky slopes, in ravines and river valleys, and meadows and pastures from low plains to mountains
[25][26][33,34].
In Romania,
P. spinosa L., can be found in lowland, plain areas but is more abundant in hilly areas, extending to mountainous areas with altitudes of 900–1000 m, being present at the edge of agricultural lands, decorating the landscape or on abandoned pastures, as well as on the edge of oak and beech forests
[18][27][28][29][26,35,36,37].
Figure 1. The habitat of
P. spinosa L. (Plants of the World Online. Royal Botanic Gardens, Kew, 2023)
[30][38]. 1—In Romania, it can be found in all areas; 2—It can also be encountered on the slopes of uncultivated areas in Bosnia and Herzegovina; 3, 4—Native to central and southern Europe, except the lower part of the Iberian Peninsula, it spreads towards the north, up to the south of the Scandinavian Peninsula; 5, 6—Isolated populations in Tunisia and Algeria, being also widespread in lower and higher areas, up to 1600 meters altitude in the Southern Alps of Switzerland; 7—Locally, it can be found in New Zealand, Tasmania; 8, 9—Locally, it can be found in the east of North America, the northwest of Pacific and New England in the United States; 10—Widespread in Western Asia, temperate regions of Asia—central, Northern Western and Southern Anatolia; 11, 12, 13—Widespread in Asia Minor, Caucasus, Caspian Sea and North and Western Africa.
It is a 2–3 m shrub with dark blue-violet bark and dense, stiff, spiny branches that grow well on clay, loam, sandy, calcareous, and well-drained soils and is recommended for its ability to improve degraded land.
P. spinosa L. is a frost- and drought-tolerant species that develops well in sunny areas, where it benefits from exposure to light, as it is a thermophilic thorny shrub. It is also found on mesic to dry soils, on the edges of oak and beech forests, or the banks of rivers with willows and poplars, making it an unlimited source of berries—raw material for the food industry. It does not require any special care
[4][18][31][32][33][4,26,39,40,41].
The leaves are oval, 2–4.5 cm long, and 1.2–2 cm wide with a serrated edge, and the flowers are white (
Figure 2). They have five petals, are hermaphrodite, insect-pollinated, and possess vasoprotective, anti-inflammatory, diuretic, vermicide, detoxifying (blood purifying), and spasmolytic activities
[4][31][32][4,39,40]. The first flowers appear in early to mid-March, depending also on the temperature, continuing until mid-April
[27][28][34][35,36,42].
The fruits of the
P. spinosa L. shrub are small, spherical, blackish drupes (
Figure 2), about 10–12 mm in diameter, covered with blue bloom, and have therapeutic and functional properties
[35][43]. The flesh is greenish yellow, adherent to the stone, with a pronounced astringent aroma due to the high tannin content and an acidic taste, which is why they can only be eaten fresh when overripe and in very small quantities
[36][44]. Harvesting time is late autumn, in November, after the fall of the mist, due to the decrease in astringency. The fruits can be harvested even in winter because they persist well on the branches
[2][19][30][2,27,38].
Figure 2.
Different anatomical parts and phytochemicals content of L. Sources: [2,6,8,23,24,45,46,47].
Data obtained to date have reported a total polyphenol and anthocyanin content contributing significantly to the anti-oxidant capacity of
P. spinosa L. fruit based on the rich content of cyanidin-3-rutinoside (53.5%), peonidin-3-rutinoside (32.4%) and cyanidin-3-glucoside (11.4%)
[41][48].
The fruits have proven functional effects on heart strengthening, in myocarditis and atherosclerosis
[42][43][49,50]. Ethnopharmacological sources show that
P. spinosa L. buds, popular in southern Europe, possess antihypertensive properties
[44][51].
3. Nutritional composition of P. spinosa L.
The nutritional composition and estimated energy value of the blackthorn fruits are presented in Table 1.
Table 1.
Nutritional value of blackthorn fruits based on literature.
|
6.65 ± 2.03 |
|
|
nd |
|
| 0.69 ± 0.04
|
2.72
|
1.18 ± 0.56
|
Fiber (g/100 g)
|
nd
|
9
|
5.79 ± 0.1
|
4.6
|
0.67 ± 0.26
|
The observed variations in the nutrient content of P. spinosa L. fruits (as shown in Table 1) can primarily be attributed to climatic conditions. Fruits grown in hot, dry climates are distinguishable by a lower level of moisture.
Differences were noted in the sugar content values (Table 1), ranging from 8.64 to 88.51 g/100 g. The variation in sugar content may be attributed to the intrinsic physicochemical properties and ripeness of blackthorn, as well as the environmental conditions [45][54].
An analysis of the amino acid composition of P. spinosa L. fruits [46][58] revealed that leucine, was found in a concentration of 122.6 mg/100 g. This amount is equivalent to 7.66% of the FAO (Food and Drug Administration) and WHO/DRIs (World Health Organization/Dietary Reference Intakes) recommended daily allowances (RDAs).Additional essential amino acids detected in P. spinosa L. were Valine (87.8 mg/100 g), Phenylalanine (84.7 mg/100 g), Lysine (50.6 mg/100 g), and Threonine (47.6 mg/100 g) [46][58].
Fatty acids found in P. spinosa L. fruits include oleic acid, linoleic acid, arachidonic acid, linolenic acid, EPA (eicosapentaenoic acid), DPA (docosapentaenoic acid) and DHA (docosahexaenoic acid) [47][57]. Fatty acid content was dominated by monounsaturated fatty acids [47][57], followed by polyunsaturated fatty acids. According to the study conducted by Babalau-Fuss (2021) [47][57] on the analysis of fatty acid content in P. spinosa L. fruits, it was found that monounsaturated fatty acids (MUFA) were the most abundant, accounting for 46.20% of the total fat content. Polyunsaturated fatty acids (PUFA) were identified in a proportion of 34.54%.
Among the mineral elements identified in P. spinosa L., potassium had the highest amount, followed by phosphorus, calcium, and sodium. The potassium levels varied between 1035.826 and 2014.23 mg/kg, the calcium levels ranged from 19.86 to 1504.41 mg/kg, and the sodium levels varied between 2.56 and 534.81 mg/kg [24][48][47][32,54,57].
4. The Polyphenol Composition in Various Parts of the P. spinosa L. Shrub
Polyphenols are secondary metabolites with important and various functions in the plant world, representing an extensive group of phytochemicals.
Table 23 includes data from the most recent literature (from the last few years) on the detection of phytochemical content identified in
P. spinosa L. fruits, leaves, flowers, and branches.
Table 23. The phytochemical composition (phenolic acids, anthocyanins, and flavonoids) of blackthorn fruits, flowers, leaves, and branches is based on literature data from the previous few years.
Organs of P. spinosa
|
Type of Sample/
Technique
|
Phenols
|
References
|
Fruits
|
Cold solution (1% BHT [w/v], 3% formic acid [v/v] in methanol)
HPLC–DAD–MS
|
Phenolic acids
Cinnamic acid derivatives:
· 3-p-Coumaroylquinic acid;
· 4-p-Coumaroylquinic acid 1;
· Caffeic acid hexoside 1;
· Caffeic acid hexoside 3;
· p-Coumaric acid hexoside 1;
· 3-Caffeoylquinic acid;
· 4-Caffeoylquinic acid;
· 5-Caffeoylquinic acid 1;
· 3-Feruloylquinic acid;
Flavanols
· Catechin;
· Epicatechin;
· Procyanidin dimer 1;
· Procyanidin dimer 2;
· Procyanidin dimer 3;
· Procyanidin trimer 2;
Flavonols
· Quercetin triglycoside;
· Quercetin acetyl hexoside;
· Quercetin acetyl rutinoside;
· Quercetin hexosyl pentoside 2;
· Quercetin hexosyl rhamnoside;
· Quercetin-3-xyloside;
· Quercetin pentoside 2;
· Quercetin pentoside 3;
· Quercetin rhamnosyl hexoside;
· Querectin-3-galactoside;
· Quercetin-3-glucoside;
· Quercetin-3-rhamnoside;
· Quercetin-3-rutinoside;
· Isorhamnetin hexoside;
· Kaempferol pentoside hexoside;
· Kaempferol rhamnosyl hexoside 1;
· Kaempferol rhamnosyl hexoside 2;
· Kaempferol pentoside;
Flavones
· Apigenin pentoside;
Anthocyanins
· Cyanidin pentoside;
· Cyanidin 3-acetylglucoside;
· Cyanidin-3-glucoside;
· Cyanidin-3-rutinoside;
· Pelargonidin-3-glucoside;
· Peonidin-3-acetylglucoside;
· Peonidin-3-glucoside;
· Peonidin-3-rutinoside;
· Petunidin-3-rhamnoside.
|
[65]
|
|
Ethyl acetate fraction of methanol-water extract (75:25, v/v) in dried fruit
UHPLC-PDA-ESI-MS
|
Phenolic acids
· Protocatechuic acid 4-O-hexoside;
· Protocatechuic acida;
· 3-O-Caffeoylquinic acid;
· p-Hydroxybenzoic acida;
· Caffeoylshikimic acid derivative;
· Vanilloyl malate hexoside;
· 3-O-p-Coumaroylquinic acid;
· p-Coumaric acid O-hexoside;
· 5-O-Caffeoylquinic acid;
· cis-3-O-Feruloylquinic acid;
· 4-O-Caffeoylquinic acid;
· Caffeic acid 3/4-O-hexoside;
· 3-O-Feruloylquinic acid;
· Vanillina;
· 4-O-Caffeoylshikimic acid;
· 4-O-Feruloylquinic acid;
· Caffeoylshikimic acid;
· Caffeoylshikimic acid;
· p-Coumaroylshikimic acid;
· Aromadendrin hexoside;
· p-Coumaroylshikimic acid;
Flavonols
· Quercetin 3-O-β-D-galactoside;
· Quercetin 3-O-(6′′-O-α-L-rhamnopyranosyl)-β-D-glucopyranoside;
· Quercetin 3-O-β-D-glucopyranoside;
· Quercetin 3-O-α-D-xylopyranoside;
· Quercetin 3-O-α-L-arabinopyranoside;
· Quercetin 3-O-α-L-arabinofuranoside;
· Quercetin 3-O-(4′′-O-β-D-glucopyranosyl)-α-L-rhamnopyranoside;
· Quercetin 3-O-α-L-rhamnopyranoside;
· Quercetin malyl-pentoside;
· Quercetin acetyl-hexoside-rhamoside.
|
[24]
|
Flowers
|
Defatted methanol-water extract
RP-HPLC-PDA
|
Phenolic acids
· 3-O-Caffeoylquinic acid (neochlorogenic acid);
· 5-O-Caffeoylquinic acid (chlorogenic acid);
· 4-O-Caffeoylquinic acid (cryptochlorogenic acid);
· Caffeic acid;
· p-Coumaric acid;
Flavanols
· (+)-Catechin;
· (–)-Epicatechin;
Flavonols
· Kaempferol 3-O-α-L-arabinopyranoside-7-O-α-L-rhamnopyranoside;
· Kaempferol 3-O-β-D-xylopyranoside-7-O-α-L-rhamnopyranoside (lepidoside);
· Kaempferol 3,7-di-O-α-L-rhamnopyranoside (kaempferitrin);
· Kaempferol 3-O-α-L-arabinofuranoside-7-O-α-L-rhamnopyranoside;
· Kaempferol 3-O-β-D-xylopyranoside;
· Kaempferol 3-O-(4’’-O-β-D-glucopyranosyl)-α-L-rhamnopyranoside (multiflorin B);
· Kaempferol 3-O-α-L-arabinofuranoside (juglanin);
· Kaempferol 3-O-α-L-rhamnopyranoside (afzelin);
· Kaempferol 7-O-α-L-rhamnopyranoside;
· Kaempferol 3-O-(2’’-O-E-p-coumaroyl)-α-L-arabinofuranoside-7-O-α-Lrhamnopyranoside;
· Kaempferol 3-O-(6’’-O-α-L-rhamnopyranosyl)-β-D-glucopyranoside;
· Kaempferol 3-O-(2’’-O-E-p-coumaroyl)-α-L-arabinofuranoside.
· Kaempferol;
· Quercetin 3-O-(6’’-O-α-L-rhamnopyranosyl)-β-D-glucopyranoside (rutin);
· Quercetin 3-O-(2’’-O-β-D-glucopyranosyl)-α-L-arabinofuranoside;
· Quercetin 3-O-β-D-glucopyranoside (isoquercitrin);
· Quercetin 3-O-β-D-galactopyranoside (hyperoside);
· Quercetin 3-O-α-D-xylopyranoside (reinutrin);
· Quercetin 3-O-α-L-arabinopyranoside (guaiaverin);
· Quercetin 3-O-(4’’-O-β-D-glucopyranosyl)-α-L-rhamnopyranoside (multinoside A);
· Quercetin 3-O-α-L-arabinofuranoside (avicularin);
· Quercetin 3-O-α-L-rhamnopyranoside (quercitrin);
· Quercetin;
|
[66]
|
Leaves
|
70% (v/v) aqueous-methanolic extract
UHPLC-PDA-ESI–MS
|
Phenolic acids
· 3-O-caffeoylquinic acid (neochlorogenic acid);
· 3-O-p-coumaroylquinic acid;
· 3-O-feruloylquinic acid;
· 4-O-caffeoylquinic acid (cryptochlorogenic acid);
Flavanols
· procyanidin type-B dimer;
· procyanidin type-B dimer;
· (+)-catechina;
Flavonoids
· kaempferol 3-O-a-L-arabinopyranoside-7-O-a-L-rhamnopyranosidea;
· kaempferol 3-O-b-D-xylopyranoside-7-O-a-L-rhamnopyranoside (lepidoside);
· quercetin 3-O-(200-O-b-D-glucopyranoside)-a-L-arabinofuranosidea;
· kaempferol 3,7-di-O-a-L-rhamnopyranoside (kaempferitrin);
· kaempferol 3-O-a-L-arabinofuranoside-7-O-a-L-rhamnopyranosidea;
· quercetin 3-O-a-L-arabinofuranoside (avicularin);
· kaempferol hexoside-pentoside;
· kaempferol 3-O-a-L-arabinofuranoside (juglanin);
· kaempferol 3-O-a-L-rhamnopyranoside (afzelin);
· quercetin acetyl-hexoside-rhamnoside;
· kaempferol acetyl-hexoside-rhamnoside;
· kaempferol 7-O-a-L-rhamnopyranosidea;
· kaempferola;
· kaempferol 3-O-(2”-E-p-coumaroyl)-a-L-arabinofuranoside-7-O-a-L-rhamnopyranoside.
|
[67]
|
Branches
|
Lyophilized extract
HPLC/MS
|
Phenolic acids
· Protocatechuic acid;
· Gallic acid;
· Caffeic acid;
Proanthocyanidins or flavan-3-ols
· Ent-(epi)-catechin-(2α→O→7,4α→8)-(epi)-catechin-3′-O-gallate;
· Ent-(epi)-afzelechin-(2α→O→7,4α→8)-(epi)-catechin-3′-O-gallate;
· Ent-(epi)-gallocatechin (2α→O→7, 4α→8)(epi)-catechin;
· Ent-(epi)-catechin (2α→O→7, 4 α→8)-catechin;
· Ent-(epi)-gallocatechin (2α→O→7, 4α→8)-(epi)-catechin;
· Ent-(epi)-catechin (2α→O→7, 4 α→8)-(epi)-catechin;
· Ent-(epi)-afzalechin (2α→O→7, 4α→8) catechin;
· Epigallocatechin;
·Ent-(epi)-afzalechin (2α→O→7, 4α→8)-(epi)-catechin;
· Gallocatechin;
· Epicatechin;
· Catechin;
· Epiafzelechin;
· Afzelechin;
Coumarins
· 5-hydroxy-6-methoxy-7-O-β-D-glucosyl coumarin;
· 5-hydroxy-6-methoxy-7-O-β-D-rhamnosyl coumarin;
Flavonols
· Quercetin 3-O-rutinoside;
· Kaempferol 3,7-O-dirhamnoside;
·Kaempferol 3-O-arabinoside-7-O-rhamnoside; kaempferol 3-O-arabinoside;
· Quercetin;
· Kaempferol
|
[6]
|
[51][66]. Among the compounds identified in the 70% (v/v) water-methanol extract of the dried P. spinosa L. leaf using UHPLC-PDA-ESI–MS, the predominant compounds were flavonoids, such as kaempferol 3,7-di-O-a-L-rhamnopyranoside (kaempferitrin) and kaempferol 3-O-a-L-arabinofuranoside-7-O-a-L-rhamnopyranosidea [52][67]. Also, the presence of isolated flavonoids with a high abundance of kaempferitrin and 3-O-a-L-arabinofuranoside-7-O-a-L-rhamnopyranoside, represents a unique characteristic of the P. spinosa L. plant [52][53][67,68]. Regarding the compounds present in the branches of P. spinosa L., Pinacho et al., 2015 [6] isolated phenolic compounds from air-dried branches (Table 23), then ground them into a fine powder and successively extracted by sequential cold maceration with dichloromethane, ethyl acetate, ethanol and water at room temperature in a closed container several times, evaporated and finally lyophilized. From the lyophilized extract obtained, 26 compounds were isolated, among which one was unidentified, and among those identified, phenolic acids, such as protocatechuic acid, gallic acid, and caffeic acid, were identified for the first time in the genus Prunus.