**1. Black chokeberries: historical background, taxonomy and botanical aspects**

The use of medicinal plants in the prevention and treatment of diseases is an old practice that has been maintained over time and is currently being given special attention by scientists, as well as by people aiming to preserve their health or treat a disease. In the past, the therapeutic properties of the plants were discovered by observing their effects on the animals that ate them [1–3]. People gathered knowledge about the therapeutic effects of plants and several traditional medicines were born [4]. At the beginning of the nineteenth century, the first plant compounds were isolated and later some of them served as a model for the development of synthetic drugs [4, 5]. Plant-derived products are intensively studied and they are

important sources in drug discovery [1]. Studies are directed toward the identification of mechanisms of action of plant compounds [6], exploiting their capacity of reducing the side effects of synthetic drugs [7] and development of new delivery systems that can increase the efficacy of phytochemicals [8].

One of the plants whose health benefits led to numerous studies is black chokeberry, also known as black-fruited Aronia. Its fruits enjoy presently a high recognition as a health food, despite lacking the historical advantage of other well-known rosaceous berry crops (strawberries, raspberries and blackberries). The highly regarded berries (botanically: pomes), cultivated in many European countries and North America, have an unusual history, which reflects on the taxonomic confusions surrounding the plant.

Unlike other edible plants, black Aronia spread from America to Europe due to its decorative interest. The ancestor of today's cultivated black-fruited Aronia is *Aronia melanocarpa* (Michx.) Elliott, a species that grows wildly in North America [9] along with two other *Aronia* species. The small genus *Aronia* Medik. (chokeberry) includes multistemmed, deciduous shrubs that differ in the color and size of fruits (pomes), as well as in the pubescence of leaves, stems and inflorescences. Three North American and one European species are recognized [10]. Red chokeberry, *A. arbutifolia* (L.) Pers., grows up to 3 m tall and has obovate to elliptical leaves, which are shiny green on the upper side and tomentose, slightly gray on the lower side. The margins are serrated and the tip is short, acuminate. Flowers are white, in compound corymbs. In late September to early October, red fruits are produced. Black chokeberry, *A. melanocarpa* (Michx.) Elliott, has a smaller habit (up to 1.5 m) and is not pubescent [11]. Its fruits are black, shiny, with a diameter of 0.8–1.3 cm; they typically ripen in August. A third species native to North America, *A. prunifolia* (Marshall) Rehder, or purple chokeberry, is considered by certain authors to be a hybrid between the former two species, a distinct species or a variety of black or red chokeberry. It has dark purple to black fruits, and the leaf pubescence is intermediate between *A. arbutifolia* and *A. melanocarpa* [12].

*A. melanocarpa* is cold-hardy member of the Rosaceae family, where it is assigned to the Amygdaloideae subfamily and Maleae tribe [13]. Wild-growing black chokeberry plants were introduced to Europe in the nineteenth century as ornamental shrubs. The first record of the species in Russia (1816) mentions black Aronia under the name *Mespilus melanocarpa* in the catalog of plants of the Kremenets Botanical Garden [14]. Soon, it was grown as a cold-resistant ornament in other botanical gardens; before the twentieth century, it was however not grown for its fruits, which, though edible, are poorly palatable and astringent. The blackfruited Aronia is cultivated nowadays as a distinct morphology in comparison to its wild-growing North American counterparts: its leaves are wider, flowers are larger and more numerous, fruits have a larger diameter, and corymbs bear a higher number of fruits [15]. It has been proposed that this species is the result of breeding and selection experiments performed in the early twentieth century by Ivan Michurin, and that all *Aronia* plants cultivated in the former Soviet Union originate from the Russian pomologist's nursery [14]. Then, it spread to other European countries such as Poland, Norway, Finland, Sweden or Germany [16]. In 1976, chokeberry was introduced to Japan [17]. The distinct differences from its wild-growing progenitors and the constancy in characteristics supported the assignment of the large-fruited chokeberry to a new species, *Aronia mitschurinii* A.K.Skvortsov & Maitul [18]. Its origin is however not completely elucidated. One of the hypotheses is that the species is a hybrid obtained by backcrossing *A. melanocarpa* with an F1 x*Sorbaronia* hybrid (*Sorbus aucuparia* × *A. melanocarpa*). Leonard and co-workers using amplified fragment length polymorphism (AFLP) were able to show similarities of *A. mitschurinii* to x*Sorbaronia* hybrids [19]. Further studies with more sensitive and

*Cardioprotective Effects of Cultivated Black Chokeberries (*Aronia *spp.): Traditional Uses… DOI: http://dx.doi.org/10.5772/intechopen.92238*

complex tools (like multilocus nuclear data) are proposed in order to firmly establish the origin of *A. mitschurinii* [20].

An important feature of the cultivated black-fruited Aronia is its extremely low variability due to the apomictic formation of seeds, a process occurring without fertilization of the egg. Plants resulting from apomixis are clones of the mother plant. Cultivated varieties of *A. mitschurinii*, including 'Nero,' 'Viking' and 'Galicjanka,' have in fact undistinguishable phenotypes [21] and are tetraploid (2n = 68) [14]. On the contrary, 'Hugin' and 'Elata' cultivars are considered true *A. melanocarpa* genotypes [21].

Taking into account the better understanding of *Aronia* taxonomy and genetics, in recent years, it has become accepted that the cultivated black-fruited Aronia berries, which were the subject of most biomedical and phytochemical studies, are not *A. melanocarpa* fruits as reported. Research results should rather be assigned to *A. mitschurinii*, which is the only species used for commercial fruit production [21].

Further developments on the subject of black-fruited Aronia taxonomy should certainly lead to a more stable and correct nomenclature of the chokeberry species investigated by biomedical research. A unified, proper nomenclature is essential to enable researchers to assign correctly a therapeutic activity to *A. melanocarpa*, *A. mitschurinii*, or even *X Sorbaronia mitschurinii,* all of them used in various publications to assign cultivated black-fruited chokeberry.
