Red chokeberry

Aronia is a genus of deciduous shrubs, the chokeberries, in the family Rosaceae, native to eastern North America and most commonly found in wet woods and swamps. The genus is usually considered to contain two species, one of which is naturalized in Europe. A fourth form that has long been cultivated under the name Aronia is now considered to be an intergeneric hybrid, Sorbaronia mitschurinii.

Chokeberries are cultivated as ornamental plants and as food products. The sour berries can be eaten raw off the bush, but are more frequently processed. They can be found in wine, jam, syrup, juice, soft spreads, tea, salsa, chili starters, extracts, beer, ice cream, gummies and tinctures. The name "chokeberry" comes from the astringency of the fruits, which create a sensation making one's mouth pucker.

Chokeberries are often mistakenly called chokecherries, which is the common name for Prunus virginiana. Further adding to the ambiguity, a variety of Prunus virginiana is named melanocarpa, readily confused with Aronia melanocarpa, commonly referred to as "black chokeberry" or "aronia". Aronia berries and chokecherries are both high in polyphenolic compounds, such as anthocyanins, yet the two plants are distantly related within the Rosaceae family.

Identification and taxonomy
The leaves are alternate, simple, and oblanceolate with crenate margins and pinnate venation; in autumn the leaves turn a bold red color. Dark trichomes are present on the upper midrib surface. The flowers are small, with 5 petals and 5 sepals, and produced in corymbs of 10-25 together. Hypanthium is urn-shaped. The fruit is a small pome, with an astringent flavor.

Aronia has been thought to be closely related to Photinia, and has been included in that genus in some classifications,

In eastern North America are two well-known species, named after their fruit color, red chokeberry and black chokeberry, plus a purple chokeberry whose origin is a natural hybrid of the two. A fourth species, Aronia mitschurinii, that apparently originated in cultivation, is also known as Sorbaronia mitschurinii. Red chokeberry, Aronia arbutifolia (Photinia pyrifolia), grows to 2–4m tall, rarely up to 6 m and 1-2 m wide. Leaves are 5–8 cm wide and densely pubescent on the underside. The flowers are white or pale pink, 1 cm wide, with glandular sepals. The fruit is red, 4–10 mm wide, persisting into winter.

Black chokeberry, Aronia melanocarpa (Photinia melanocarpa),tends to be smaller, rarely exceeding 1 m tall and 3 m wide, and spreads readily by root sprouts. The leaves are smaller, not more than 6-cm wide, with terminal glands on leaf teeth and a glabrous underside. The flowers are white, 1.5 cm wide, with glabrous sepals. The fruit is black, 6–9 mm wide, not persisting into winter.

Purple chokeberry, Aronia prunifolia (Photinia floribunda) apparently originated as a hybrid of the black and red chokeberries but might be more accurately considered a distinct species than a hybrid (see also nothospecies). Leaves are moderately pubescent on the underside. Few to no glands are present on the sepal surface. The fruit is dark purple to black, 7–10 mm in width, not persisting into winter. There are purple chokeberry populations which seem to be self-sustaining independent of the two parent species – including an introduced one in northern Germany where neither parent species occurs – leading botanist Alan Weakley to consider it a full species rather than a hybrid. The range of the purple chokeberry is roughly that of the black chokeberry; it is found in areas (such as Michigan and Missouri) where the red chokeberry is not.

Products and uses
The chokeberries are attractive ornamental plants for gardens. They are naturally understory and woodland edge plants, and grow well when planted under trees. Chokeberries are resistant to drought, insects, pollution, and disease. A number of cultivars, including A. arbutifolia 'Brilliant' and A. melanocarpa 'Autumn magic', have been selected for their striking fall leaf color.

An aronia wine is made in Lithuania. In Poland, aronia berries are dried to make an herbal tea sometimes blended with other flavorful ingredients, such as blackcurrant. Aronia is also used as a flavoring or colorant for beverages or yogurts. Juice from the ripe berries is astringent, semi-sweet (moderate sugar content), sour (low pH), and contains a low level of vitamin C. The berries have their own unique flavor and, in addition to juice, can be baked into breads. In the United States and Canada, aronia berries are used in juice blends for color and marketed for their antioxidant properties.

Polyphenol content
Aronia melanocarpa (black chokeberry) has attracted scientific interest due to its deep purple, almost black pigmentation that arises from dense contents of polyphenols, especially anthocyanins. Total polyphenol content is 1752 mg per 100 g in fresh berries, anthocyanin content is 1480 mg per 100 g, and proanthocyanidin concentration is 664 mg per 100 g.

The plant produces these pigments mainly in the leaves and skin of the berries to protect the pulp and seeds from constant exposure to ultraviolet radiation and production of free radicals. By absorbing UV rays in the blue-purple spectrum, leaf and skin pigments filter intense sunlight, serve antioxidant functions and thereby have a role assuring regeneration of the species. Brightly colorful pigmentation also attracts birds and other animals to consume the fruit and disperse the seeds in their droppings.

Analysis of polyphenols in chokeberries has identified the following individual chemicals (among hundreds known to exist in the plant kingdom): cyanidin-3-galactoside, cyanidin-3-arabinoside, quercetin-3-glycoside, epicatechin, caffeic acid, delphinidin, petunidin, pelargonidin, peonidin, and malvidin. All these except caffeic acid are members of the flavonoid category of phenolics.

For reference to phenolics, flavonoids, anthocyanins, and similar plant-derived phytochemicals, Wikipedia has a list of phytochemicals and foods in which they are prominent.

Preliminary research
Basic research on aronia has addressed potential mechanisms for reducing risk of disease. Models under evaluation include:
 * reduction of blood cholesterol
 * colorectal cancer
 * cardiovascular disease
 * chronic inflammation
 * gastric mucosal disorders (peptic ulcer)
 * eye inflammation (uveitis)
 * liver failure
 * anti-adhesion properties
 * platelet function in patients with breast cancer
 * arterial hypertension
 * cervical cancer
 * immunomodulation