Soursop / Guyabano (Annona muricata Linnaeus)

October 16th, 2008

Botanical Name: Annona muricata
Kingdom: Plantae
Order: Magnoliales
Family: Annonaceae
Genus: Annona
Species: A. muricata
Spanish: guanábana,
Portuguese : graviola
Other Names:Annona muricata,Guanábana, guyabano, Annona sericea Dunal,Annona macrocarpa Wercklé, A. bonplandiana H.B. & K., A. cearensis Barb.Rodr.Guanabanus muricatus
Habitat :Native to Mexico, Central America, the Caribbean and northern South America.Today, it is also grown in some areas of Southeast Asia.
Native Range: Native to the West Indies, today the soursop has spread throughout the humid tropics and is widely grown commercially.

Description:
(Rain-tree)Generally a small-medium tree to 8m/25ft. The soursop tree is low-branching and bushy but slender because of its upturned limbs, and reaches a height of 25 or 30 ft (7.5-9 m). Young branchlets are rusty-hairy. The malodorous leaves, normally evergreen, are alternate, smooth, glossy, dark green on the upper surface, lighter beneath; oblong, elliptic or narrowobovate, pointed at both ends, 2 1/2 to 8 in (6.25-20 cm) long and 1 to 2 1/2 in (2.5-6.25 cm) wide. The flowers, which are borne singly, may emerge anywhere on the trunk, branches or twigs. They are short stalked, 1 1/2 to 2 in (4 5 cm) long, plump, and triangular-conical, the 3 fleshy, slightly spreading, outer petals yellow-green, the 3 close-set inner petals pale-yellow.

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The fruit is more or less oval or heart-shaped, some times irregular, lopsided or curved, due to improper carper development or insect injury. The size ranges from 4 to 12 in (10-30 cm) long and up to 6 in (15 cm) in width, and the weight may be up to 10 or 15 lbs (4.5-6.8 kg). The fruit is compound and covered with a reticulated, leathery-appearing but tender, inedible, bitter skin from which protrude few or many stubby, or more elongated and curved, soft, pliable “spines”. The tips break off easily when the fruit is fully ripe. The skin is dark-green in the immature fruit, becoming slightly yellowish-green before the mature fruit is soft to the touch. Its inner surface is cream-colored and granular and separates easily from the mass of snow-white, fibrous, juicy segments—much like flakes of raw fish—surrounding the central, soft-pithy core. In aroma, the pulp is somewhat pineapple-like, but its musky, subacid to acid flavor is unique. Most of the closely-packed segments are seedless. In each fertile segment there is a single oval, smooth, hard, black seed, l/2 to 3/4 in (1.25-2 cm) long; and a large fruit may contain from a few dozen to 200 or more seeds.

It is a broadleaf flowering evergreen tree.The soursop is adapted to areas of high humidity and relatively warm winters, temperatures below 5 °C will cause damage to leaves and small branches, and temperatures below 3 °C can be fatal.

Comparisons of its flavour range from strawberry and pineapple mixed together to sour citrus flavour notes contrasting with an underlying creamy roundness of flavour reminiscent of coconut or banana. The fruit is somewhat difficult to eat, as the white interior pulp is studded with many large seeds, and pockets of soft flesh are bounded by fibrous membranes. The soursop is therefore usually juiced rather than eaten directly.

Growing Environment: Will not survive outside anywhere in the continental US except in Southern Florida, where it is grown commercially only to a limited extent. Soursop trees require much warmth and humidity, lots of water, and will be killed by temperatures below 32F/0C. In the tropics, soursops are grown from sea level to 1000m, particularly in humid regions where the tree grows particularly well. Soursop’s cannot tolerate standing water, and its roots are shallow, so it does not require a very deep soil base.

Propagation: Despite many named cultivars, soursops are commonly grown from seed. Trees can also be propagated by grafting and budding methods. Grafting of cherimoya and sugar apple trees (and vice versa) onto soursop has thus far been unsuccessful. Soursop seeds can be stored for several months before planting. Germination of seeds usually takes three weeks, but under sub-optimal conditions can be delayed for up to 2-3 months. Seedlings of 6-9 month age are usually large enough to be set out in the field, or used as rootstocks for grafting.

Cultivation :
The plant is grown as a commercial crop for its 20-30 cm long prickly green fruit, which can have a mass of up to 2.5 kg.

Away from its native area, there is some limited production as far north as southern Florida within USDA Zone 10; however these are mostly garden plantings for local consumption. It is also grown in parts of southeastern Asia. The soursop will reportedly fruit as a container specimen, even in temperate climates if protected from cool temperatures.

Uses:
A well-known fruit throughout much of the world, the soursop’s delicious white pulp, with tones of fruit candy and smooth cream is commonplace in tropical markets, but is rarely found fresh anywhere else. Inside its thin, leathery, green flesh is a large mass of creamy pulp, usually intermixed with 50-100 black seeds.

The Soursop is usually processed into ice creams, sherbets and drinks, but fiber-free varieties are often eaten raw. The large, elongated, somewhat ovaloid fruit, can be up to 12″ long and 6″ wide and usually weighs several pounds. The fruit is covered in small knobby spines that easily break off when the fruit is ripe. The thin, inedible, leathery green skin cuts easily to yield the large mass of cream colored, fragrant, juicy, and somewhat fibrous, edible flesh. A typical soursop contains anywhere from 30-200 black-brown seeds, each about 1/2″ long and 1/4″ wide and enclosed in a separate “pocket” of flesh. There are known seedless varieties, but they are rare, and tend to have fibrous flesh. Soursop’s are processed into excellent ice creams, sherbets and beverages throughout much of Central and South America. Sweet varieties of the fruit can be eaten raw, and are often used for dessert. Today, Soursop ice cream, marketed under its Spanish name “Guanabana,” can be found in some gourmet supermarkets. Preserved soursop in syrup can also be found in many ethnic markets. The canned pulp can be pureed or blended in the home, and easily transformed into a delicious desert, although fresh pulp is more desirable. Immature soursops are often cooked, and eaten as a vegetable. The leaves and roots of the tree have various medicinal properties. Soursops are high in vitamins B1, B2 and C.

The flesh of the fruit consists of an edible white pulp and a core of undigestible black seeds. The species is the only member of the genus Annona that is suitable for processing and preservation. The sweet pulp is used to make juice as well as candies, sorbets, and ice cream flavorings.

A thick tea can be used to kill bedbugs and head lice. Mixing pulverizing Soursop seeds with soap & water is an effective spray against caterpillars, armyworms and leafhoppers on plants.

In Mexico it is a common fruit often used for dessert as the only ingredient, or as an agua fresca beverage. Ice cream, and fruit bars made of soursop are also very popular. The seeds are normally left in the preparation, and removed while consuming.

Fruit: In the Virgin Islands, the fruit is placed as a bait in fish traps.

Seeds: When pulverized, the seeds are effective pesticides against head lice, southern army worms and pea aphids and petroleum ether and chloroform extracts are toxic to black carpet beetle larvae. The seed oil kills head lice.

Leaves: The leaf decoction is lethal to head lice and bedbugs.

Bark: The bark of the tree has been used in tanning. The bark fiber is strong but, since fruiting trees are not expendable, is resorted to only in necessity. Bark, as well as seeds and roots, has been used as fish poison.

Wood: The wood is pale, aromatic, soft, light in weight and not durable. It has been used for ox yokes because it does not cause hair loss on the neck.

In Colombia, it is deemed to be suitable for pipestems and barrelstaves. Analyses in Brazil show cellulose content of 65 to 76%, high enough to be a potential source of paper pulp.

Medicinal Uses:
To reduce fever, a decoction or tea made from Soursop leaves can be taken internally. Leaves added to bathing water has the same effect. The crushed fresh leaves can be applied on skin eruptions to promote healing. A poultice of young Soursop leaves is applied on the skin to alleviate rheumatism and other skin infections like eczema. The tea has also been used as a wet compress on swollen feet and other inflammations. The juice of the fruit can be taken orally as a remedy for urethritis, haematuria and liver ailments.

Nutritionally, the fruit is high in carbohydrates, particularly fructose. The fruit also contains significant amounts of vitamin C, vitamin B1, and vitamin B2. The fruit, seeds, and leaves have a number of herbal medicinal uses among indigenous peoples of regions where the plant is common.

The tea, fruit, and juice are used medicinally to treat illness ranging from stomach ailments to worms.

In the Caribbean it is believed that laying the leaves of the soursop on a bed below a sleeping person with a fever will break the fever by the next morning. Also, boiling the leaves and drinking may help induce sleep.

The juice of the ripe fruit is said to be diuretic and a remedy for haematuria and urethritis. Taken when fasting, it is believed to relieve liver ailments and leprosy. Pulverized immature fruits, which are very astringent, are decocted as a dysentery remedy. To draw out chiggers and speed healing, the flesh of an acid soursop is applied as a poultice unchanged for 3 days.

In Materia Medica of British Guiana, we are told to break soursop leaves in water, “squeeze a couple of limes therein, get a drunken man and rub his head well with the leaves and water and give him a little of the water to drink and he gets as sober as a judge in no time.” This sobering or tranquilizing formula may not have been widely tested, but soursop leaves are regarded throughout the West Indies as having sedative or soporific properties. In the Netherlands Antilles, the leaves are put into one’s pillowslip or strewn on the bed to promote a good night’s sleep. An infusion of the leaves is commonly taken internally for the same purpose. It is taken as an analgesic and antispasmodic in Esmeraldas Province, Ecuador. In Africa, it is given to children with fever and they are also bathed lightly with it. A decoction of the young shoots or leaves is regarded in the West Indies as a remedy for gall bladder trouble, as well as coughs, catarrh, diarrhea, dysentery and indigestion; is said to “cool the blood,” and to be able to stop vomiting and aid delivery in childbirth. The decoction is also employed in wet compresses on inflammations and swollen feet. The chewed leaves, mixed with saliva, are applied to incisions after surgery, causing proudflesh to disappear without leaving a scar. Mashed leaves are used as a poultice to alleviate eczema and other skin afflictions and rheumatism, and the sap of young leaves is put on skin eruptions.

The roots of the tree are employed as a vermifuge and the root bark as an antidote for poisoning. A tincture of the powdered seeds and bay rum is a strong emetic. Soursop flowers are believed to alleviate catarrh.

Health risks & Toxicity
Research carried out in the Caribbean has suggested a connection between consumption of soursop and atypical forms of Parkinson’s disease due to the very high concentration of annonacin.

The presence of the alkaloids anonaine and anoniine has been reported in this species. The alkaloids muricine, C19H21O4N (possibly des-N-methylisocorydine or des-N methylcorydine) and muricinine, C18H19O4 (possibly des-N-methylcorytuberine), are found in the bark. Muricinine is believed to be identical to reticuline. An unnamed alkaloid occurs in the leaves and seeds. The bark is high in hydrocyanic acid. Only small amounts are found in the leaves and roots and a trace in the fruit. The seeds contain 45% of a yellow non-drying oil which is an irritant poison, causing severe eye inflarnmation.

Disclaimer:The information presented herein is intended for educational purposes only. Individual results may vary, and before using any supplements, it is always advisable to consult with your own health care provider.

Resources:

http://en.wikipedia.org/wiki/Guyabano

http://consejo.bz/belize/bushmedicine.html

http://www.tradewindsfruit.com/soursop.htm

http://www.hort.purdue.edu/newcrop/morton/soursop.html