''Ximenia afra'', the sourplum, is a small tree or small shrub that is thinly branched. It is part of the

Olacaceae Olacaceae is a family of flowering plants in the order Santalales. They are woody plants, native throughout the tropical regions of the world. , the circumscription of the family varies; some sources maintain a broad family, others split it int ...

family which is native throughout

tropical regions The tropics are the regions of Earth surrounding the equator, where the sun may shine directly overhead. This contrasts with the temperate or polar regions of Earth, where the Sun can never be directly overhead. This is because of Earth's ax ...

. In particular, the sourplum is native to regions in South East Africa, mainly

Botswana Botswana, officially the Republic of Botswana, is a landlocked country in Southern Africa. Botswana is topographically flat, with approximately 70 percent of its territory part of the Kalahari Desert. It is bordered by South Africa to the sou ...

Kenya Kenya, officially the Republic of Kenya, is a country located in East Africa. With an estimated population of more than 52.4 million as of mid-2024, Kenya is the 27th-most-populous country in the world and the 7th most populous in Africa. ...

Malawi Malawi, officially the Republic of Malawi, is a landlocked country in Southeastern Africa. It is bordered by Zambia to the west, Tanzania to the north and northeast, and Mozambique to the east, south, and southwest. Malawi spans over and ...

Mozambique Mozambique, officially the Republic of Mozambique, is a country located in Southeast Africa bordered by the Indian Ocean to the east, Tanzania to the north, Malawi and Zambia to the northwest, Zimbabwe to the west, and Eswatini and South Afr ...

South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. Its Provinces of South Africa, nine provinces are bounded to the south by of coastline that stretches along the Atlantic O ...

Tanzania Tanzania, officially the United Republic of Tanzania, is a country in East Africa within the African Great Lakes region. It is bordered by Uganda to the northwest; Kenya to the northeast; the Indian Ocean to the east; Mozambique and Malawi to t ...

Uganda Uganda, officially the Republic of Uganda, is a landlocked country in East Africa. It is bordered to the east by Kenya, to the north by South Sudan, to the west by the Democratic Republic of the Congo, to the south-west by Rwanda, and to the ...

Zambia Zambia, officially the Republic of Zambia, is a landlocked country at the crossroads of Central Africa, Central, Southern Africa, Southern and East Africa. It is typically referred to being in South-Central Africa or Southern Africa. It is bor ...

, and

Zimbabwe file:Zimbabwe, relief map.jpg, upright=1.22, Zimbabwe, relief map Zimbabwe, officially the Republic of Zimbabwe, is a landlocked country in Southeast Africa, between the Zambezi and Limpopo Rivers, bordered by South Africa to the south, Bots ...

.C, Orwa, Mutua A, Kindt R, Jamnadass R, and Simons A. "Ximenia Caffra." Agroforestree Database: A Tree Reference and Selection Guide Version 4.0. 2009. http://www.worldagroforestry.org/treedb2/AFTPDFS/Ximenia_caffra.pdf Sourplum fruits are generally sour, with a dry aftertaste, and contain significant amounts of

potassium Potassium is a chemical element; it has Symbol (chemistry), symbol K (from Neo-Latin ) and atomic number19. It is a silvery white metal that is soft enough to easily cut with a knife. Potassium metal reacts rapidly with atmospheric oxygen to ...

.Ndhlala, A.R., Muchuweti, M., Mupure, C., Chitindingu, K., Murenje, T., Kasiyamhuru, A., Benhura, M.A. (2008) Phenolic content and profiles of selected wild fruits of Zimbabwe: ''Ximena caffra'', ''Artobotrys brachypetalus'' and ''Syzygium cordatum''. International Journal of Food Science and Technology, Vol. 43, p 1333-1337. The tree is fairly hardy, with

frost resistance Frost resistance is the ability of plants to survive cold temperatures. Generally, land plants of the northern hemisphere have higher frost resistance than those of the southern hemisphere. An example of a frost resistant plant is ''Drimys winteri' ...

and

drought tolerance In botany, drought tolerance is the ability by which a plant maintains its biomass production during arid or drought conditions. Some plants are naturally adapted to dry conditions'','' surviving with protection mechanisms such as desiccation tole ...

. The tree, fruit, seed, leaves, and roots are all used for human consumption, medicinally, or for fuel.

Description

The sourplum tree is a sparsely branched shrub or small tree around 2 m in height with a shapeless untidy

crown A crown is a traditional form of head adornment, or hat, worn by monarchs as a symbol of their power and dignity. A crown is often, by extension, a symbol of the monarch's government or items endorsed by it. The word itself is used, parti ...

. It has been known to grow to about 6 m in height. The branches are either smooth or covered with flattened hairs and armed with spines at their bases. The bark of the tree is grayish-brown to black in colour, and is longitudinally fissured. The leaves are simple, alternate, and elliptic in shape. When the tree flowers, the flowers are greenish to creamy white in colour although they have been seen to be sometimes tinged pink or red. The sourplum fruit itself is

ellipsoidal An ellipsoid is a surface that can be obtained from a sphere by deforming it by means of directional scalings, or more generally, of an affine transformation. An ellipsoid is a quadric surface; that is, a surface that may be defined as the ze ...

in shape. The skin is smooth and starts green, and then ripens to an orange or red. Similarly the flesh is also orange or red in colour, and when ripe has a juicy pulp. The sourplum is 3.5 cm in length and 2.5 cm in diameter. The seed is smooth, ellipsoid, and yellow-brown to red in colour. The seed is hard and around 2.5 cm in length.

History, geography and ethnography

A related species, the yellow plum (''

Ximenia americana ''Ximenia americana'', commonly known as tallow wood, hog plum, yellow plum, sea lemon, or pi'ut (Chamorro language, Chamorro), is bush-forming shrub/small tree; a species from the ''Ximenia'' genus in the Olacaceae family. It is mainly found in ...

''), occurs in western United States. The sourplum can be located from Tanzania to

KwaZulu-Natal KwaZulu-Natal (, also referred to as KZN) is a Provinces of South Africa, province of South Africa that was created in 1994 when the government merged the Zulu people, Zulu bantustan of KwaZulu ("Place of the Zulu" in Zulu language, Zulu) and ...

. In the wild, it is found in woodlands, grasslands, rocky outcrops and sometimes termite mounds. All parts of the tree and its fruits are used in cultural remedies.

Growing conditions

It will generally flower in September to October during the dry season to the onset of the rains. The fruits from this flowering are produced in December to January during the rains. This varies from region to region as in Tanzania, flowering occurs in January, May, July, and October, with the fruit being produced generally in October and January. The sourplum can tolerate altitudes of up to 2000 m, and requires annual rainfall of 250–1270 mm. It generally requires clay or loam soils for effective growth. Once planted the seeds will

germinate Germination is the process by which an organism grows from a seed or spore. The term is applied to the sprouting of a seedling from a seed of an flowering plant, angiosperm or gymnosperm, the growth of a sporeling from a spore, such as the sp ...

after 14–30 days, and have a moderate growth rate of 0.5 m per year.Baloyi, Joseph K., and Yvonne Reynolds. "Ximenia Caffra." National Biodiversity Institute, Aug. 2004

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Uses

Food

The fruit is sour but can be eaten raw; it is best eaten when slightly overripe. More typically, it is put into cold water to soak, and then the skin and seed are removed by pressing. The remaining pulp is then mixed with pounded tubers to create a porridge. Alternatively, the fruits can also be processed into a storable jam. The fruits are also known to be used for desserts and jellies.

Wood

The wood of the tree is hard and fine-grained. Typically, it is used as a firewood. However, it can also be used to make handles for tools, utensils, or for construction purposes.

Oil

To extract the oil, the seeds are roasted, then mashed, and the oil extracted. The oil serves several purposes, and can be used to soften leather, oiling bowstrings, or as a general

ointment A topical medication is a medication that is applied to a particular place on or in the body. Most often topical medication means application to body surfaces such as the skin or mucous membranes to treat ailments via a large range of classes ...

. Alternatively, the oil can be used cosmetically for the hair or for the skin to soothe chafing.Saka, J.D.K., Msonthi, J.D. (1994) Nutritional value of edible fruits of indigenous wild trees in Malawi. Forest Ecology and Management, Vol 64, p 245-248. The oil can also be used as fuel for lamps.

Phytochemicals and its antioxidant and anti-inflammatory activities

The chemical profile of ''X. afra'' leaf was comprehensively analyzed and led to the identification of 10 polyphenol compounds, including phenolic acid and flavonoids. Further bioactivity investigations showed that extracts of ''X. afra'' leaves exhibit anti-oxidant, anti-proliferation, and anti-inflammatory activities. The underlying molecular mechanism may partially be contributed by the inhibition of NF-κB activation, a shared signal pathway between proliferation and inflammation.

Reported medicinal purposes

The roots are used to treat

abscess An abscess is a collection of pus that has built up within the tissue of the body, usually caused by bacterial infection. Signs and symptoms of abscesses include redness, pain, warmth, and swelling. The swelling may feel fluid-filled when pre ...

es, stomach aches, colic,

malaria Malaria is a Mosquito-borne disease, mosquito-borne infectious disease that affects vertebrates and ''Anopheles'' mosquitoes. Human malaria causes Signs and symptoms, symptoms that typically include fever, Fatigue (medical), fatigue, vomitin ...

, coughs, and bilharzias. They can also be pounded, turned into porridge and eaten to reportedly prevent sterility in women. It is thought that powdered roots can also be added to beer to act as an

aphrodisiac An aphrodisiac is a substance that increases libido, sexual desire, sexual attraction, sexual pleasure, or sexual behavior. These substances range from a variety of plants, spices, and foods to synthetic chemicals. Natural aphrodisiacs, such as ...

. The tree’s bark is used as a remedy for

syphilis Syphilis () is a sexually transmitted infection caused by the bacterium ''Treponema pallidum'' subspecies ''pallidum''. The signs and symptoms depend on the stage it presents: primary, secondary, latent syphilis, latent or tertiary. The prim ...

hookworm Hookworms are Gastrointestinal tract, intestinal, Hematophagy, blood-feeding, parasitic Nematode, roundworms that cause types of infection known as helminthiases. Hookworm infection is found in many parts of the world, and is common in areas with ...

, chest pains, and body pain. The seeds are generally roasted and then pounded for their oils to be used for wounds as an ointment. The leaves can be used to soothe inflamed eyes and as a reported cure for tonsillitis. Most of these claims do not appear to have been scientifically validated, and further research is required.

Animal uses

The fruits are eaten by birds and various other animals. Several butterfly species are known to feed on the leaves. Various mammals are known to graze on the leaves of the tree, with particular emphasis in times of drought.Owen-Smith, N., Cooper, S.M. (1987) Palatability of woody plants to browsing ruminants in a South African savanna. Ecology Vol 68, No. 2, p 319-331.

Nutritional information

The ripe fruit has a vitamin C content of 27%, a protein content of 18%, and is high in potassium. The seed has a 65% oil content.Chivandi, E., Davidson, B.C., Erlwanger, K.H. (2012. The red sour plum (''Ximenia caffra'') seed: a potential non-conventional energy and protein source for livestock feeds. International Journal of Agriculture and Biology, Vol 14, p 540-544.

Amino acid profile

Constraints to wider adoption

The seedlings may perish to extended periods of drought, as they are not as drought tolerant. The local fauna has a tendency to graze upon the leaves of the tree, and during the dry season animals will actively select this tree to graze upon.

Practical information

The ripe fruit has a high amount of tannins, leading to an

astringent An astringent (sometimes called adstringent) is a chemical that shrinks or constricts body tissues. The word derives from the Latin '' adstringere'', which means "to bind fast". Astringency, the dry, puckering or numbing mouthfeel caused by t ...

dry aftertaste. The fruit’s astringent qualities will intensify during storage. The seeds have no special requirements for storage. The tree can be used as a natural fence to designate tracts of land or set a perimeter. The plant is moderately frost tolerant and drought resistant. The fruits are known to be sold in small markets.Maundu, P. (1987). The importance of gathered fruits and medicinal plants in Kakuyuni and Kathama Areas of Machakos. In: K.K. Wachiira, Women’s use of off-farm and boundary lands: agroforestry potentials, p 56-60, Final Report, ICRAF, Nairobi, Kenya.

References

{{Taxonbar, from=Q128943630, from2=Q15357170 Olacaceae Flora of Africa Fruits originating in Africa Plants described in 1850 Taxa named by Otto Wilhelm Sonder