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OXALIS PES-CAPRAE
GENERAL DESCRIPTION
Scientific name
with author
Oxalis pes-caprae L.
Plant photo – live
plant
Reference
Evenor, Z. (2013). Oxalis pes-caprea. Zachi Evenor - Flickr:
http://www.flickr.com/photos/zachievenor/8736387982/in/set-72157625674893618/ Synonyms
Oxalis cernua Thunb.
Family
Oxalidaceae
Vernacular/
traditional/
regional names
Suring, wilde suring, geelsuring, klawersuring (Afrikaans); african wood sorrel, buttercup oxalis, cape
sorrel, english weed, goat's-foot, sourgrass, soursob, soursop (English); isithathe, isitate (Zulu)
Botanical
description
Oxalis pes-caprae is a slow growing, perennial broadleaf herb with small bulb-like structures below the
ground. The characteristic trifoliate leaves are lobed, long-stalked, clover-like and usually basal. The leaves
fold up at night and unfurl during the day. Leaflets are heart-shaped, glabrous above and hairy beneath. O.
pes-caprae is a dichotyledonous plant that produces copious small corms. It has bright yellow flowers with
five petals borne in loose clusters on long stems. The flowers characteristically open only during sunny
periods and close again at night or during dull weather conditions. Flowering occurs mainly from early
winter through to late spring.
References
South African National Biodiversity Institute. (2004).Oxalis L.
http://www.plantzafrica.com/plantnop/oxalis.htm
Van Wyk, B.-E. and Gericke, N. (2007). People’s plants: a guide to useful plants of southern Africa. Briza,
Pretoria.
Geographical
distribution
O. pes-caprae occurs mainly in the Western and Eastern Cape of South Africa.
Distribution map
ETHNOBOTANICAL INFORMATION
Medicinal uses
The raw corms have been used to deal with tapeworm and possibly other worms.
The leaves make a soothing dressing on burns and skin irritations, and leaves warmed in hot water can be
applied as a poultice on boils and abscesses.
The plant has been used as a diuretic, possibly hazardously.
O. pes-caprae is palatable and in modest quantities is reasonably harmless to humans and livestock.
Caution must be taken to use this herb sparingly. The high oxalic acid content of the herb is harmful if
eaten in large quantities over a short period of time.
References
Bryant, A.T. (1966). Zulu medicine and medicine men. Struik, Cape Town.
Roberts, M. (1990). Indigenous healing plants. Southern Book Publishers, South Africa.
Van Wyk, B-E. and Gericke, N. (2007). People’s plants: a guide to useful plants of southern Africa. Briza,
Pretoria.
QUALITY STANDARDS
Macroscopial
O. pes-caprae is a perennial herb with erect flowering stems usually up 15-30 cm high. It produces a
rosette of leaves at ground level and rhizomes, corms and tubers. The aboveground stems and leaves are
annual and die back each year. The slender flowering stems are sparsely hairy, leafless, and round in
cross-section. The leaves emerge from the top of a rhizome at or just below the soil surface. They are
borne on long petioles 5-22 cm long and consist of three heart-shaped leaflets. The leaflets are 5-30 mm
long and 4-35 mm wide, mostly green in colour, and fold downwards during darkness. They are hairless
with entire margins and deeply-notched. The bright yellow flowers are 25-40 mm across and borne in loose
clusters, each with 3-25 flowers, at the top of the stems on individual stalks up to 20 mm long. They are
tubular with five broad overlapping petals, 15-25 mm long, that are fused together towards their bases.
These flowers also have five sepals, ten stamens and an ovary topped with five styles. They open only
during sunny conditions and close again at night or during dull conditions.
References
South African National Biodiversity Institute. (2004). Oxalis L.
http://www.plantzafrica.com/plantnop/oxalis.htm
Wikipedia. (2015). Oxalis pes-caprae. http://en.wikipedia.org/wiki/Oxalis_pes-caprae
Microscopial
Scattered tanniferous secretory cells are generally found.
CHEMICAL CONSTITUENTS
Chemical
constituents –
compounds diagrams
Chemical
constituents –
compounds description
O. pes-caprae is characterized by the presence of oxalic acid, usually in the form of potassium oxalate. The
plants are without ellagic acid and are only seldom cyanogenic. This herb has a pleasant sour flavor caused
by an exceptionally high content of soluble oxalic acid.
Reference
Watt, J.M. and Breyer-Brandwijk, M.G. (1962). The medicinal and poisonous plants of southern and eastern
Africa. 2nd ed. Livingstone, London.
Chemical
constituents –
organoleptic
properties
O. pes-caprae produces copious small corms. It has bright yellow flowers. The characteristic trifoliate
clover-like leaves fold up and night and unfurl during the day. Leaflets are heart-shaped, glabrous above
and hairy beneath. The herb has a pleasant sour flavor. This sourness is caused by the exceptionally high
content of oxalic acid.
Reference
Roberts, M. (1990). Indigenous healing plants. Southern Book Publishers, South Africa.
Chemical
constituents –
TLC / HPLC / GC
Chemical
constituents –
NIR Spectroscopy
image
Chemical
constituents –
NIR
Purity tests /
Requirements
TLC, HPLC and GC are used.
Assay
Not yet available.
USAGE
Plant part used
Corms and leaves are used.
Plant part used
photograph
Dosage forms
To be determined.
Pharmacology/
bioactivity
Oxalic acid is corrosive and oxalates combine with serum calcium to form insoluble calcium oxalate. O. pescaprae, which contains soluble oxalic acid, can lead to human and animal fatalities if excessive amounts are
consumed in a short space of time. Chronic poisoning may lead to death from kidney failure, following the
formation of calcium oxalate deposits in the kidney tubules.
References
South African National Biodiversity Institute. (2004). Oxalis L.
http://www.plantzafrica.com/plantnop/oxalis.htm
Watt, J.M. and Breyer-Brandwijk, M.G. (1962). The medicinal and poisonous plants of southern and eastern
Africa. 2nd ed. Livingstone, London.
Contraindications
Adverse
reactions
Oxalic acid is corrosive and oxalates O. pes-caprae, which contains soluble oxalic acid, can lead to human
and animal fatalities if excessive amounts are consumed.
Precautions
This plant is harmful if eaten in large quantities over a short period of time.
Dosage and
preparation
A dessertspoon portion of corms, taken on an empty stomach first thing in the morning, acts as a
vermifuge.
The leaves make a soothing dressing on burns and skin irritations, and leaves warmed in hot water can be
applied as a poultice on boils and abscesses.
The high oxalic content of this plant may cause digestive disorders and heartburn if too much is ingested.
Care should be taken to use this herb sparingly.
Reference
Roberts, M. (1990). Indigenous healing plants. Southern Book Publishers, South Africa.
Source Reference
Hutchings, A., Scott, A.H., Lewis, G. and Cunningham, A.B. (1996). Zulu Medicinal Plants: an inventory. Natal University Press,
Pietermaritzburg.