User:Jklaasen/Galenia africana

thumb|Galenia africana (Kraalbos, a [[monoculture stand of this pioneer plant]]

Description
Galenia africana (Kraalbos, geelbos, perdebos, d/kooi dabee) belongs to the family Aizoaceae and is a southern African plant species. This Galenia species is an aromatic, woody perennial sub-shrub, growing 0.5 - 1.5 m high; having oppositely arrranged green leaves (~5 cm long and hairless) which turn yellow with age. Inflorescence is born at the ends of the twigs and is 30 - 100 mm long, with many small yellow flowers. The flowers are about 1.5 mm in diameter, yellowish green and born in large loose heads. flowering time is from October to December.

Traditional Uses


Watt & Breyer-Brandwijk (1962) summarised folklore medicine reports of 1923 and 1928 on the traditional uses of G. africana in South Africa as follow: "A decoction of G. africana is used as a lotion for wounds in man and animal. The Khoi-San indigenous community chew the plant to relieve toothache and it is said to blister the mucous membrane of the mouth if used too much. The plant is also used in the treatment of venereal diseases and still figures in folk medicine in the Western Cape Province, a decoction being used as a lotion for skin diseases and for the relief of inflammation of the eyes. An ointment made by frying the herb with Cyanella lutea, Lobostemon frutocosus, Melianthus major, Melianthus comosus, Tiendaegeneesblare and Jakkalsoorblare in butter, is used as a dressing for wounds especially wounds on legs of women. In syphilis the external lesions are washed with a decoction of the plant and L. fructucous, M. major and M. comosus and for lupus, a decoction of the plant with M. major, M. comosus and Berglelie."

An ethnobotanical survey by De Beer & van Wyk (2011) between 2009 and 2011 documented and confirm with particpants in the Calvinia district of the Northern Cape Province, South Africa the following traditional uses of G. africana: "Make a leaf infusion and wash head to treat pimples, rashes on head; used to treat dandruff and lice; treatment of dry skull; leg pains and swollen legs; used to clean wooden floors; used as lye when drying fruits, e.g. prunes." Similar accounts of traditional uses were recorded by Nortje (2011) in the Kamiesberg, Namaqua district, Northern Cape Province e.g. used as shampoo for sores on child's scalp or for ringworm.

Bioprospecting


As a signatory to the Convention on Biological Diversity, South Africa promulgated the South African Biodiversity Act in 2004. It seeks to combat biopiracy and to ensure that indigenous communities (e.g. Khoi-San) share equally and equitably in the benefits from bioprospecting and indigenous knowledge. The University of the Western Cape (UWC) is the owner of the first patent on G. africana. In 2011, the South African Department of Agriculture, Fisheries and Forestry (DAFF) granted to UWC a provisional agricultural spray adjuvant registration for the patented Galenia africana extract under the Fertilizers, Farm Feeds, Agricultural Remedies and Stock Remedies Act 36 of 1947. Eucrasia (Rapitrade 670) (Pty) Ltd is the first bioprospecting permit holder for the extraction and purification of chemical compounds from G. africana.

Ecology


Galenia africana is a active invader, and is especially abundant in disturbed areas around kraals (stockpost), along roads and trampled veld. This plant is not only an indicator of disturbance, but is also a pioneer plant, being the first perennial to regrow after soil disturbances. The luxuriant seedlings produce monoculture stands, which appear after even light rains, are highly favoured by livestock that is in a poor condition. High grazing intensities favours the establishment of G. africana leading to large monospecific stands in communal and commercial rangeland and can contribute to more than 60% of the perennial shrub cover. Vegetation studies in Kamiesberg area, Namaqua District recorded 150 to 200 Galenia shrubs per 100 m2 over a period of three years from 1999 to 2001 at one site and 50 to 100 shrubs per 100 m2 on a second site. In Kamiesberg area over distances of 50 m and 100 m from a livestock post (kraal) G. africana contributed 68% and 74% to total shrub cover, respectively. Galenia is associated with the driest soils, which may ensure dominance even when grazing pressure is removed. Invasion of old lands by Galenia may be a necessary step in restoring their productivity.

Toxicology


Although not normally eaten by livestock but as a final stand-by in drought and heavily grazed areas both sheep and goat will eat Galenia leading to a condition known as waterpens. Waterpens is characterised by the development of an atrophic or hypertonic arrhasis of the liver. It was suggested that the plant contains an unidentified toxin responsible for hepatic damage and ascites. Apart from weight loss, the habitus and appetite of sheep suffering from waterpens remain fair up to the terminal stages of the disease, after which the animals become apathetic and recumbent, and eventually die.

An in vitro cytotoxic study using vero cells (mammalian kidney cell wall) reported that G. africana extract had an IC50 value of 118.2 μg/ml. Cytotoxicity for whole blood cultures using lactate dehydrogenase leakage (LDH) showed no toxicity at 625 μg/ml and an IC50 value of 975 μg/ml, while LDH leakage for human breast adenocarcinoma cell line (MCF-7) obtained an IC50 value of 1127 μg/ml.

For environmental toxicology studies of G. africana extracts the Vibrio fischeri bioluminescent test showed EC50 values of 1 and 0.7 μg/ml at 15 and 30 min exposures, respectively. The Daphnia pulex acute toxicity tests showed EC50 values of 40 and 30 μg/ml at 24 and 48 hr exposures, respectively.

Chemistry


Flavonoids were identified as major compounds in G. africana. Flavonoids identified in purified fractions of the Galenia extracts have identical or similar chemical structures to pinocembrin (5,7-dihydroxyflavanone), 7-Hydroxyflavanone, 2,4 Dihydroxychalcone, sakuratin and chrysin.

Antimicrobial Studies
G. africana extracts and flavonoid fractions showed antifungal  and  antimycobacterial  activities.