Hoodia gordonii (PROTA)

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Plant Resources of Tropical Africa Introduction

List of species

General importance
Geographic coverage Africa
Geographic coverage World
Medicinal
Ornamental

Hoodia gordonii (Masson) Sweet ex Decne.

File:Map Hildebrandtia sepalosa.gif

distribution in Africa (wild)

Protologue: in A.DC., Prodr. 8: 665 (1844).

Family: Asclepiadaceae (APG: Apocynaceae)

Chromosome number: 2n = 22

Synonyms

• Hoodia pillansii N.E.Br. (1909).

Vernacular names

• Hoodia cactus, ghaap (En).

Origin and geographic distribution

Hoodia gordonii occurs in arid and very arid areas from Namibia through the Great Karoo region to Free State and North Cape and West Cape provinces of South Africa.

Uses

The San people of Namibia occasionally eat the fresh or cooked young juicy stems of Hoodia gordonii and related species as food, but more importantly, they chew pieces of the bitter stems to suppress hunger and thirst during long hunting trips or periods of food scarcity. This use has led to the development of ‘Hoodia extract’ widely used as a food additive to fight obesity.

This development process has been the subject of a long and bitter controversy over intellectual property rights and compensation for the use of traditional knowledge of plants between the San people on one hand and a South African research organization and pharmaceutical companies on the other. The use of Hoodia was noted by scientists of the South African Council of Scientific and Industrial Research (CSIR) in the 1960s. Following research into the food value and chemical composition of the plant, CSIR filed for a patent on the use of the purported active compound ‘P57A53’, which was granted in 1995. In 1998 CSIR licensed the use of P57A53 to the British pharmaceutical research company Phytopharm, specialized in the development of phytomedicines. The aim was the development and worldwide marketing of the patented extract P57A53 from Hoodia for suppressing appetite, treatment of eating disorders, obesity and diabetes mellitus. In 1998 Phytopharm reported completed pre-clinical studies and a proof-of-principle clinical study. In the same year Phytopharm signed a sub-licensing agreement with Pfizer to raise additional funds to develop and commercialise P57A53.

In 2001 representatives of the San people were informed about the patent. As a result of the outrage over the patent and in line with the Convention on Biological Diversity (CBD) signed in 1992 at the Earth Summit in Rio de Janeiro, negotiations were started between San representatives and CSIR. This resulted in apologies from CSIR for not consulting with the San, and in the first benefit-sharing agreement compensating for the use of traditional knowledge of a plant species, signed in 2003. Under the agreement the San would be entitled to 8% of all payments CSIR receives from its licensee, as well as 6% of all royalties once a drug is commercialised. After the shutdown of its Natureceuticals group, Pfizer pulled out of the agreement and a new agreement was signed between Phytopharm and Unilever. Although Phytopharm announced successful progress towards regulatory approval, results of a clinical study using Hoodia extract in a drink-based product led Unilever to conclude that prospects of further development of the product concept were bleak. While Unilever had developed and patented several technological inventions including methods for the micropropagation of Hoodia plants in 2008, it pulled out of the agreement at the end of the year. Although Phytopharm was negatively impacted by the Unilever decision, it still believes that the pre-clinical and clinical data of the Hoodia extract justify further studies on appetite suppression and obesity, as well as for pharmaceutical and veterinary applications. In recent years the extract has been developed into appetite suppressant food additives used worldwide, although scientific proof of the efficacy and safety is still limited. Products based on the extract are often sold through the Internet. Unfortunately, Hoodia extracts of doubtful quality are also sold through Internet and their compliance with intellectual property rights law and with CITES regulations is often questionable.

In traditional medicine the San use the plant also as a stomachic, and against indigestion, diabetes, tuberculosis and hypertension. Made into a tincture with brandy it is applied against haemorrhoids. Honey from the flowers is reportedly used in the treatment of cancer.

Hoodia gordonii is occasionally grown as ornamental.

Production and international trade

Trade in Hoodia plants, including Hoodia gordonii and its products, is subject to strict regulation under Appendix II of CITES. Although a permit is required for the collection, possession and transport and export, uncontrolled illicit trade, especially through Internet, seems common, but amounts traded are unknown. Recently commercial cultivation of Hoodia gordonii grown for its appetite-suppressing products, has started in South Africa and Namibia. The regulated production is organized through the Southern African Hoodia Growers Association in which growers in Namibia, Botswana and South Africa are organized. In 2006 the Association signed a profit-sharing agreement with representatives of the San people.

Properties

The most characteristic secondary metabolites in Hoodia species are pregnane glycosides. In Hoodia gordonii many of them have been identified, including more than 25 hoodigosides, several hoodistanalosides and gordonosides. The glycosides consist of a 12-hydroxypregnane aglycon linked with several 6-deoxy sugars or 2,6-dideoxy sugars. The most common aglycons are hoodigogenin A and calogenin. Hoodigogenin A is a 3β,12β,14β-trihydroxy-pregn-5-en-20-one. The active appetite-suppressing compound has been identified as 12-tigloyloxy-14-hydroxypregn-5-en-20-one linked at the 3-position with a chain of 3 sugars (D-thevetose, D-cymarose and D-cymarose). It is commonly referred to as P57A53 or simply P57. Quantitative analyses showed big differences in the contents. An extract of dried Hoodia gordonii contained 2.1% total steroid glycosides. The content of the single compound P57A53 was found to be between 0.05% and 0.005%. In commercial Hoodia gordonii extract a very similar glycoside is also present, differing only in the presence of a chain of 4 sugar units. P57A53 has also been identified in Hoodia currorii (Hook.) Decne., Hoodia ruschii Dinter, Hoodia pilifera (L.f.) Plowes and Hoodia parviflora N.E.Br.

Feeding experiments in which rats were given extracts of Hoodia gordonii or pure P57A53 have shown a reduction in both food intake and body weight. Direct injection of P57A53 into the brain of rats also showed a reduction of food intake and an increased level of ATP in the hypothalamus, suggesting an effect of the active compound on the central nervous system. In patent applications, antidiabetic effects of the extract and reduction of damage caused by excessive production of gastric acid have been reported. Information on the appetite depressing effect of P57A53 in humans is scarce. In a trial with humans, consumption of purified Hoodia gordonii extract during 15 days appeared to be associated with significant adverse side effects, including episodes of nausea, emesis, and disturbances of skin sensation, while blood pressure, pulse, heart rate, bilirubin and alkaline phosphatase were increased. The extract was less well tolerated than the placebo and did not show any significant effects on energy intakes or body weights. A phase 2 clinical trial on humans was discontinued for unknown reasons. It has been suggested that the experiment showed a lack of pharmacological efficacy of the drug as administered, although several experiments had earlier shown its efficacy. Traditionally, San people chewed parts of the stem for prolonged periods of time. Intake of P57A53 e.g. as tablet or as drink may not produce the same result. Results of other experiments have not yet been published. Hoodia gordonii extract did not show genotoxicity in 2 assays in vitro, a bacterial mutation assay and a gene mutation assay using mouse lymphoma cells. A bone marrow micronucleus assay in the mouse, with high doses of extract injected, showed no change in mean frequencies of micronucleated polychromatic erythrocytes of treated animals. The results were taken to indicate that Hoodia gordonii extract is non-genotoxic under the conditions of the test. In tests with pregnant rabbits and mice, test animals were given high daily doses of Hoodia extract (maximum 12 mg/kg and 50 mg/kg, respectively) for several weeks during pregnancy. The higher doses showed reduced food intake. At doses that reduced maternal feed consumption in mice, Hoodia gordonii extract delayed foetal development.

While traditional use of Hoodia suggest that it is safe if used appropriately, experiments testing the safety have given mixed results. In addition, results of studies on the safety of long-term use of Hoodia extract by humans have not yet been reported.

Adulterations and substitutes

The origin and identity of many Hoodia appetite-supressing products, especially those offered via Internet, is questionable. Adulterations with other Hoodia species and even with material of Cereus, Echinopsis and Opuntia (Cactaceae) and Aloe (Asphodelaceae) have been reported. In a test 2 out of 10 samples showed low contents of the active ingredient, the other 8 samples did not contain P57A53 at all. Hoodia species and species of related genera are very similar and harvested material is very difficult to identify unless the exact location of origin is known or if accompanying herbarium material is available. Standard chemical methods of analysis are inadequate and specialized TLC or HPLC chromatographic methods are needed. Alternatively, the P57A53 content should be measured.

Description

Many-stemmed, spiny, succulent shrub up to 100 cm tall and 60 cm broad. Stems 10–100 cm long, 2.5–5 cm thick, erect, obtusely angular, fleshy and fairly hard, glabrous, grey-green to grey-brown. Leaves reduced to spiny tubercles; stipules absent; tubercles prominent, 5–15(–20) mm long, deltoid, laterally flattened, fused in lower half of stem into 11–17 obtuse, vertical ridges, each tipped with a sharp spine 6–12 mm long. Inflorescence mainly at apex of stem, 1–4-flowered, glabrous, with many deltoid bracts. Flowers opening successively, bisexual, regular, 5-merous, malodorous; pedicel 8–30 mm long; sepals ovate-lanceolate and overlapping at base, 5–6 mm × 2–4 mm, acuminate, appressed to corolla; corolla somewhat rotate, nearly circular to 5-lobed, (4–)5–10 cm in diameter, outside pale flesh-coloured with darker veins, inside flesh-coloured to deep purple-red usually with darker veins, smooth to covered with small conical papillae, each tipped with a bristle up to 2.0(–2.5) mm long, tube 1–1.5 mm × 4.5–6 mm at mouth, enclosing most of gynostegium, formed entirely by annular thickening near base, lobes broadly ovate, up to 1.5 mm × 5 cm, spreading, abruptly narrowing into subulate, 3–6 mm long point; corona 1.5–2.0 mm × 4–6 mm, purple-black, glabrous, divided in small outer and inner lobes; anthers united with gynoecium forming a gynostegium with anthers horizontal on top of style-head, filaments joined forming a short sheath around the style. Fruit composed of 2 follicles, these erect, slender, horn-like, 9–11.5 cm long, diverging at 30–60°, greenish, glabrous, smooth, 180–190-seeded. Seeds with tuft of hairs at one side.

Other botanical information

Hoodia comprises about 13 species that all occur in southern Africa, from Angola to the Cape provinces and the Orange river basin in South Africa, with a single species also in Botswana and Zimbabwe. Hoodia gordonii is very variable. In the past it has been subdivided into numerous species, but in a review covering the whole range of the current species, the subdivision was not maintained.

When not in flower, Hoodia gordonii is easily confused with Hoodia currorii (Hook.) Decne., but the latter is a more tangled, untidy-looking shrub. Natural hybrids have been recorded between Hoodia gordonii and Hoodia flava (N.E.Br.) Plowes. The plants were fertile and backcrosses with the parents successful. Natural intergeneric crosses include: Hoodia gordonii × Orbeopsis lutea (N.E.Br.) L.C.Leach subsp. vaga (N.E.Br.) L.C.Leach and Hoodia gordonii × Stapelia arenosa Luckhoff.

Several other Hoodia species are used in traditional medicine.

Hoodia parviflora

Hoodia parviflora N.E.Br. is the largest Hoodia with stems up to 2 m tall and 11 cm thick and large flowers. It occurs in south-western Angola and north-western Namibia. It is traditionally used for vermin control.

Hoodia pedicellata

Hoodia pedicellata (Schinz) Plowes (synonym: Trichocaulon pedicellatum Schinz) is a succulent herb with many stems with ridges of non-persistent spines on the tubercles, endemic to an 80 km wide coastal strip in the Namib desert region to south-western Angola. It is occasionally grown by succulent enthusiasts, but is difficult to grow, as both high temperatures combined with sunshine and low temperatures with high humidity are detrimental. Topnaar people in Namibia eat the succulent core of the stems raw like those of Hoodia currorii (Hook.) Decne. in spite of their bitterness. This lowers blood pressure, cures indigestion, stomach pain and colds. The fleshy part of the stem is also applied to the eyes to relieve eye-pain. Sugar water to which pieces of stem are added, makes a refreshing drink.

Hoodia pilifera

Hoodia pilifera (L.f.) Plowes is a succulent shrub up to 80 cm tall and 2 m in diameter, stems up to 6 cm thick, with 20–34 ridges of spiny tubercles, flowers up to 3 cm in diameter, foul-smelling. It occurs mainly in the Karoo region of South Africa. In traditional medicine it is used to treat pulmonary tuberculosis and haemorrhoids and as stomachic. Hoodia pillansii, now a synonym of Hoodia gordonii, has been classified as a subspecies of Hoodia pilifera. Because of this confusion it is not always clear from the literature if P57A53 is present in Hoodia pilifera.

Hoodia officinalis

Hoodia officinalis (N.E.Br.) Plowes is a small succulent shrub with erect or sprawling stems up to a maximum of 40 cm long and 7 cm in diameter, with small flowers. It occurs from southern Namibia eastward just reaching western Free State province of South Africa. In traditional medicine Hoodia officinalis is used to treat haemorrhoids. It is occasionally cultivated as ornamental by succulent enthusiasts, but pollination is difficult and seed hard to obtain. Propagation by cuttings is possible using stems cut near the base. Stem tips often suffer from sun scorch and rotting.

Growth and development

Hoodia gordonii flowers annually in spring in the western parts of its distribution area, and in summer in central parts. Inflorescences persist and old inflorescences may produce flowers in subsequent years but the newest inflorescences near the apex bear most flowers. Flowering disrupts the arrangement of the ridges of tubercles along the stem. Growth between consecutive flowering seasons is usually small in extent and the orderly arrangement of ridges is not restored, so that they can only be counted at the base of the stem. Each tubercle bears a leaf-rudiment that is modified into a sharp spine. In young seedlings the leaf-like nature of this spine can still be recognized in traces of the blade and midrib. The spines on the tubercles are normally very hard, but become soft and pliable when moistened as during a nocturnal mist.

Ecology

Hoodia gordonii occurs in a wide range of arid habitats in desert, semi-desert and savanna vegetation, from coastal to mountainous, on gentle to steep shale ridges, in dry rocky places to sandy spots in riverbeds. It is most common in summer-rainfall areas and is of only scattered occurrence in drier winter-rainfall areas where some summer rainfall occurs. An exception is the population in the Tankwa Karoo area, which is also the only population on sandstone-derived soil.

Populations tend to originate in scrub vegetation and may grow to become dominant.

Propagation and planting

Hoodia gordonii is propagated by seed. Methods of micropropagation have been developed and patented. When seedlings are 6–8 months old and about 5 cm tall they are transplanted into the field.

Management

In parallel with chemical investigations, CSIR started agronomic research on Hoodia in 1998, which demonstrated that large-scale, commercial production is possible. Work started with the identification of a large, well-documented natural stand of Hoodia gordonii on a farm in Pella district in the Northern Cape Province. Plant material for research and seed for further work were collected from there. Between 1999 and 2004, a series of experiments were conducted to develop and optimise techniques for seed collection and storage, seedling propagation, irrigation and fertilizer requirements, pest and disease identification and control measures as well as harvesting techniques. The results of these trials, which are so far unpublished, provided the basis for large, commercial scale trials (70 ha). Since 2005 commercial farms have been established. In the field, plants are grown under drip irrigation, with fertilizer applications optimized for glycosides production. The use of pesticides is avoided to ensure that the crop is as free of chemical contamination as possible.

Harvesting

When harvesting Hoodia gordonii, whole plants are collected and brought to a central point where they are cleaned and where roots are removed. Conservation authorities in South Africa issue permits for controlled harvesting. Harvesting from the wild is done throughout the year with a peak during the flowering season.

Handling after harvest

After collection stems are cut into small pieces and dried. The active compound seems stable in the dried material. As part of its Hoodia programme, CSIR developed a method of commercial processing of cultivated plants. After harvesting stems are washed, cut up and dried under controlled conditions, then finely ground. The ground material is extracted with aqueous methanol at 50–80°C. Fats and waxes are removed by cooling and filtration followed by washing with n-heptane. To further concentrate and purify the extract it is extracted with n-butanone and n-heptane and subsequently cleaned with an EDTA solution and active carbon. After removal of any remaining solvent and chemical testing for purity, the Hoodia extract is ready for packing and distribution.

Genetic resources

Although Hoodia gordonii is widespread, occurring over an estimated 850,000 km², it has undergone significant decline as a result of indiscriminate harvesting. As a result of the high economic value of this species even remote areas of its distribution range are likely to have been harvested. However, no data exist to quantify the degree of decline. The conservation situation is complicated by the similarity of many Hoodia and related species, which makes it likely that they are all affected by illicit harvesting. This may affect the conservation status of rarer species. Three Hoodia species are listed in the IUCN Red list of threatened species: Hoodia juttae Dinter, Hoodia ruschii Dinter and Hoodia triebneri (Nel) Bruyns. In South Africa and Namibia most Hoodia species are protected.

Breeding

Information on breeding or selection aiming at higher P57A53 yields or better agronomic characteristics have not yet been published.

Prospects

The efficacy and safety of P57A53 and Hoodia gordonii extract as appetite suppressing food additives in humans needs to be established beyond doubt if they are to outgrow their current status as ‘cult food’. Even more rigorous testing is required if they are to become accepted as pharmaceutical drugs for the treatment of obesity, diabetes mellitus.

Major references

• Bruyns, P.V., 1993. A revision of Hoodia and Lavrania (Asclepiadaceae - Stapelieae). Botanische Jahrbücher 115: 145–270.
• Bruyns, P.V., 2005. Stapeliads of Southern Africa and Madagascar. Vol. 2. Umdaus Press, Pretoria, South Africa. pp. 331–600.
• Glasl, S., 2009. Hoodia: A herb used in South African traditional medicine - A potential cure for overweight? Pharmacognostic review of history, composition, health-related claims, scientific evidence and intellectual property rights. Schweizerische Zschrift für GanzheitsMedizin 21(6): 300–306.
• Knight, T.L., Swindells, C.M., Craddock, A.M., Maharaj, V.J., Buchwald-Werner, S., Ismaili, S.A. & McWilliam, S.C., 2012. Cultivation practices and manufacturing processes to produce Hoodia gordonii extract for weight management products. Food and Chemical Toxicology 50: S1–S5.
• Oliver, J., 2005. Hoodia gordonii. [Internet] South African National Biodiversity Institute, Kirstenbosch, South Africa. http://www.plantzafrica.com/ frames/ plantsfram.htm. Accessed May 2012.
• Russell, P.J. & Swindells, C., 2012. Chemical characterisation of Hoodia gordonii extract. Food and Chemical Toxicology 50: S6–S13.
• van Heerden, F.R., 2008. Hoodia gordonii: a natural appetite suppressant. Journal of Ethnopharmacology 119: 434–437.
• van Heerden, F.R., Horak, R.M., Maharaj, V.J., Vleggaar, R., Senabe, J.V. & Gunning, P.J., 2007. An appetite suppressant from Hoodia species. Phytochemistry 68: 2545–2553.
• van Wyk, B.E., 2008. A broad review of commercially important southern African medicinal plants. Journal of Ethnopharmacology 119: 342–355.
• Vermaak, I., Hamman, J.H. & Viljoen, A.M., 2011. Hoodia gordonii: An up-to-date review of a commercially important anti-obesity plant. Planta Medica 77: 1149–1160.

Other references

• Archer, R.H. & Victor, J.F., 2003. Plant portraits: 479. Hoodia pilifera subsp. pillansii (Apocynaceae: Asclepiadoideae). Curtis’s Botanical Magazine 20(4): 219–224.
• Blom, W.A.M., Abrahamse, S.L., Bradford, R., Duchateau, G.S.M.J.E., Theis, W., Orsi, A., Ward, C.L. & Mela, D.J., 2011. Effects of 15-d repeated consumption of Hoodia gordonii purified extract on safety, ad libitum energy intake, and body weight in healthy, overweight women: a randomized controlled trial. American Journal of Clinical Nutrition 94: 1171–1181.
• Bruyns, P.V., 2000. Phylogeny and biogeography of the Stapeliads, 1. Phylogeny. Plant Systematics and Evolution 221: 199–206.
• Dent, M.P., Wolterbeek, A.P.M., Russell, P.J. & Bradford, R., 2012. Safety profile of Hoodia gordonii extract: Mouse prenatal developmental toxicity study. Food and Chemical Toxicology 50 (Suppl. 1): S20–S25.
• Dent, M.P., Wolterbeek, A.P.M., Russell, P.J. & Bradford, R., 2012. Safety profile of Hoodia gordonii extract: Rabbit prenatal developmental toxicity study. Food and Chemical Toxicology 50 (Suppl. 1): S26–S33.
• Eloff, J.N., Brendler, T., Gurib-Fakim, A. & Phillips, L.D., 2010. The African Herbal Pharmacopoeia. Association for African Medicinal Plants Standards (AAMPS), Reduit, Mauritius. 324 pp.
• Goswami, P., Khale, A. & Shah, S., 2011. Medicinal herbs and obesity: a review. International Journal of Pharmaceutical Sciences Review and Research 11(1): 69–74.
• Loots, S., 2005. Red data book of Namibian plants. Southern African Botanical Diversity Network Report No. 38. SABONET, Pretoria, South Africa and Windhoek, Namibia. 153 pp.
• Poddar, K., Kolge, S., Bezman, L., Mullin, G.E. & Cheskin, L.J., 2011. Nutraceutical supplements for weight loss: a systematic review. Nutrition in Clinical Practice 26: 539–552.
• Raimondo, D., Wynberg, R., Newton, D. & Victor, J.E., 2008. Hoodia gordonii (Masson) Sweet ex Decne. National assessment: Red list of South African plants, version 2011.1. [Internet] http://redlist.sanbi.org/species.php?species=2705-13 . Accessed May 2012.
• Rumalla, C.S., Avula, B., Shukla, Y., Wang, Y., Pawar, R., Smillie, T. & Khan, I., 2008. Chemical fingerprint of Hoodia species, dietary supplements, and related genera by using HPTLC. Journal of Separation Science 31: 3959–3964.
• Scott, A.D., Orsi, A., Ward, C. & Bradford, R., 2012. Genotoxicity testing of a Hoodia gordonii extract. Food and Chemical Toxicology 50 (Suppl. 1): S34–S40.
• SEPASAL, 2012. Hoodia officinalis. [Internet] Survey of Economic Plants for Arid and Semi-Arid Lands (SEPASAL) database. Royal Botanic Gardens, Kew, Richmond, United Kingdom. http://www.kew.org/ ceb/sepasal/. Accessed July 2012.
• Shukla Y.J., Pawar, R.S., Ding, Y.Q., Li, X.C., Ferreira, D. & Khan, I.A., 2009. Pregnane glycosides from Hoodia gordonii. Phytochemistry 70: 675–683.
• Tibe, O., Modise, D.M. & Mogotsi, K.K., 2008. Potential for domestication and commercialization of Hoodia and Opuntia species in Botswana. African Journal of Biotechnology 7(9): 1199–1203.
• Tränkle, U. & Hübner, F., 1992. Hoodia pedicellata (Schinz) Plowes. Asclepios 56: 9.
• Van den Eynden, V., Vernemmen, P. & Van Damme, P., 1992. The ethnobotany of the Topnaar. University of Gent, Belgium. 145 pp.
• Vermeylen, S., 2007. Contextualizing ‘fair’ and ‘equitable’: The San’s reflections on the Hoodia benefit-sharing agreement. Local Environment 12(4): 423–436.
• Wynberg, R., 2004. Rhetoric, realism and benefit sharing: Use of traditional knowledge of Hoodia species in the development of an appetite suppressant. Journal of Intellectual Property 7(6): 851–876.
• Yuliana, N.D., Jahangir, N., Korthout, K., Choi, Y.H., Kim, H.K. & Verpoorte, R., 2010. Comprehensive review on herbal medicine for energy intake suppression. Obesity Reviews 12: 499–514.

Author(s)

• L.P.A. Oyen, PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands

Correct citation of this article

Oyen, L.P.A., 2013. Hoodia gordonii (Masson) Sweet ex Decne. In: Schmelzer, G.H. & Gurib-Fakim, A. (Editors). Prota 11(2): Medicinal plants/Plantes médicinales 2. PROTA, Wageningen, Netherlands. Accessed 14 October 2025.

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