The native inhabitants of the Kalahari Desert, known as the San, the Khwe, the Basarwa or the Bushmen, are considered to be the world's oldest living culture dating back over 100,000 years. Traditionally they were hunter gatherers, a small number of them still following that way of life today, and living in arguably the world's harshest and most inhospitable terrain this meant continually moving around to find the resources to survive, seeking out edible plants and water and tracking game over long distances. The survival skills needed in the Kalahari are naturally immense, but the Desert's natives have always been equal to the challenge.
In 1937 a Dutch anthropologist studying the Bushmen of the Kalahari noted that they did not take any food with them to eat during hunts, even when on trips lasting 2 or 3 days. Instead they would seek out a particular plant which grew in the Desert and eating this alone enabled them to survive, it apparently acting as an appetite suppressant and thirst quencher. This plant was identified as Hoodia Gordonii, known to the Bushmen as Xhoba and used by them for thousands of years to stave off hunger, allowing them to hunt for days without being concerned at the lack of food.
The secret of Hoodia or Xhoba may have been out, but at that time it was of little interest to the world outside the Kalahari. However, the recorded use of the plant as a drink substitute and appetite suppressant turned out to be significant, because in 1963 it led directly to South Africa's Council for Scientific and Industrial Research including it in a study on the properties of edible wild plants. In this study Hoodia was fed to laboratory mice, which were then found to eat less and lose weight and without suffering any ill effects. The potential of Hoodia as a way of suppressing appetite appeared obvious, and it immediately became the subject of further research to try and establish exactly how it worked on the appetite in order that a patent could be applied for. However, the methods of the time proved unequal to the task of identifying the active ingredients and in 1968 the project was mothballed. But then in 1986 the CSIR acquired technology which brought the project back to life, specifically a high-field nuclear magnetic resonance spectroscopy which enabled them to effectively isolate the bioactive compound in Hoodia responsible for appetite suppression. In 1995 the work was complete and a patent application was filed in South Africa for the isolated chemical substance, which was named as "3-O-[-beta-D- thevetopyranosyl-(1—>4)-beta-D-cymaropyranosyl-(1—>4)- beta-D-cymaropyranosyl]-12beta-O-tigloyloxy-14-hydroxy- 14beta-pregn-5-en-20-one". This is a steroidal glycoside, a steroid molecule chemically bonded to a sugar molecule, or in this case a chain of 3 sugars.
The one thing that was still not clear at this time was how this steroidal glycoside acted to suppress appetite and research now centred on this last piece of the jigsaw. The compound clearly induced the sense of satiety in the brain and further study eventually yielded the secret of how it manages to cause this effect. Normally food is broken down by the body's digestive system into glucose, the glucose is absorbed into the bloodstream, and it's this glucose in the blood that leads the brain to form the sense of satiety. The steroidal glycoside found in Hoodia appears to work by mimicking the effect of glucose, as its presence in the bloodstream affects the brain in exactly the same way as glucose does, giving the brain the impression that the body is full of food. Just as with the presence of glucose, the brain responds by switching off the sensation of appetite.