Sceletium tortuosum is a succulent plant indigenous to South Africa, utilized for centuries by the native Khoi and San peoples. Commonly known as Kanna or Kougoed, the herb has a long history of traditional application for its ability to affect mood and perception. Modern science is exploring the phytochemical composition of this plant to understand the biological basis for its historical use.
Botanical Identity and Historical Use
This perennial succulent grows primarily in the Fynbos biome of the Western and Northern Cape Provinces of South Africa. The name Sceletium is derived from the Latin word sceletus, referring to the distinctive, skeletonized appearance of its dried leaves.
Traditionally, the Khoi and San peoples would harvest the plant, often fermenting it before chewing the material or using it as a snuff or tea. The traditional preparations were used to suppress hunger and thirst during long journeys.
The plant’s most documented historical purpose was for social and spiritual rituals. It was consumed to relieve stress, elevate mood, and provide a sense of well-being. Written accounts of this practice date back to 1662, confirming its established place in South African ethnobotany.
The Active Compounds and Their Mechanisms
The actions of the plant are primarily attributed to a group of structurally similar alkaloids, with Mesembrine, Mesembrenone, and Mesembrenol being the most prominent. These compounds interact with the central nervous system through a dual mechanism that affects the availability and signaling of brain chemicals.
The primary mechanism involves the inhibition of the serotonin transporter (5-HT), which recaptures the neurotransmitter serotonin after it has been released. By functioning as a Serotonin Reuptake Inhibitor (SRI), the alkaloids allow serotonin to remain active in the synaptic space for a longer duration, contributing to mood elevation and reduced anxiety. Mesembrine is considered the most pharmacologically potent of these alkaloids, having a strong affinity for the 5-HT transporter.
The secondary mechanism involves the inhibition of the enzyme Phosphodiesterase 4 (PDE4). PDE4 is a family of enzymes that downregulate the activity of cyclic adenosine monophosphate (cAMP), a molecule involved in cellular signaling pathways. When PDE4 is inhibited, cAMP activity increases, which is associated with anti-inflammatory effects and may support memory and cognition.
Documented Modern Applications
Contemporary research on standardized extracts, such as Zembrin, has focused on translating the plant’s traditional uses into measurable clinical benefits. Studies have shown that supplementation can effectively attenuate the subcortical threat circuitry in the brain, the neural network associated with fear and threat detection. This effect supports the extract’s ability to reduce perceived stress and anxiety in healthy volunteers.
Further investigations have explored its potential for cognitive support, particularly in executive function. In randomized trials, Sceletium extract has been linked to improvements in complex reactive performance, a measure that involves quick decision-making and motor response under pressure. Other research suggests the extract may induce frequency changes in brain waves that correlate with enhanced attention and memory processing.
Safety Profile and Regulatory Status
The consumption of standardized Sceletium extracts is associated with a favorable safety profile, with reported side effects usually being mild and transient. Some individuals may experience minor adverse effects such as headache, mild nausea, or temporary changes in appetite.
However, its mechanism as an SRI necessitates caution regarding potential drug interactions, particularly with other substances that increase serotonin levels. The alkaloids in Sceletium can interact with selective serotonin reuptake inhibitors (SSRIs), monoamine oxidase inhibitors (MAOIs), and other psychiatric medications.
Using Sceletium alongside these drugs could lead to an excessive accumulation of serotonin, a condition known as serotonin syndrome. Because the plant is typically sold as a dietary supplement, a lack of stringent federal regulation means the concentration of active alkaloids can vary significantly between products. Consumers should seek out standardized extracts and consult a healthcare professional, especially if they are currently taking any other medication that influences brain chemistry.