A look into the plants of the Kropotkin Centre: Sceletium Tortuosum
Following the issuing of a Royal Charter, the Kropotkin Centre is now the hub of the Tellus Horticultural Cooperative. One of the objectives of the new cooperative is to publish “regular updates to both Sandus and the micronational community at-large on the progress of plants, projects and research,” and part of that is going to come in the form of these profiles of species being cultivated at the Centre and across Sandus. This is the first update in the « Kropotted Garden » series.
As such, the first of these profiles is on the succulent plant, Sceletium tortuosum, also known as kanna more commonly. It’s a plant with primarily medicinal applications, hardy to both drought and damp to reasonable degrees, with 12 specimens currently growing in the centres gardens.
Native to South Africa, where it is known as kanna, channa or kougoed, kanna has a long history of use amongst hunter-gatherers in the region. This use, primarily through chewing either fresh of fermented leaves, dates to prehistoric times; this includes the San and Nama people. Leaves were chewed for their narcotic and mood-lifting properties.
It wasn’t until 1662 that the properties of this plant were documented by Western colonist and explorer Jan Van Riebeek, when the Nama gave kanna amongst their gifts in exchange with a Dutch party. Kolben, a later naturalist, noted kanna as the “greatest Chearer of the Spirits, and the noblest Restorative in the World”.
In the modern era, the more traditional methods of ingestion have been broadened. Modern users may prepare kanna as a snuff, a smokeable mixture or a more traditional chewed leaf product. Additionally, isolates and extracts have been made available, with mixed profiles of alkaloids removed from the plant material. One of the key steps in these preparations, however, is fermentation.
Kanna plants contain significant oxalic acid, and this must be broken down to make the plant more suitable for human consumption. The solution worked out from antiquity is to crush the leaves, and leave them in the sun to stay warm. During the fermentation, enzymes breakdown the oxalic acid, and the final product (once it has stopped bubbling and has turned a darker green-brown) can then be dried to form a product which can then be chewed, or ground to powder. Additionally, soluble calcium ions can serve as an oxalate precipitating agent, removing the bioavailability of the otherwise harmful free acid.
Kanna contains various alkaloids, most notably mesembrine and mesembrenone. These are primarily abnormal selective serotonin reuptake inhibitors (a class shared by many modern antidepressants) with rapid onset of effect, with some further evidence of effects on the acetylcholine and cannabinoid systems. There is also evidence for a more balance monoamine releasing effect, mediated by VMAT2 (vesicular monoamine transporter 2), and some minor activity as a PDE4 inhibitor (phosphodiesterase 4). Additionally, some evidence of opioid receptor activity may explain the sedative and pain-killing effect of the plant.
In animal studies, kanna and its extracts have been used to treat excessive nocturnal vocalisation of dogs and cats with dementia. Additionally, in rats, the effects of kanna showed pain-killing and sedative effects. Tests of tolerability in human subjects of kanna extract Zembrin™ showed no adverse effects even with long term use (25mg per day for 3 months).
Kanna is easily propagated from either its plentiful seeds, or from cutting (like many succulents). Cuttings root readily in water, or in sterile substrate (a mix of perlite and vermiculite). Seeds germinate readily on moist cactus soil in sealed takeaway containers. It tolerates a wide range of temperatures, thriving in both full sun and partial shade. It is drought resistant (owing both to being a succulent and its adaptation to its naturally dry South African habitat) but can tolerate relative frequent watering. It does, however, require soil to dry between waterings.
It favours a cactus soil with sand, perlite and gravel added to improve drainage. It requires a mild fertiliser, most suitable is a low nitrogen cactus feed, or a doubly dilute standard feed.
The plant produces broad ovate leaves with a thick, succulent form. The surface is waxy and repels water. The plant branches rapidly, forming long shooting “arms” which spread in multiple directions from the central stem. It flowers in summer, forming white, pale yellow, pale pink or salmon flowers with long thin petals.These are 20-30mm in diameter. The final seeds are small and kidney shaped, ~2mm.