Monday, July 16, 2012
Solanaceae: a family portrait
by Rishidev Chaudhuri
Like some eccentric prominent family, whose genius shades easily into the occult, the evil and the mad, Solanaceae, the family of the nightshade (so often prefixed by “deadly”), both contains several of our most ubiquitous food plants (typically of New World origin) and many of the multifarious toxins and deliriants beloved of witches, shamans and poisoners throughout history. The plants of Solanaceae are a dramatic-looking group, full of trumpet-like flowers that open at dusk and branches and stems that curl together like gnarled witches claws. They are also the source of eerie legends and origin myths, as exemplified by mandrake, said to grow from the ejaculate of a hanged man, and whose scream (when pulled out of the ground) will kill everyone in earshot.
To anyone who has ever shuddered at or been baffled by the thought that for most of history the Italians have had no tomatoes, the South Asians have had no chillies and no one in the Old World (including the Irish, the Germans and the Russians) has had potatoes, the gifts of Solanaceae are apparent. These are the bounty of the New World, plants that were brought over from the Americas by European explorers, introduced into their home countries and then spread to the rest of the world (many of the sins of the Portuguese colonists should be offset by their introduction of the chilli to India). Traces of this recency exist on the linguistic map, and several cultures label tomatoes and potatoes as some sort of eggplant or apple1.
While the major Solanaceae food crops that we eat are from the New World, most of the family members used in the Old World were used as hallucinogens, medicines (in small doses) or as poisons (with the notable exception of eggplant). Both tomatoes and potatoes suffered from these associations, and it took a while before people became convinced that they were safe to eat. One is generally not responsible for one's relatives (except children), but there is some truth to this fear. The leaves and stems of tomato plants are mildly toxic, and potato sprouts can be quite dangerous (in recent years, much of this has been bred out of the plant varieties that we eat, though the same is probably not true for non-mass-market varieties). Once they broke through to acceptance, though, they spread widely and now both are cultivated widely all over the world. Potatoes in particular were an essential new source of cheap calories for the Industrial Revolution and were declared by Engels to be the equivalent of iron for their historically revolutionary role. They are thought to be responsible for a significant fraction of Old World population growth in the 18th and 19th centuries, with the downside that potato crop failures lead to severe famines.
The classical Old World members of Solanaceae are plants like deadly nightshade (belladonna), datura, mandrake, angel's trumpet and henbane; these are famously the plants of Hecate and the occult. They are striking examples of the weird intersection of the toxic, the medicinal and the religious that characterize our relationship with a number of plants, and of the thin line between the altered states of revelation and transcendent experience and those of poisoning and death.
These plants inherit their toxicity from a group of compounds called tropane alkaloids, specifically atropine (after Atropos, the oldest of the Three Fates and the one who snips the thread of life), scopalamine and hyoscyamine. These alkaloids reduce the activity of acetylcholine, one of the brain's primary neuromodulators, by competing with it to lock onto neural receptors (and hence are called anticholinergics). Viewing the brain through the lens of the various substances that act on it, particularly the natural mimics of our neuromodulators, is an intriguing route of study. For the most part, we don't have good unifying theories for what each of the major neuromodulators does, and it is far from obvious that each will correspond to a well-defined computational role, as opposed to a complex set of roles that depends strongly on everything else that is going on. But studying neuromodulators through their derangement might give us phenomenological clues on how to proceed.
Anyhow, these plants show a number of physiological effects, generally related to inhibition of the parasympathetic nervous system, and at low doses this allows for medical uses, including stimulating the heart and reducing various secretions, like saliva. They have been used to dilate pupils both for examination or for cosmetic reasons; pleased or aroused people have dilated pupils and the name “Belladonna” is said to come from women using these to dilate their pupils and make themselves more attractive. They have also been used for anesthesia and, along with opiates, as components of the “twilight sleep” induced in women during childbirth in the early 20th century.
More dramatically, though, these compounds cause powerful hallucinations. The hallucinations produced by anticholinergics are often contrasted with the hallucinations reported from psychedelics (think LSD and the drugs of the sixties); the former are described as “true” hallucinations, unfounded in sensory stimulus, as opposed to those caused by the psychedelics, which are typically thought of as distortions of sensory stimuli. Sometimes these substances are called deliriants, highlighting the nature of the intoxication. Despite their potential to produce altered states (and their legality), they seem to rarely be used recreationally. The hallucinations are reported as too strong and too terrifying; they can last for days and there is little euphoria. They are very clearly poisons. The only people who seem to use them are naïve teenagers looking to get high (there are still occasional reports of poisonings from this) and brave people curious about various derangements of the senses.
The major exception that I can think of to this lack of recreational use is the use of henbane in medieval beers, before the passage of the Bavarian Purity Law requiring only grain, hops and water to be used. The use of hops as a flavoring and preservative agent in beer is ancient, but a number of other herbs and spices were used as alternatives, including henbane, a member of the Solanaceae cabal, and possibly mandrake. Christian Ratsch, the ethnopharmacologist, has recipes for henbane and mandrake beers, and the beer is reported to be both stimulating and intoxicating, though dangerous in quantity2.
On the other hand, as their long association with witches attests, the members of Solanaceae have been used for spiritual and occult practices for quite a while. The “flying ointments” used by witches often contained Solanaceous plants and many people speculate that reports of flying and meeting with the Devil were the result of Solanaceae-induced delirium3. Datura has also been reported in initiation and shamanic ceremonies in the Southwestern United States and Mexico (most famously in the writings of Carlos Castaneda, which are very entertaining but of dubious veracity), in various parts of Africa and in India. Like several other intoxicants, Datura is sacred to Shiva, and he is often pictured with a datura flower.
In higher doses, they cause amnesia and death. Again, this has not gone historically unnoticed, and the members of Solanaceae have been beloved of swindlers and poisoners through the ages. The Thuggees of Central India (whence “thug”) supposedly used Datura to drug their victims before strangling them, and there have been a number of reports of Datura being used to drug travelers in the subcontinent since. On the other side of the world, it is thought that the Haitian witch doctors created zombies using a mixture of tetrodotoxin (a fascinating compound extracted from pufferfish and used by neuroscientists to block neural spiking in the brain) and Solanaceous herbs. Both Julius Caesar and Hannibal are reported to have used mandrake wine to drug enemies before attacking them and, fittingly given the occult associations of the play, so has the historical Macbeth.
The most prominent missing member so far (and many would argue, the most prominent member of the family in terms of cultural impact) is tobacco. Like potatoes, chillies and tomatoes, tobacco is a child of the New World, making its way from the Americas and then spreading rapidly all over the world. And, like those plants, it met significant resistance (at times its possession was punishable by beheading or, in the Ottoman Empire, crushing). It is also a dangerous toxin, not just because of the damage caused by smoking (which is mostly a consequence of the various tars and such; small quantities of vaporized nicotine are much safer) but also because nicotine, like the tropane alkaloids, is a powerful neuromimic and toxic except in small doses. Unlike these, however, nicotine activates (rather than suppresses) acetylcholine receptors4. It has a number of other neuromodulatory effects, including increasing dopamine levels.
Tobacco is now enmeshed in most cultures, having found its way into our rituals and habits and our metaphors, especially those of ending (post-coital cigarettes and the last cigarettes of the condemned or fatally wounded perhaps stem from similar places). Dale Pendell calls it the archetypal poison and nowhere else is the dual-edged nature of Solanaceae more visible than in the smoking herb that pleases and energizes and also kills.
This dual-edge is emblematic of Solanaceae and the diverse ways its members have found their way into our cultures, into our food, religion and crime. It is also a microcosm of the spectrum of our relationship with plants and the various ways that animal and vegetable histories intertwine and, especially, of the ways in which the Old and New Worlds have talked to each other. That the banal modern pairing of ketchup and fries, so representative of bland modernity and uniformity, found its way to the plate via domestication by Aztecs in Mexico and Peruvian peasants in the Andes, followed by a contentious series of negotiations and promotions leading to acceptance, then mass-cultivation and detours through Indonesia and France, makes it hard to dehistoricize and deglobalize what we eat. And the fragile boundary between these staple food crops and the poisons, medicines and sacraments that live in the other members of the family and that lurk in the stems and the leaves and the sprouts of the food plants that we so carelessly eat, reminds us that plants are not merely fungible sources of nutrition but create and shape human experience in a multiplicity of ways.
Images are from Wikipedia. Dale Pendell's books are fun explorations of intoxicating plants and their history and biology and are highly recommended.
1For example, potatoes are “earth apples” in French and tomatoes are “golden apples” in Italian and “English eggplant” in some parts of Bengal. The scientific name of tomatoes means “wolf peach” (possibly after nightshade's role in summoning werewolves).
2I've never tried these. If you enjoy brewing and want to, the recipe should be available on the Internet. Be cautious though; these are dangerous.
3This shouldn't be taken too far, of course. The modern category of chemically-induced hallucinations is too often used to decontextualize and lump together a variety of social and religious experience.
4Atropine and its relatives act on muscarinic acetylcholine receptors. Nicotine acts mostly on the other major type of receptor, called nicotinic; the name is a testament to nicotine's prominence. It's interesting that both major classes of acetylcholine receptors are named after intoxicating plants; muscarinic comes from the scientific name of the intoxicating mushroom fly agaric.
Posted by Rishidev Chaudhuri at 12:30 AM | Permalink