Belladonna

Small Belladonna plant

This month we are returning to our core theme of toxic plants and we will be discussing one toxic plant in particular: Atropa belladonna, also known as Deadly Nightshade.  But first the usual legal warning:  THIS BLOG IS FOR EDUCATIONAL PURPOSES ONLY.  DO NOT TRY THIS AT HOME.  ANY OF IT.  EVER.

Belladonna has a long history of use by humans both in medicine and in warfare.  It was used by the ancient Greeks to induce drowsiness and numbness before surgery.  It was used in larger doses by the ancient Romans as a biological weapon, for example on arrowheads, or for poisoning the enemy’s water supply.  The Roman emperors Claudius and Augustus are reputed to have been poisoned by it.

Many toxic plants are therapeutic in small doses but toxic or fatal in large doses.  The medieval herbalists and “cunning folk” who used the plant therapeutically probably trod a fine line between being called healers if things went well, but poisoners if they didn’t.  Many of them were executed as witches during the European religious purges of the 15th to 18th centuries.

In Renaissance times, women used it to dilate their pupils and flush their cheeks to make them look more alluring, which is probably where the common name “Belladonna” came from (it means “beautiful lady” in Italian).

Belladonna plants were farmed in the UK during World War 1 and 2 when the usual sources of supply from overseas were cut off by the German U-boat blockade.

The fatal dose of Belladonna is said to be two berries in a small child.  Adults can survive much larger doses, although as far as I know, nobody has done any experiments on people to find out scientifically what the fatal dose is.  Treatment of Belladonna poisoning is mainly supporting the patient until the poisons are eliminated from the body naturally.  In severe cases, particularly in children, Physostigmine can be used as an antidote.

So how does Belladonna work?  The main active ingredients are the tropane alkaloids scopolamine and hyoscyamine, from which the synthetic alkaloid atropine can be made.  Atropine is still widely used today in medicine and is on the World Health Organisation List of Essential Medicines.  Its main uses are as eyedrops to dilate the pupil (cycloplegia) for better inspection of the posterior structures of the eye, or in anaesthetics and emergency medicine to speed up the heart rate if the heart is beating too slowly.  It does this by blocking the transmission of nerve impulses at muscarinic receptors which are found in the parasympathetic nervous system, which runs in the background regulating body functions.  So, for example, if it blocks the nerve impulses which cause the pupil to contract, the pupil will dilate.  If it blocks the nerve impulses which cause the heart to slow down, the heart will speed up.  If it blocks the nerve impulses which slow down breathing rate, the breathing rate will speed up.

In cases of severe atropine intoxication or poisoning, brain, heart and lung functions are all disrupted, and respiratory depression, hallucinations, confusion, coma, circulatory collapse and death may occur.

Growing Belladonna in the Isle of Man is not easy.  The plant’s natural habitat is the warm chalk downlands of southern England, so trying to grow it in the cool, windy Isle of Man is a bit of an ask.  Under ideal conditions the plant should form a bush up to 5 feet high, but my plants only reached 1 foot.  When young it is also very susceptible to attack by slugs and snails, which seem to find it delicious.  Nevertheless, I manage to persuade some plants to grow, flower and produce berries. 

I grew my plants from roots supplied by a specialist herb nursery.  Growing wild perennials from seed is generally difficult due to the slow and unpredictable germination rate.  However, once the plants are established they should re-grow from the same rootstock every year.

Belladonna flower

Belladonna berry

The berries only last a week or two before drying out and shrivelling down into what look like large peppercorns.  These are seed pods, with the former skin of the berry turning into the hard outer case of the seed pod, and the interior packed with seeds.

Blackcurrants

Elderberries

The berries could be mistaken for other similar black glossy berries which are edible, for example blackcurrants and elderberries.  I therefore make sure to grow the toxic plants in a separate part of my allotment from the edible ones, and I don’t allow anyone on the allotment unless I am with them.  However, if trespassers come onto my allotment and start eating my stuff without my permission, well, I guess that’s their lookout. 

Belladonna seed pods

Belladonna seed pod contents

Here is a little experiment which it is safe to do at home.  Go to Google Images:

https://images.google.com/

and type “Deadly Nightshade flower” into the search box.  Look at the first page of images which comes up.  On my screen there are 30 images, of which 19 are Deadly Nightshade, 10 are the relatively harmless Woody Nightshade and one is a foxglove.  Here is a photograph of a Woody Nightshade flower, which I also grow in my herb garden: it is so different from a Deadly Nightshade flower that a blind person could tell them apart just by touch.

Woody nightshade flower

There are two lessons which one can learn from this:

1. Our ancestors were probably much better at identifying wild plants than we are; and
2. Don’t believe everything you see on Google. 

And finally, what is the effect on an adult of eating a single Deadly Nightshade berry?  I was up for this, dear reader, I really was.  In the interests of furthering medical knowledge I was planning to eat a berry (a small amount at a time) and report on the effects.  Unfortunately that ship sailed without me, because by the time I got around to it, the tempting juicy berries had all turned themselves into dry unappetising seed pods (see above).  So that will have to be another experiment for another time.  

Slaynt vie, bea veayn, beeal fliugh as baase ayns Mannin