Are you a plant lover and love to spend your time with plants and gardening? If yes then you are suggested to read about the top most deadly plants of the world, so next time you will be aware and more cautious in the selection of new plants for your indoor planting or outdoor nursing garden.
You will be surprised to know that in Pakistan there are 5691 species of the flowering plant out of which 1150 are classified as poisonous plants or suspected to cause several types of toxicities.
Poisonous plants are well known to humanity since the ancient period or stone age when people use plants for both purposes either as a medicine or as a poison. Later on, this concept was more enhanced by experts & researchers that dose of any substance is a key factor to utilize it either for benefits or harmful effects but poisonous plants can be defined as those plants which are harmful to mankind even in small doses. These plants have a tendency to cause medicinal emergency that may or may not be controlled & proved to be fatal if the antidote is not administered immediately
In the light of History
Let’s step backward to have an eye that how these poisonous plants were used in the past by mankind. It will highlight the toxicity and complications that can be caused by poisonous plants.
- It is used as an arrow poison by tribes of Africa and South America for hunting animals and enemies.
- Many plants extracts were being used as a source of poison and responsible for different toxicities.
- Thug used the poisonous plants to loot the travelers as there was no concept of anesthesia like chloroform.
Difference between Poisonous and Non-poisonous Plants
It is easy to elaborate the differences between poisonous and non-poisonous plants by saying that plants that cause toxicity are termed as poisonous, while those that do not cause toxicity are termed as non-poisonous plants. This is not as easy with the fact that high dose of non-poisonous plants can also make it toxic for the human body. Therefore, the above-mentioned difference is not a satisfactory answer.
The correct description of the term poisonous can be well explained by WHO that states: A plant will act as a functionally poisonous plant if it can transfer its chemical constituents even in low concentration that affect the normal physiology of a man or animal. From this description, we can generate two concepts about poisonous plants:
- A Plant that can cause toxicity even in a small amount is termed as poisonous.
- In order to term a plant poisonous, it must disturb the normal cellular function of a human or animal body.
7 Poisonous plants you must know
Here we are mentioning the details of 7 poisonous plants along with their toxicities and management. The conditions in which they cause toxicity may differ from one another. So let’s begin!
1. Atropa Belladonna
Atropa belladonna or deadly nightshade plant belongs to the family Solanaceae and is based on chemical constituents like atropine and hyoscyamine which are responsible for its poisonous activity even in small quantities. It affects the autonomic nervous system by blocking parasympathetic nerves. Its excessive dose can cause death and causes symptoms like:
- Mental confusion
- Memory loss
- Lethal dose: The case study shows that Atropa Belladonna’s preparation that contains a high amount of atropine can be fatal and cause an individual to be on mechanical ventilation. Even a small dose of 50 ml can be proved as fatal.
- Route of toxicity: Oral
- Antidote: Physostigmine
2. Datura stramonium
It also belongs to the family Solanaceae. It’s commonly known as “Thorn Apple” due to its thorny fruit. It is a toxic plant that contains potentially tropane alkaloids like scopolamine and hyoscyamine. Its seed is reported to affect children and cause death. Symptoms of toxicity involve:
- Impaired vision
- Dilated pupil
- Skin dryness
- Extreme thirst
Antidote: Intravenous administration of physostigmine
3. Hyoscyamus Niger
It’s commonly known as Henbane and belongs to family Solanaceae. The seeds, roots, flowers, and leaves of these plants are all poisonous by nature, having scopolamine as the main chemical constituent. These plants can directly affect the central nervous system and can cause sedation. It’s psychoactive by nature that can cause:
- Visual hallucinations
- Sensation of flight
While rare and less-common effects include
- Irregular heartbeats
- Antidote: Intravenous administration of physostigmine
4. Melia Azadirachta
It is a small tree that is well known for its toxicity and belongs to the family Meliaceae. Commonly, this plant is known by the general public by more than one name and that all are listed below for your convenience:
- Pride of India
- Chinaberry tree
- Persian lilac
- Indian lilac
- Cape lilac
Toxicity caused by this plant is mainly due to its fruits.Its fruit is composed of resinous materials and is responsible for the poisonous behavior of this tree. Symptoms of toxicities involve:
- Hepatic damage
- Fatty degeneration of the liver
- Severe irritation
5. Nerium Oleander
It belongs to the family Apocynaceae. It is a small shrub that is used for ornamental purposes. Commonly, it is known as “Nerium” or “Oleander”, having pink or white color flowers. These plants are based on chemical constituents like cardiac glycosides, such as oleandrin and oleandrigenin. Its leaves and seeds oleandrin, which are the glycoside of gitoxigenin. The leaves and seeds are reported to cause toxicity in children. The toxicity of this plant is usually associated with the ingestion of any part of the plant. Its effects on the gastrointestinal system include:
- Abdominal pain
- Excess salivation
Its effect on the central nervous system includes irregular heartbeats. In extreme situations, the skin becomes cold and pale due to improper supply of blood. Its effects on the central nervous system include:
The sap of this plant can affect skin and cause chronic skin inflammation with allergic reactions. It can also cause eye irritation which is one of the most sensitive parts of the human body.
6. Ricinus communis
It belongs to the family Euphorbiaceae. It is commonly known as “Castor bean”. The alkaloid that is responsible for its toxicity is ricin and ricinine. The toxicity profile of ricin is so high in mammals that one seed’s cp is enough to cause the death of a human being. However, the variation in consumption, metabolism and absorption will not be fatal. Its toxic symptoms include:
- Antidote: Antilethal factor is now available as an antidote do plant toxins
- Lethal dose: One milligram per kilogram for humans
- Route of toxicity: Orally it is not harmful but the administration of its extract by the intravenous route is fatal
7. Urtica Dioicia
These plants belong to the family Urtica, it is a Latin word which means “burning sensation”, its other name is “Stinging metal”. It causes skin toxicity and skin inflammation and if this inflammation takes place with contraction, it will be termed as contracting dermatitis.
- Route of toxicity: As it is a skin toxicant, therefore, mild contact of skin with this plant is enough to show toxic symptoms. This plant contains small hair with cuticle which is filled with formic acid and histamine and induces skin inflammation.
- Antidote: There is no proper antidote of histamine based toxins, however, wash your affected area of skin with water as soon as possible to make it histamine free.
Prevention steps help you to avoid any uncovered exposure with poisonous plants. The following steps should be strictly followed:
- Read the label of plants very carefully whenever visit the nursery for purchasing any new plant.
- Use gloves to touch each plant either poisonous or not, for safe side.
- Keep little children away from plants to avoid any mishap of intake of leaves of poisonous plants.
Before you leave!
People having the hobby of gardening or planting should be aware of poisonous plants and their toxicities, and avoid such plants for indoor planting, especially if you have kids at the crawling stage since they love to put everything into their oral cavity at this age.
A student of Pharm D from University of Karachi. She has keen interest in all the attributes towards pharmacy especially community pharmacy and hospital pharmacy with an objective to make medications sound and safe. She loves to provide information about Pharmaceutical Analysis and Pharmacology in a best way so people with no medical background can understand.