Plants are important for the very existence of humans and all other living things on the earth. Plants convert carbon dioxide to oxygen, they provide primary food, shelter, fuel and other important things required for the life of humans and other animals. Besides all these plants are important sources of a large number of drugs.
Plants are the oldest sources of drugs, most of the medicines ancient people used are drugs from plants. From the archeological findings it is proven that humans are using herbs and plants as medicine even during the Neanderthal age, some of those herbs are still used for their medicinal properties. Ancient scholars like Hippocrates, Aristotle, Diascorides etc have recorded medicinal properties of a number of herbs and plants. Different systems of medicines like Ayurveda, Unani and Chinese traditional systems use drugs from plants for most treatments.
Some of the important drugs used in the modern system of medicine like aspirin, digoxin, atropine etc and important anti cancer drugs like vincristine, vinblastine, etoposide, Paclitaxel, Camptothecin are obtained from plant kingdom.
Some important drugs and their sources are given below
| Drug | Plant source | Medicinal use |
| Atropine | Atropa belladonna ( Deadly nightshade) | Anticholinergic |
| Caffeine | Camellia sinensis (Tea, coffee and cocoa plants ) | CNS stimulants |
| Camptothecin | Camptotheca acuminata | Anticancer drug |
| Cocaine | Erythroxylum coca (coca plant) | Local anaesthetic |
| Codeine | Papaver somniferum (poppy) | antitussive |
| Colchicine | Colchicum autumnale (autumn crocus) | antigout |
| Etoposide | Podophyllum peltatum (mayapple) | Antitumor agent |
| Digoxin | Digitalis purpurea ( foxglove) | Cardiotonic |
| Morphine | Papaver somniferum (poppy) | Analgesic |
| Papain | Carica papaya (papaya) | Proteolytic, mucolytic |
| Quinine | Cinchona ledgeriana (quinine tree) | Anti malarial |
| Reserpine | Rauvolfia serpentina | Antihypertensive, tranquilize |
| Nicotine | Nicotiana tabacum (tobacco) | Insecticide |
Advantages of using drugs from plants
- Safety:
It has been shown that drugs from plants are comparatively safer than synthetic or semisynthetic drugs. People trust systems of medicines like Ayurveda and unani in terms of safety because they use medicines from herbal sources.
- Reduces cost in drug development:
Most of the drugs from plants are used by humans for their medicinal or non medicinal purposes for a long time. It allows researchers to find efficacy and safety of their active compounds easily. Also they can make safer synthetic or semi synthetic molecules by smaller alteration to the natural active molecules. It helps reduce cost and time required for the development of new drugs.
- Helpful for local economy:
Cultivating medicinal plants locally and collecting active ingredients from that helps in improving the local economy. It gives large job opportunities, reduces importing APIs, proper use lands etc.
Disadvantages of using drugs from plants
- Difference in quality:
It is shown that the same medicinal plant cultivated in different geological locations gives a difference in quality and quantity of active products. It is very difficult to standardize these variations in quality as compared to synthetic drugs. Also these herbal drugs can be adulterd easily by using low quality varieties.
- Chances of poisoning:
There is a general concept that herbal drugs are free of side effects, but it is not true. A large number of these drugs obtained from the herbal sources have their own side effects. Some of them are highly poisonous also. Cultivating medicinal plants widely leads to availability of these active drugs locally and people can use it on their own without proper knowledge leads to poisoning and drug abuse.
- Quantity of crude drug needed:
Sometimes in order to get the required quantity of active drug we have to collect a large amount of crude drugs. It will increase the cost of production. Also cultivating large quantities of these plants in some areas may affect the ecological system in that area.
- Loss of crops due to environmental factors:
There are chances of happening loss due to environmental factors like storm, draught, floods, insects etc. it will affect proper supply of active drugs.
Drugs obtained from different parts of plants
In the case of collecting drugs from plants it is important to understand which part of the plant provides the required type, quality and quantity of active drugs. In some cases different parts of the same plant provide different drugs. We can discuss some examples of drugs obtained from different parts of plants.
- Drugs obtained from leaves
Examples:
- Leaves of digitalis purpurea is the source digoxin and digitoxin which are used as cardiac glycosides
- Tobacco leaves gives nicotine
- Atropa belladonna gives atropine which is an anticholinergic.
- Drugs obtained from barks
Examples
- Cinchona bark provides Quinine which is an anti malarial drug and quinidine Which is an antiarrhythmic drug.
- Drugs obtained from stems
Examples
- Ephedrine is obtained from stems of Ephedra sinica
- Drugs obtained from flowers
Examples
- Opium is obtained from Papaver somnifera
- Vincristine obtained from vinca
- Drugs obtained from fruits
Examples
- Physostigmine is obtained from calabar beans
- Anthracene alkaloids obtained from senna pods
- Drugs obtained from seeds
Examples
- Strychnine is obtained from seeds of nux vomica which is a CNS stimulant
- Castor oil is synthesized from castor seeds.
- Drugs obtained from roots
Examples
- Reserpine is obtained from Rauwolfia serpentina which is used as antihypertensive.
- Emetine is obtained from ipecacuana roots which is
Read more:
- What are the different sources of drugs
- Facts about aspirin
- What is a vaccine and What are the different types of vaccines
- What is dosage form
- What is a Pharmaceutical tablet and what are the different types of tablets..?
- What is a Pharmacist
- Pros and cons of being a pharmacist
- What is a Community pharmacy
- Types of adverse drug reactions
- What is ointment and Types of Ointments
- Oxymetazoline nasal spray
