Unit 4: Drug-yielding Plants

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Therapeutic Drugs

Therapeutic drugs are substances derived from plants used to treat or prevent diseases.

1. Rauwolfia (Rauwolfia serpentina)

• Common Name: Sarpagandha.
• Family: Apocynaceae.
• Morphology: An erect perennial undershrub with tuberous roots.
• Active Principle: Reserpine.
• Uses: Primarily used to treat high blood pressure (hypertension) and mental disorders like schizophrenia.

2. Cinchona (Cinchona officinalis)

• Family: Rubiaceae.
• Part Used: Dried bark of the stem or root.
• Active Principle: Quinine.
• Uses: Famous as an anti-malarial drug; also used as a bitter tonic.

3. Withania (Withania somnifera)

• Common Name: Ashwagandha.
• Family: Solanaceae.
• Morphology: An erect branching undershrub with fleshy roots.
• Uses: Used to boost immunity, reduce stress, and improve memory and physical strength.

4. Digitalis (Digitalis purpurea)

• Common Name: Foxglove.
• Part Used: Dried leaves.
• Uses: Used to treat congestive heart failure and cardiac arrhythmias by strengthening heart muscle contractions.

5. Aloe vera

• Family: Xanthorrhoeaceae (Liliaceae).
• Morphology: Succulent plant with thick, fleshy leaves containing gel.
• Uses: Used in treating burns, skin diseases, and as a laxative.

6. Taxus (Taxus baccata)

• Common Name: Yew.
• Part Used: Bark and leaves.
• Active Principle: Taxol.
• Uses: Potent anti-cancer drug used specifically in breast and ovarian cancer treatment.

Habit-forming Drugs

These plants contain psychoactive substances that can lead to physical or psychological dependence if misused.

1. Opium Poppy (Papaver somniferum)

• Morphology: An annual herb with large, showy flowers; the fruit is a capsule.
• Processing: Incisions are made in the unripe capsules to collect the milky latex (opium).
• Alkaloids: Morphine, Codeine, and Papaverine.
• Uses/Hazards: Used medically as a powerful painkiller (analgesic); however, it is highly addictive and can lead to severe respiratory depression.

2. Cannabis (Cannabis sativa)

• Common Names: Marijuana, Ganja, Bhang.
• Morphology: An erect annual herb with palmate leaves.
• Processing: Dried leaves, flowering tops, or resin (charas) are extracted.
• Uses/Hazards: Used to treat glaucoma and nausea in chemotherapy; recreational use causes hallucinations, impaired judgment, and potential long-term cognitive issues.

Tobacco (Nicotiana tabacum)

• Morphology: An annual herb with large, sticky leaves and tubular flowers.
• Processing: Leaves undergo curing (slow drying), fermentation, and aging to develop flavor and aroma.
• Active Principle: Nicotine.
• Uses: Smoking, chewing, or snuff.
• Health Hazards: Causes lung cancer, heart disease, chronic bronchitis, and emphysema; Nicotine is highly addictive.

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