In an era where herbal products and plant-based medicines are gaining global demand, fields and greenhouses have become just as important as laboratories. The cultivation of medicinal plants is no longer a traditional practice—it is a scientific process ensuring consistent quality, safety, and sustainability of natural drugs.
UNIT 2 explores how medicinal plants are cultivated, improved through biotechnology, and protected from extinction. From plant hormones to conservation strategies, pharmacognosy now combines agriculture, genetics, and environmental science.
Cultivation and Collection of Drugs of Natural Origin
Why Cultivation Matters
Wild collection of medicinal plants often leads to inconsistency and overexploitation. Scientific cultivation ensures:
- Uniform quality
- Higher yield
- Standardized active constituents
- Continuous supply
This approach supports both pharmaceutical industries and environmental protection.
Methods of Collection
Collection must occur at the correct stage of growth for maximum potency.
Examples
- Leaves before flowering
- Roots after maturity
- Seeds when fully ripened
- Bark during dormant season
Proper drying and storage prevent loss of active principles.
Factors Influencing Cultivation of Medicinal Plants
Plant growth and phytochemical content depend on several environmental and agricultural factors.
Climatic Factors
Temperature, rainfall, and sunlight significantly affect metabolite production. For example, alkaloid content may vary with season and altitude.
Soil Conditions
Soil type, pH, fertility, and drainage influence plant health. Loamy soils with good aeration are preferred for many medicinal crops.
Water and Irrigation
Adequate water ensures optimal growth, but excessive moisture may promote fungal infections.
Fertilizers and Nutrients
Balanced nutrients enhance biomass and active compound production.
Essential Nutrients
- Nitrogen
- Phosphorus
- Potassium
- Trace elements
Careful nutrient management improves drug quality.
Plant Hormones and Their Applications
Plant hormones regulate growth and development. In medicinal plant cultivation, they are used to enhance yield and quality.
Major Plant Hormones
Auxins
Promote root growth and vegetative propagation.
Gibberellins
Stimulate stem elongation and flowering.
Cytokinins
Encourage cell division and delay aging.
Ethylene
Controls fruit ripening.
Abscisic Acid
Regulates dormancy and stress tolerance.
Applications in Pharmacognosy
- Tissue culture propagation
- Increased secondary metabolite production
- Rapid multiplication of rare plants
- Improved crop yield
Hormone-assisted cultivation ensures faster and controlled production.
Polyploidy, Mutation, and Hybridization
Modern genetic techniques help improve medicinal plants.
Polyploidy
Polyploid plants have multiple chromosome sets.
Benefits
- Larger plant size
- Higher metabolite content
- Improved resistance
Polyplody is artificially induced using chemicals like colchicine.
Mutation
Mutations create new traits through genetic changes.
Used to:
- Increase yield
- Enhance active constituents
- Develop disease-resistant varieties
Induced mutations are achieved using radiation or chemicals.
Hybridization
Hybridization combines desirable traits of two plants.
Advantages
- Better productivity
- Enhanced quality
- Disease resistance
- Adaptability to environment
Hybrid varieties ensure superior medicinal crops.
Conservation of Medicinal Plants
Why Conservation Is Necessary
Overharvesting, habitat loss, and climate change threaten many medicinal species. Conservation protects biodiversity and ensures sustainable supply.
Conservation Methods
In-Situ Conservation
Protection within natural habitats.
Ex-Situ Conservation
Botanical gardens, seed banks, and tissue culture.
Sustainable Harvesting
Controlled collection without harming populations.
Cultivation Programs
Reducing dependence on wild sources.
These strategies ensure long-term availability of valuable plants.
Why This Knowledge Matters in Pharmacy
Scientific cultivation and conservation:
- Improve drug consistency
- Prevent adulteration
- Ensure sustainability
- Support large-scale production
Modern pharmacognosy depends on these agricultural and genetic principles.