lec 12 Flashcards
What is the estimated number of plant species in Sudan and South Sudan?
More than 3156/4000 plant species
This includes 1137 genera and 170 families.
Name three examples of compounds derived from plants using the ethnobotanical approach.
- Curare (tubocurarine) from C. tomentosum spp.
- Quinine from various Cinchona spp.
- Artemisinin from Artemisia annua L.
What are taxonomically related plants likely to contain?
Structurally similar compounds
Examples include Digitalis lanata & D. purpurea (cardiotonic glycosides) and Datura species (solanaceous tropane alkaloids).
What is the goal of pharmacognosy?
To extract novel bioactive molecules from plants.
What is reverse pharmacognosy?
A known bioactive molecule is used to find new sources of known bioactive compounds.
This process can accelerate the drug discovery process.
What factors should be considered when collecting plant samples?
- Stage of growth
- Season of the year/day
- Part of the plant
- Purity (free from contamination and disease)
What is a herbarium?
Systematically-arranged specimens for botanical reference and research.
What are some sources for literature surveys in pharmacognosy?
- Official local books on medicinal plants
- Reputed books like WHO monographs
- Relevant online databases like PubMed
Why is drying plant materials performed immediately after collection?
- Facilitate storage, transport & grinding
- Inhibit growth of microorganisms and molds
- Preserve constituents
What are the two main categories of drying methods for plant materials?
- Natural drying methods
- Artificial drying methods
What is the purpose of size reduction and homogenization in pharmacognosy?
To improve extraction efficiency by increasing surface area.
What is the maceration extraction method?
Soaking plant material in a suitable solvent for a specific period of time.
What is continuous extraction (Soxhlet Extraction)?
A process where plant material is placed in a thimble and solvent is recycled through it.
What is the primary advantage of supercritical fluid extraction (SFE)?
Improved solvating and mass transfer properties of gases above their critical point.
What should be considered when choosing solvents for extraction?
- Selectivity for the substances to be extracted
- Ease of removal or recoverability
- Inertness and non-toxicity
- Cost-effectiveness and environmental safety
Fill in the blank: In selective extraction, the plant material is extracted using a solvent of appropriate _______.
polarity.
What is the purpose of qualitative phytochemical screening?
To presume the presence of certain types of secondary metabolites using chemical reagents.
What does quantitative phytochemical screening involve?
Determining the amounts of specific phytochemicals present in a plant extract.
What is the main goal of the new trends in drug lead finding from natural sources?
To find novel biological targets for natural compounds.
