1. MUHIMBILI UNIVERSITY OF HEALTH
AND ALLIED SCIENCES
SCHOOL OF PHARMACY
DEPARTMENT OF PHARMACOGNOSY
SAMBAYI G. L. (Bpharm,Mpharm)
2. • Teaching methods Class contact teaching
Lectures
Laboratory sessions
• Assessment
• Examination
-Written examination without oral presentation
-Closed book
-Open-question
3. Content
• History of Pharmacognosy
• Scope of pharmacognosy
• Evaluation of plant drugs
4. • The word pharmacognosy is derived from two
words, pharmakon means medicine (drug) and
gignosco means to acquire knowledge of
something
• The word ‘drug’ is derived from Latin term
Droog means dried, when dried plants were
commonly used as medicine
4
5. • Pharmacognosy is systematic study of these
crude drugs obtained from natural origin like
plant, animal and minerals
6. • Now a day’s pharmacognosy has become a kind
of multidisciplinary subject which embraces
phytochemistry, analytical pharmacognosy,
pharmacotherapy, medicinal plant biotechnology,
herbal formulations and nutraceuticals
• Zoopharmacognosy is branch of
pharmacognosy which involves observation of
animal behavior for discovery and development of
new drugs
• Now a day’s drug from natural origin are studied,
formulated and regulated in the framework of
modern medicine
6
7. SCOPE OF PHARMACOGNOSY
• A pharmacognosist should possess a sound
knowledge of the terms used to describe the
vegetable and animal drugs as covered under
botany and zoology, respectively.
• The knowledge of plant taxonomy, plant
breeding, plant pathology and plant genetics is
helpful in the development of cultivation
technology for medicinal and aromatic plants
7
8. • Plant-chemistry (phytochemistry) has
undergone significant development in recent
years as a distinct discipline
• It is concerned with the enormous variety of
substances that are synthesized and
accumulated by plants and the structural
elucidation of these substances
8
9. • Extraction, isolation, purification and
characterization of phytochemicals from natural
sources are important for advancement of
medicine system
• The knowledge of chemotaxonomy, biogenetic
pathways for formation of medicinally active
primary and secondary metabolites, plant
tissue culture and other related fields is
essential for complete understanding of
Pharmacognosy
9
10. • Pharmacognosy is important branch of
pharmacy which is playing key role in new drug
discovery and development by using natural
products.
• Pharmacognosy has given many leads for new
drug discovery and development
10
11. • It is acting as bridge between pharmacology,
medicinal chemistry and pharmacotherapeutics
and also pharmaceutics.
• It also bridges pharmaceutics with other
pharmacy subjects
11
12. • Pharmacognosy includes knowledge about
safe use of herbal drugs including toxicity,side
effects, drug interaction thereby increasing
effectiveness of modern medicine
• Pharmacognosy is the base for development of
novel medicines.
• Most of the compounds obtained from natural
product serve as prototype or base for
development of new drug which are more
active and less toxic
12
13. • By means of pharmacognosy, natural products
can be dispensed, formulated and
manufactured in dosage forms acceptable to
modern system of medicine
• Development of pharmacognosy also leads to
development of botany, taxonomy, plant
biotechnology, plant genetics, plant pathology,
pharmaceutics, pharmacology, phytochemistry
and other branches of sciences
13
14. Contribution of medicinal
plants to modern medicine
• Over 120 pharmaceutical products
currently in use are plant derived
• 75% of these were discovered by
examining the use of these plants in
traditional medicine
• A large proportion has come from
tropical forest species.
14
15. 15
Derive name from
catalogue of frequ
ently used plants
Review
literature
Evaluate data in
literature
Decide on
Need to test
Select tests
Establish prior-
ties for testing
Collect plants
Prepare bioassay pro
tocols for safety and
toxicity
Develop criteria for
safety and toxicity
tests
Determine safety
from published
studies
Collect plants
Determine
type of biologi
cal activity
Prepare, stabili
ze and standar-
dize extracts
Isolate and iden
fy active princi
ples
Carry out
human studies
Develop methods
of industrial pro-
duction
Carry out tests
for safety and
toxicity
16. • Ergastic Substances or Cell Inclusions Cell
Inclusions are non-living substances present in
the cells.
• They are also called ergastic substances or
ergastic bodies.
• They may be present in soluble or insoluble
state and can be organic or inorganic in nature.
• These are present in components or sub-
components of cell
17. Cell inclusions
• Parenchyma cells
• Contain characteristic contents of living protoplasts
• Eg nucleus, cytoplasm, vacuoles, plastids,
mitochondria
• Not diagnostically useful
• Non-protoplasmic components
• Classified as ‘ergastic’ substances
• Starch
• Protein
• Oil
• Crystals
• Very useful for identification
18. 1. CALCIUM OXALATE
• Crystals may be reserve or waste products of
cellular activity
• Oxalate ions removed in making crystals
• Don’t know why they arise (could be pH)
• Or why they are found in particular locations
(vascular tissue) and not others (near veins)
• Clearing agents:
• Chloral hydrate solution to remove chlorophyll
(cell walls etc remain)
• Show in crossed polaroids
• Comment on size, shape, frequency
19. (a) Prisms
One prism per parenchyma cell
Cells form a sheath around fibres in vascular bundle
Eg cascara, senna, liquorice
Hyoscyamus leaf
Twin crystals
20. Calcium oxalate of
Cassia acutifolia
(senna) leaflet
(viewed under high
power)
Note – cluster
crystals also present
in senna leaflet
23. (c) Needles (acicular)
• Occupy the whole parenchyma cell
• Next cell contains none
• Eg ipecacuahna, squill
Calcium oxalate of Cephaelis
ipecacuanha rhizome
(viewed under high power)
24. (d) Microsphenoids (crystal sand)
• Very small
• Adjacent cells don’t store them
• Eg belladonna
Calcium oxalate of Atropa belladonna
leaf (viewed under high power)
25. 2. CALCIUM CARBONATE
• Not as common as calcium oxalate
• Eg cannabis cell
Calcium carbonate
deposit
26. 3. STARCH GRAINS
• More common
• Occur as discrete grains
• Commonly show layering of amylose & amylopectin
around a point ‘hilum’
• Found in parenchyma of pith, cortex, vascular tissues,
fruits, cotyledons & seed endosperms
• Generally not found in leaves – transported out
• Staining:
• Dilute glycerin
• Chloral hydrate to dissolve pigments
• * I2 blue-black stain
• * Polarised light – not bright
‘Maltese cross’
effect (page 15
microscopy
notes)
* Characteristics
of plant starch
27. • Shape
• One shape will be dominant or characteristic of a plant Eg
• Polyhedral – maize starch
• Ovoid with a few round – potato
• Sac shape – ginger
• Aggregation
• Can be single, 2, 3 -> multi-compound grain
• Eg ipecacuanha
• Size
• Rice 6 µm
• Potato 45-70 µm
28. • Hilum
• Striations
• Present or absent
• Layers of amylose and amylopectin
• Frequency
• Absent – rare – abundant (90% of plant material)
• Location
• Where they are found Eg root, rhizomes, seeds etc
• May just be in specific tissues Eg pith, cortex, perisperm
Single
point
Line in a
grain Cleft Stellate
Punctate
(hole)
29. 4. PROTEIN
• Indicative of seed material
• Diagnostic feature:
• Picric acid stains protein yellow
• Allow a few minutes to stain, wash away rest
Amorphous
Crystalloid protein
Amorphous protein
Globoid
Calcium
oxalate
Phosphorus
protein
Aleurone Eg Linseed
30. 5. OILS, FATS
• May float out in stain to below coverslip
• Fixed oil
• Esters of glycerol
• Eg linseed, olive
• Volatile (essential) oil
• Look the same
• Turpine and hydrocarbons
• Eg peppermint
• Can smell
• Staining:
• Sudan III, Tincture of Alkanne
• Some plants contain so much oil that it needs to be removed
to see other structures
• Light petroleum removes fat
• Mix, decant off, repeat several times, then can stain
Globules
31. 6. MUCILAGE
• Sometimes present
• Has to be stained to be seen
• Staining:
• Ruthenium red -> pink
• Eg senna leaves
32. ng and
al compounds
Ethnopharmacological
survey
Bioguided isolation of useful bioactiv
(s)
Useful information for
management of SCD
and Malaria
Biological testing
Standardize natural
medicines
Safety evaluation
Lead molecules for
drug development
