Course: medicinal
plants
Muhammad Qasim Hayat
Alkaloids
▪ group of naturally occurring chemical
compounds that contain mostly basic nitrogen
atoms.
▪ also includes some related compounds with neutral and
even weakly acidic properties
▪ Low molecular weight Nitrogenous compounds
▪ Mostly metabolic by-products derived from amino
acids.
▪ A.k.a. secondary metabolites
▪ produced by a large variety of organisms,
including bacteria, fungi, plants, and animals.
Chemical structure
▪ Alkaloids contain;
▪ carbon,
▪ hydrogen
▪ nitrogen
▪ In addition, may also contain
▪ oxygen,
▪ sulfur and
▪ rarely other elements such as chlorine, bromine,
and phosphorus.
▪ contain one or more phenolic or indole rings, usually with
a nitrogen atom in the ring
▪ position of the nitrogen atom in the carbon ring varies
with different alkaloids
▪ it is the precise position of the nitrogen atom that effects
the properties of these alkaloids.
▪ The boundary between alkaloids and other
nitrogen-containing natural compounds is not
clear-cut.
▪ Compounds like amino acid peptides,
proteins, nucleotides, nucleic acid, amines,
and antibiotics are usually not called alkaloids.
▪ alkaloids are at times called a special case of amines.
Chemical properties
▪ Bitter and alkaline
▪ Oxygen-containing alkaloids;
▪ usually colorless crystals at ambient conditions.
▪ Oxygen-free alkaloids;
▪ are typically volatile, colorless, oily liquids.
▪ Some alkaloids are colored eg: sanguinarine (orange).
▪ Alkaloids are poorly soluble in water but readily
dissolve in organic solvents, such as diethyl
ether, chloroform
▪ Exceptions such as caffeine dissolves well in boiling water.[
▪ With acids, alkaloids form salts of various strengths.
▪ Those salts are usually soluble in water and alcohol and
poorly soluble in most organic solvents.
Identification tests: Qualitative
▪ Mayor’s test
▪ 1 ml of extract + 1 ml of Mayer’s reagent (potassium mercuric iodide
solution). Whitish or cream colored precipitate indicates the presence of
alkaloids.
▪ Wagner’s test
▪ 1 ml of extract + 2 ml of Wagner’s reagent (iodine in potassium iodide).
Reddish brown colored precipitate indicates the presence of alkaloids
▪ Dragendorff’s test
▪ 1 ml of extract + 1 ml of Dragendroff’s reagent (potassium bismuth iodide
solution). An orange-red precipitate indicates the presence of alkaloids.
▪ Hager’s test
▪ 1 ml of extract + 3 ml of Hager’s reagent (saturated aqueous solution of
picric acid). Yellow colored precipitate indicates the presence of alkaloids
Identification tests : Quantitative
▪ Spectrophotometric determination
▪ HPLC (high performance liquid chromatography)
Extraction
▪ Because of the structural diversity of alkaloids,
there is no single method of their extraction from
natural raw materials.
▪ Most methods exploit the solubility of most
alkaloids in organic solvents but not in water, and
the opposite tendency of their salts.
▪ Many alkaloids can be purified from crude extracts
by acid-base extraction.
Most plants contain alkaloid mixtures, which are first
extracted separated.
Plants are thoroughly ground . Mostly alkaloids are
present in the raw plants in the form of salts of organic
acids.
Base extraction is achieved by processing the raw material
with alkaline solutions and extracting the alkaloid bases
with organic solvents, such as chloroform or benzene.
Then, the impurities are dissolved by weak acids; this
converts alkaloid bases into salts that are washed away
with water.
If necessary, an aqueous solution of alkaloid salts is again
made alkaline and treated with an organic solvent. The
process is repeated until the desired purity is achieved.
Toxicology
▪ Many alkaloids are toxic to other organisms.
▪ Example
▪ Pyrrolizidine alkaloids (PAs) are a large group of
natural toxins produced by plants, several of which
are known to be highly hepatotoxic and have been
shown to be carcinogenic in rats.
▪ They have been associated with a number of livestock
diseases and with cases of human poisoning following
consumption of herbal remedies or after contamination
of staple foods.
▪ Example plants in
▪ Boraginaceae, Asteraceae, Orchidaceae families
Medicinal properties
▪ Alkaloid-containing plants have been used by
humans since ancient times for therapeutic and
recreational purposes.
▪ For example, A Chinese book on houseplants
written in 1st–3rd centuries BC mentioned a
medical use of opium poppies.
▪ They often have pharmacological effects and are
used as medications
▪ Some alkaloids have remarkable structural
similarities with neurotransmitters in the central
nervous system of humans, including dopamine,
serotonin and acetylcholine.
▪ The amazing effect of these alkaloids on humans has led
to the development of powerful pain-killer medications.
Applications
Plant
Alkaloid
Effect
Coca plant,
family Erythroxylaceae
cocaine
Stimulant, local anesthetic
Coffea arabica (coffee
plant)
caffeine
Stimulant
Nicotiana tabacum
(Tobacco )
Nicotine
Stimulant
Vinca rosea (periwinkle
plant)
Vincristine
Anticancer
Phellodendron
lavallei (Cork-tree)
Berberine
antibacterial
Galanthus wornorii
(Caucasian snowdrop plant)
Galantamine
Cholino-mimeric
Cinchona tree
Quinine
Antimalarial , antipyretic
Fats AND OILS
Muhammad Qasim Hayat
INTRODUCTION
• Fats and Oils belong to a group of biological subtance called
Lipids.lipids are biological chemicals do not dissolve in water
FUNCTIONs
1. Regulatory messenger
2. Structural component of membrane
3. Energy store house
How fats differ from oils?
Fats differ from oils in that, they are solid at room temperature while oils
are liquid they have same molecular structure
Molecular structure of fats and oils.
They are also called triglycerides.one of the reaction of
triglycerides is is hydrolysis of ester groups.
Structures of few important oils and fats.
1.
2.
Docosahexaenoic acid
4.
Castor oil
3.
Olive Oil
Triglycerides
Triglyceride of linseed oil
Medicinal properties of fats and oils
Fats and oils have high medicinal value
• They are high energy foods, providing about 9 calories per gram of
fat.
• They are needed for your brain and nervous system, for energy
production and for making most of the body’s vital hormones
• two omega-3 essential fatty acids needed for development of the
nervous system.
• coconut oil, along with coconut milk and coconut water, is highly
praised today due to its high content of lauric acid, a natural infection
fighter.
• MCT or medium chain triglygcerides appear to assist energy
production in some diseases such as Alzheimer’s disease omega-3
fatty acids which are also sometimes called essential fatty acids. They
are critical chemicals in our body that can help reduce inflammation,
are needed for cell membranes, for nervous system development, and
for many other functions in the body.
• Cholesterol is an essential fat compound manufactured in
our livers that is needed to make all of the sex hormones
and steroid hormones. It is mainly made in our bodies.
• Symptoms of omega-3 deficiency include rashes, dry skin,
boils, joint pain, irritability, mental problems and much
more.
• Fats and oils coat the nerves with myelin, an important
fatty substance that is needed to conduct nerve impulses
properly.
• Castor oil is cathartic it is also used as an emollient.
• Shark liver oil is used in joint pain and with Vit-D used in
burns and sun burns.
• Linseed oil is used in scabies and skin diseases.
• Olive oil is used as laxative.
Chemical properties of fats
• Fats and oils can be classified according to their degree of
unsaturation as measured by their ability to absorb iodine at
the double bonds.
• Fats have relatively low iodine values and consist of
glycerides containing high percentages of such saturated
acids as lauric, myristic, and palmitic.
• ; milk fats are usually characterized by the presence of shortchain carboxylic acids (butyric, caproic, and caprylic)
• Fats and oils are hydrolized readily. This property is used
extensively in the manufacture of soaps and in the
preparation of fatty acids for industrial applications.
Toxicity of fats and oils.
▪ When an oil is saturated, that means that the molecule has
all the hydrogen atoms it can hold. Unsaturation means that
some hydrogen atoms have been removed, and this opens
the structure of the molecule in a way that makes it
susceptible to attack by free radicals.
▪ Free radicals are reactive molecular fragments that occur
even in healthy cells, and can damage the cell. When
unsaturated oils are exposed to free radicals they can create
chain reactions of free radicals that spread the damage in
the cell, and contribute to the cell's aging.
▪ Rancidity of oils occurs when they are exposed to oxygen, in
the body just as in the bottle. Harmful free radicals are
formed, and oxygen is used up.
Identification tests for oil and fats
used
1.Quality evaluation of oils and fats
▪ Transparency
▪ Determination of impurity
▪ Color
▪ Determination of acid
▪ Odour
▪ Taste
▪ Relative density
value
▪ Determination of
phospholipids
▪ Refractive Index
▪ Determination of soap
▪ Smoke point
▪ Determination of
▪ Melting point
▪ Freezing point
saponification value
▪ .Determination of
2. QUANTITATIVE CHEMICAL TESTS
Physical Constants
Chemical Constants
▪ Specific Gravity
▪ Acid Values
▪ Melting / Congealing
▪ Saponification Value
Point
▪ Refractive Index
▪ Viscosity
▪ Optical Rotation
▪ Ester Value
▪ Iodine Value
▪ Unsaponifiable Matter
▪ Acetyl value
Extraction procedure
▪ Extraction by Expression
Cold Expression
Hot Expression
▪ Extraction by Solvents
▪ Hydrogenation
▪ sparging
1. Extraction by expression
crew presses are normally used to express oils from plant
material because they give a better yield than older
hydraulic presses.
They also operate at higher pressure and continuously (not in
batches).
• EXTRACTION BY EXPRESSION
▪ COLD EXPRESSION
▪ HOT EXPRESSION
Oils for medicinal uses are
extracted at room
temperature. Only a portion
of the oil is obtained.
The residue left after cold
expression is broken down
and treated with steam.
This causes the remaining
oil cells to rupture.
2.EXTRACTION BY SOLVENT
This type of method is used only for technical oils (not
medicinal oils).
Seeds used: Intact or partially extracted by expression.
Solvent: Normally hexane (BP: 65 ºC)
3. Hydrogenation
▪ Oils may be partially hydrogenated to produce various ingredient
oils. Lightly hydrogenated oils have very similar physical
characteristics to regular soy oil, but are more resistant to
becoming rancid. Margarine oils need to be mostly solid at 32 °C
(90 °F) so that the margarine does not melt in warm rooms,
4. Sparging
▪ In the processing of edible oils, the oil is heated under
vacuum to near the smoke point, and water is introduced at
the bottom of the oil. The water immediately is converted to
steam, which bubbles through the oil, carrying with it any
chemicals which are water-soluble. The steam sparging
removes impurities that can impart unwanted flavors and
odors to the oil.
EXAMPLE OF MEDICINAL
PLANTS HAVING OILS AND FATS
Name Of
Medicinal Plant
Source
Family
1. Castor oil.
Recinus
Euphorbiacea
communis linn e
Cathartic, emollient,
bectericidal, in perfumed
hair oil
2. Linseed oil
Linum
usitatissimum
linn
Linaceae
Emollient, diuretic,
expectorant diuretic,
demulcent, scabies and
other skin diseases
3. Olive oil
Ripe fruit of
olea european
linn
Oleaceae
Laxative ,emollient, soap
formation, demulcent
4. Omega-3 fatty
acid
Marine and
plant oils
----------
Uses
Cancer, cardia vasculer
disease, inflammation.
Glycosides
Definition: Glycosides are a class of molecules in which, a sugar
molecule (glycone) is bonded to a "non-sugar" (aglycone) molecule.
Many plants store medicinally important chemicals in the form of
inactive glycosides. The non-sugar portion contains the biochemically
active properties of medical interest.
Classification of glycosides according to a glycone part :
1-Anthracene -------  anthraquinone glycoside
2-Steroid ------------- steroidal glycoside (cardiac)
3-Triterpenoid –------ saponin glycoside
Chemical structure
Chemical properties
1.Separation between glycosides parts:
Glycosides Hydrolysis
+HCLdil
Filtration
glycone +aglycone +HCL Neutralization by
Using alkaline
(H2O+G)+A chloroform
G + A +salt+H2O
(H2O+G)+(chloroform+ A)
We can separate them by using separatory funnel
The best solvent to extract aglycone is Ethyl acetate because:
i- immiscible in water.
ii- always presents in the upper layer.
2. Glycosides also hydrolyzed by temperature or by using enzymes
3. They are water soluble compounds, insoluble in organic solvents. when a
glycosides has a lot of sugars its solubility in water decrease.
Toxicology
 Therapeutic use of herbal cardiac glycosides continues to be a source of
toxicity today.
 Recently, D lanata was mistakenly substituted for plantain in herbal
products marketed to cleanse the bowel; human toxicity resulted.
 Cardiac glycosides have been also found in Asian herbal products and
have been a source of human toxicity.
Identification test(s) (qualitative + quantitative)
A. Colorless, solid, amorphous, nonvolatile
B. Give positive reaction (after hydrolysis) with
1. Molisch's solution test
2. Fehling's solution test
Extraction procedure
Always glycosides founded in the plant with the enzymes which hydrolyzed them.
First damage these enzymes first to extract these glycoside by the following steps:
1-drying the plants fresh in special oven at 100 c for 30 minutes.
2-boiling them with organic solvents for 20 minutes
3- boiling them with acetone 5 minutes
If present in this plant tannins or resins we add lead acetate to precipitate them.
Examples (medicinal plants)
1-Salicin –salix2-Cascaroside _cascara
3-Aloin- Aloe vera
4- Sennoside – senna5-Frangulin – frangula
6- Glycyrrhizin – glycyrrhiza
Known bioactivities
 Local irritant group:
a-Sinigrin(Black mustered seeds_Brassica nigra)
b-Sinalbin(White mustered seeds_Brasica alba)
 Analgesics and antipyretics:
Salicin
Salisylic acid - Willow or Salix bark.
 Keeping elasticity of blood vessels like:
Rutin_Rutoside (Bitter orange peels, Lemon peels)
 Anti-inflammatory group:
a- Aloin for 1)acne
2)peptic ulcer
b-Glycyrrhizin
Phyto-constituents
of Medicinal Plants:
Steroids
Muhammad Qasim Hayat
What are Steroids?
▪ Steroids are artificial compounds, which have a similar
composition to the natural male hormone testosterone.
▪ Commonly referred to as anabolic(“to build” ) or androgenic
(“masculinizing” )steroids.
History of steroids
▪ Developed in the 1030’s to prevent the atrophy or
break down of muscles in patients.
▪ Nazi doctors gave steroids to their soldiers in an
attempt to make them more aggressive.
▪ The soviet union then decided to give steroids to
their athletes. Once the U.S learned the soviet's
secret, the also began giving steroids to their
athletes, starting in the 1950’s
How steroids work
▪ Anabolic steroids work by
stimulating the anabolic
effects by binding or
plugging
into
protein
receptors in or on the cells
that help create new
proteins in the cells.
▪ Anabolic steroids are taken
orally, by injection, or with
creams and patches
How steroids work
Chemical Structure
▪ Steroids are a general class of agents that all have
the steroid ring in common.
▪ Comprised of three 6-carbon rings and one 5-carbon ring
joined.
▪ Cholesterol is the most basic form and, indeed, the
precursor.
▪ Shape very important for biological activity
▪ 3D determined by ring junction AB – CD
Trans AB
isomer
Cis AB
isomer
▪ AB-CD trans junction tend to have a flat, planar structure
▪ important for hormonal activity
▪ AB-CD cis junction are bent
▪ allows them to fit on heart / smooth muscle and blood protein receptor sites
▪ poisonous steroids – some used in heart disease
Types of steroids
▪ Corticosteroids
▪ Testosterone
Sources
[1] Dioscoreaceae (yam family)
▪
Dioscorea genus – dicots – vines
▪
sweet yam – food source, very low steroid content
▪
bitter yam – Mexico, South America – high content
[2] Liliaceae family
▪
monocots – Far East, Phillipines
▪
very important since these provide sapogenins for manufacture of corticosteroids
▪
Smilax or Yucca
[3] Amaryllidaceae
▪
Agave sisalana sisal leaf, East Africa
▪
can be used when supply of [1] and [2] short or too expensive
▪
Solanum sp. contain steroidal saponins
[4] Solanaceae
▪
as well as tropane alkaloids, atropine, etc
▪
eg tomato, potato, woody nightshade
[5] Scrophulariaceae
▪
Digitalis seeds full of steroids, rich source
[6] Leguminosae
▪
Trigonella-foeum-graecum fengreek seed
Chemical properties
▪ Naturally occurring or synthetic fat-soluble organic
compounds commonly known as lipids.
▪ Occur in animal and Plant oils and fats
▪ Have different colors like golden, yellow, blue, orange, green
and even red.
▪ They are crystalline compound and contain an alcoholic group
Medicinal properties of steroid
compound
Toxicology
Toxicology
▪ Examples:
▪ Corticosteriods (immunosuppressant and cause changes in
the skin)
▪ Glucocorticoids (increases the risk of gastritis and peptic
ulcer)
▪ Plants contain toxic Steroids
▪ Foxglove
▪ Asparagus fern
▪ Corn plant
Toxicology
Foxglove
Asparagus
fern
Corn plant
Identification tests
▪ Qualitative:
▪ Thin layer chromatography (TLC) on sulphuric acid
to indicate spot position (chloroform solvent)
▪ Quantitative:
▪ i) colorimetric assay – sulphuric acid produces
orange colour with steroids
▪ ii) IR spectrometry – 960cm-1
▪ need a lot of plant material
▪ iii) GLC micromethod – draw up assay with suitable
standard and do many samples in one day
▪ quickest
▪ qualitative and quantitative
Extraction procedure
▪ Hot water extraction
▪ 5gm of dried finely powdered plant material was taken in
a beaker and 200ml of distilled water was added.
▪ The mixture was heated on a hot plate with continuous
stirring at 30º-40ºC for 20 minutes.
▪ Then the water extract was filtered through filter paper
and the filtrate was used for the phytochemical analysis.
▪ The water extract was kept in refrigerator when not in
use.
Extraction procedure
▪ Solvent extraction
▪ Crude plant extract was prepared by Soxhlet extraction
▪
▪
▪
▪
▪
method.
About 20gm of powdered plant material was uniformly
packed into a thimble and extracted with 250ml of
different solvents separately.
Solvents used were methanol, ethanol, and acetone.
The process of extraction continues for 24 hours or till
the solvent in siphon tube of an extractor become
colorless.
After that the extract was taken in a beaker and kept on
hot plate and heated at 30-40ºC till all the solvent got
evaporated.
Dried extract was kept in refrigerator at 4ºC for their
future use in phytochemical analysis.
Examples (medicinal plants)
Known activities
▪ Anabolic
steroids (by structurally altering
testosterone) treat certain disorders of the blood,
bone mass deterioration, protein wasting states,
and as a replacement therapy for male children
deficient in testosterone and muscle stimulant.
▪ Corticosteroids which act as anti-inflammatory
Course: Medicinal Plants
Coumarins & Tannins
Muhammad Qasim Hayat
Phytochemicals
▪ Non nutritive chemical substances
giving medicinal value to the plants
and
that
produce
a
definite
physiological action on the human
body.
Coumarin : A natural volatile active
compound found in many plants. At
ambient temperature it is a white crystal
with a smell similar to that of vanilla and
melting point of 341-344K.
Tannin: An astringent, bitter plant
polyphenolic compound that binds to
and precipitates proteins and various
other organic compounds including
amino acids and alkaloids.
Chemical structure
Tannins – core of D-glucose carbohydrate esterified with
phenolic
groups
Benzopyrone
Chemical Properties of Tannins
▪ Obtained as an amorphous fluffy or
dense powder, yellowish-white to
light-brown in color.
▪ Essentially with no odor, and a
strongly astringent taste.
▪ Commercial
tannic acid contains
many
ester
linkages
and
is
hydrolysable in the presence of acids,
alkalies, or enzymes.
Chemical properties of Coumarins
▪ Coumarins are colourless or yellow
crystals, soluble in organic solvents
and insoluble in water.
▪ In
ammoniacal
solution
these
compounds have a blue, blue-green
or violet fluorescence.
▪ While heated to 180ºC they sublime.
Extraction Procedure
▪ Maceration
▪ Percolation
▪ Ultrasound assisted
extraction
▪ Microwave assisted
extraction
▪ Column Chromatography
Qualitative
Identification Test
Tannins:
2 ml of extract was added to few drops of 1% lead
acetate. A yellowish precipitate indicated the
presence of tannins.
Coumarins:
In a test tube one g of plant sample was placed and
covered with filter paper moistened with dil. NaOH ,
then heated on water bath for a few minutes. The
filter paper was examined under UV light, yellow
fluorescence is indicative for the presence of
coumarins
Quantitative Identification Test
▪ High
Performance
Chromatography
▪ Spectroscopic Characterization
Liquid
Medicinal plants
Coumarins
▪ Mellilotus officinalis
(Cardioprotective)
▪ Mikania glomerata
(Respiratory
Diseases)
Tannins
▪ Ageratum conyzoides (antibacterial)
properties
Coumarins:
•Precursor molecule in the synthesis
of
a
number
of
synthetic
anticoagulant pharmaceuticals.
•Anti-tumor, anti-hypertension, antiarrhythmia, anti-inflammatory, antiosteoporosis,
antiseptic,
and
analgesic.
Tannins
▪ Important ingredient in the process
of tanning leather.
▪ When incubated with red grape
juice and red wines with a high
content of condensed tannins, the
poliovirus, herpes simplex virus,
and various enteric viruses are
inactivated.
▪ Tannins
have
potential
antiviral,antibacterial
antiparasitic effects.
shown
and
▪ Effective in protecting the
kidneys
Toxicology
▪ Coumarin is moderately toxic to the liver and kidneys,
50) of 275 mg/kg.
with a "Median Lethal Dose" (LD
▪ A potent rodenticide that can cause internal hemorrhage
and death.
▪ USFDA banned coumarin direct use as human food, as
reported that coumarin content of alcoholic beverages
cause headaches.
▪ Coumarin is subject to restrictions on its use
in perfumery as some people may become
sensitised.
▪ A tolerable daily intake established by the
German
Federal
Assessment is
body weight.
0.1
Institute
for
Risk
mg coumarin per kg
▪ Tannins negatively affect an animal's feed intake, feed
digestibility, and efficiency of production
▪ These effects vary depending on the content and type of
tannin ingested and on the animal's tolerance
▪ Tannin toxicity to rumen microorganisms has been
described
for
several
bacteria
species
such
as
Streptococcus bovis, Butyvibrio fibrosolvens, Fibrobacter
succinogenes, Prevotella ruminicola, and Ruminobacter
amylophilis.
Monogastrics animals fed diets with a level of tannins under
experience
5%
▪ depressed growth rates,
▪ low protein utilization,
▪ damage to the mucosal lining of the digestive tract,
▪ alteration in the excretion of certain cations, and
▪ increased excretion of proteins and essential amino acids.
In poultry, small quantities of tannins in the diet cause adverse
effects
▪ levels from
production,
▪ levels from
0.5 to 2.0%
can cause depression in growth and egg
3 to 7% can cause death.
▪ Thank You