Medicinal-Plant-Chemical-Constituents

1. CHEMICAL CONSTITUENTS OF MEDICINAL PLANTS

2. Figure 1. Pie chart representing the
major groups of plant secondary
metabolites according to Croteau et al.
(2000).
Based on their numbers and diversity,
terpenes offer much potential in an array
of industrial and medicinal applications.
Gallic acid
Pelargonidin

3. Foxglove and
Digitalis
• 1775 herbal remedy for
dropsy (congestive heart
failure)
• Withering tested various
ingredients
• Isolated the active plant
ingredient--Digitalis
purpurea
• Cardiac glycosides, slow
heart rate and increase
strength

4. Morphine
• From the opium
poppy
• Papaver somniferum
• Isolated in 1806
• First active principle
isolated
• Depresses pain
reception
• Synthetic derivatives
include heroin and
methadone

5. Papaver Alkaloids

6. Aspirin
• Willow bark used by
Greeks and Native
Americans for pain and
fever
• Glycoside of salicylic acid,
identified in 1828,
synthesized late 1800’s
• Found in various plants
• Acetylsalicylic acid is
aspirin
• Mode of action still not
completely understood

7. Salix - Aspirin
Hippocrates (Greece) – used willow bark to treat pain
1897 – Bayer Co. (Germany) Chemist – synthesizes, names aspirin

8. Effects of aspirin
• Low doses suppress prostaglandins
– Prostaglandins are hormones produced in
response to injury, etc.
– Prostaglandins can lead to headaches, blood
clots
– They also prevent overproduction of stomach
acid and promote mucus formation
• May be involved in systemic acquired
resistance in plants

9. Malaria and Quinine
• World’s most prevalent disease
– 2-3 million people die every year
– caused by a protistan, carried by a mosquito
– protistans multiply in red blood cells
– people heterozygous for sickle cell anemia
are resistant

10. • Quinine, an alkaloid, kills
protistans in the blood
• From Cinchona tree, in Peru
• Quinine purified in mid-1800’s

11. Snakeroot (Rauwolfia serpentina)
• Hindu healers used for snakebites, to
induce meditation
• Reserpine, other alkaloids isolated since
1952
• Original use as tranquilizer, now mostly to
treat high blood pressure
– blocks neurotransmitters, relaxes blood
vessels
• The alkaloids can be synthesized but it’s
cheaper to extract from the plant

12. Ephedrine
• Alkaloid from gymnosperm
Ephedra
• Plant extracts used as
decongestant, stimulant in
many cultures
• Alkaloid identified 1887,
used still
• CNS stimulant (abuse
problems)
• Weight-loss pills

13. Madagascar periwinkle
(Vinca rosea)
• Traditional healers
used for diabetes
• Leaf extracts
effective against
leukemia cells
• Active alkaloid
called vincristine
• Prevent mitosis in
cancer cells

14. Effective drugs vs. lymphomas (Hodgkin’s disease)

15. Taxus brevifolia
• Active ingredient taxol
• Similar activity to
vincristine
• Used in breast cancer
treatment
• Initial problems with
supply
• Now synthesized
• Related chemicals
being tested

16. Table 1. Common Dietary Flavonoids
Flavonoid Subclass Dietary Flavonoids Some Common Food Sources
Anthocyanidins Cyanidin, Delphinidin, Malvidin,
Pelargonidin, Peonidin, Petunidin
Red, blue and purple berries, red
and purple grapes, red wine
Flavanols Monomers (Catechins):
Catechi, Epicatechin,
Epigallocatechin, Epicatechin gallate,
Epigallocatechin gallate
Dimers and Polymers:
Theaflavins, Thearubigins,
Proanthocyanidins
Catechins: Teas (particularly green
and white), chocolate, grapes,
berries, apples
Theaflavins, Thearubigins: Teas
(particularly black and oolong)
Proanthocyanidins: Chocolate,
apples, berries, red grapes, red wine
Flavanones Hesperetin, Naringenin, Eriodictyol Citrus fruits and juices, e.g.,
oranges, grapefruits, lemons
Flavonols Quercetin, Kaempferol, Myricetin,
Isorhamnetin
Widely distributed: yellow onions,
scallions, kale, broccoli, apples,
berries, teas
Flavones Apigenin, Luteolin Parsley, thyme, celery, hot peppers,
Isoflavones Daidzein, Genistein, Glycitein Soybeans, soy foods, legumes

17. PHENOLICS Example compounds Example sources Some effects and uses
Phenolic acids caffeic, chlorogenic all plants cause oxidative damage,
browning in fruits and wine
Coumarins umbelliferone carrots, parsnip cross-link DNA, block cell
division
Lignans podophyllin urushiol mayapple poison ivy cathartic, vomiting, allergic
dermatitis
Flavonoids anthocyanin, catechin almost all plants flower, leaf color; inhibit
enzymes, anti- and pro-oxidants,
estrogenic
Tannins gallotannin, condensed
tannin
oak, hemlock trees,
trefoil, legumes
bind to proteins, enzymes, block
digestion, antioxidants
Lignin lignin all land plants structure, toughness, fiber

18. Class Example Compounds Example Sources Some Effects and Uses
NITROGEN-CONTAINING
Alkaloids nicotine cocaine
theobromine
tobacco coca plant
chocolate (cocao)
interfere with neurotransmission,
block enzyme action
NITROGEN-AND
SULFUR-CONTAINING
Glucosinolates sinigrin cabbage, relatives
TERPENOIDS
Monoterpenes menthol linalool mint and relatives,
many plants
interfere with neurotransmission,
block ion transport, anesthetic
Sesquiterpenes parthenolid Parthenium and
relatives (Asteraceae)
contact dermatitis
Diterpenes gossypol cotton block phosphorylation; toxic
Triterpenes, cardiac
glycosides
digitogenin Digitalis (foxglove) stimulate heart muscle, alter ion
transport
Tetraterpenoids carotene many plants antioxidant; orange coloring
Terpene polymers rubber Hevea (rubber) trees,
dandelion
gum up insects; airplane tires
Sterols spinasterol spinach interfere with animal hormone
action

19. Terpenoids
Terpenes are varied class of hydrocarbons with a basic unit of isoprene.
Terpenoid compound is formed by combination of units of 5 carbon
isoprene.
1 unit isoprene – 5C Hemiterpenoid.
2 unit isoprene – 10C Monoterpenoid
3 unit isoprene – 15C Sesquiterpenoid
4 unit isoprene – 20C Diterpenoid.
6 unit isoprene – 30C Triterpenoid.
8 unit isoprene – 40C Tetraterpenoid
> 40C Polyisoprenoid.

23. Monoterpenoids - Volatile Oil
A substance of oily consistency and feel, derived from a plant and containing the volatile aroma
compounds from plants.
They are also known as essential or ethereal oils.
A volatile oil evaporates when exposed to the air and thus is capable of distillation;
It may also be obtained by expression or extraction; many volatile oil's, identical to or closely
resembling the natural oil's, can be made synthetically.
Volatile oils are used in medicine as stimulants, stomachaches, correctives, carminatives, in perfumes
and cosmetics and for purposes of flavoring.

30. Abietic acid is an irritant compound present in pine wood and resin.
It is the most abundant compound present in rosin, the solid fraction of the
oleoresin of coniferous trees.
It is mainly used to make lacquers and varnishes and metal resinates.
Exhibited potent testosterone 5α-reductase inhibitory activity in vitro.

31. Steviol is the aglycone of stevia's sweet glycosides.
The steviol glycosides (stevioside) are responsible for the sweet taste of the
leaves of Stevia rebaudiana, Asteraceae.
These compounds are 40 to 300 times sweeter than sucrose.
They are developed to be used in sweet drinks.

32. Dehydroleucodine was isolated from Artemisia douglasiana, a popular
medicine in Argentina
have several physiological and therapeutic properties:
Anti-proliferative activity in G2 phase,
Cytoprotective agent for gastric ulcers
Antioxidant.

33. Cafestol is diterpene esters in the oil derived
from coffee beans (Coffea arabica).
Anticarcinogenic properties in rats.
Has neuroprotective effects in a Drosophila fruit fly model
of Parkinson's disease.

34. Phorbol is a diterpene isolated in 1934 from croton oil of seeds of Croton
tiglium.
Various fatty acid esters of phorbol have important biological properties as
tumor promoters in biomedical research tool in models of carcinogenesis.

35. Andrographolide is a bicyclic diterpenoid lactone of Andrographis
paniculata.
Extremely bitter substance extracted from the stem and leaves of A.
paniculata.
Antiviral, antiinflammatory, antiapoptotic, and antihyperglycemic properties.

36. Dioscorea steroids
Wild Yam – convenient source for steroidal saponins which can be converted
into synthetic hormones for use in contraceptives

39. Saponin
Saponins are natural surfactants, or detergents, found in many plants, especially certain desert plants.
- glycosides of steroids with a distinctive foaming characteristic.
- have long been known to have strong biological activity.
They consist of a polycyclic aglycone that is either a choline steroid or triterpenoid attached via C3 and
an ether bond to a sugar side chain.
The antifungal and antibacterial properties of saponins are important in cosmetic applications, in
addition to their emollient effects.
Commercially, saponins appear in beverages and cosmetics as emulsifiers or sweeteners.
They're also fed to livestock to cut down on odor because they bind to ammonia, which contributes to
foul smells.

41. Cholesterol Lowering
Body uses cholesterol to make bile acids needed for proper digestion.
When we eat, bile acids are released into your intestines. The detergent
qualities of saponins allow them to bind to bile and prevent its reabsorption.
Once bound to saponins, cholesterol leaves your body in waste.
A lower cholesterol level means less risk of heart attack or stroke.

42. Improved Immune Function
Saponins cause death of fungal cells, such as Candida albicans, which is
responsible for yeast infections, thrush and many hospital-acquired
infections.
Saponins appear to enhance your immune system's ability to fight off
viruses and parasites as well.

43. Preventing Cancer
Saponins found in soybeans slow the growth of human cancer cells.
These plant compounds may also cause the death of tumor cells

44. The Most Important Classes of Phenolic Compounds in Plants
number of C-atoms basic skeleton class
6 C6 simple phenols, benzoquinones
7 C6 - C1 phenolic acids
8 C6 - C2 acetophenone, phenylacetic acid
9 C6 - C3
hydroxycinnamic acid, polypropene,
coumarin, isocoumarin
10 C6 - C4 naphtoquinone
13 C6 - C1 - C6 xanthone
14 C6 - C2 - C6 stilbene, anthrachinone
15 C6 - C3 - C6 flavonoids, isoflavonoids
18 (C6 - C3)2 lignans, neolignans
30 (C6 - C3 - C6)2 biflavonoids
n
(C6 - C3)n
(C6)n
(C6 - C3 - C6)n
lignins
catecholmelanine
(condensed tannins)

47. Flavones
It is present in green vegetables, fruits, berries and beverages such
as tea, red wine and fruit juices.
Naturally occurring flavones includes Apigenin, Luteolin and
Tangeritin.
It provides many health benefits like protect against damage in blood
vessels, thus decreasing the risk of cardiovascular diseases, prevent
cancer and enhances immune system of body.

48. Alkaloid
Organic compound, with N, usually in ring structure.
Physiologically active on vertebrate nervous systems.
Diverse class of compounds.

53. Tannin
Tannins are naturally occurring plant polyphenols.
They are composed of a very diverse group of oligomers and polymers.
Their main characteristic is to bind and precipitate proteins.
Tannins are located mainly in the vacuoles or surface wax of the plants.
It is mainly used in tanning animal hides into leather.
Acacia catechu is an example of a plant having high tannin content.

56. Resin
Plant resins are simply secretion of plants, obtain either from the entire plant or from specific parts of the
plant.
Resin is mainly consist of volatile terpenes, along with essential oils and gums in little amount.
Insoluble in water and soluble in alcohol.
Plant resins used in many purposes such as varnishes, adhesives, as an important raw material for organic
synthesis or for incense and perfume.

58. Treat Wounds
Some claim that pine resin has healing/antibacterial properties.
The resin once applied to a cut or scrape will inhibit the growth of bacteria
because it denies the bacteria the moisture it needs to survive.
Because of its very sticky nature, resin can be applied directly to a bleeding
cut to help stem the flow of blood and close the wound up similar to
stitching.
There have been reported cases where serious bleeding wounds have
been stemmed using pine resin.
Use the resin to treat burns, abscesses and blisters.

59. Mucilage
Mucilage is naturally occurring gum or glutinous substance, comprised mainly of polysaccharides.
It swells but does not dissolve in water and form a jelly like mass.
Mucilage is secreted by various plant parts. It is the chief constituent of agar.
It serves to check water loss , food storage and in the process of seed dispersal.
Mucilage is edible, and has got wide application as an emollient , adhesive or a demulcent in
cough syrups and in others medicines.

60. Examples of plants are known to contain far greater concentrations of
mucilage:
Ulmus rubra, is a typical mucilaginous herb.
Aloe vera
Basella alba (Malabar spinach)
Cactus
Dioscorea opposita (nagaimo, Chinese yam)
Drosera (sundews)
Liquorice root
Psyllium seed husks
Plantago major

62. Gum arabic, also known as acacia gum, chaar gund, char goond,
or meska.
Acacia tree: Senegalia (Acacia) senegal and Vachellia (Acacia) seyal.
Producers harvest the gum commercially from wild trees, mostly in Sudan
(80%) and throughout the Sahel, from Senegal to Somalia.
Historically cultivated in Arabia and West Asia.
Gum arabic is used primarily in the food industry as a stabilizer.
Gum arabic is a key ingredient in traditional lithography and is used in
printing, paint production, glue, cosmetics and various industrial
applications, including viscosity control in inks and in textile industries.

63. Gum arabic

64. Glycosides
Glycosides are compounds containing a carbohydrate and a noncarbohydrate
residue in the same molecule.
An acetyl linkage at carbon atom 1 attaches the carbohydrate residue to a
noncarbohydrate or non sugar residue or AGLYCONE.
The nonsugar component is known as the AGLYCONE.
The sugar component is called the GLYCONE.
If the carbohydrate portion is glucose, the resulting compound is a
GLUCOSIDE.

65. CLASSIFICATION OF GLYCOSIDES
When the chemical nature of the aglycone group is used as the basis of systematization,
the classification of the glycoside of the glycoside-containing drugs is as follows:

66. THE GLYCOSIDES OF DIGITALIS
1. Digitoxin.
- cardiotonic glycosides obtained from Digitalis purpurea.
- cardiotonic, increasing the tone of cardiac muscle, thus causing the heart to be emptied more effectively.
2. Digitonin
Is a crystalline saponin which is present in the leaves and seeds of Digitalis purpurea.
when hydrolyzed it yields one molecule of digitogenin, two of glucose, two of galactose and one of xylose.
It is practically insoluble in water but forms a soapy suspension.
Used in the determination of cholesterol in blood plasma, bite and tissue, because it forms an insoluble complex
with cholesterol.

67. SAPONIN GLYCOSIDES.
Sarsaparilla -dried root of Smilax aristolochiaefolia, Smilax regelii.
- contain sarsasapogenin, smilagenin, phytosterds, resin, volatile oil, starch and calcium oxalate.
- Flavoring agent.
Glycyrrhiza - dried rhizome and roots of glycyrrhiza glabra.
- also called licorice root.
- Contain saponinlike glycoside, glycyrrhizin, liquiritin, isoliquiritin, herniarin, umbelliferone, asparagine,
glucose, mannitol.
- Use as demulcent, expectorant, laxative, flavoring agent to mask the taste of bitter drugs.
- Commercially, licorice is added to chewing gums, chocolate candy, cigarettes, chewing tobacco.

68. Amino Acid
Amino acids are very small biomolecules and consist of two functional
groups i.e. amino group and carboxyl acid group.
They are the major building blocks of proteins and enzymes.
They act as intermediates in metabolism and help in growth, repair and
maintenance of cells and tissues.