This document discusses various terpenoid compounds found in plants, including iridoids, terpenes, and modified terpenoids. It provides classifications of terpenoids based on carbon atom count and discusses the occurrence, extraction, biosynthesis, and biological activities of specific compounds like iridoids, gentian, picrorhiza, quassia, tinospora, artemisia, taxus, and andrographis. Structures of important constituents from each plant are also shown.

1. Iridoids &
Misc.
compounds

2. Introduction-
Terpenoid
• Terpenes constitute one of the most important groups of
essential oils.
• The group includes constituents such as limonene,
phellandrene, cedrene etc. and their oxygenated derivatives
such as geraniol, citral, carvone, camphor, cineol and many
others.
• These compounds arise at the geranyl pyrophosphate and
fernesyl pyrophosphate levels respectively, in the acetate
mevalonate pathway from the fundamental building block
termed as isoprene (C5H8) unit.
2-Methyl-1,3-butadiene

3. Terpenoid-Classification
SR
NO.
NO. OF
CARBON
ATOM
VALUE
n
CLASS
1 10 2 MONOTERPENOIDS (C10H16)
2 15 3 SESQUITERPENOIDS (C15H24)
3 20 4 DITERPENOIDS (C20H32)
4 25 5 SESTERPENOIDS (C25H40)
5 30 6 TRITERPENOIDS (C30H48)
6 40 8 TETRATERPENOIDS (C40H64)
7 >40 >8 POLYTERPENOIDS (C5H8)n

4. Introduction-Iridoids
 Monoterpene
 Cyclopenta[c]pyranoid skeleton
 Iridane skeleton cis-2-oxa-bicyclo-[4,3,0]-nonane
 Type: Secoiridoids by cleavage of the 7,8 bond of the
cyclopentane ring
 Some authors limits the definition up to: Methyl cyclopentane
 Iridoid glycosides (>300)
 Secoiridoid glycoside (>100)
 Non-glycoside compounds (>100)

5. Iridoids: How derived?
• Named after ants of the Iridomirmex genus, from which were
isolated compounds involved in the defence mechanism of
the insects: iridoidal, iridomyrmecin and related compounds.
• Exists in plants as well: nepetalactone from Nepeta cataria
(Lamiaceae), or teucriumlactone C from Teucrium marum
have marked properties
• Nepeta cataria: effects on cats, so termed as Catnip,
katzenmelisse, herbe-aux-chats
• Iridoid: generally 10 carbons, may even have more or multiple
structure variation up to polycyclic structures

6. Iridoids: Structure

7. Iridoids: Occurence
• Biosynthetically homogenous
• Insects: ants
• Plants: dicotyledon: Angiosperm
• Plant family: Dipsacales, Gentianales, Lamiales,
Scrophulariales
• Iridoid glycoside: glucoside- glycosidic linkage between –OH
group on anomeric carbon of D-glucose and the –OH group
in the 1-position of aglycone
• Small no. of structure: 1 sugar portion is oligosaccharide
(e.g. Rehmaniosidesa)
• Glucose is linked to: 11-hydroxylmethyl group (e.g.
ebuloside in caprifoliaceae
• Non-glycosidic iridoid: alkaloid: skytanthine

8. Iridoids: Occurrence
10 carbon atom
• Polycyclic compounds: Plumericin, Polyesters(valepotriates) or
intramolecular ethers (Rehamaglutin B)
• Non-glycosidic secoiridoids: Syringa spp., Olea spp.
• C-11: carboxymethyl group (loganin, geniposide) or part of
carboxylic acid (monotropein)
• Hydroxymethyl group: Valerianceae, Caprifoliaceae
• Aldehyde or methyl group: Lamioside
• C-11 is absent: Aucubin, Catalpol, Harpagoside

9. Iridoids: Occurrence
10 carbon atom
• Pyran ring is exceptionally open: gentiobiosides of Iridodidal &
Nepatariaside (precursor of nepetalactone)
• Methyl group at C-8: aucumbin, monotropein, epoxide
(valtrate) & rarely absent (deutzioside)
• Unsaturation at 7,8 position: Geniposide, Aucumbin
• Vinyl group at C-9: gentiopicrin
• Oleoside: ethylidene-hydroxyethylidene at C-9
• Carboxy group is esterified: Oleuropein

10. Iridoids: biosynthesis

11. Iridoids: Extraction
• Delicate due to their great instability
• Instability darkening that takes place soon after plant
collection in many species containing iridoids
• Extraction with polar solvent alcohols of various concentration
• Initial separation, re-dissolving the extraction residue in water,
then re-extracting this with immiscible solvents of increasing
polarity
• Fractionation: chromatography on alumina on charcoal (with
risk of irreversible adsorption), on porous polymers (e.g. XAD-
2) with polar eluents & more and more by polar reverse phase
HPLC
• Purification TLC, HPLC
• Detection Trim and Hill color reagent: Dilute solution of
CuSO4 and HCl, blue color
• Detection spray: vanillin H2SO4, Hot HCl

12. Iridoids: Biological-
Pharmacological properties
• Defensive function in ants
• Anti-inflammatory: weak by oral route and stronger by topical
route
• 1 mg of aucubin, verbenalin or loganin have an activity almost
similar to that of 0.5 mg of indomethacin on the TPA induced
mouse ear edema

13. Drugs category
Iridoids:
1. Gentian (bitter glycoside)
2. Picrorrhiza (bitter glycoside)
Modified Terpenoids
1. Quassia (bitter, triterpenoid lactone)
2. Tinospora (sesquiterpene glucoside)
3. Artemisia (sesquiterpenoid)
4. Taxus (diterpenoid)
5. Andrographis

14. 1. Gentian
• Syn: yellow gentian root
• Source: dried fermented roots and
rhizomes of Gentiana lutea
• Family: Gentianaceae
• GS: Mountainous regions of Central and
south Europe, Turkey, Yugoslavia
• Now: France, Italy, Germany
• Use: bitter tonic, GIT problems, anti-
inflammatory, wound healing,
choleretic-stimulating bile production,
anti-oxidant, hepato-protective, anti-
fungal, anorexia

15. Constituents & Structures
• Bitter glycoside, alkaloids, yellow
coloring agent, sugar, pectin, fixed oil
• Seco-iridoid: gentiopicroside
(gentiopicrin-gentiomarine)
• Hydrolysis product: gentiogenin +
glucose
• Biphenolic acid ester of
gentiopicrosideamarogentinhighest
bitter
• Sweroside, swertiamarine
• Yellow color is due to
Xanthonegentistin or gentiamarine,
isogentistin, gentioside, gentisic acid
• Alkaloid: gentianine, gentialutine

16. 2. Picrorrhiza
• Syn: Kutki, Yellow gentian
• Source: dried rhizomes of Picrorrhiza
kurroa
• Family: Scrophulariaceae
• GS: North-west Himalaya region at 3000-
4000 m
• Use: Bitter tonic, Hepatoprotective,
Immunomodulator, curing different types
of jaundice, skin disease, improves eye
sight, Cholagogue- stimulates gallbladder
contraction to promote bile flow

17. Constituents & Structures
1. Iridoid glycoside:
• Picroside I
• Picroside II
• Kutkoside
• Pikoroside
• Picrorhizinon
hydrolysispicrorhizetin +
dextrose
2. Phenolic glycoside:
• Picein
• Androsin
3. Cucurbitacin glycoside

18. 3. Quassia
• Syn: Bitter wood, Jamaica Quassia
• Source: dried wood of the stem of
Aeschrion excelsa (Picroena or Picrasma
excelsa)
• Family: Simaroubaceae
• GS: West indies, Jamaica, Guadeloupe,
Martinique, Barbados, St. Vincent
• Use: Bitter tonic, Insecticide, vermicide
for thread worms, slightly narcotic & acts
on flies, increase appetite

19. Constituents & Structures
1. Terpenoid : Amaroid
• quassin, an intensely bitter lactone
• Neoquassin
• Isoquassin (picrasmin)
• 18-hydroxy quassin
• Scopoletin
2. Alkaloid: Cathine-6-one
3. Volatile Oil
4. Inorganic salt: CaCl2, NaCl, sulphate of
lime, oxalate, ammonical, KNO3,
Neoquassin

20. 4. Tinospora
• Syn: Guduchi, Gulvel, Heartleaved
moonseed
• Source: dried matured stem of Tinospora
cordifolia
• Family: Menispermaceae
• GS: Himalaya, South India, Srilanka
• Use: Rejuvenator,
Hypoglycemic,Detoxifier,
Immonuomodulatory, astringent,
antipyretic, blood purifier, anti-
neoplastic, cardiotonic, anti-asthamatic,
pyrexia, skin disease

21. Constituents & Structures
1. Furanoditerpenoids:
• Columbin
• Tinosporaside-lignan
• Tetrahydrofuran
2. Alkaloid:
• Jactrorhizine
• Palmatine
• Berberine
• Tembeterine
3. Sesqui terpene glucoside
4. Phenylpropene disaccharide
Cordifolioside A, B
Tinosporic acid, Tinosporone,
Tinosporal, Choline

22. 5. Artemisia
• Syn: A.cina (Santonica, wormseed)
A. annua (Sweet annie, Qinghaosu)
• Source: dried un-expanded flower heads
of Artemisia cina, A. annua, A.brevifolia,
A.maritima & other spp. Of Artemisia.
• Family: A. cina (Compositae)
A. annua (Asteraceae)
• GS: A. cina (Pakistan, Turkestan),
A. annua (China-native, Europe, US,
Turkey, Australia, Iran, Vietname, India (GJ,
UP, JK, HP, KA)

23. Constituents & Structures
A. Cina
• Sesquiterpene
lactone:santonin
• Artemisin
• Irone
A. annua
• Artemisinin
• Deoxyartemisinin
• Artemisic acid
• Arteanniun A, B
• Cadinene type
sesquiterpene
Santonin
Artemisin
Artemisinin

24. USES
• A.cina:
Strong althelmintic against round worms and less
effect against thread worms.
• A.annua
• Artemisinin: Chloroquine resistant Plasmodium falciparum
and particularly cerebral malaria
• Derivative: Artesunate, Artemether: effective
• Artemisic acid: anti-inflammatory, cytotoxic, antibacterial

25. 6. Taxus
• Syn: Yew
• Source & GS: dried bark of
• Taxus baccata (Europe)
• Taxus brevifolia &
• T. canadensis (North america)
• Taxus cuspidata (Japan)
• Taxus wallichiana (Himalaya)
• Family: Taxaceae

26. Constituents & Structures
Tricyclic diterpenoids:
• Taxane skeleton
• Taxusines
• Taxagifen
• Baccatin-III
• Taxine
• Taxol
• Cephalomannine
• Taxicine

27. USES
• Paclitaxel: mitotic spindle
poison
• M/a: it promotes assembly
of tubulin dimers into
microtubules which is stabilized
by inhibiting their
depolymerization
• Indication: Advanced ovarian
cancer, metastatic breast cancer
• S/e: neutropenia, peripheral
neuropathy, CVS, alopecia
• Posology: 135-175 mg/m2
• Docetaxel:
• Indication: breast
cancer
• S/e: severe
neutropenia,
hypersensitivity
reaction, water
retention, cutaneous
reaction
• Posology: 100 mg/m2

28. 7. Andrographis
• Syn: Kalmegh, King of bitter, kirayet
• Source: leaves and entire aerial part of
Andrographis paniculata
• Family: Acanthaceae
• GS: growing -India, Pakistan, Srilanka,
Indonesia
• Cultivated-China, Thailand, west indies,
Mauritius
• Use: bitter tonic, febrifuge-reduce fever,
anthelmintic, astringent, cholagoggue,
cholera, diabetes, weakness, blood
purifier, jaundice, GI disturbances,
itching

29. Constituents & Structures
• Diterpene lactone: kalmeghin
• Andrographolide
• Neoandrographolide
• 14-deoxy-11,12-
didehydroandrographolide
• 14-deoxy-11-oxo-
• Andrographolide
• Andrographiside

30. Carrot
• Syn: Gajar, Queen annie’s lace
• Source: dried roots of Daucus carota
• Family: Umbelliferae
• GS: Temperate regions of Asia, Africa
& Europe
• Use: food, condiment,
Anthelmintic, flatulence,
Immunomodulatory, antioxidant,
Vitamin A supplement

31. Constituents & Structures
Diterpenoids
Carotene
Carotol
Daucol
Trans-asarone
Pinene
Limonene
Geraniol
Retinol
Asarone
C
a
R
O
T
E
n
e

32. Chirata
• Syn: Indian gentian, Indian
balmony, chirayta
• Source: entire herb of Swertia
chirata
• Family: Gentianaceae
• GS: India, Nepal, Bhutan
• Use: ingredient of Mahasudrashan
& Sudarashan churna, chronic fever,
bitter tonic, stimulant, liver
protective, promoting flow of bile,
cures constipation and useful in
treating dyspepsia

33. Constituents & Structures
Chirata:
• chiritin, gentiopicrin and
amarogentin
• Amarogentin: phenol
carboxylic acid ester of
sweroside: related to
gentiopicrin
• Ophelic acid
• Gentianine
• Gentiocrucine