This document provides an introduction to iridoids, terpenoids, and naphthoquinone derivatives. Iridoids are cyclic monoterpenoids found in many plant families. They can be classified into iridoid glycosides, simple iridoids, secoiridoids, and bisiridoids. Terpenoids are volatile compounds that give plants fragrance and flavor, and are found in essential oils. They are classified based on the number of rings in their structure. Naphthoquinones are organic compounds derived from naphthalene, with vitamin K as a notable example. These secondary metabolites play important roles in plant defense.

1. Introduction of Iridoids , other
Terpinoids and Napthoquinones.
Presented by:- Aadesh khilari
Roll no:- 44

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Iridoids:
 Iridoids are a class of secondary metabolites found in wide variety of
plants and some animals .
 These are type of Monoterpenoid
 Cyclic derivative with fused –Cyclopentane and pyran ring system.
[Bi-cyclic cis fused cyclopentano-pyron] Example: Catalpol,
Aucubin.
Iridoids:
R=H Or Glucose

3. Occurrence and Distribution:
• Aucubin and catalpol are two of the most
common iridoids in the plant kingdom.
• Plant Families:- Ericaceae, Loganiaceae,
Gentianaceae, Rubiaceae, Verbenaceae,
Lamiaceae, Oleaceae, Plantaginaceae,
Scrophulariaceae, Valerianaceae, and
Apocynaceae.
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4. Classification:
Four main groups
1. Iridoids Glycoside [Harpagoside, Loganin]
2. Simple iridoid / Non-glycosylated [Valtrate]
3. Secoiridoids [Gentiopicroside]
Cleavage of the 7-8 bonds of cyclopentane ring of
iridoids
4. Bisiridoids [Sylvestroside]
Formed by the dimerization of iridoids and
secoiridoids.
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5. • Iridoid Glycoside:-
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Aucuba japonica Catalpa bignonioides
Aucubin
Catalpol

6. • Secoiridoids
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Gentiana lutea plant Gentiana lutea root
Gentiopicroside

7. • Non-Glycosidic iridoids
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Valeriana Wallichii plant
Valerian Jatamansi Valeriana Wallichii roots
Valtrate

8. • Role in plants:-
Regarded as a defence chemical against herbivores and
pathogens (Plant protectant against infection by micro-
organisms
Biosynthetically derived from 8-oxo-geranial
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8-oxo-geranial

9. • Terpenoids are volatile substances which give
plants and flowers their fragrance. They occure
widely in the leaves and fruits of higher plants,
conifers, citrus, and eucalyptus.
• The term ‘terpene’ was given to the compounds
isolated from terpentine, a volatile liquid is
isolated from pine trees.
• The simpler mono and sesqui terpene is a Chief
constituent of the essential oils obtained from
sap and tissues of certain plant and trees.
• The di and Tri terpenoids are not steam
volatile. They are obtained from plant and tree
gums and resins.
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TERPENOIDS

10. • Terpenes and terpenoids are the primary
constituents of the essential oils of many types
of plants and flowers. Essential oil are used
widely as a natural flavor additives for food, as
fragrances is perfumery, and in medicine and
alternative medicines such as Aromatherapy.
• Terpenoids contain only the most volatile
terpenes (i.e Mol. Wt. is not to high) (mono and
sesquiterpens). May occur as oxygenated
derivatives, e.g alcohols, aldehydes, ketones,
phenols, oxides and esters.
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11. Physical parameters
• Terpens are colourless liquid.
• It is soluble in organic solvents and
insoluble in water.
• It is volatile in nature.
• Boiling point of terpenoid is in the range of
150-180C
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13. Each class can be further subdivided into
subclasses according to the number of
rings present in the structure.
1) Acyclic Terpenoids: They contain open
structure
2) Monocyclic Terpenoids: They contain one
rings in the structure.
3) Bicyclic Terpenoids: They contain two
rings in the structure.
4) Tetracyclic Terpenoids: They contain four
rings in the structure.
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14. NAPTHAQUINONE DERIVATIVES:
Napthaquinone are a class of organic compounds derived
from Napthalene.
• Sevral isomeric Napthoquinones are known [1,2-
Napthoquinone, 1,4-napthoquinone = para Napthoquinone]
• 1,4 Napthoquinone forms volatile yellow triclinic crystals
and has sharp odor reminiscent of benzoquinone.
• It is almost insoluble in cold water, slightly soluble in
petroleum ether, and more soluble in polar organic solvents.
• In alkaline solution it produces a reddish brown colour.
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1,4- Napthoquinone/
Para-Napthoquonone
1,2- Napthoquinone

15. • Vitamin K is a derivative of 1,4-
napthoquinone. Napthoquinones are produced
by higher plants, fungi and actinomycets
bacteria and have significant biological
actions including antibacterial, fungicidal,
insecticidal, cytostatic and anticarcinogenic.
• They have been shown to be biosynthesized via
a variety of pathways including acetate and
malonate ( e.g plumbagin),
shikimateshikimate/succinyl co-A combined
pathway (e.g lawsone) and
shikimate/mevalonate combined pathway
(e.g alkannin.)
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Thank you…!