TERPENOID

(ISOPRENOID)

Natural products that posses a carbon framework comprised of units of five carbon arrangement as below:

isoprenic isoprenic isoprenic isoprenic

commonly indicated by

symbol C5

Terpenes:

DEFINITION

1. Hemiterpenes (1 x C5)

3-methylbut-2-en-1-ol

HO

(γ,γ-dimethylallyl alcohol)

Prenol

Etil isovalerat

Classification of Terpenes

Based on isoprenic

Asam isovalerat

2. Monoterpenes (2 x C5)

OH

menthol geraniol

OH

limonene

(mint) (roses) (orange fruit)

Sources: volatile oil (minyak atsiri)

β-Mircena

3. Sesquiterpenes (3 x C5)

OH

farnesol bisabolen

Zingiberene

Sources: volatile oil (minyak atsiri)

β-Kurkumena

α-(-)-Bisabolol

Bunga, daun, buah dan akar dari bermacam tumbuhan mengandung bahan yang mudah menguap dan berbau wangi

Minyak atsiri terdapat pada

cengkehkayu manispinaceaepinusumbelliferae ketumbarsaladri adas

4. Diterpenes (4 x C5)

OH

manoolCOOH

pimaric acid

Sources: pine resin

Cembren

Kafestol

5. Sesterterpenes (5 x C5)

gascardic acid

COOH HO

ophiobolin F

Gascardic acid is the first sesterterpenes that was isolated in 1965 from the secretion of an insect, Gascardia madagascariensis

6. Triterpenes (6 x C5)

dammarane

HO

dammarenediol

OH

HO

OOH

malabaricol

Source: damar

7. Tetraterpenes (8 x C5)

lycopene

a-carotene

B-carotene

Source: carotenoid pigment (carrots)

β-

8. Polyterpenes (> 8 x C5) : polyisoprene

natural rubber

n

Frequently occur in nature, polyisoprene chains made up with more than 10 C5 units, bound tail to head

Source: natural rubber

Irregular Terpenoids

O

cryptone

O

2-methylhept-2-en-6-one β-phellandrene

Those with a skeleton of less than ten carbon atoms ►(Apparent and False Monoterpenes)

Those compounds are a defense substance from certain insects

Cryptone and 2-methylhept-2-en-6-one:Very likely derives from the oxidative cleavage of the C2-C3 bond of an acyclic monoterpene

OH

lavandulol

chrysanthemic acid

O

nezukone

OH

fenchol

those compounds contain ten carbon atoms but they do not follow the isoprene rule

It is more difficult to find a biogenetic explanation for the structures of above compounds

O

O

R

OO

R = H; CoriamyrtinR = OH; Tutin

O

O

HO

OO

Mellitoxin

OH

HO OH

OHHO

OHCHO CHOOH

Gossypol

Toxic sesquiterpenes

Coriaria species

seeds from cotton plants

Secara umum biosintesis terpenoid dengan terjadinya 3 reaksi dasar yaitu :1.Pembentukan isopren aktif (IPP dan DMAPP) berasal dari asam asetat melalui asam mevalonat 2.Penggabungan kepala ke ekor dari 2 unit isopren akan membentuk mono-, seskui-, di-, sester- dan poli-terpenoid3.Penggabungan ekor ke ekor dari unit C-15 atau C-20 menghasilkan triterpenoid (dan steroid) dan tetraterpen

Biosynthesis of Terpenoids

Biosynthesis of Terpenoids

(IPP) (DMAPP)

OPP OPP

H

MonoterpenesMonoterpenes

OPP

H

OPP

geranyl pyrophosphate (GPP)

Farnesyl pyrophosphate (FPP)

OPP SesquiterpenesSesquiterpenes

OPP

Hgeranyl-geranyl pyrophosphate (GGPP)

OPP DiterpenesDiterpenes

TriterpenesTriterpenes

2x

2x

TetraterpenesTetraterpenes

▪Hydrolysis

▪Cyclisation

▪Oxidation

▪Reduction

▪Isomerization

▪Dehydration

▪Decarboxylation

▪etc

Other reactions on GPP, FPP and GGPP to produce terpenoids:

OPP

geranyl pyrophosphate (GPP)

geraniol

OH

β-Mircena

citronellal

citral

Example:

Example:

limonene

?

α-Terpeneol

Example:

bisabolen

Example:

Reactions of Terpenoids

3-methylbut-2-en-1-ol

HO

OH

menthol

geraniol

OH