Download Secondary Metabolites from Plants Plant Secondary Metabolites

Secondary Metabolites from
Plants
David S.-Y. Wang
Assistant Professor
Department of Forestry, NCHU
Plant Secondary Metabolites
• Secondary metabolites are those metabolites which are
often produced in a phase of subsequent to growth, have
no function in growth (although they may have survival
function), are produced by certain restricted taxonomic
groups of microorganisms, have unusual chemicals
structures, and are often formed as mixtures of closely
related members of a chemical family.
• The simplest definition of secondary products is that they
are not generally included in standard metabolic charts.
1
Plant Secondary Metabolites
• A metabolic intermediate or product, found as a
differentiation product in restricted taxonomic groups, not
essential to growth and the life of the producing
organism, and biosynthesis from one or more general
metabolites by a wider variety of pathways than is
available in general metabolism.
• Secondary metabolites are not essential for growth and
tend to be strain specific. They have a wide range of
chemical structures and biological activities. They are
derived by unique biosynthetic pathways from primary
metabolites and intermediates.
Plant Secondary Metabolites
• Biochemical pathways that are not necessary for growth
or reproduction of an organism, but which can be
demonstrated genetically, physiologically or
biochemically.
2
Plant Secondary Metabolites
• Plants produce as amazing diversity of low molecular
weight compounds.
• Of the estimated 400,000 – 500,000 plant species around
the globe, only a small percentage has been investigated
phytochemically and the fraction subjected to biological or
pharmacological screening is even lower.
Plant Secondary Metabolites
• The ability to synthesize secondary metabolites has
been selected through the course of evolution in different
plant lineage when such compounds address specific
needs.
– Floral scent volatiles and pigments have evolved to attract insect
pollinators and thus enhance fertilization.
– To synthesize toxic chemical has evolved to ward off pathogens
and herbivores or to suppress the growth of neighboring plants.
3
Plant Secondary Metabolites
– Chemicals found in fruits prevent spoilage and act as signals (in
the form of color, aroma, and flavor) of the presence of potential
rewards (sugars, vitamins and flavor) for animals that eat the fruit
and thereby help to disperse the seeds.
– Other chemicals serve cellular functions that are unique to the
particular plant in which they occur (e.g. resistance to salt or
drought).
Natural Products Drug Discovery and
Development
• Over the ages, human have relied on nature fro their
basic needs for the production of foodstuffs, shelters,
clothing, means of transportations, fertilizers, flavors and
fragrances, and not least medicine.
• Plants have formed the basis of sophisticated traditional
medicine system that have been in existence thousands
of years in countries such as China and India.
4
Natural Products Drug Discovery and
Development
• About 25% of all prescriptions sold in the US are for
natural products, while another 25% are for structural
modifications of a natural products.
• According to Fransworth (1990) claims that 119
characterized drugs are still obtained commercially from
higher plants and that 74% were found from
ethnobotanical information.
. Fransworth, N.R. (1990) In bioactive compounds from plants.
John and Wiley Co..
Primary and Secondary Metabolism
• Primary metabolism
– The biological reactions are essential to maintain life in living
organisms and are known as primary metabolism.
– Plant convert sunlight energy to chemical energy, such as ATP,
NADPH, by the mediation of chlorophyll in chloroplasts and
synthesize sugars and starch from CO2 by using ATP and
NADPH+.
– These carbohydrates are stored and used for differentiation
and formation of plant tissues.
5
Primary and Secondary Metabolism
• Secondary metabolism
– The metabolisms which are not directly related to maintaining
life, are known as secondary metabolisms.
– The products formed by secondary metabolism are called
secondary metabolites.
– Secondary metabolite play a role in reinforcement of tissue and
tree body (e.g. cellulose, lignin, suberin), protection against
insects, dieses, and plant regulation (plant hormones).
Primary and Secondary Metabolism
• All organisms need to transform and interconvert a vast
number of organic compounds to enable them to live,
grow and reproduce.
• All organisms need to provide themselves with energy in
the form of ATP, and a supply of building blocks to
construct their own tissues.
• An integrated network of enzyme-mediated and carefully
regulated chemical reactions in used for this purpose,
collectively referred to as intermediary metabolism, and
the pathways involved are termed metabolic pathway.
6
Primary and Secondary Metabolism
• The pathways for generally modifying and synthesizing
carbohydrates, proteins, fats, and nucleic acids are
found to be essentially to same in all organisms, apart
from minor variations.
– These processes demonstrate the fundamental unity of all living
matter, and are collectively described as primary metabolism,
with the compounds involved in pathways being termed primary
metabolites.
Primary Metabolisms
• Degradation of carbohydrates and sugars generally
proceeds via the well characterized pathways, known as
glycolysis and the kerbs / citricacid / tricarboxylic acid
cycle, which release energy from the organic compounds
by oxidative reactions.
• Oxidation of fatty acids from fats by the sequence called
β-oxidation also provides energy.
7
Primary Metabolisms
• Aerobic organisms are able to optimize these processed by
adding on a further process, oxidative phosphorylation.
This improves the effeiciency of oxidation by incorporating
a more general process applicable to oxidation of a wide
variety of substrates rather then having to provide specific
process for each individual substrate.
Primary Metabolisms
• Proteins taken in via the diet provide amino acids, but
the proportions of each will almost certainly vary from the
organism’s requirements.
• Most organisms can synthesize only a proportion of the
amino acids they actually require for protein synthesis.
Those structures not synthesized, so-called essential
amino acids, must be obtained from external sources.
8
Secondary Metabolisms
• The compounds which synthesized from the secondary metabolisms
are so-called secondary metabolites.
• Secondary metabolites are formed in only specific organisms, or
groups of organisms, ane are expressioin of the individuality of
species.
• Secondary metabolites are not necessarily produced under all
conditions, and in the vast majority of cases the function of these
compounds and their benefit to the organism is not yet known.
• It is this area of secondary metabolism that provides most of the
pharmacologically active natural products.
Secondary Metabolisms
• To make such compounds as sugars, waxes, lignin starch, pigments,
or alkaloids, plants utilize very specific enzymes, each of which
catalyzes a specific metabolic reaction.
– The enzymes are proteins called organic catalysts.
– These enzymes are coded by specific genes in the plants DNA and are
made via processed we call transcription and traslation.
– When there is a series of enzymatically catalyzed reaction in a welldefined sequence of step, we have what is termed a metabolic pathway.
9
Biosynthetic Pathway
• Nucleoside diphosphate sugar pathway: cellulose,
hemicellulose, glycosides.
• Shikimate-cinnamate pathway: lignin, lignans,
hydrolyzed tannins.
• Mixed pathways of 3 and 4: some prenylflavonoids,
quinones and stilbenes.
Primary and Secondary Metabolism
• Primary and secondary metabolites leave a “grey area”
at the boundary, so that some groups of natural products
could be assigned to either divisions.
• Primary metabolites → Biochemistry
Secondary metabolites → Natural products Chemistry
10
The Classes of Secondary Metabolites
• The majority of secondary metabolites belong to one of a
number of families, each of which have particular structural
characteristics arising from the way in which they are built up in
nature (biosynthesis).
• The classes of secondary metabolites are:
– Polyketides and fatty acids
– Terpenoids and steroids
– Phenylpropanoids
– Alkaloids
– Others (specialize amino acids and carbohydrates)
Polyketide and Fatty acids
• Polyketides are formed by the linear combination of
acetate units derived from the “building block” acetyl coenzyme A.
• The acetate origin of these compounds leads to a
preponderance of even-numbered carbon chains.
• Many plant oils and animal fats contain long-chain
monocarboxylic acids know as fatty acids.
• In the fatty acids, the carbonyl group of the acetate units
is reduced during the course of the chain assembly
process. Dehydrogenation and oxidative processed may
subsequently give the unsaturated fatty acids.
11
Polyketide and Fatty acids
• The common fatty acids have an even number of
carbon atoms, typically C12 – C20, linked together in a
straight chain with up four double bonds.
• In plants the fatty acids and the corresponding alcohol
are found in leave waxes and seed coating:
– Myristic acid (C14) is found in nutmeg seeds.
– Palmitic acid (C16) is found in almost all plant oils.
– Stearic acid (C18) occurs in long amounts in animal
fat.
Polyketide and Fatty acids
• Unsaturated fatty acids are
important to us in food.
– Oleic acid is the most widely
distributed, and a major
constituent of olive oil.
– Linoleic and linolenic acids are
most highly unsaturated and
are found in linseed oil.
– Linolenic acid is easily oxidized
by air, and is one of the “drying
oil” used in paint and varnishes.
12
Polyketide and Fatty acids
– Linolenic acid is oxidized
by plants to jasmonic acid,
which is a signaling
substances that stimulates
plant defense mechanisms.
– Arachidonic acid (C20) is a
precursors of the
prostaglandin hormones.
Polyketide and Fatty acids
• Polyacetylenes
– They are a group of naturally
Falcarinol
OH
occurring hydrocarbon
derivatives characterized by
O
one or more acetylenic groups
O
COOH
Wyerone acid
in their structures.
– Araliaceae(五加科),
OH
Campanulaceae(桔梗科),
HO
Safynol
Apiaceae(繖形花科),
Asteraceae, Pittosporaceae(海
桐科), and some fungi.
OH
1,2-dihdroxytrideca-5,7,9,11-tetrayne
OH
13
14
Terpenes
• The terpenes are among the most widespread and
chemically diverse groups of natural products.
• Terpenes are a unique group of hydrocarbon-based
natural products whose structures may be derived from
isoprene.
• Terpenes are classified by the number of 5-carbon units.
15
Terpenes
• Isopentenyl pyrophosphate (IPP) and dimethylallyl
pyrophosphate (DMAPP) combined to yield geranyl
pyrophosphate (GPP), leading to monoterpenes.
Similarly, compounds derived from farnesyl
pyrophosphate (IPP) lead to sesquiterpenes, and
triterpenes are formed from two equivalents of FPP, and
triterpenes are formed from two equivalents of FPP.
Terpenes
• The function of terpenes in plants is generally
considered to be both ecological and physiological
– Allelophathy
– Insecticidal
– Insect pollinators
– Plant hormone (Abscisic acid, gibberlellin)
16
Myrcene
Greek Bay (Laurus nobilis)
Hops (Humulus lupulus)
Myrcene is found in the essential oil of bay leaves
as well as hops. It is used as an intermediate in
the manufacture of perfumes.
Geraniol and Linalool
OH
Geraniol
OH
Linalool
Geraniol is isomeric with linalool, constitutes the
major part of the oil of roses and is also found in
citronella
essential oils of citronella, lemon grass, and others.
17
Menthol
OH
Menthol is a well-known monoterpenewhich is
found in the essential oil of peppermint and
other members of the mint family.
Sesquiterpenoids
• More than 10000 sesquiterpenoids have been identified,
representing a wide variety compounds of different
skeletal types from acyclic to tetra cyclic systems.
α-cedrene
α-muurolene
logifloene
δ-cadinene
juniperol
α-cadinol
nootkatin
chanootin
18
cadinenes
Wormwood
(Artemisia maritima)
O
O
O
santonin
caryophyllene
Cloves (Syzygium aromaticum)
Dandelion (Taraxacum officinale )
OH
O
O
tetrahydroridentin B
19
Bioactive Compounds Contributing to
Decay Resistance of Taiwania Wood
• Fungi and termites
are two of the most
harmful organisms to
wooden structures
worldwide
• To develop methods
for prolonging the
service life of wood is
one of challenges of
wood utilization
researchers
• As regards decay resistance, Taiwania is
classified as the species with an excellent
durability in Taiwan
• There are several papers dealing with the
antifungal and antitermitic activities of
Taiwania:
.For. Prod. Industries. 1998, 17, 287.
.Holzforschung. 1999, 53, 487.
.Holzforschung. 2000, 54, 241.
. J. Chem. Eco. 2001, 27, 717.
20
Commonly Occurring Brown-rot and
White-rot Fungi
White rot fungi
Brown rot fungi
Coriolus versicolor
Laetiporus sulphureus
Lenzites betulina
Antrodia taxa
Pycnoporus coccineus
Fomitopsis pinicola
Trichaptum abietinum
Phaeolus schweinitzii
Oligoporus lowei
Extractives of Taiwania against Whiterot Fungi
Taiwania Heartwood
MeOH extraction
MeOH Extractives
Hex Fr.
Chl. Fr.
EtoAc Fr.
MeOH Fr.
21
Extractives of Taiwania against Brown-rot
Fungi
Taiwania Heartwood
MeOH extraction
MeOH Extractives
Hex Fr.
Chl. Fr.
EtoAc Fr.
MeOH Fr.
Antifungal Indices of Compounds Isolated
from Taiwania Heatwood
Suginol
Hinokiol
C. v.
Ferruginol
α-Cedrol
α-Cadinol
Helioxanthin
Taiwanin C
L. s.
Savinin
Taiwanin A
0
20
40
60
Antifungal index
80
100
22
Effectiveness of α-Cadinol against
White-rot and Brown-rot Fungi
• Among the compounds
isolated from Taiwania
heartwood, α-cadinol
has demonstrated to
possess the highest
antifungal effectiveness.
H
H
O
H
H
H
H
O
H
H
O
23
Quantification of the Cadinane Skeletal Sesquiterpenoids
Distribution in Different Parts of Taiwania
H
O
H
T-cadinol
H
O
H
The amounts of hexane extractives and essential
oils distilled from various parts of Taiwania
1
H
T-muurolol
H
O
H
2
H
α-cadinol
3
GC chromatograms of essential oils distilled
from Taiwania heartwood.
Amounts of Cadinanes in Various Parts of Taiwania
Amounts of cadinanes (mg/kg)
8
t-cadinol
6
6.49
t-muurolol
α-cadinol
total cadinols
4
1.77
2
0
0.04
0.36
n-Hex
extracts
Heartwood Heartwood
Essential oil
Leafs
Sapwood
24
Antifungal Indices of α-Cadinol, T-Cadinol,
and T-Muurolol
equatorial
hydroxyl group
trans ring junction
Fungi
α-Cadinol
C. v.
100
L. s.
100
T-Cadinol
47.1
100
T-Muurolol
38.8
82
Diterpenoids
• Diterpenoids constitute a major
part of oleoresin.
• This group can be divided into
geranyl-linalool
β-epimanool
acylic, bicyclic, tricyclic,
tetracyclic, and macrocyclic
structural types.
cis-abienol
manoyloxide
• Diterpenoids are present either
as hydrocarbons or as
derivatives with hydroxyl,
carbonyl, or carboxyl groups.
pimaral
pimarol
cembrene
25
Phenolic Constituents
• Heartwood and bark
contain a large variety of
complex aromatic
extractives. Most of them
are phenolic compounds,
and many are derived
from the phenylpropanoid
structure.
Classification of Phenolic Compounds
Numbers of C
6
Basic skeleton
Name
C6
Benzoquinones
10
C6-C4
Naphthoquinones
14
C6-C2-C6
Stilbenes
15
C6-C3-C6
Flavonoids
17
C6-C3-C2-C6
Norlignans
18
(C6-C3)2
Lignans
(C6-C3-C6)n
Condensed tannins
n
26
Phenolic Compounds
H2COH
CH
CH
CHO
OCH3
OH
CH2
CH
CH2
OCH3
OCH3
O GLUCOSE
Vanillin
Coniferin
OH
Eugenol
O
CHO
OCH3
CH3O
OCH3
OCH3
CH3O
OH
OH
Syringaldehyde
Guaiacol
O
2,6-Dimethoxy
benzoquinone
Summery of the Biogenetic Connection between a Selection
of Familiar Phenolic metabolites
27
Summery of the Biogenetic Connection between a Selection
of Familiar Phenolic metabolites
Summery of the Biogenetic Connection between a
Selection of Familiar Phenolic metabolites
28
Lignans
Isolation Procedures
• Lignans can be isolated from the bark, fruit,
heartwood, leaves, roots and resin of plants
• Most isolation procedures involve solvent
extraction, chromatography separations, and
crystallization
• Lignan yields can vary from 0-30%
29
Lignans
Commercialization
• Large amount of research devoted to investigating
medicinal properties of lignans
– Particularly from tropical hardwoods and grasses
• Example 1999 reference: 35 lignans isolated from the twigs of
Tazus mairei
– Antiviral
– Antitumor
– Biocidal
– Bioactive Agents
30
•
The heartwood of Taiwania is
yellowish red with
distinguished purplish pink
streaks, which fascinates
people very much.
•
The yellowish red color in
Taiwania is susceptible to
change to dull black after
exposure it to nature
environment.
31
Optical Micrographs of Different Parts of Taiwania
Optical Micrograph Observation of
Discoloration in Red Taiwania Heartwood
2 weeks
4 weeks
After exposed Taiwania heartwood under indoors
condition, its color changed from red to dull black.
32
Color Compounds Isolated from
Taiwania Heartwood
O
O
O
O
O
O
O
O
O
HO
O
O
O
HO
O
O
O
O
O
Taiwanin A
O
O
O
Savinin
O
O
Helioxanthin
Pluviatolide
OH
OH
H
HO
HO
OH
O
H
OMe O
Taiwanin I
CHO
CHO
O
Ferruginol
T-Cadinol
Secoabietane dialdehyde
33
Cytotoxicity of Lignans and Sesquiterpenoids from Taiwania
Heartwood (ED50 values in mM)
Taiwanin A
Taiwanin E
Dimethylmatairesinol
α-Cadinol
Cytotoxicity of Dibenzyl-γ-butyrolactone Type of
Lignans Isolated from Taiwania Heartwood
O
O
O
O
O
O
O
O
O
O
O
R
O
R
R
R
O
• An unsaturated double bond
between C7-C8 and/or C7’-C8’
is associated with stronger
cytotoxicity.
• The presence of two 3, 4dimethoxyphenyl groups in
lignans may increase the
cytotoxicity, as dimethylmatairesinol was stronger than
arctigenin and hinokinin
34
Cytotoxicity of Dibenzyl-γ-butyrolactone Type of
Lignans Isolated from Taiwania Heartwood
O
O
O
O
O
O
O
O
O
O
O
• An unsaturated double bond
between C7-C8 and/or C7’-C8’
is associated with stronger
cytotoxicity.
• The presence of two 3, 4dimethoxyphenyl groups in
lignans may increase the
cytotoxicity, as dimethylmatairesinol was stronger than
arctigenin and hinokinin
O
R
O
R
R
R
Cytotoxicity of Dibenzyl-γ-butyrolactone Type of
Lignans Isolated from Taiwania Heartwood
O
O
O
O
O
O
O
O
O
O
O
MeO
O
MeO
OMe
MeO
O
• An unsaturated double bond
between C7-C8 and/or C7’-C8’
is associated with stronger
cytotoxicity.
• The presence of two 3, 4dimethoxyphenyl groups in
lignans may increase the
cytotoxicity, as dimethylmatairesinol was stronger than
arctigenin and hinokinin
35
Cytotoxicity of Arylnaphthalide Type of Lignans
Isolated from Taiwania Heartwood
OH
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
• Taiwanin E showed the
strongest cytotoxicity
in this group.
• It appears that the
hydroxyl group at the
C7 position enhances
the cytotoxicity.
Cytotoxicity of Arylnaphthalide Type of Lignans
Isolated from Taiwania Heartwood
OH
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
• Taiwanin E showed the
strongest cytotoxicity
in this group.
• It appears that the
hydroxyl group at the
C7 position enhances
the cytotoxicity.
36
Flavonoids/Tannins
Isolation of Flavonoids
• Isolation of flavonoids accomplished
through solvent extraction
– Hot water
– Alcohols
• Solvent fractionation of extract
• Salting out
• Crystallization
Flavonoids/Tannins
Isolation of Flavonoids
• Flavonoids concentrated in certain parts of
plants
• Plant sources
– Pulp of fruits
– Broccoli, green peppers, onions, etc.
– Green tea, red wine
– Herbs
– Tree bark
37
Blockade of tumor induction by
EGCG
OH
OH
O
HO
OH
OH
O
OH
C
OH
O
OH
(-)-epigallocatechin-3gallate
RH: procarcinogens
(aflatoxins, poly-cyclic aromatic
hydrocarbons, and nitrosamines)
GST: glutathione S-transferase
GlcT: UDP-glucuronyl transferase
ROS: reactive oxygen
(superoxide anion, hydrogen peroxide,
hydroxyl radical, nitric oxide,
peroxynitrite, and nitric dioxide anion)
Chemical Composition of Tea
• Caffein: 3-4 %
• Catechins (including Tannin): 15-30 %
• Flavonols and Metal: 5 %
¾P,K, Ca, Mg, Mn, Zn, Cu, Al
• Vitamins: A, B1, B2, C, E, Nicotinic acid
38
Flavonoids/Tannins
Polymerization Reactions
• Condensed tannins are
formed through the
polymerization of flavan-3-ol
(catechin) and flavan–3,4diols (leucoanthocyanidins)
O
OH
OH
Flavan-3,4-diols
(Leucoanthocyanidins)
– In tree, polymerization
through acidic enzymatic
non-oxidative coupling
O
OH
– 2-50 units
Flavan-3-ols
(Catechins)
• Typically 2-8
– Linkages can be through a
variety of sites
Flavonoids/Tannins
Polymerization Reactions
3'
• Examples of linkages
– 4 alpha – 8
– 4 beta – 8
– 4 beta – 6
• Stereochemistry
• A variety of monomers
2'
8
7
O
A
C
5
4
6
2
B
4'
5'
6'
3
39
Flavonoids/Tannins
Polymerization Reactions
OH
OH
OH
O
HO
O
O
HO
OH
+
(H )
OH
OH
O
-H2O
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
HO
OH
OH
OH
OH
OH
O
HO
+
+H
O
OH
OH
-H
O
HO
OH
+
O
HO
OH
OH
OH
OH
(+)
OH
Flavonoids/Tannins
Polymerization Reactions
• Flavan-3-ols are
incapable of
OH
O
HO
polymerizing without
flavan 3,4-diol
OH
OH
HO
OH
HO
• Flavan-3-ol form
terminating unit
O
OH O
OH
HO
OH
OH
OH
40
Flavonoids/Tannins
Polymerization Reactions
OH
OH
• All 4-8 linkages
O
HO
OH
• This structure has
been isolated from
OH
OH
OH
O
HO
pine bark
OH
OH
OH
OH
O
HO
OH
OH
Flavonoids/Tannins
Polymerization Reactions
• Flavan-3-ols can
polymerize through
an oxidative
enzymatic coupling
reaction forming
oligo and polymeric
materials
– Linkages 8-6’
OH
OH
O
HO
OH
OH
O
OH
O
HO
OH
O
– Causes loss of
brightness in wood
41
Flavonoids/Tannins
Location in Tree: Tannins
• Western hemlock
– Bark: 18% tannins
– Wood: 2% tannins
• Quebracho
– In wood, tannins found in heartwood
– Majority (80%) located in vessel lumina
– Tannins deposit in dead cell starting at CML and
ending in secondary wall
42
Condensed Tannins
Properties
• The term condensed tannins refers to a mixture
of polyflavonoids of different MW (500-5000)
characterized by different linkages, functional
groups, and stereochemistry.
• Protein binding capacity: tannins will bind with
proteins causing them to precipitate.
– This was the definition of tannins: compound which
will precipitate proteins.
Condensed Tannins
Sources
• Condensed tannins more prevalent in
hardwoods but present in softwoods
– Wattle (Acacia - Southern Africa)
– Quebracho (Schnopsis - South America)
– Mangrove (Rhizophora -)
– Hemlock (North America)
43
Condensed Tannins
Biological Significance – Insects/Animals
• Protection of plants against
insects/animals
– Some evidence for/some against
• Bad Taste/Astringency (bitter taste)
• Appears to be major factor
• Particularly bad for insects not used to tannins
• Animals: tannins reduce digestion of food
– Interaction with digestion enzymes
• Toxic to bacteria
Condensed Tannins
Biological Significance - Fungus
• Pine calluses: created by fungal invasion
– Tree forms calluses as protective tissue
– Calluses contain high levels of tannins (Chinese 50-80%)
– Concentrations of tannins as low as 0.1% or 0.8 % have
been shown to retard the growth of a large number of
parasitic fungi
• Quote: Edwin Haslam (tannin chemist)
– “serious and nagging fear that a part at least of (their)
scientific career(s) has been spent inspecting the loot in the
garbage bin of plant metabolism”
44
Hydrolyzable Tannins
Structure
• Polymers of a sugar (usually glucose) with one or
more polyphenolic carboxylic acids: linked through
ester linkages
• Gallotannins: Gallic acid polymer
• Ellagitannins: Ellagic Acid
polymer
OH
OH
HO
OH
HO
O C
OH
HO
O
OH
O
OH
HOOC
COOH
C
C
O
O
OH
OH
OH
Ellagic Acid
Digallic Acid
Gallic Acid
O
Hydrolyzable Tannins
Polymer Structure Example
OH
OH
OH
O
HO
Sugar
OH
O
HO
O
O O
O
O
O
OH
O
OH
OH
O
HO
HO
OH
O
HO
OH
OH
O
n
OH
O
45
Hydrolyzable Tannins
Tree Information
• Rare to nonexistent in softwoods
• Hardwoods which contain large amounts:
– Oak (gallic and ellagic tannins)
– Eucalyptus (Ellagitannins)
– Chestnut (gallic tannins)
– Myrobalan fruits (cherry plum)
• Hydrolyzable tannins located in heartwood
Condensed Tannins
Uses
• Leather tanning: 10,000+ year old industry
– Vegetable tannins & chrome
– Tannins interacting with proteins in hides
• Adhesives
– In phenol formaldehyde systems, tannins
speed up the set:
• Oil well drilling fluids: old but effective use:
taken over by chrome lignosulfonates
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Stilbene
二苯乙烯類之化合物是以α，β-Diphenyl
ethylene 為骨架之化合物稱之，廣泛地分
佈在針葉樹皮及闊葉樹之許多樹種。由於
具有共軛雙鍵，此類化合物為反應性極強
之化合物，除了在製漿蒸煮過程中會與藥
劑反應外，並會阻止可溶性之木質素磺酸
鹽的形成，阻礙木質素的溶解。此外，二
苯乙烯類亦與木材之抗蟻性有密切的關
係。
Alkaloids
• Derived from plants
• With a basic character (hence the term
alkaloid from alkali)
• Contained a nitrogen based heterocylic
ring within their molecules
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• Alkaloids can be
sub-categorized
according to:
– Monocyclic
alkaloids
– Bicyclic alkaloids
– Polycyclic alkaloids
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Narcotic analgesics
Opium
Papaver somniferum - used for 5000
years. Arabs introduced opium to China in
7th century. Opium addiction became a
problem so Chinese officials outlawed it.
England traded opium to China for goods
even though it was illegal in their own
country and in China. China and England
fought two wars over the English import of
opium, China lost both, ceded Hong Kong
to British at end of first war. Use of opium
in China did not drop until Communist
Revolution in 1949. Most opium is
currently grown in SE Asia.
Morphine is purified from
opium and is a very potent
painkiller.
OR
O
N CH3
R=H
R = CH3
HO
morphine
codeine
Ma Huang or Ephedra has been used in
China since 2800 BC It was used primarily
for colds, asthma, hayfever, bronchitis,
edema, arthritis, fever, hypotension and
hives. Potency is based upon the herb's
alkaloid content. Side effects include
increased blood pressure, heart rate and
anxiety. FDA suggest that those with heart
Ma huang
(disease or high blood pressure), thyroid,
Ephedra sinica,
diabetes or prostrate problems may be
Ephedra intermedia,
affected adversely. It should definitely NOT
Ephedra equisetina
be taken with antihypertensive or
antidepressant drugs.
CH3
CH3
H C N CH3
H
H C OH
l-ephedrine
H C N CH3
H
HO C H
d-pseudoephedrine
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Catharanthus roseus
長春花
Vinblastine is a drug used in the treatment of cancer. It interferes with the
multiplication of cancer cells and slows or stops their growth and spread in the
body.
Berberis fremontii
小檗
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