1

BIOLOGICALLY ACTIVE COMPOUNDS

IN PLANT RAW MATERIALS

PRIMARY METABOLITES:
carbohydrates
amino acids, peptides, proteins

lipids
nucleic acids
chlorophyll
SECONDARY METABOLITES:
glycosides
alkaloids
essential oils
tannins
bitter compounds
etc.

PRIMARY METABOLITES:

CARBOHYDRATES

Monosaccharides

Glucose, fructose, rhamnose, arabinose – constituents of numerous glycosides and polysaccharides

Digitoxose (deoxyrhamnose) – component of cardiac glycosides of foxglove (Digitalis sp.)

Oligosaccharides – consist of 2-10 monosaccharides

Rutinose (rhamnose + glucose) – component of rutin=rutoside (quercetin-3-rutinoside)

obtained from buckwheat (Fagopyrum esculentum) herb

Polysaccharides – consist of ≥ 10 monosaccharides

Starch

Celulose

Inulin – storage polysaccharide in the roots of plants from the family Asteraceae,

e.g. elecampane (Inula helenium), Jerusalem artichoke (Helianthus tuberosus),
common dandelion (Taraxacum officinale);
– sweetener for diabetes
– prebiotic

– source of fructose

Polysaccharides with immunomodulatory activity
– e.g. in purple coneflower (Echinacea purpurea) herb, aloe (e.g. Aloë arborescens) leaf,
European goldenrod (Solidago virgaurea) herb, common dandelion (Taraxacum officinale) flowers

2

Mucilages – mixtures of polysaccharides

- occur in special cells or reservoirs
- in water form slippery colloidal dispersions
- activity: coating, protecting, demulcent, soothing, mildly laxative
- internally used – in irritation and inflammations of mucous membranes

of gastrointestinal tract (they are not absorbed and act locally)
and respiratory tract (dry irritating cough)

- externally used – to alleviate skin irritation

Mucilage-containing raw materials: flax (Linum usitatissimum) seed,
fenugreek (Trigonella foenum-graecum) seed, marshmallow (Althaea officinalis) root,
black hollyhock (Althaea rosea var. nigra) flower, wool mullein (Verbascum densiflorum) flower,
ribwort plantain (Plantago lanceolata) leaf, psyllium (e.g. Plantago ovata, P. arenaria) seed,
coltsfoot (Tussilago farfara) leaf


PEPTIDES

R

CH

CO

NH

2

NH

CH

COOH

R

1

• dipeptides: consist of 2 amino acids

• oligopeptides: consist of 3-10 amino acids

• polypeptides: consist of > 10 amino acids

viscotoxins – in mistletoe (Viscum album) herb;

- injected subcutaneously cause necrosis of skin tumours

in shepherd’s purse (Capsella bursa-pastoris) herb – peptides with hemostyptic action

PROTEINS – polypeptides with molecular weight > 10 000

Simple proteins (composed of amino acids only)

Complex proteins, e.g.:



glycoproteins = proteins + carbohydrates

• glycoproteins with immunostimulatory activity – in purple coneflower (Echinacea

purpurea) herb, aloe (Aloë vera, A. arborescens) leaf

• lectins – in herb of mistletoe (Viscum album);

- agglutinate red blood cells
- agglutinate cancer cells



chromoproteins – proteins + pigments/metal ions

e.g. chlorophyll – obtained from stinging nettle (Urtica dioica L.) herb

peptide bond

by binding sugars in cell membranes

3

LIPIDS
Simple lipids, e.g. fats (composed of triglycerides = esters of glycerol and fatty acids)

Complex lipids – e.g. phosphoglycerides (e.g. lecithin in soy seeds)

Plant fats (oils) contain mainly unsaturated fatty acids and have a liquid form.

PUFA – polyunsaturated fatty acids
EFA – essential fatty acids

Essential fatty acids:

------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Biological activity of essential fatty acids:



constituents of cell membranes



take part in biosynthesis of prostaglandins, prostacyclins, thromboxanes, leukotrienes



take part in cholesterol transport



affect body immune resistance



important in prophylaxis of atherosclerosis



used in chronic skin diseases, allergic diseases, rheumatoid arthritis, disorders of central

nervous system (e.g. in supportive therapy of multiple sclerosis)

Plant oils rich in γ-linolenic acid:



evening primrose (Oenothera paradoxa, O. biennis) seed oil



borage (Borago officinalis) seed oil



black currant (Ribes nigrum) seed oil

H

3

C

COOH

H

3

C

COOH

H

3

C

COOH

linoleic acid
18:2, n-6

α-linolenic acid
18:3, n-3

γ-linolenic acid
18:3, n-6

soy oil,
sunflower oil,
evening primrose seed oil

flax seed oil

evening primrose seed oil,
borage seed oil,
black currant seed oil

4

SECONDARY METABOLITES:

GLYCOSIDES

– consist of glycone (sugar moiety) and aglycone

Classification of glycosides in regard to the type of bond between glycone and aglycone:
O-glycosides
C-glycosides
S-glycosides
N-glycosides

Classification of glycosides in regard to aglycone:



flavonoid glycosides



anthocyanosides



saponosides



cardiac glycosides – cardenolide and bufadienolide glycosides



anthraglycosides



coumarin glycosides



phenolic glycosides



iridoid glycosides



sterol glycosides



glucosinolates

FLAVONOIDS



yellow pigments, occurring in vacuoles, esp. in aerial parts of plants (flowers, leaves)



occur as free compounds or as O-, rarely C-glycosides

Flavones – e.g. apigenin, luteolin

Flavone glycosides – e.g. vitexin (apigenin-8-C-glucoside) – in hawthorn (e.g. Crataegus
monogyna) inflorescence – improves coronary flow

Flavonols

e.g. quercetin, kaempferol, myricetin

Flavonol glycosides
e.g.
rutin (quercetin-3-rutinoside) – in buckwheat (Fagopyrum esculentum) herb,
rue (Ruta graveolens) herb, heartsease (Viola tricolor) herb,
black elder (Sambucus nigra) flower

- decreases capillary permeability
- antioxidant (e.g. prevents the oxidation of ascorbic acid)

hyperoside (quercetin-3-galactoside) – e.g. in St. John’s wort (Hypericum perforatum) herb,
birch (Betula pendula, B. pubescens) leaf

quercetin

5

Isoflavones

genistein, daidzein – in soy seeds

– phytoestrogens; anti-cancer activity

Biflavonoids

bilobetin, ginkgetin – in maidenhair tree (Ginkgo biloba) leaf

– enhance coronary and brain flow

Flavonolignans

Silymarin (main compound – silybin) – in milk thistle (Silybum marianum) fruit

– anti-hepatotoxic, regenerating liver cells, anti-inflammatory action

Biological activity of flavonoids:



reducing blood vessel permeability and fragility



prevent bleeding, ecchymosis, varicose

veins, atherosclerosis



anti-aggregatory (inhibiting platelet aggregation)



antioxidant



diuretic



spasmolytic



anti-inflammatory



detoxifying – they chelate metal ions, e.g. Cu



UV-protecting



antiviral

Flavonoid-containing raw materials: field horsetail (Equisetum arvense) herb,
common knotgrass/knotweed (Polygonum aviculare) herb, birch (Betula pendula) leaf,
heartsease (Viola tricolor) herb, European goldenrod (Solidago virgaurea) herb,
lime (Tilia cordata, T. platyphyllos) inflorescence, black elder (Sambucus nigra) flower,
hawthorn (Crataegus monogyna ) inflorescence,
sandy everlasting (Helichrysum arenarium) inflorescence,
St. John’s wort (Hypericum perforatum) herb, chamomile (Matricaria chamomilla) flower head

O

OH

O

OH

O

H

genistein

amenthoflavone
bilobetin
ginkgetin

6

ANTHOCYANINS

• plant pigments: pink-red-blue-violet

• usually occur as O-glycosides – anthocyanosides;

aglycone – anthocyanidin:

Biological activity of anthocyanins:



reducing capillary permeability and fragility



slightly diuretic



anti-inflammatory



anti-aggregatory



UV-protecting



antiviral



antioxidant



improving microcirculation in eye



improving visual acuity

Anthocyanin-containing raw materials:
bilberry (Vaccinium myrtillus) fruit, black elder (Sambucus nigra) fruit,
bluebottle (Centaurea cyanus) flower, black hollyhock (Althaea rosea var. nigra) flower

SAPONINS



triterpene saponins



steroid saponins

Biological activity of saponins:



they lower the surface tension of water solutions (



foaming)



facilitate dissolving and absorption of other active substances



haemolytic



lowering blood cholesterol level



expectorant (by irritating stomach mucous membrane)



diuretic



anti-inflammatory



antifungal



psychostimulant



immunomodulatory



chemopreventive



antioxidant



toxic for fish and other cold-blooded animals;

for mammals – when given parenterally;
some of them (e.g. saponins of Agrostemma githago, Cyclamen) – also after ingestion

Raw materials containing triterpene saponins: soapwort (Saponaria officinalis) root, cowslip
(Primula veris) root [e.g. primulasaponin A], liquorice (Glycyrrhiza glabra) root [e.g. glycyrrhizin],
horse chestnut (Aesculus hippocastanum) seed [escin – decreases capillary permeability],
pot marigold (Calendula officinalis) flower, ginseng (Panax ginseng) root [ginsenosides]

Raw materials containing steroid saponins: yam (e.g. Dioscorea zingiberensis) tuber, fenugreek
(Trigonella foenum-graecum) seed [diosgenin]

pelargonidin
cyanidin
delphinidin
malvidin
peonidin
petunidin

e.g. ginsenosides

7

CARDIAC GLYCOSIDES



cardenolide type



bufadienolide type

e.g.

digoxigenin

e.g.

scillarenin

Glycone: 1-4 sugars at C-3

primary glycosides



secondary glycosides

e.g.:

lanatoside C (digoxigenin-digitoxose-digitoxose-acetylodigitoxose-glucose)



digoxin (digoxigenin-digitoxose-digitoxose-digitoxose)

Biological activity of cardiac glycosides:



increase the force of contraction of the heart muscle (positive inotropic effect)



decrease the rate of contractions (negative chronotropic effect)



increase cardiac output



indirect diuretic effect; reduction of swellings



indications: systolic heart failure, arrhythmia: atrial flutter, atrial fibrillation

Aglycone is responsible for the direction of activity.

Sugar moiety affects the solubility, absorption, strength and time of action,
ability to bind blood plasma proteins.

Strength of activity: aglycones < primary glycosides < secondary glycosides

Raw materials containing cardenolide glycosides: Grecian foxglove (Digitalis lanata) leaf [used
only for isolation of cardiac glycosides], lily of the valley (Convallaria majalis) herb,
spring adonis (Adonis vernalis) herb

Raw materials containing bufadienolide glycosides: sea squill (Drimia maritima) bulb

Aglycone:

8

ANTHRAGLYCOSIDES
Aglycone: anthrone, dianthrone, anthranol or anthraquinone
Glycone: 1-3 sugars, mainly glucose and rhamnose
Type of glycoside bond: O- or C-

Biological activity of anthraglycosides:



laxative

 reduce water absorption from the large intestine
 irritate colon walls



stimulate peristalsis



accelerate colonic transfer

The most active compounds are dianthrones and anthrones.
Anthraglycosides are hydrolysed by colon microflora to aglycons and reduced to anthrones.
More sugar moieties in a glycoside and C-glycoside bond



stronger laxative activity.



cholagogue



enhancing gastric juice secretion



long-term use



irritation of gastrointestinal tract



vomiting, bloody diarrhoea



contraindications: pregnancy, lactation, acute intestinal inflammation, e.g. colitis ulcerosa

Raw materials containing anthraglycosides: alder buckthorn (Frangula alnus) bark,
senna (Senna alexandrina) leaf, rhubarb (Rheum palmatum) root, aloe (Aloë ferrox) leaf juice

Naphthodianthrones

anthraquinone

anthrone

anthranol

dianthrone

hypericin R=H
pseudohypericin R=OH

Biological activity of hypericin:

- photosensitising
- antidepressant
- anti-inflammatory
- antiviral (e.g. against HIV-1)
- anticancer

in St. John’s wort (Hypericum perforatum) herb

9

COUMARINS

Coumarin is a product of hydrolysis of glycosides of coumaric acid (e.g. melilotoside) during
drying of raw material → specific smell
Hydroxycoumarins – occur in plants as free compounds or aglycones of glycosides (e.g. esculin=
esculetin glycoside).

Biological activity of coumarins:



UV-protecting, e.g. esculin, umbelliferone



sedative, e.g. coumarin



spasmolytic, e.g. coumarin



hypotensive, e.g. scopoletin



anticoagulant, e.g. dicoumarol, coumarin



cholagogue, e.g. fraxidin, isofraxidin



antioxidant



hepatotoxic, e.g. coumarin

Raw materials containing coumarins:
coumarin: yellow melilot (Melilotus officinalis) herb, sweet woodruff (Galium odoratum) herb,
Southern sweetgrass (Hierochloë australis) herb
hydroxycoumarins: chamomile (Matricaria chamomilla) flower head [umbelliferone],
common ash (Fraxinus excelsior) bark [isofraxidin], southernwood (Artemisia abrotanum) herb,
horse chestnut (Aesculus hippocastanum) bark [esculin],
raw materials obtained from plants from the family Apiaceae, e.g. lovage (Levisticum officinale)
root, garden angelica (Angelica archangelica) root









Biological activity of furanocoumarins:



photosensitising, e.g. psoralene, bergaptene, xanthotoxin (but not angelicin)



used for the treatment of vitiligo and psoriasis



spasmolytic, e.g. angelicin



vasorelaxant



blocking Ca

2+

channels in heart, e.g. imperatorin



cns depressant, e.g. angelicin

Raw materials containing furanocoumarins: rue (Ruta graveolens) herb, garden angelica (Angelica
archangelica) root and fruit, parsnip (Pastinaca sativa) fruit
hogweed (Heracleum sp.)

COOH

O

Glu

Coumarins

Furanocoumarins

COOH

OH

O

O

melilotoside

coumarinic acid

coumarin

O

O

O

O

O

O

psoralene-type

angelicin-type

10

PHENOLIC GLYCOSIDES
Aglycone: phenol or its derivative

Phenolic acids

- occur in plants as free compounds, depsides (e.g. chlorogenic acid)

or aglycones of glycosides

- some of them are precursors of tannins

Biological activity of phenolic acids:



choleretic and cholagogue



antiviral



immunotropic



anti-inflammatory



detoxifying



antioxidant

Raw materials rich in phenolic acids:
knotweed (Polygonum aviculare) herb,
oregano (Origanum vulgare) herb,
lemon balm (Melissa officinalis) leaf,
purple coneflower (Echinacea purpurea) herb,
poplar (Populus nigra) buds

O

O

O

CH

3

O

Glu

OH

O

Glu

OH

O

Glu

arbutin – hydroquinone glucoside

bearberry (Arctostaphylos uva-ursi) leaf
lingonberry (Vaccinium vitis-idaea) leaf

Hydroquinone (product of hydrolysis of arbutin in urinary tract):

- disinfects urinary tract
- potent mutagenic activity

salicin – glucoside of salicylic alcohol (saligenin)

willow (Salix alba, S. purpurea) bark

poplar (Populus nigra) buds

Activity: antipyretic, anti-inflammatory



esp. in rheumatic disorders

O

Glu

HOH

2

C

leiocarposide

European goldenrod (Solidago virgaurea) herb

Activity: diuretic

O

H

O

H

CH

CH

COO

Glu

Glu

Rmn

O

CH

2

CH

2

OH

OH

echinacoside – phenylpropane derivative

narrow-leaf purple coneflower (Echinacea angustifolia) root

Activity: immunostimulant, antiviral

OH

OH

O

O

H

O

H

O

OH

O

OH

O

H

O

H

OH

O

O

OH

OH

salicylic acid

caffeic acid

chlorogenic acid

11

IRIDOID GLYCOSIDES

Raw materials: eyebright (Euphrasia rostkoviana) herb,

wool mullein (Verbascum densiflorum) flower, ribwort plantain (Plantago lanceolata) leaf,
common plantain (Plantago major) leaf

harpagoside – in devil’s claw (Harpagophytum procumbens) root

– analgesic (in arthritic pains)
– anti-inflammatory

STEROLS

Occur in plants as free sterols (e.g. β-sitosterol, stigmasterol, campesterol), sterol glycosides or
sterol esters.

Biological activity of sterols:



lowering blood cholesterol level



antioxidant



anticoagulant



preventing prostatic hyperplasia



anti-inflammatory



preventing colon cancer



immunostimulatory



anti-ulcer

Raw materials with high sterol content:
stinging nettle (Urtica dioica) root, fireweed (Chamerion angustifolium) herb,
pumpkin (Cucurbita pepo) seed,
red stinkwood (Prunus africana) bark, saw palmetto (Serenoa repens) fruit

O

H

CH

3

CH

3

CH

3

CH

3

H

H

H

H

H

H

C

H

3

O

O

Glu

CH

2

OH

OH

aucubin (aucuboside)

- bacteriostatic
- anti-inflammatory
- hepatoprotective

β-sitosterol

12

TANNINS

- large-molecule polyphenolic substances capable of binding proteins



hydrolysable tannins: gallotannins (esters of gallic acid),

ellagitannins (esters of ellagic acid)



condensed tannins (composed of numerous catechin molecules)

Biological activity of tannins:



astringent (protein coagulating)



wound healing



reduce bleeding from gastrointestinal tract



anti-inflammatory



anti-diarrhoea



antibacterial



antiviral



detoxifying (e.g. they bind alkaloids)



antioxidant



used for a long time in larger doses – decrease absorption of vitamins and minerals

Raw materials with high tannin content: oak (Quercus robur, Q. petraea) bark,
bistort/snakeweed (Bistorta officinalis) rhizome, tormentil (Potentilla erecta) rhizome,
common avens (Geum urbanum) herb and rhizome, great burnet (Sanguisorba officinalis) herb,
silverweed (Potentilla anserina) herb, bilberry (Vaccinium myrtillus) fruit,
willow (Salix alba, S. purpurea) bark, lingonberry (Vaccinium vitis-idaea) leaf,
sage (Salvia officinalis) leaf


BITTER COMPOUNDS

- bitter taste
- varied chemical structures, most often:

 sesquiterpene lactones, e.g. absinthin in wormwood (Artemisia absinthium) herb
 secoiridoids:

e.g. gentiopicroside – in yellow gentian (Gentiana lutea) root

amarogentin

sweroside

loganin

Activity:



increase the secretion of saliva and gastric juice



improve appetite and digestion



improve intestinal absorption

in bogbean (Menyanthes trifoliata) leaf

13

ESSENTIAL OILS



obtained mainly by steam distillation of plant raw materials



in plants they occur in special cells or reservoirs:

 exogenous:

- glandular trichomes:

• simple, e.g. capitate trichomes

• multicellular (e.g. asteraceous glandular trichomes – in the family Asteraceae,

peltate glandular trichomes – in the family Lamiaceae)

 endogenous:

- essential oil cells
- secretory reservoirs
- secretory ducts (e.g. in caraway fruit, anise fruit, angelica root)
- resin canals (e.g. in pine needles)



physical traits of essential oils:

- usually liquid consistence
- usually colourless or yellowish; also brownish, blue or green
- readily volatile
- intensive smell
- insoluble in water
- usually of lower density in comparison with water



mixtures of volatile compounds of different chemical nature, mainly:

- terpenes (mono- and sesquiterpenes)

monoterpenes: e.g. menthol (peppermint essential oil), carvone (caraway essential oil),
thujone (wormwood e.o., tansy e.o.)
sesquiterpenes: e.g. α-bisabolol, chamazulene (chamomile e.o.)

- phenols and their derivatives

phenols: e.g. thymol (thyme e.o.), anethol (anise e.o., fennel e.o.)

- heterocyclic derivatives of aromatic compounds: phthalides (lovage e.o.)
- esters of organic acids
- coumarins

Biological activity of essential oils:



skin irritating, hyperemic (e.g. rosemary, pine, eucalyptus)



diuretic (e.g. juniper)



expectorant (e.g. anise, fennel, thyme, eucalyptus)



antiphlogistic (e.g. chamomile)



antiseptic (e.g. thyme, clove, marjoram)



choleretic, cholagogue (e.g. peppermint, pine)



anti-spasmodic, carminative (e.g. chamomile, caraway, fennel, dill, coriander, peppermint)



antineuralgic (e.g. pine, juniper)



sedative (e.g. valerian, lemon balm)



anthelmintic (e.g. wormwood, tansy, rosemary)

Essential oil-containing raw materials:

- obtained from plants from the family Lamiaceae: peppermint (Mentha x piperita) leaf,

lemon balm (Melissa officinalis) leaf, sage (Salvia officinalis) leaf,
rosemary (Rosmarinus officinalis) leaf, thyme (Thymus vulgaris) herb,
marjoram (Origanum majorana) herb, lavender (Lavandula angustifolia) flower

- obtained from plants from the family Apiaceae: caraway (Carum carvi) fruit,

fennel (Foeniculum vulgare) fruit, dill (Anethum graveolens) fruit,
coriander (Coriandrum sativum) fruit, anise (Pimpinella anisum) fruit,
garden angelica (Angelica archangelica) root, lovage (Levisticum officinale) root and leaf

14

- obtained from plants from the family Asteraceae: chamomile (Matricaria chamomilla)

flower head, yarrow (Achillea millefolium) herb, wormwood (Artemisia absinthium) herb,
tansy (Tanacetum vulgare) herb

- obtained from other plants: hop (Humulus lupulus) strobile, pine (Pinus sylvestris) buds,

juniper (Juniperus communis) cone berry, calamus/sweet flag (Acorum calamus) rhizome

Some plants contain scentless, non-volatile precursors of volatile compounds. These plants also
contain specific enzymes catalysing the conversion of these precursors to volatile forms. The
precursors and the enzymes are stored in separate compartments of the cell. Releasing of volatile
compounds is only possible after plant injury (e.g. during chopping or crushing).

GLUCOSINOLATES – S-glycosides commonly occurring in the family Brassicaceae,
e.g. sinigrin – in black mustard (Brassica nigra) seed, horseradish (Armoracia rusticana) root














SULPHUR COMPOUNDS IN ALLIUM SP. (e.g. in garlic)

sinigrin

myrosinase

N

C

S

allyl isothiocyanate

H

2

O



highly volatile



irritates skin and mucous membranes



pungent taste



enhances gastric juice and bile secretion

non-volatile

non-volatile



volatile



burning taste, intensive smell



antibacterial, antifungal,

anti-aggregatory activity

other sulphur compounds

allicin

alliinase

alliin

x 2

15

ALKALOIDS

True alkaloids

• derivatives of amino acids containing nitrogen in a heterocyclic ring

- tropane alkaloids

e.g.

atropine, scopolamine

Raw materials: downy thorn-apple (Datura inoxia) leaf,

Jimsonweed (Datura stramonium) leaf, deadly nightshade (Atropa belladonna) root

- isoquinoline alkaloids

e.g.

morphine, codeine – in opium poppy (Papaver somniferum)

papaverine – in opium poppy (Papaver somniferum)

chelidonine – in celandine (Chelidonium majus) root

- indole alkaloids

e.g.

ergometrine, ergotamine, ergotoxine – in ergot (Claviceps purpurea)

vinblastine, vincristine – in Catharanthus roseus leaf

- quinoline alkaloids

e.g.

quinine, quinidine – in Cinchona officinalis bark

- quinolizidine alkaloids

e.g.

sparteine – in Scotch broom (Sarothamnus scoparius) herb

- pyrrolizidine alkaloids

e.g. in borage (Borago officinalis), comfrey (Symphytum officinale),

coltsfoot (Tussilago farfara) → hepatotoxic, carcinogenic

- pyridine alkaloids

e.g. nicotine – in tobacco (Nicotiana tabacum)

Pseudoalkaloids

• nitrogen-containing compounds biogenetically not related to amino acids;

derivatives of terpenes, steroids, purines

e.g. purine alkaloids: caffeine, theobromine, theophylline

Protoalkaloids

• derivatives of amino acids,

but nitrogen in their molecules is not included in a heterocyclic ring

e.g. capsaicin – in red pepper (Capsicum annuum) fruit

ephedrine – in Chinese ephedra (Ephedra sinica)