1. Anthaquinones
Active components of many crude drugs with purgative properties
Colored compounds traditionally used as dyes
Mostly glycosides (mainly glucosides or rhamnosides)
Sugar residue is prerequisite for pharmacological effects
9,10-anthraquinone as basic st.

2. Classes of Anthraquinones
Based on degree of oxidation status
oxid.
red.

3. Biosynthesis of Anthraquinones
Mainly produced via acylpolymalonate (acetate-malonate) pathway in Polygonaceae & Rhamnaceae & Leguminosae….
Starts with acetyl CoA carboxylation to malonly CoA then continues in the usual way of formation of the poly-keto-methylene-chain with simultaneous loss of CO2 followed by cyclisation
Shikimate-mediated in Rutaceae, Rubiaceae & Gesneriaceae
ACP= Acyl carrying protein

4. In the biosynthesis of the anthraquinones for the formation of the poly-keto-methylene-chain : 1 acetyl CoA and 7 Malonyl CoA are used.

5. Anthraquinones from Shikimic Acid
Shikimic acid reacts with alpha ketoglutaric acid which can be formed either by deamination of glutamic acid or via the citric acid cycle
Succinylbenzoic acid intermediate binds with mevalonic acid (formed from aceteate) to prduce anthraquinones

6. Important anthraquinones: OH at C-1 and C-8 R at C-3: CH3………………Chrysophanol R at C-3: CH2OH………….Aloe-emodine R at C-3: COOH…………. Rhein R at C-3: CH and at C OH Frangula-emodine R at C-3: CH and at C OCH3 Phycion

7. Natural Sources Widespread in plant kingdom
Produced by microorganimsms e.g. Penicillium & Aspergillus spp
Anthraquinone-rich plant families:
Liliaceae, Polygonaceae, Rhamnaceae, Rubiaceae, Fabaceae, Rutaceae
Animals produce anthraquinones e.g. cochineal insect

8. Medicinal Use of Antharquinones
Purgatives
Pure compounds are rarely prescribed
Mostly used as simple extracts of crude drugs
Sugar moiety increases solubility & facilitates transport to the site of action
Aglycone is active part
Anthrone is the most effective form
Normal flora in colon liberates aglycone to stimulate peristalsis
Too much anthrones in crude drugs are not suitable for use (frangula bark storing to allow {O} to anthraquinone

9. Frangula Bark Dried bark of Rhamnus frangula L. (Rhamnaceae)
Fresh frangula rich anthrones (too strong)
Storing for one year to oxidize (mild activity and widely used)
2-4% glucofrangulins
Frangulin A & B are minor

10. Dried bark of Rhamnus purshiana (Rhamnaceae)
Cascara Bark
Dried bark of Rhamnus purshiana (Rhamnaceae)
Cascara (Spanish word from cascara sagrada=sacred bark)
Fresh cascara like frangula (must be stored before use)
6-9% Anthraquinones mainly Cascarosides A-D
A & B aloe-emodine anthrone (aglycone)
C & D chrysophanol anthrone (aglycone)
Crude bark from west coast of North America, British Columbia & Canada
Cascarosides of 2 steroisomeric pairs differ in their aglycones

11. Aloe spp (Liliaceae)
Aloe barbadensis, A. ferox dried juice from the leaves (from leave base)
Strong purgative
Barbaloin A & B (stereoisomers)
Aloinosides A & B (stereoisomers)
Aloin= H2O-sol. components of aloe
Aloin might be used for barbaloin
Best avoid aloin (ambiguous term)

12. Other Aloe Preparations
Aloe vera leaf mucilage from parenchymatous layer
Herbal remedy for sunburn
Cosmetic industry
FREE FROM ANTHRAQUINONES

13. Rhubarb radix الرواند
Dried rhizomes & roots of Rheum palmatum (Polygonaceae)
Active Ingredients: mixture of complex anthraquinone glycosides. Aglycone classification
Noncarboxyllated chrysophanol, aloe-emodin, emodin & physcion
COOH-containing e.g. rhein
Anthrones & dianthrones of the above
Hetero-dianthrones of anthrones
Tannins of rhubarb responsible for mild activity

14. Raponticin: A stilbene glucoside from Rheum raponticum, R
Raponticin: A stilbene glucoside from Rheum raponticum, R. undulatum; estrogenic action, treatment of menopausol symptoms; Alzheimer’s disease(?)

15. Senna Folium
Dried leaves of Cassia angustifolia or Cassia senna = C. acutifolia (Fabaceae)
Sennosides A-D
Sennosides A & B (Homodiantrone)
Sennosides C & D (heterodianthrone)
Sennosides A & B are ingredients of many products in the market

16. Senna fructus Dried fruit of C. senna or C. angustifolia
Same active ingredients as leaves in addition to rhein dianthrones containing up to 10-sugar molecules
Milder laxative than leaves