Coumarins and Related Compounds Coumarins are derivatives of benzo--pyrone, or lactones of o-hydroxycinnamic acid (o-coumaric acid). The parent compound is coumarin, umbelliferone is the 7-OH derivative of Coumarin. The glycoside of umbelliferone is called skimmin. These compounds are used to protect skin from UV light as they absorb short wave length (280- 366 nm).

Dicoumarol Uses: anticoagulant and rodenticide. It is a phytoalexin (phytochemical antibiotics) formed due to fungal effect on Melilotus officinalis (Red Clover), an example of microbial transformation. It is a dimer of 4-hydroxycoumarin that is now produced synthetically under the trade name of Dicoumarol. Uses: anticoagulant and rodenticide.

Furanocoumarins They are coumarin derivatives with additional furan ring. Ammi majus contain a group of furanocoumarins, the parent compound is called Psoralene. They are used for the treatment of psoriases and leucodermia.

Furanochromones They are benzo--pyrone derivatives resist alkalis. Ammi visnaga contain furanochromones, the major is Khellin. Khellin is a smooth muscle relaxant used as: Bronchodilator. Antispasmodic. Renal colic. Coronary vasodilator. Khellin

Flavonoidal Glycosides Flavonoids are C-15 compounds (C6-C3-C6) Flavonoids, constitute one of the most diverse and widespread group of natural products. They are one of the most important constituents of the human diet. They are found in fruits, vegetables, nuts, seeds, stems, flowers and common drinks e.g. tea. Flavonoids bind to a range of cellular receptor sites and show a wide range of biological activities. They are classified into many groups based on the oxidation level at ring C. They are benzo--pyrone derivatives, so not open by alkalis. They are responsible for the colours of flowers and fruits.

General Tests of flavonoids: Yellow colour with Alkalis. Yellow colour with AlCl3. Blue colour with FeCl3.!!! Biological properties: -Antibacterial, antifungal, antioxidant, hepato-protective, anti-inflammatory, cytotoxic, anti-tumor, anti-ulcer, for capillary fragility (vasotonic, vasoprotective), spasmolytic Pharmaceuticals: Remanal jel®, Daflon® tablets, Ruta C®, Diosmin tablets,……..

1- Diosmin Source: Buchu leaves (Barosma betulina). Nature: Flavone glycoside. Uses: varicose veins (vasoprotective, for capillary fragility))

2- Hesperidin Source: Citrus fruits. Nature: Flavanone glycoside. Uses: varicose veins (vasoprotective, for capillay fragility)

3- Rutin Source: Ruta graveolens (family Rutaceae) Nature: Flavonol glycoside. Uses: Cold, Influenza, varicose veins (vasoprotective). Essential for vit C absorption.

4- Genistein and Genistin Source: Andria spp. (Genistein) Genista and Lupinus spp., Soy bean Nature: Isoflavone & it Glycoside. Uses: Estrogenic activity, antioxidant, anti-aging

5- Anthocyanidin Source: Grape and Berries. Nature: Anthocyanidins (aglycones), cyanins (glycosides), color depend on PH of cell sap.. Uses: Antioxidant, coloring matter

6- Rotenone Source: Derris Roots. Nature: Isoflavanone derivatives. Uses: Insecticides (interfere with oxidative phosphorylation).

7- Amentoflavone Source: Ginkgo biloba, Nature: Bioflavones. Uses: Antioxidant, Enhance cerebral circulation- Delaying diabetic cataract and Diabetic neuropathies.

Flavano-lignans 1- Silymarin Source: Silybum marianum. Nature: Condensation product of flavanone with hemilignans. Silymarin is a mixture of isomers the major isomer is Silybin. Uses: Very effective hepatoprotective and antihepatotoxic agent.

Mechanism of Action of silymarin: Antioxidant, so protect liver cells from free radicals. Stimulate liver cell regeneration. Anti-fibrotic and anti-cirrhotic activity.

Lignans 1- Podophyllotoxin Source: Podophyllum Rhizomes. Nature: Lignan derivatives. Lignans are C18 compounds resulted from condensation of two hemilignans C9. Uses: Anticancer. Treatment of skin warts

Etoposide podophyllotoxin (Semisynthetic derivative)

Side Effects of podophyllotoxin: GIT upset, Nausea and Vomiting. Semisynthetic Derivatives: Etoposide: Lung and testicular cancer Teniposide: Leukaemia and brain cancer in children.