Course 2 Anthocyanins PDF

Pharmacognosy Secondary Metabolite Enseignant Intervenant : Pr. Ikrame Zeouk Élément de Module: pharmacognosy Chapitre: Anthocyanins Semestre: 5 CHAPITRE 2 Anthocyanins Faculté Euromed de Pharmacie Course outline : ❑Anthocyanins - Definition - Di...

Pharmacognosy Secondary Metabolite Enseignant Intervenant : Pr. Ikrame Zeouk Élément de Module: pharmacognosy Chapitre: Anthocyanins Semestre: 5 CHAPITRE 2 Anthocyanins Faculté Euromed de Pharmacie Course outline : ❑Anthocyanins - Definition - Distribution throughout the plants - Physico-chemical properties - Chemical structure and classification - Biological properties - Anthocyanin- rich plants (of therapeutic interest) Faculté Euromed de Pharmacie  ANTHOCYANINS I. Definition Anthocyanins are water-soluble pigments responsible for the red, purple, or blue coloration of flowers, fruits, and sometimes leaves. They are found in nature only in the form of glycosides (anthocyanosides). Their aglycones (anthocyanidins) are derivatives of the 2-phenylbenzopyrylium cation, or flavylium cation.  ANTHOCYANINS II. Distribution and localization in the plant Rare in Gymnosperms, widespread in several families of Angiosperms. They are characteristic of flower petals (mallow, poppy, hibiscus…) and fruits (cherry, eggplant, elderberry…), but can also be found in certain leaves (red vine) and roots (radish, red onion). They are localized in the vacuoles of epidermal cells.  ANTHOCYANINS III. Chemical structure Anthocyanidins are derivatives of the 2-phenylbenzopyrylium cation, or flavylium cation. They are most often hexasubstituted : Hydroxyl (-OH) Methoxy (-OCH3) − Aglycones, sugars, glycosides.  ANTHOCYANINS III. Chemical structure Genin Color R1 R2 Genin Pelargonidin Orange-Red H H Cyanidin Red OH H Peonidin Pink OCH3 H Delphinidin Bleue-Purple OH OH Petunidin Purple OCH3 OH Malvidin Mallow OCH3 OCH3  ANTHOCYANINS III. Chemical structure Sugars : are most often glucose or rhamnose, and sometimes xylose or galactose. Glycosides: Mono: The sugar is attached to C3 of the aglycones. Bi: The second sugar is linked at C5, and exceptionally at C7.  ANTHOCYANINS IV. Physicochemical properties The flavylium core is a weak dicarboxylic acid and an electrophile, depending on the pH of the medium : In strongly acidic conditions (pH < 4): The cation is stable and colored red. In weakly acidic conditions (pH between 4 and 6): The cation is blue. In neutral conditions (pH > 7): The cation is unstable and becomes colorless. Anthocyanosides are soluble in alcohol and water but insoluble in non-polar organic solvents. Anthocyanosides are sensitive to oxidation, temperature, and light.  ANTHOCYANINS V. Extraction, characterization and quantification  ANTHOCYANINS VI. Pharmacological properties & uses Anthocyanosides : ▪ ttt of vascular diseases (venous insufficiency…), ▪ Promote the regeneration of retinal purple ➔ increased visual acuity, ▪ They have vitamin P properties: they increase capillary resistance and decrease their permeability, ▪ Anti-edematous properties, ▪ Antioxidant, antibacterial and antiviral properties.  ANTHOCYANINS VI. Pharmacological properties & uses Anthocyanoside drugs are used in nature, in the preparation of pharmaceutical forms, or in the isolation of pure anthocyanosides effective for the symptomatic ttt of disorders related to venolymphatic insufficiency and capillary fragility (phlebology, proctology, and gynecology). Anthocyanosides are used in the food industry as natural and non-toxic colorants (beverages, jams, confectionery) (E163).  ANTHOCYANINS VII. Anthocyanin-rich plants 1. Red vine : Vitis vinifera F/ Vitaceae; Woody plant with a creeping stem equipped with tendrils. Cultivated for its edible cluster fruits. Seed → Grape seed oil (dietary).  ANTHOCYANINS VII. Anthocyanins drugs 1. Red vine : Vitis vinifera Drug : Leaves ▪ Tannins → Venotonics ▪ Anthocyanin Pigments « Malvidin » Vitamin P  ANTHOCYANINS VII. Anthocyanins drugs 2. Blackcurrant : Ribes nigrum F/ Saxifragaceae Drug : Leave and fruit, Indigenous shrub with lobed leaves, drooping flower clusters, and fruits consisting of globular black berries.  ANTHOCYANINS VII. Anthocyanins drugs 2. Blackcurrant : Ribes nigrum Fruit: Diet and treatment of capillary fragility. ▪ Anthocyanosides → Rutin, cyanidin and delphinidin ▪ Essential oil, riche in vitamin C. Leave : Diuretic and anti-rheumatic.  ANTHOCYANINS VII. Anthocyanins drugs 3. Blueberry : Vaccinium myrtillus F/ Ericaceae Drug : fruit Fruit: A small blackish-purple berry when ripe.  ANTHOCYANINS VII. Anthocyanins drugs 3. Blueberry : Vaccinium myrtillus Fruit: ▪ 0.5% anthocyanins: Myrtillin (derivative of delphinidin). ▪ Industrial extraction of anthocyanins. Ttt of capillary fragility, Association with beta-carotene → ttt of night vision disorders « DIFRAREL* ».