Flavonoid (Part 1) PDF

02 Flavonoids (part 1) Suphattra Sangmalee Faculty of Pharmacy, Thammasat University  1 Flavonoids Definition : group of polyphenolic compounds which are...

02 Flavonoids (part 1) Suphattra Sangmalee Faculty of Pharmacy, Thammasat University  1 Flavonoids Definition : group of polyphenolic compounds which are found in fruits, flowers, seeds and vegetable ส ดไ ด้ เหลือง - แหล Flavonoids (named from the Latin word flavus meaning yellow, their colour in nature) are a class of plant secondary metabolites They are more common in higher plants being abundant in families ; Polygonaceae, Rutaceae, Leguminosae, Umbelliferae and Compositae กั สี 2  Flavonoids 3 Physiological role: องกันพ ช จากแพลง , ต ภ Ø Role in plant defense mechanism – they have a very limited role in this respect due to their low toxicity when compare with other plant secondary metabolites such as alkaloids ให เ อ พช อ แม ้ Ø They are the pigments of flowers and attract pollinating insects Ø They play a role in plant growth control by inhibiting and activating enzymes ศั ริ ป้ สี ล่ ก่ รู  Flavonoids 4 Structure of flavonoids The flavonoids are possessing 15 carbon atoms; two benzene rings joined by a linear three carbon chain the skeleton can be represented as the C6 – C3 – C6 system ตรงกลา งเ อม 3 อะต ชื่  Flavonoids 5 The -C3- may be included through an oxygen bond between the two phenyl rings into : 23 ต ัวจะ = น ส าง 8 bo 1. A five membered heterocyclic ring (furan) 2. A six membered heterocyclic ring (pyran) as in aurones to give flavonoids which constitute the ~ า งแล้วเป่น 6 เห ่นม (P ็น 5 เห ส า งแล้วกล ลายเป ่ยม ( largest group =flavonoid aurones flavan ร้ ร้ ลี ลี กั ร้  ้ พบ ได ้ง glyc agly con Flavonoids 6 Flavonoids occurs as aglycones, glycosides and methylated derivatives The flavonoids aglycone consists of a benzene ring : (A) condensed with a six membered ring (C) pyran ring, which in the 2-position carries a phenyl ring (B) as a substituent The flavonoid glycosides ต าลม ารกา 23 Glycosides = aglycone (non-sugar part) + glycone (sugar part) When glycosides are formed, the glycosidic linkage can be located in positions 3 and 7 and may be L-rhamnose, D-glucose, ต galactose or arabinose น้ น้ ที่ ทั ำ ำ Flavonoids 7 Classification of flavonoids Flavonoids are divided into six main subclasses according to their chemical structure: flavones, isoflavones, flavanones, flavonols, flavan-3-ols (flavanols), and anthocyanins Flavonoids are often conjugated to either an acid or a sugar moiety [glycoside]  8 Flavonoids biosynthesis The initial step in the biosynthesis of most Acetate-malonate pathway Shikimate pathway flavonoids is the condensation of p-coumaroyl- ไ CoA molecule (shikimate derived, B ring and C ring! ไ ring g 3,- ring) with three molecules of malonyl-CoA ~ าน I pathway เ อบสมบ enZ. (acetate-malonate pathway, A ring) to give chalcone. This reaction is carried out by the :flavonone จ -สม ร enzyme chalcone synthase (CHS). อ งใช้ 2 Pathw 2 ใ สม enz. น พา Chalcone is subsequently isomerized by the ๆ เ ดเป่นหลลาย อน enzyme chalcone flavanone isomerase (CHI) to flavanone. From these central intermediates, the pathway diverges into several side branches, each yielding a different class of 3 อา จอ. flavonoi ม ring flavonoids ด้ ต้ กิ กื ด้ ด้ ผ่ บู บู อื่  ไ สม ร ณ์ แ เ น prec Flavonoids : 9 flavonoid งห 1. chalcones & dihydrochalcones / ของ chalcones are the precursors of all flavonoids chalcone skeleton contains two aromatic rings linked by an aliphatic three-carbon chain The two rings of chalcone are interconnected by a highly electrophilic three-carbon α, β-unsaturated carbonyl system that assumes linear or nearly planar structure chalcone dihydrochalcone B A ring & ง ด ไ ยั ป็ ปั ม่ ม่ ทั้ ต่ บู  บใน ตร ลสัม,พ Flavonoids : /พ 10 · 2. flavanones & flavanonols (dihydroflavonols) The flavanones are the first flavonoid products of the flavonoid biosynthetic pathway flavanones present mainly in citrus fruits, are characterized by a 2,3-dihydro-2- phenylchromen-4-one structure, with the pyran ring of non-planar flavanones antioxidant E.g. hesperidin, naringenin, isosakuratenin, and heridictyol flavanone flavanonol (dihydroflavonol) ring & วไ พิ พ่ ยั กุ ชั ส์ พั  Flavonoids : 3. anthocyanidins / anthocyanins 11 anthocyanins are colored water-soluble pigments belonging to the phenolic group พ บใน ก, ผลไ ไ แด ง, อง (ตร ลb anthocyanins responsible for the colors, red, purple, and blue, are in fruits and vegetables Berries, currants, grapes, and some tropical fruits have high anthocyanins content Red to purplish blue-colored leafy vegetables, grains, roots, and tubers are the edible vegetables that contain a high level of anthocyanins ต้ พั กุ ส์ ม่  Flavonoids : 3. anthocyanidins / anthocyanins 12 aglycone ( glycoside Anthocyanidins are common plant pigments, the sugar-free counterparts of anthocyanins Anthocyanins, the pigments are in glycosylated forms  Flavonoids : 3. anthocyanidins / anthocyanins 13 ไว อแสง , temp, PH, enz., 02 (sensitive Stability of anthocyanins is dependent on เส ยร & ค คง ว the type of anthocyanin pigment, pelargonidin copigments, light, temperature, pH, metal (orange to red) ions, enzymes, oxygen, and antioxidants เ ่ > กจ. hyd r oxyl มห รถทน ท Anthocyanidinʼs stability is also influenced by the B-ring in the anthocyanidin structure cyanidin and the presence of hydroxyl or methoxyl (red to magenta) าม์ OH อย จ - งห อง ่งม groups เ มO 1 07 จ.แด ง ง ชา กค ค งต ว on มาก ๆ จ - า, More hydroxy groups, give more blue shade colour delphinidin These groups are known to decrease (magenta to purple) anthocyanidin stability in a solution ต่ ด้ นั ที มู่ บั ล้ ตั ยั ม่ ต็ ฟ้ น้ ตั สิ่ พิ่ ถี  Flavonoids : 4. flavones & flavonols 14 Flavones apigenin They are colorless or yellow molecules that accumulate mainly in the outer and aerial parts 2-phenyl- -benzopyrone (leaves and skin), and act as co- pigment in many plants ของ anthrocyanidin ( แ precursor Flavonols quercetin (ไ ่ม apigenin, luteolin, kaempferol, quercetin, myricetin 3-hydroxy-2-phenyl- -benzopyrone มีสี ม่  Flavonoids : 5. isoflavonoids 15 2 isoflavonoids are a class of flavonoid polyphenolic compounds with 3- 3 phenylchroman backbone These are a well-known group of ฤทธ phytoestrogens abundantly produced in 3-phenylchroman leguminous members via a branch of general phenyl propanoid pathways มrbeton 2 isoflavonoids and their derivatives are sometimes vos Cring referred to as phytoestrogens, as many isoflavonoid compounds have biological effects isoflavonoids via the estrogen receptor ทีี่  16 Flavonoids : 6. proanthocyanidins ได่มี Leucoanthocyanidins is a flavan-3,4-diol derivative The name originates from the acid hydrolysis during which anthocyanidins are formed and a red color appears ม ion ไว เลข sensitive อ อง-ขภ นอก acid Leucoanthocyanidins า= บกรด จ.กลาบ anthocyanidin ท่ ป้ ส์ กั ต่  Flavonoids : 6. proanthocyanidins 17 enz. เป ่ย ANS Leucoanthocyanidins ANS Anthocyanidins Anthocyanidin Synthase gene = ANS Anthocyanins ลี่  Flavonoids : 7. catechins 18 trav (+)-catechin Catechin is a polyhydroxy flavan-3-ol structure, 2 part of the chemical family of flavonoids 3 There are also two chiral centers within this molecule, carbons 2 and 3, respectively ci (-)-epicatechin Isomers of the molecule in a trans positioning, called catechin, while the other in a cis configuration, called epicatechin  Flavonoids : 8. biflavonoids =Vit & 19 biflavonoids are a class of flavonoids, which consist of flavonoid dimers formed by the covalent bond (C-C or C-O-C) between two mono-flavonoids ผล ก. ให 2 ผล ก. เ อ แบบ C- C C- 8 - - ชื่  20 Test of Flavonoids Chemical tests commonly performed for detection of flavonoids involve 4 types of reactions: 11. Shinoda test 2 2. Pew test 33. Lead acetate test 4.4 Anthocyanins test  Test of Flavonoids 21 1. Shinoda test 1 mL of dry powder/ extract in 95% ethanol (5mL) sensitive for flavonoids that เต contain -benzopyrone nucleus + 0.5 g Magnesium ribbons flavones, flavanones and + few drops conc. HCl dihydroflavonols observed for appearance of pink to red color =flavonoi  Test of Flavonoids 22 Shinoda test reduction General flavone backbone Anthocyanidin skeleton Yellow colour Pink to red colour สาร ส ด ช กั พื  Test of Flavonoids 23 2. Pew test 1 mL of dry powder/ extract in 95% ethanol (5mL) Similar to Shinoda test but the + 0.5 g Zinc dust zinc was used in the reaction + few drops conc. HCl instead of Mg sensitive for dihydroflavonols observed for appearance of pink to red color  Test of Flavonoids 24 Small amount of extract 3. Lead acetate test (residue from Shinoda test) ทดสอ บ า ไอ บ flavonoid ทุกก sensitive to all flavonoids + lead acetate solution Formation of intense yellow colour, which becomes colourless on addition of 1% hydrochloric acid solution, indicates the presence of Observed for appearance of flavonoids าน างข ของ Yellow colored precipitation ตกตะกอ นงห อ ด้ กั ง่ ล้ ล่ Test of anthocyanins 25  Test of anthocyanins 26 ไอ อ ! เห อ ง รถาง ส ชมพ เ red purple blue องเข The stability of anthocyanin and its color changes in different pH conditions In acidic condition, anthocyanin appears as red pigment while blue pigment anthocyanin exists in alkaline condition ต่ ม่ฝ่น้ ม่ ำ ลื  Test of anthocyanins 27 pH 8-9 pH 7-8 pH 6-7 pH 1-3  Test of Flavonoids 28 4. Anthocyanins test ญ ัญม นาว -> ีบ สนา ว ( เ มกรด) => ปป บ Ethanol extract from petals or other parts + HCl (acidic) or + NH4OH (alkaline) Compared the color before & after อั ติ ชั  Any Questions ???