12: Phytochemicals Flashcards
phytochemicals are __________ metabolites
- essential? explain
- only found in what? vs opposite?
- which parts contain higher amount of phenolic acids? why?
- secondary metabolites
- NOT essential –> ingested and may have biological effect but not nutritionally essential
- only found in plants vs zoochemicals (only in animals)
- peels of fruits > than flesh –> to protect form invaders!
what are the 6 main phytochemical classes?
+ subclasses!
*make distinction between class and subclass during exam!
- PHENOLIC COMPOUNDS
- flavonoid pigment, anthocyanins, flavonols/flavones, tannins
- phenols/phenolic acids, phenylpropanoids, minor flavonoids, xanthones, quinine pigments - TERPENOID COMPOUNDS
- essential oils, triterpenoids and steroids, carotenoids
- diterpenoids and gibberellins - ORGANIC ACIDS, LIPIDS AND RELATED COMPOUNDS
- sulfur compounds!
- other ones - NITROGEN COMPOUNDS
- alkaloids!
- aa, amines, indoles, purines… - SUGAR AND THEIR DERIVATIVES
- not on exam: monosacs, oligosacs, sugar alcohols - MACROMOLECULES
- nucleic acids, proteins, polysacs
phenolic compounds:
- soluble in what?, located where?
- describe (2 main components)
- cool characteristic?
- water-soluble, usually located in vacuole
- wide range of plants substances which possess aromatic ring bearing one or more hydroxyl substituent (ring + OH = phenol)
- as AROMATICS, show intense absorption in UV region
flavonoid pigment = subclass of which class?
- usually present in plants bound to what?
- 2 types ish
- general structure?
- subclass of phenolic compounds
- bound to a sugar = glycoside
- glycoside vs aglycone
- 6-3-6 carbons –> general structure of 15C skeleton –> 2 phenyl rings (and and B) and a heterocyclic ring (bc there’s an O)
- occurs with various sugars attached
what are 5 flavonoid classes ish and their pigment?
- anthocyanins: scarlet, red, mauve, blue
- flavonols: colourless co-pigments in flowers, widespread in leaves
- flavones: colourless co-pigments in flowers, widespread in leaves
- flavanones: colourless, in leaves and fruit
- isoflavones: colourless, often in roots –> only common in leguminaceae
difference between flavonols and flavones? common ones for each (know examples for exam!)
FLAVONOLS:
- occur most frequently in glycosidic combinations
- kaempferol, quercetin, myricetin
FAVONES:
- differ in that they lack a 3-OH substitution –> affects their UV absorption
- apigenin (camomille) and luteolin (artichoke) corresponding to the hydroxylation of kaempferol and quercetin
describe what foods contain + activity + differences btw the 3 (ie where the OH are)
KAEMPFEROL
QUERCETIN
MYRICETIN
KAEMPFEROL
- apples, grapes, tomatoes, potatoes…
- anti –> oxidant, inflammatory, microbial, cancer, diabetic + cardioprotective, neuroprotective…
- one OH on top right aromatic ring
QUERCETIN
- capers, radish leaves, dill, cilandro, kale…
- quercetin glycosides have estrogenic activity
- 2 OH on top right aromatic ring
MYRICETIN:
- swiss chard, sweet potato leaves, lemon, blueberries, blackberries
- antioxidant/pro-oxidant activity + anticancer activity + anti-hypertensive, antiinflammatory…
- 3 OH!
what are the 2 main flavones
- structure differences to flavonols? how many OH
- what color, found where, mechanism of action
APIGENIN:
- no OH on heterocyclic ring, 1 OH on top right ring (like Kaempferol)
- no color
- parsley, celery, chamomile tea
- monoamine transport activity –> weak ligand for benzodiazepine receptors (GABA receptor) –> anxiolytic and sedative properties
- PAM on GABA receptors + acute antagonist of NMDA receptors
LUTEOLIN:
- no OH on heterocyclic ring, 2 OH (like quercetin)
- yellow pigment
- artichoke!!, celery, broccoli, green peppers…
- natural PDE4 inhibitor –> PDE4 degrades cAMP –> cAMP produces prots needed for long-term potentiation
*don’t need to know functions or example of foods… just that they are flavones
Tannins
- part of which class?
- occur widely where?
- have ability to what? –> consequence?
- what taste?
- phenolic compounds
- in plants, associated with woody tissue
- ability to react with protein –> cross-link with protein (especially when tissue is damaged/someone eats them) –> make them less accessible to digestive proteases (KNOW THIS)
- astringent taste!
what are the 2 main types of tannins? explain + subtypes + where do they occur?
*KNOW THIS
- CONDENSED TANNINS:
- occurs in ferns and connifers
- widespread woody flowering plants
- formed by condensation of single catechin or gallocatechin to form dimers and high oligomers - HYDROLYSABLE TANNINS:
- limited to dicotyledon plants (flowering plants that are NOT grasses)
a) gallic tannins (gallotannins); glucose core surrounded by 5 or more galloyl ester groups
- release glucose and gallic acid by hydrolysis at low ambien pH
b) ellagic tannins (ellagitannins); esters of hexahydroxydiphenic acid (ellagic acid) and glucose
which type of tannin has reduced astringency?
condensed tannins have reduced astringency vs hydrolysable
- condensed are naturall present in skins and seeds of grapes! –> catechins in wine!
(not) ON EXAM ?
- Coumarins –> member of what family?
- 3 most widespread coumarins in nature?
- describe compound
- serves as what?
- potentially strong what?
*is a phenolic compound but kinda à part
- benzopyrone family!
- umbelliferone, esculetin, scopoletin
- odourless crystallin solid with a sweet odour resembling scent of vanilla and bitter taste
- serves as a chemical defense against predators by inhibiting synthesis of vitamin K –> Warfarin (drug name of coumadin…) –> anti-coagulant activity
- potentially strong photocontact sensitizers (BOLD) but do not evoke phototoxic reactions
terpenoids:
all based on what molecules
- general formula? –> classification based on what?
- plays important roles in (3)
- isoprene!
- (C5H8)n –> based on n values!
- plant growth, metabolism and ecology
difference btw terpenes and terpenoids
- arranged into which functional groups? (4) (not in exam)
- give example of name
- terpene = hydrocarbon
- terpenoids: derived from terpenes but have an OXYGEN atom!
- alcohols OH (-ol), ketones C=O (-one), aldehydes CHO (-al), esters COOC (-ate or acetate)
- ie linalool = monoterpene (2 isoprene units) alcohol (bc OH)
describe number of isoprene units, number of carbons and examples
ISOPRENE
MONOTERPENOIDS
SESQUITERPENOIDS
DITERPENOIDS
SESTERTERPENOIDS
TRITERPENOIDS
TETRATERPENOIS
POLYTERPENOIDS
ISOPRENE
- 1 unit, 5C, hamamelis japonious leaves
MONOTERPENOIDS:
- 2 units, 10C, menthol or limonene
SESQUITERPENOIDS
- 3 units, 15 C: sesquiterpene lactones
DITERPENOIDS:
- 4 units, 20C: retinol (vit A)
SESTERTERPENOIDS
- 5 units, 25C, very rare in nature
TRITERPENOIDS
- 6 units, 30C: sterols, saponins
TETRATERPENOIS
- 8 units: 40C, carotenoids
POLYTERPENOIDS
- >8units, >40C, rubber
terpenoids
- water or fat soluble?
- located where?
- what is common? examples
- pigments?
- which 2 types of terpenoids have distinctive smell and odours
- fat soluble, lipid properties
- in cytoplasm! essential oils sometimes occur in glandular cells in leaf surface
- isomerism is common! ie cyclohexane ring can be in chair or boat conformation
- carotenoids are accessory pigments in photosynthesis: coloured pale yellow to bright orange to bright red
- mono (2 units) and sesquiterpenoids (3units) have distinctive smell and odours
essential oils are part of which class of phytochemicals?
- divided into 2 groups
- further divided into 5 subgroups
- terpenoids!
1. monoterpenes (C10)
2. sesquiterpenes (C15) - acyclic
- monocyclic
- bicyclic
- tricyclic
- polycyclic
- triterpene = how many C and H?
- what are 4 groups of triterpenes?
- occur where?
- has what taste?
C30H48
1. true triterpenoid
2. steroids
3. saponins
4. cardiac glycosides
- occur in waxy coating of leaves and fruit to protect from microbial attack
- has bitter taste: limonin is the bitter principle in citrus fruit
what is a true terpenoid? –> describe ish
- vs steroids? –> 2 biological roles
true terpene = squalene–> precursor of ALL plant and animal sterols, including cholesterol (true terpenoid! bc has OH) and steroid hormones
- both squalene (acyclic) and cholesterol (cyclic) are true triterpenoids/triterpene
steroids: biosynthesis of steroid hormones from cholesterol
- ie pregnenolone, progesterone, aldosterone, cortisol, estradiol…
1. contribute to membrane fluidity in all cells
2. signaling molecules
SAPONINS
- part of which class/subclass?
- what are they? describe
- what do they do?
- example
- subclass: triterpenes (class: terpenoids)
- amphipathic glycosides grouped by soap-like foam they produce when shaken in water + structurally by having one of more hydrophilic glycoside moieties combined with lipophilic triterpene or steroid derivative
- reduce surface tension of water with foaming and will break down lipids
- solanine! steroidal alkaloid saponin (in potatoes) + arolaside A, bacoside A, ginsendoside, withaferin A
cardiac glycoside
- what class/subclass?
- class of organic compounds that do what? (2) how?
- consist of a _______ molecule attached to (2)
- ex:
- terpenoid class –> triterpene subclass (C30H48)
- increase output force of heart and increase its rate of contraction by acting on cellular sodium-potassium ATPase pump
- consist of steroid molecule attached to a sugar (glycoside) and an R group
- ie digoxin from digitalis purpurea
carotenoids
- what class and subclass?
- water or lipid soluble
- 2 functions
- 2 classes
- terpenoids! tetraterpenoids (C40H64)
- lipid soluble pigment
1. pigments in flowers and fruits (orange or yellow)
2. accessory pigments in photosynthesis
1) hydrocarbons –> based on lycopene (acyclic) (8 isoprene units), no oxygen
- cyclization on 1 end = y-carotene
- cyclization on both ends = b-carotene
2) oxygenated derivatives (with OH groups!)
- lutein, rubixanthin, zeaxanthin, violaxanthin
which compounds give these colours to leaves
- green
- yellow
- orange
- red
- green: chlorophyll
- yellow: carotenoids and flavonoids (lutein, flavonol, flavone
- orange: carotenoids (b-carotene, volaxanthin)
- red: anthocyanins and carotenoids (ie lycopene)
what is the largest single class/subclass of phytochemicals?
- color? taste?
- describe
- toxic?
- absent in (3)
ALKALOIDS! (subclass) vs nitrogen compounds = class
- usually colourless and have a bitter taste
- diverse class that contains one or more nitrogen atoms, usually as part of a cyclic system
- often toxic to humans and may have dramatic physiological activities (most psychotropics are alkaloids)
- gymnosperms (conifers), ferms and mosses
what are 3 groups of alkaloids? + describe and examples
- TRUE ALKALOIDS
- contain N in heterocycle and originate from aa
- atropine, nicotine, morphine - PROTOALKALOIDS
- simple amine in which amino acid N is NOT in a heterocyclic ring (ephedrine) - PSEUDOALKALOIDS
- alkaloid-like compounds that DO NOT originate from aa
- includes terpene-like and steroid0like alkaloids, as well as purine-like alkaloids
- ie caffeine, theobromine and theophyline
name 7 subclasses of true alkaloids + describe them + examples (dont need to know examples)
*have to recognize!
- TRUE ALKALOIDS
a) pyridine alkaloid (conjugated) and piperidine alkaloid (single bond)
- piperidine is produced by hydrogenation of pyridine
- pyridine (nicotine, actinidine, arecoline)
- lobeline, piperine, coniine)
b) pyrrolizidine alkaloid (butterfly)
- presence of reactive carbon –> high level of hepatotoxicity
- senecionine/groundsel, retronecine/comfrey
c) tropane alkaloids (basket)
- tropane ring
- cocaine, atropine, scopalamine, hyoscamine, deadly nightshade)
d) quinoline alkaloid (2 aromatic rings with N on bottom)
- quinine
e) isoquinoline (2 rings + N on bottom side)
- morphine and papverine, emetine, tubocurarine, berberine…
f) indole alkaloid (2 rings: 6 + 5 with N in the 5 ring)
- strychnine, physostigmine, vincristine
g) imidazole alkaloid (5-membered ring with 2 N)
- pilocarpine
- 1 subclass of protoalkaloid + describe
- 1 subclass of pseudoalkaloid + describe
- PROTOALKALOIDS
- alkylalamine –> lack of cyclic nitrogen (N on outside tails)
ie: ephedrine (ma huang), mescaline (peyote) - PSEUDOALKALOIDS
- purine –> nitrogen-containing ring structure that resembles purines (lots of N everywhere in ring)
- ie caffeine, theobromine, theophylline
