PH1125 - Natural Products Flashcards
what are natural products?
- organic molecules biosynthesized by living organisms
what are secondary metabolites?
- molecules not directly essential to the function/survival of the organism they are isolated from
what do natural products provide in terms of drug development?
- the lead compound
what is phytochemistry?
- the study of single molecules extracted from a plant
what are alkaloids?
- large class of nitrogen-containing natural products very well known for their medicinal properties
what are the chemical properties of alkaloids? (3)
- always contain nitrogen
- often basic (although varies and can be neutral at physiological pH)
- often white crystalline solids when pure
what are examples of alkaloids? (4)
- nicotine
- quinine
- atropine
- caffeine
how do tropane alkaloids work? (2)
- they are competitive with acetylcholine for binding to muscarinic receptors in smooth muscle
- this blocks the nerve impulse and hence causes the muscle to relax
what is morphine? (2)
- well known alkaloid natural product
- classifies as isoquinoline alkaloid but has undergone further biosynthetic chemistry
what contains many medicinally important alkaloids?
- opium; a latex produced by the opium poppy
what is the problem with morphine as a treatment of pain/analgesic?
- in is very addictive and causes euphoria
what are polyketides?
- large class of natural products formed by condensation of acetate monomers
what is a biological form of acetate?
- acetyl CoA
what effect does senna have on body?
purgative effect by increasing gut motility
what are sennosides metabolised to?
- rhein and aglycone believed to be the active species
what is doxorubicin?
- polyketide derivative isolated from the bacterium Streptomyces peucetius
what is doxorubicin used for?
- broad spectrum anti-cancer drug
what reaction do polyketides readily undergo?
- aldol reactions
The aldol reaction is used to join two identical aldehydes or ketones together (dimer), or two different aldehydes or ketones (crossed-aldol).
what is erythromycin used for?
- antibiotic often used in penicillin-resistant patients
what is tetracycline? (2)
- widely used antibiotic
- originally isolated as a trace molecule from Streptomyces aureofaciens
what is amphotericin B and why is it IV treatment? (2)
- anti-fungal drug
- used for life threatening diseases which are harder to kill due to fungi being eukaryotic and same cell types as us
what are the difference from natural products and herbal medicine? (2)
- natural products are single molecules
- herbal medicines are a mixture of many compounds
what is the drug substance of herbal medicines?
dried, unprocessed plant material
what is st johns wort used for?
- herbal medication used for mild to moderate depression
what is a significant problem for st johns wort medication?
- drug interactions with prescribed drugs
what is paclitaxel? (3)
- terpenoid produced by the yew tree
- it is used to treat ovarian, breast and other solid cancers
- it is too complex to synthesize and is currently produced by biotechnology
what are terpenoids?
- built from isoprene building blocks
what is an excellent biological leaving group?
- pyrophosphate
how are terpenoids classified?
- they are classified by the number of carbon atoms in their structure
what is monoterpene geraniol?
- fragrant volatile oil produced by many plants and used commercially in perfumery
what is menthol? (2)
- isolated from peppermint
- its volatile properties are widely used in medicine for cold relief
what is fusidic acid? (2)
- steroidal antibiotic produced be a fungus
- narrow spectrum but can be applied topically
what is paclitaxel? (3)
- terpenoid produced by the yew tree
- it is used to treat ovarian, breast and other solid cancers
- it is too complex to synthesize and is currently produced by biotechnology
what are terpenoids?
naturally occurring organic chemicals
- built from isoprene building blocks
what are the intermediates used in terpenoid biosynthesis? (2)
- isopentene-OPP
- dimethylallyl-OPP
how are terpenoids classified?
- they are classified by the number of carbon atoms in their structure
what is monoterpene geraniol?
- fragrant volatile oil produced by many plants and used commercially in perfumery
what is menthol? (2)
- isolated from peppermint
- its volatile properties are widely used in medicine for cold relief
what is a precursor for steroids?
- squalene
what is fusidic acid? (2)
- steroidal antibiotic produced be a fungus
- narrow spectrum but can be applied topically
why do carbohydrates have excellent water solubility?
- they contain many hydroxyl groups that can readily form hydrogen bonds with water
what is a glycoside?
- generally used to describe any natural product that contains an additional carbohydrate group
what are O-glycosides?
- natural products containing a sugar bonded via an oxygen atom
what is digoxin solubilized by?
- the very non-polar (hydrophobic) steroid portion of the drug is solubilized by the polar hydrophilic O-glycoside
