PH1125 - Natural Products

Question 1

what are natural products?

Answer 1

• organic molecules biosynthesized by living organisms

Question 2

what are secondary metabolites?

Answer 2

• molecules not directly essential to the function/survival of the organism they are isolated from

Question 3

what do natural products provide in terms of drug development?

Answer 3

• the lead compound

Question 4

what is phytochemistry?

Answer 4

• the study of single molecules extracted from a plant

Question 5

what are alkaloids?

Answer 5

• large class of nitrogen-containing natural products very well known for their medicinal properties

Question 6

what are the chemical properties of alkaloids? (3)

Answer 6

• always contain nitrogen
• often basic (although varies and can be neutral at physiological pH)
• often white crystalline solids when pure

Question 7

what are examples of alkaloids? (4)

Answer 7

• nicotine
• quinine
• atropine
• caffeine

Question 8

how do tropane alkaloids work? (2)

Answer 8

• 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

Question 9

what is morphine? (2)

Answer 9

• well known alkaloid natural product

- classifies as isoquinoline alkaloid but has undergone further biosynthetic chemistry

Question 10

what contains many medicinally important alkaloids?

Answer 10

• opium; a latex produced by the opium poppy

Question 11

what is the problem with morphine as a treatment of pain/analgesic?

Answer 11

• in is very addictive and causes euphoria

Question 12

what are polyketides?

Answer 12

• large class of natural products formed by condensation of acetate monomers

Question 13

what is a biological form of acetate?

Answer 13

• acetyl CoA

Question 14

what effect does senna have on body?

Answer 14

purgative effect by increasing gut motility

Question 15

what are sennosides metabolised to?

Answer 15

• rhein and aglycone believed to be the active species

Question 16

what is doxorubicin?

Answer 16

• polyketide derivative isolated from the bacterium Streptomyces peucetius

Question 17

what is doxorubicin used for?

Answer 17

• broad spectrum anti-cancer drug

Question 18

what reaction do polyketides readily undergo?

Answer 18

• aldol reactions
  The aldol reaction is used to join two identical aldehydes or ketones together (dimer), or two different aldehydes or ketones (crossed-aldol).

Question 19

what is erythromycin used for?

Answer 19

• antibiotic often used in penicillin-resistant patients

Question 20

what is tetracycline? (2)

Answer 20

• widely used antibiotic

- originally isolated as a trace molecule from Streptomyces aureofaciens

Question 21

what is amphotericin B and why is it IV treatment? (2)

Answer 21

• anti-fungal drug

- used for life threatening diseases which are harder to kill due to fungi being eukaryotic and same cell types as us

Question 22

what are the difference from natural products and herbal medicine? (2)

Answer 22

• natural products are single molecules

- herbal medicines are a mixture of many compounds

Question 23

what is the drug substance of herbal medicines?

Answer 23

dried, unprocessed plant material

Question 24

what is st johns wort used for?

Answer 24

• herbal medication used for mild to moderate depression

Question 25

what is a significant problem for st johns wort medication?

Answer 25

- drug interactions with prescribed drugs

Question 26

what is paclitaxel? (3)

Answer 26

- 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

Question 27

what are terpenoids?

Answer 27

- built from isoprene building blocks

Question 28

what is an excellent biological leaving group?

Answer 28

- pyrophosphate

Question 29

how are terpenoids classified?

Answer 29

- they are classified by the number of carbon atoms in their structure

Question 30

what is monoterpene geraniol?

Answer 30

- fragrant volatile oil produced by many plants and used commercially in perfumery

Question 31

what is menthol? (2)

Answer 31

- isolated from peppermint | - its volatile properties are widely used in medicine for cold relief

Question 32

what is fusidic acid? (2)

Answer 32

- steroidal antibiotic produced be a fungus | - narrow spectrum but can be applied topically

Question 33

what is paclitaxel? (3)

Answer 33

- 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

Question 34

what are terpenoids?

Answer 34

naturally occurring organic chemicals | - built from isoprene building blocks

Question 35

what are the intermediates used in terpenoid biosynthesis? (2)

Answer 35

- isopentene-OPP | - dimethylallyl-OPP

Question 36

how are terpenoids classified?

Answer 36

- they are classified by the number of carbon atoms in their structure

Question 37

what is monoterpene geraniol?

Answer 37

- fragrant volatile oil produced by many plants and used commercially in perfumery

Question 38

what is menthol? (2)

Answer 38

- isolated from peppermint | - its volatile properties are widely used in medicine for cold relief

Question 39

what is a precursor for steroids?

Answer 39

- squalene

Question 40

what is fusidic acid? (2)

Answer 40

- steroidal antibiotic produced be a fungus | - narrow spectrum but can be applied topically

Question 41

why do carbohydrates have excellent water solubility?

Answer 41

- they contain many hydroxyl groups that can readily form hydrogen bonds with water

Question 42

what is a glycoside?

Answer 42

- generally used to describe any natural product that contains an additional carbohydrate group

Question 43

what are O-glycosides?

Answer 43

- natural products containing a sugar bonded via an oxygen atom

Question 44

what is digoxin solubilized by?

Answer 44

- the very non-polar (hydrophobic) steroid portion of the drug is solubilized by the polar hydrophilic O-glycoside