Lecture 9

Question 1

Where do drug leads often come from?

Answer 1

Terrestrial plants, marine organisms, microorganisms

Question 2

What techniques can be used to extract bioactive compounds?

Answer 2

Various techniques (more details in Lecture 14)

Question 3

What methods are used for characterization of natural products?

Answer 3

NMR, mass spectrometry, IR spectroscopy

Question 4

How do natural products (NPs) compare to conventional synthetic drugs?

Answer 4

NPs are complex and chemically diverse

Question 5

What are typical characteristics of natural products?

Answer 5

Higher molecular mass, more sp3 carbons, fewer nitrogen/halogens, more H-bond donors/acceptors, greater rigidity

Question 6

What are primary metabolites?

Answer 6

Essential for organism survival (e.g., amino acids, carbohydrates)

Question 7

What are secondary metabolites?

Answer 7

Not essential but provide advantages (e.g., defense, signaling)

Question 8

What medicinal bioactivities do secondary metabolites often have?

Answer 8

Anticancer, antimicrobial

Question 9

List the four major classes of secondary metabolites

Answer 9

• Alkaloids
• Terpenoids (Isoprenoids)
• Phenylpropanoids
• Polyketides

Question 10

What are alkaloids?

Answer 10

Contain nitrogen, often basic or neutral

Question 11

What pharmacological activities are associated with alkaloids?

Answer 11

• Analgesics (morphine)
• Antimalarials (quinine)
• Stimulants (caffeine)
• Anticancer (vincristine)

Question 12

How are alkaloids biosynthesized?

Answer 12

From amino acids via reactions like Schiff base formation

Question 13

What are terpenoids derived from?

Answer 13

5-carbon isoprene units

Question 14

What is the largest class of plant secondary metabolites?

Answer 14

Terpenoids (Isoprenoids)

Question 15

What are the two pathways for terpenoid biosynthesis?

Answer 15

• Mevalonate pathway
• Non-mevalonate pathway

Question 16

Give an example of a terpenoid

Answer 16

Paclitaxel (anti-cancer), limonene

Question 17

What are phenylpropanoids derived from?

Answer 17

Phenylalanine or tyrosine via the shikimic acid pathway

Question 18

List some examples of phenylpropanoids

Answer 18

• Lignols
• Flavonoids
• Coumarins
• Stilbenes

Question 19

What is an example of a phenylpropanoid?

Answer 19

Vanillin

Question 20

How are polyketides produced?

Answer 20

From precursors with alternating ketones via cyclization and aldol reactions

Question 21

What is an example of a polyketide?

Answer 21

Brevetoxin B (marine neurotoxin)

Question 22

What sustainability challenges exist in natural product extraction?

Answer 22

• Low natural yield of bioactive compounds
• Harvesting can harm or kill organisms
• Damage to ecosystems

Question 23

What is the natural yield of paclitaxel from Pacific yew bark?

Answer 23

<0.05%

Question 24

Why is chemical synthesis crucial for natural products?

Answer 24

To produce NPs at scale and enable drug development

Question 25

What are the three main approaches for the synthesis of natural products?

Answer 25

* Total synthesis * Semi-synthesis * Biosynthesis

Question 26

What is total synthesis?

Answer 26

Complete chemical construction from simple starting materials

Question 27

What is semi-synthesis?

Answer 27

Modification of natural products extracted from nature

Question 28

What is biosynthesis?

Answer 28

Using engineered organisms or enzymes to produce NPs

Question 29

What role do natural products often serve in drug development?

Answer 29

Lead compounds

Question 30

What is the purpose of designing structural analogues?

Answer 30

To improve efficacy, reduce toxicity, or enhance pharmacokinetics