Goodman and Gilman's The
Pharmacological Basis of Therapeutics
14th Edition
Author(s)Laurence Brunton; Bjorn Knollmann
Print ISBN: 9781264258079
,Question 1
Which characteristic of medicinal plants makes them valuable starting
points for drug discovery?
A. They contain only one pharmacologically active molecule.
B. They provide structurally diverse molecules that may have biological
activity.
C. Plant-derived compounds generally have no adverse effects.
D. Plant extracts can be administered clinically without further
evaluation.
,Correct Answer: B. They provide structurally diverse molecules that
may have biological activity.
Rationale:
B is correct because medicinal plants contain chemically diverse natural
products that can interact with biological targets and provide starting
points for identifying drug leads. Natural products have historically
contributed important pharmacologically active compounds.
A is incorrect because plants usually contain numerous constituents,
not a single active molecule.
C is incorrect because natural origin does not eliminate toxicity, adverse
effects, or drug interactions.
D is incorrect because an active plant extract still requires isolation,
characterization, efficacy assessment, and safety evaluation before
therapeutic use.
Question 2
In the context of drug discovery, what is a lead compound?
A. A compound that has already received regulatory approval
B. A molecule selected for further optimization because it shows
promising biological activity
C. A formulation designed to improve patient adherence
D. A metabolite that is always responsible for drug toxicity
Correct Answer: B. A molecule selected for further optimization
because it shows promising biological activity.
Rationale:
B is correct because a lead compound is a promising molecule identified
during discovery that can undergo chemical modification to improve
, potency, selectivity, pharmacokinetic properties, and safety.
A is incorrect because regulatory approval occurs much later than lead
identification.
C is incorrect because formulation development addresses drug delivery
rather than defining a lead compound.
D is incorrect because metabolites are not inherently toxic and are not
synonymous with lead compounds.
Question 3
A researcher isolates several individual molecules from a medicinal
plant extract after demonstrating that the extract has antibacterial
activity. What is the primary purpose of this isolation step?
A. To determine which constituent may be responsible for the biological
activity
B. To guarantee that the active molecule will be clinically effective
C. To eliminate the need for pharmacokinetic studies
D. To establish that all isolated molecules have identical mechanisms
Correct Answer: A. To determine which constituent may be responsible
for the biological activity.
Rationale:
A is correct because isolating constituents permits individual
compounds to be tested so that biological activity can be associated
with specific chemical entities. This can lead to identification of a
candidate or lead molecule.
B is incorrect because laboratory activity does not establish clinical
effectiveness.
C is incorrect because pharmacokinetic evaluation remains essential for
understanding absorption, distribution, metabolism, and elimination.