Goodman and Gilman's The
Pharmacological Basis of Therapeutics
14th Edition
Author(s)Laurence Brunton; Bjorn Knollmann
Print ISBN: 9781264258079
,Question 1
A research team is investigating a plant traditionally used by local
communities to relieve inflammatory symptoms. Which step most
directly represents the starting point of a medicinal-plant drug-
discovery program?
A. Determine the crystal structure of the presumed drug target
B. Identify and characterize potentially active constituents from the
,plant
C. Optimize the lead compound for oral bioavailability
D. Conduct a phase III randomized clinical trial
Correct Answer: B
Rationale:
B is correct because medicinal-plant drug discovery commonly begins
by identifying potentially bioactive constituents through extraction,
fractionation, isolation, and biological testing. This establishes which
chemical components may contribute to the observed biological
activity.
A is incorrect because structural studies of a target usually occur after a
relevant biological target has been identified.
C is incorrect because lead optimization occurs later, after an active
compound or lead has been identified.
D is incorrect because phase III trials are conducted much later during
clinical development after extensive preclinical and earlier clinical
evaluation.
Question 2
What is the primary purpose of bioassay-guided fractionation during
natural-product drug discovery?
A. To determine the maximum tolerated dose in humans
B. To identify which chemical fraction is responsible for the observed
biological activity
C. To predict the clinical efficacy of the entire plant extract
, D. To determine the molecular structure of every compound in the
extract
Correct Answer: B
Rationale:
B is correct because bioassay-guided fractionation repeatedly separates
a complex mixture while testing fractions for biological activity, allowing
investigators to track activity toward the active constituent or
constituents.
A is incorrect because human maximum tolerated dose studies occur
during clinical development rather than initial fractionation.
C is incorrect because activity of an extract does not establish clinical
efficacy in humans.
D is incorrect because the purpose is to identify active constituents, not
necessarily to structurally characterize every compound present.
Question 3
A compound isolated from a medicinal plant produces a reproducible
biological effect in an assay. In early drug discovery, this compound
would most appropriately be described as a:
A. Lead candidate
B. Biomarker
C. Hit
D. Registered medicine
Correct Answer: C