Goodman and Gilman's The
Pharmacological Basis of Therapeutics
14th Edition
Author(s)Laurence Brunton; Bjorn Knollmann
Print ISBN: 9781264258079
,Question 1
A research group investigates a medicinal plant traditionally used to
relieve severe pain. Chemical fractionation identifies a single purified
molecule that reproduces the analgesic effect of the original extract.
What is the most important immediate implication for drug discovery?
A. The purified molecule should automatically be considered an
approved drug
,B. The molecule provides a chemically defined starting point for further
pharmacological investigation
C. The entire plant extract is preferable because purification removes
synergistic activity
D. Clinical trials can begin without additional characterization of the
molecule
Correct Answer: B
Rationale:
B is correct because isolation of a pharmacologically active constituent
converts a complex natural source into a defined chemical entity that
can be studied for mechanism, activity, safety, and drug-like properties.
This is an important conceptual transition from empirical use of
medicinal plants toward systematic drug discovery.
A is incorrect because demonstration of biological activity does not
establish regulatory approval.
C is incorrect because purification can be essential for identifying the
active principle and determining its properties, even though whole
extracts may sometimes contain multiple active constituents.
D is incorrect because characterization, preclinical evaluation, and
appropriate development steps are required before clinical testing.
Question 2
A compound isolated from a natural source produces a reproducible
biological effect in a laboratory assay. Investigators modify several
chemical groups on the molecule and observe that some modifications
increase activity while others reduce it. Which concept is being
explored?
, A. Structure–activity relationship
B. First-pass metabolism
C. Therapeutic drug monitoring
D. Bioequivalence
Correct Answer: A
Rationale:
A is correct because a structure–activity relationship examines how
deliberate changes in chemical structure influence biological activity,
potency, selectivity, or related properties. This information helps
researchers identify structural features important for activity and guides
optimization.
B is incorrect because first-pass metabolism concerns loss of drug
during absorption through the gastrointestinal tract and liver.
C is incorrect because therapeutic drug monitoring concerns
measurement of drug concentrations to help guide therapy.
D is incorrect because bioequivalence compares drug exposure
between pharmaceutical products rather than examining chemical
modifications of a lead molecule.
Question 3
A pharmaceutical laboratory wants to evaluate 200,000 chemically
diverse compounds for activity against a purified enzyme using an
automated assay. Which approach is most appropriate?
A. High-throughput screening
B. Phase I clinical testing
C. Postmarketing surveillance
D. Manual isolation of every compound from medicinal plants