,Question 1
A research team investigates a plant traditionally used to relieve fever.
An extract demonstrates activity in a laboratory assay designed to
measure inhibition of an inflammatory pathway. What is the most
appropriate next step in the discovery process?
A. Recommend the plant extract for routine clinical use because its
traditional use supports efficacy.
B. Isolate and characterize the compounds responsible for the observed
biological activity.
C. Begin large-scale manufacturing of the unstandardized extract.
D. Assume that the extract's activity identifies a single compound with
an established mechanism of action.
Correct Answer: B. Isolate and characterize the compounds responsible
for the observed biological activity.
Rationale:
• A is incorrect: Traditional use can help identify promising research
candidates, but it does not establish clinical efficacy, dose, purity,
or safety.
• B is correct: Isolation and characterization help identify the active
constituents, clarify their chemical structures, and support
subsequent pharmacological evaluation.
• C is incorrect: Manufacturing an unstandardized extract before
identifying its active constituents creates problems with
consistency, reproducibility, and quality control.
, • D is incorrect: A crude extract may contain numerous active and
inactive compounds. Its observed activity does not prove that one
molecule is responsible.
Question 2
What is the principal objective of bioassay-guided fractionation during
natural-product drug discovery?
A. To determine the commercial demand for a medicinal plant.
B. To identify the plant's most abundant chemical constituent regardless
of activity.
C. To connect measurable biological activity with the chemical
constituents responsible for it.
D. To establish the clinical safety of every compound in a plant extract.
Correct Answer: C. To connect measurable biological activity with the
chemical constituents responsible for it.
Rationale:
• A is incorrect: Market demand is a commercial consideration
rather than the primary purpose of bioassay-guided fractionation.
• B is incorrect: The most abundant constituent may have little or
no relevant biological activity.
• C is correct: Researchers separate an active extract into fractions,
test the fractions, and progressively isolate and identify
compounds associated with the activity.