,
,A research team investigates a medicinal plant traditionally used to
relieve inflammatory symptoms. An extract of the plant reduces the
production of a proinflammatory mediator in a laboratory assay. Which
approach is most appropriate for identifying the constituent responsible
for this activity?
A. Administer the crude extract to patients to determine its therapeutic
effectiveness.
B. Use bioassay-guided fractionation to separate the extract and test
each fraction for activity.
C. Select the most abundant chemical constituent without further
biological testing.
D. Assume that all constituents in the extract contribute equally to the
observed activity.
Correct Answer: B. Use bioassay-guided fractionation to separate the
extract and test each fraction for activity.
Rationale:
• A is incorrect: Human administration before adequate
characterization and safety evaluation is inappropriate. Laboratory
activity alone does not establish clinical benefit or safety.
• B is correct: Bioassay-guided fractionation combines chemical
separation with repeated biological testing. Researchers can
progressively narrow the extract to fractions containing the active
constituent and subsequently isolate and characterize it.
, • C is incorrect: The most abundant constituent may be
pharmacologically inactive, whereas a minor constituent may
produce the observed biological effect.
• D is incorrect: Constituents can differ substantially in activity, and
some may be inactive, antagonistic, or responsible for unwanted
effects.
Question 2
A purified compound isolated from a plant extract produces a
reproducible biological response. Before researchers can reliably
investigate its mechanism of action and develop it as a potential drug
lead, which step is most important?
A. Determine its chemical identity and establish its purity.
B. Increase the dose until the maximum biological response is observed.
C. Immediately formulate the compound for commercial distribution.
D. Assume that its traditional source establishes its long-term safety.
Correct Answer: A. Determine its chemical identity and establish its
purity.
Rationale:
• A is correct: Chemical identification and purity assessment help
establish which molecule produces the observed effect. They also
reduce the risk of attributing activity to contaminants or other
compounds in the sample.
,A research team investigates a medicinal plant traditionally used to
relieve inflammatory symptoms. An extract of the plant reduces the
production of a proinflammatory mediator in a laboratory assay. Which
approach is most appropriate for identifying the constituent responsible
for this activity?
A. Administer the crude extract to patients to determine its therapeutic
effectiveness.
B. Use bioassay-guided fractionation to separate the extract and test
each fraction for activity.
C. Select the most abundant chemical constituent without further
biological testing.
D. Assume that all constituents in the extract contribute equally to the
observed activity.
Correct Answer: B. Use bioassay-guided fractionation to separate the
extract and test each fraction for activity.
Rationale:
• A is incorrect: Human administration before adequate
characterization and safety evaluation is inappropriate. Laboratory
activity alone does not establish clinical benefit or safety.
• B is correct: Bioassay-guided fractionation combines chemical
separation with repeated biological testing. Researchers can
progressively narrow the extract to fractions containing the active
constituent and subsequently isolate and characterize it.
, • C is incorrect: The most abundant constituent may be
pharmacologically inactive, whereas a minor constituent may
produce the observed biological effect.
• D is incorrect: Constituents can differ substantially in activity, and
some may be inactive, antagonistic, or responsible for unwanted
effects.
Question 2
A purified compound isolated from a plant extract produces a
reproducible biological response. Before researchers can reliably
investigate its mechanism of action and develop it as a potential drug
lead, which step is most important?
A. Determine its chemical identity and establish its purity.
B. Increase the dose until the maximum biological response is observed.
C. Immediately formulate the compound for commercial distribution.
D. Assume that its traditional source establishes its long-term safety.
Correct Answer: A. Determine its chemical identity and establish its
purity.
Rationale:
• A is correct: Chemical identification and purity assessment help
establish which molecule produces the observed effect. They also
reduce the risk of attributing activity to contaminants or other
compounds in the sample.
