Pharmacognosy and Natural Products
Pharmacognosy and Natural Products tests botanical identity, phytochemistry, extraction, standardization, and the safety of plant-derived medicines. The exam connects traditional use with analytical quality and clinically important herb-drug interactions.
Core rules
- Correct botanical identification uses genus, species, and plant part; different parts can have different constituents.
- Primary metabolites support growth; secondary metabolites such as alkaloids, terpenoids, and phenolics often mediate activity.
- Standardization quantifies a marker or active constituent, but a marker is not always the therapeutic component.
- Extraction depends on solvent polarity, temperature, and plant matrix; water, ethanol, and supercritical CO2 extract different profiles.
- Herbal products can induce or inhibit drug-metabolizing enzymes and transporters.
Worked example
A 500 mg capsule is labeled as containing extract standardized to 3% ginsenosides. The labeled marker content is 500 x 0.03 = 15 mg ginsenosides per capsule. If the label instead states 500 mg of a 10:1 extract, the calculation is different: 500 mg extract represents 5 g dried herb equivalent, but marker content still needs an assay. The reasoning is to separate extract mass, herbal equivalent, and marker dose rather than treating all three as the same number.
Traps
Do not assume natural means safe or free of interactions. Do not confuse the marker compound with the active constituent. Do not accept a Latin name without checking the plant part. Do not ignore adulteration, heavy metals, pesticides, or microbial contamination. St John's wort is a classic inducer of CYP3A4 and P-glycoprotein and can reduce concentrations of many drugs.