Pharmacognosy and Natural Products
Pharmacognosy and Natural Products tests medicinal plant identification, phytochemistry, extraction, standardization and the safe use of traditional medicines. Cambodia’s exam context includes medicinal plants used in community practice and quality concerns around herbal products.
Core rules
- Authentication uses macroscopic and microscopic features, organoleptic characters and, where needed, DNA or chemical fingerprinting.
- Major phytochemical classes include alkaloids, glycosides, tannins, flavonoids, terpenoids and saponins. Solubility and extraction solvent follow from polarity.
- Standardization should use a defined marker or active constituent, a reproducible extraction method and a validated assay; a marker is not always the active compound.
- Traditional medicine products need correct identification, contamination checks and clear labelling; adulteration with synthetic drugs is a major safety risk.
Worked example
50 g of dried leaf is extracted and yields 4.5 g of dried extract. Percentage extractive = 4.5/50 × 100 = 9.0% w/w. If the specification requires 8–12%, the batch passes. If the starting material were fresh leaf, the result would not be comparable unless moisture were measured and corrected.
Traps
- Comparing extractive values from fresh and dried material without moisture correction.
- Assuming the highest marker content means the best clinical product.
- Confusing a decoction with a tincture or infusion.
- Ignoring adulteration or heavy-metal/microbial contamination in herbal products.