Page 22 - Applied Pharmacognosy
P. 22
Redefining Quality - Quality Issues with Herbs
❑ Inferiority of Medicinal Plants Pre-harvesting factors
✓ Inter- or intra-species variation in many plants, causes variation in
constituents, and may be related to the country of origin.
✓ Time of harvesting and stage of development: the concentration of
constituents in a plant can vary during the growing cycle or even during the
course of a day.
✓ Plant part used: active constituents vary between plant parts and it is
common for a herbal ingredient to be adulterated with parts of the plant not
normally utilized. Plant material previously subjected to extraction and is
therefore ‘exhausted’ is sometimes used to increase the weight of a batch
of herbal ingredient.
✓ Environmental factors such as climate, altitude, growing conditions and
soil requirements.
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