Page 19 - Medicinal Plants_PharmD general

II. Harvesting and collection of medicinal plants

Collection is the most important step which comes after cultivation.
Drugs are collected from wild or cultivated plants. Several factors must be
taken into consideration during harvesting and collection such as:

1. The type of drug to be harvested

The specific plant species and part must be identified properly for
collection. Also, the pharmacopoeial standards which it needs to be
achieved must be strictly followed. Sometimes, it is very difficult to
collect the exact medicinally valuable parts so the official
pharmacopoeias have indicated in each monograph a certain amount of
foreign matter that is permissible to remain in the collected drug.
Selectivity is an advantage where the drugs other than genuine one, but
similar in appearance can be rejected at the site of collection. It is,
however, a laborious job and may not be economical. The collected
plant material must be authenticated.

2. The time (season) of harvest

It depends on the plant part to be used. Detailed information concerning
the appropriate timing of harvest is often available in national
pharmacopoeias, published standards, official monographs and major
reference books. Drugs should be collected when they contain
maximum amount of constituents. The season at which each drug is
collected is so important, as the amount, and sometimes the nature, of
the active constituents could be changed throughout the year. It is well
known that the concentration of biologically active constituents varies
with the stage of plant growth and development. This also applies to
non-targeted toxic or poisonous indigenous plant ingredients. The best

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