Page 29 - Medicinal Plants_PharmD general

V. Storage of medicinal plants

Storage and preservation of plant crude drugs need sound knowledge
of their physical and chemical properties. A good quality of the drugs can
be maintained, if they are preserved properly. There are several factors that
must be taken in consideration during storage. These factors are:

1. Moisture

The moisture, not only increases the bulk of the drug, but also causes
impairment to the quality of crude drug. The excessive moisture
facilitates enzymatic reactions resulting in decomposition of active
constituents e.g. digitalis leaves. Gentian and ergot receive mould
infestation due to excessive moisture. To control the risk, moisture must
be eliminated either from the herbs or from the atmosphere. Medicinal
herbs must be dried thoroughly, until they contain only 10-12%
moisture, which is considered to be the safe percentage. 15% moisture
content is permissible in the case of roots (radices) or sugar-containing
herbs. Storehouses must be clean and well-aired. Quicklime, silica gel
or roasted rice are used as desiccants. Air-tight packaging is desirable,
wooden boxes, drums and earthenware jars being used.

2. Temperature

The optimum temperature for medicinal herb storage is 2-8 °C, they can
also be stored at room temperature 25 °C. High temperature evaporates
the essential oils contained in herbs and also decomposes lipid-
containing herbs, giving them a sharp bitter taste. Storage places must
be well-ventilated. When stored, herbs must be periodically moved,
sorted and graded.

3. Radiation due to direct sun-light also causes destruction of

active chemical constituents, e.g. ergot and digitalis.

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