Parameters for Quality Control Microscopic Evaluation

Parameters for Quality Control Microscopic Evaluation
Quality control of herbal drugs has traditionally been based on appearance and to-
day microscopic evaluation is indispensable in the initial identification of herbs, as
well as in identifying small fragments of crude or powdered herbs, and detection
of foreign matter and adulterants. A primary visual evaluation, which seldom
needs more than a simple magnifying lens, can be used to ensure that the plant is
of the required species, and that the right part of the plant is being used. At other
times, microscopic analysis is needed to determine the correct species and/or that
the correct part of the species is present. For instance, pollen morphology may be
used in the case of flowers to identify the species, and the presence of certain mi-
croscopic structures such as leaf stomata can be used to identify the plant part
used. Although this may seem obvious, it is of prime importance, especially when
different parts of the same plant are to be used for different treatments. Stinging
nettle (Urtica urens) is a classic example where the aerial parts are used to treat
rheumatism, while the roots are applied for benign prostate hyperplasia