Extracting Information from Chromatographic Herbal Fingerprints

Natural products have served mankind as a source of medicine since — and even before — historical records began. Herbal extracts now play an important and growing role in disease prevention and therapy, and are used extensively as drugs and food additives.

Compared with synthetic chemical drug compounds, the composition of herbal extracts is far more complex. Consequently, their quality control is becoming an increasingly important issue. For example, by the European legislation (directive 2004/24/EC concerning "traditional herbal medicinal products") a more strict control on the quality and purity of these products is required. This is also the case by the State Drug Administration of China. It involves, for example, the creation of a type of monograph as a guideline to test the identity and quality.

Identity and quality can be derived from fingerprint chromatograms. These fingerprints can be defined as "a chromatographic pattern of an herbal extract showing some common pharmacologically active and/or chemical characteristic compounds". An example is shown in Figure 1. The entire fingerprints are used as a source of information because by assaying only a number of compounds from the extract, the total intrinsic quality of the herb is not necessarily assessed.