The efficacy of some herbal products is beyond doubt, the most recent examples being Artemisia Annua (artemesinin), Taxus Brevifolia (taxols) and Silybium marianum (Silymarin). Hypericum Perforatum (hypericin & hyperforin), Allium Sativum (allicin or allin), Ginkgo biloba (Ginkgolic acid) are popularly used herbal remedies among people. All these herbals are standardized for active constituent. Standardization means adjusting the herbal drug preparation to a defined content of the active constituent. Extract refers to a concentrated preparation of active constituent of a medicinal herb. The concept of standardized extracts definitely provides a solid platform for scientific validation of herbals.
Another concept sweeping the herbal drug industry is identification of marker compounds in the extract. Markers constitute chemically defined constituents, which are used for control purpose. Markers may or may not have therapeutic activity. The markers can serve as a powerful tool in the finished form of herbal drug preparations, which depends upon the quantitative determination of the marker, when the starting material is selected. Hypericum perforatum (St John”s wort) is recent example for an extract, where marker compound (hypericin) and therapeutic constituent (hyperforin), both are known.
Phytochemistry deals with the determination of chemical constituents in plant material. Chemical analysis of the plant material is a critical factor for standardization. Techniques like High Performance Liquid Chromatography (HPLC), Gas Chromatography (GC) and High Performance Thin Layer Chromatography (HPTLC) are commonly used for chemical finger print analysis. Standardized extracts provide a consistent and effective alternative to crude drugs, as they constitute calculated ratio of the active constituents. The concept of standardization is now being widely welcomed and it is a rational way to increase the acceptance of medicinal herbs among the physicians and patients.
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