**8.7 Chromatographic methods**

High Performance Liquid Chromatography (HPLC), Capillary Electrophoresis (CE) and Thin Layer Chromatography (TLC) are the most commonly used analytical techniques for the profiling of herbal products [45]. Beside these, gas chromatography (GC) can be used for the analysis of volatile components in herbal medicines [46].

## *8.7.1 Thin layer chromatography (TLC)*

TLC is the earliest of chromatographic methods employed for the separation of plant constituents. As the herbal extract is a combination of hundreds of components that are responsible for its activity, it is very important to separate those components and study each of them individually. TLC provides first characteristic fingerprints of herbs. The main advantages of using TLC to develop the fingerprint or chemical profile of herbal medicines are its simplicity, versatility, high velocity, specific sensitivity, simple sample preparation and its economy. Thus TLC is a convenient method to determine the quality and possible adulteration of herbal products [47].

### *8.7.2 High performance liquid chromatography (HPLC)*

After TLC, HPLC has become the most popular method for the analysis of herbal medicines. Though it is more complex than TLC, but still easier to learn and use and is not limited by the volatility or stability of the sample compound as is the case with GC. In general HPLC can be used to analyze almost all the compounds in herbal medicines [48]. HPLC can be linked to various detectors like UV detector, Refractive index detector and Mass Spectrometric (MS) detector that can help in knowing the exact chemical makeup of the components.

#### *8.7.3 Gas chromatography (GC)*

Volatile oils and other thermally unstable components that cannot be detected by HPLC technique can be detected by GC. The extraction of the volatile compounds or oils is relatively simple and can be standardized and the components can

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*Herbal Drugs Forensic*

*DOI: http://dx.doi.org/10.5772/intechopen.98253*

**8.8 Chemical fingerprinting**

**8.9 Molecular markers**

ate DNA polymorphisms [54–56].

**9. Conclusion**

be readily identified using GC–MS analysis. The advantages of GC lie in its high sensitivity of detection for almost all the volatile chemical compounds [46].

and purification methods, structure elucidation and purity determination.

Molecular markers are the constituents that include primary and secondary metabolites and other macromolecules like nucleic acids. DNA as a marker can be a reliable instrument as it is in cases of disputed identity of human beings, in establishing the genetic makeup and polymorphisms of each species [51]. The main advantage associated with DNA is that, it can be extracted from both fresh and dried organic tissue of the botanical material and thus is not restricted by the physiological nature of the sample to be assessed [52, 53]. Various types of DNA based molecular techniques such as hybridization based methods, polymerase chain reaction (PCR) based methods and sequencing based methods are utilized to evalu-

This chapter has provided an overview of trends and conditions relating to medicinal plants, their production, markets and malpractices. It is never possible to include each and every detail, data and analysis related to medicinal plants in a single chapter. Thus, the chapter is initial effort to increase awareness of both the potentials and problems associated with medicinal plants and its industry. Substitution of herbs can never be eliminated as with more and more dependence on ASU drugs, more than 300 medicinal plants have become red listed. So, in order to achieve constant supply of botanical drugs, experts must find suitable substitute in a regulated manner. Substitution in a well-defined manner may provide a greater scope for the physicians to utilize herbs that are easily available, cost effective and most appropriate for the clinical condition. The need of substitution should always be separated with the intention to substitute and adulterate in order to make more profits. Not all adulterations are intentional. Sometimes it is the lack of awareness of the suppliers about the spurious materials, their toxic effects, confusion in name, non-availability and lack of knowledge about authentic plant may also result in adulteration and substitution. WHO, in its publication on quality standards for medicinal plant materials, recommends rejecting any batch of raw material, which has more than 5% of any other plant part of the same plant (e.g. stem in leaf drugs), never the less if they are derived from the authentic plant. Based on these standards, adulteration whether, intentional or unintentional, should be rejected. In order to

A chemical fingerprinting is a unique pattern just like human fingerprints which is unique for every individual, which indicates the multiple chemical markers within a sample [49]. The European Medicines Agency (EMEA) defines chemical markers as chemically defined constituents, or group of constituents of herbal medicinal product which are of interest, regardless whether they possess any therapeutic activity [50]. Such chemical markers are critical in identification and authentication of the plants from which they are derived. The quantity of a chemical marker is proportional to the quality of herbal medicine. The study of chemical markers is applicable to many research areas, including authentication of genuine species, search for new resources or substitutes of raw materials, optimization of extraction

be readily identified using GC–MS analysis. The advantages of GC lie in its high sensitivity of detection for almost all the volatile chemical compounds [46].
