**4. Applied plant anatomy: quality control of herbal medicine**

#### **4.1 General overview**

Plant materials are used throughout developed and developing countries as home remedies, as over-the-counter drug products, and as raw materials for the pharmaceutical industry, which represent a substantial proportion of the global drug market [29]. Thus, the traditional herbal medicines and their preparations have been widely used for thousands of years in many countries. Therefore, it is so essential to overview here some modern control histological techniques or tests, suitable standards, and practical experiences used for assessing the quality of medicinal materials and their products. Quality control of herbal medicine using histological techniques and pharmaceutical practices is also very vital for avoiding the risks happened on patients and the beliefs in services provided by traditional healers. According to [30], quality control is a phrase that refers to processes involved in maintaining the quality or validity of the manufactured products. However, the quality control of herbal medicine is beyond this, meaning it is the management of medicinal plants and their products during cultivation, identification process of the plant species with their parts and localities (their being free from polluted environment causing diseases), and medicine preparation including its components, medication processes, storage standards, and dosage; all should be taken into account. This means, without proper all-round quality control,

**103**

*Ethiopian Common Medicinal Plants: Their Parts and Uses in Traditional Medicine - Ecology…*

there is no assurance that the contents of the herbs contained in the package are the same as what are stated outside the package [30]. Climatic factors (prevailing temperature, rainfall, humidity, altitude of the growing region, light), nutritional factors (nutrients, pH, cation exchange capacity), harvesting factors (age, season, collection time, plant organ), and post-harvesting factors (storage hygiene, drying process) are the major factors affecting the contents and composition of medicinal plant raw materials and their products [29, 30]. For these, some of the most important laboratory test methods (histological techniques), common sense, and good pharmaceutical practices are used [29]. Techniques such as thin-layer chromatography and microscopic and electrophoretic techniques are widely used to evaluate the quality of herbal drugs [14, 29, 31] and the content and quality of meats [32] as well. These techniques and good pharmaceutical practices are also used to support the development of national standards based on local market conditions, with due regard to existing national legislation and national and regional norms [29]. Therefore, improved and currently available pharmaceutical analytical methods led to improvements in harvesting schedules, cultivation techniques, storage, product

*DOI: http://dx.doi.org/10.5772/intechopen.86202*

purity, and activity and stability of active compounds [30].

plant materials and their products, described briefly here below.

*4.2.1 Macroscopic and microscopic examinations*

**products**

for medication products.

**4.2 Major quality control methods for medicinal plant materials and their** 

Among others, thin-layer chromatography, macroscopic and microscopic examinations, gas chromatography and volatile components, and electrophoretic techniques [14, 29] are the most important quality control methods for medicinal

Herbal materials are categorized based on sensory, macroscopic, and microscopic characteristics, which are the first steps toward establishing the identity and the degree of purity of such materials, and should be carried out before any further tests undertaken, according to [29]. Therefore, to establish identity, purity, and quality, visual inspection (macroscopic examination) provides the simplest and quickest means. Herbal materials should be entirely free from visible signs of contamination such as insects, molds (fungi), and other animal contamination, including animal excreta; any soil, stones, sand, dust, and other foreign inorganic matter must also be removed before herbal materials are cut or ground for testing [29]. Moreover, plant parts used for medication with abnormal odor, discoloration, slime, or signs of deterioration should be detected to exclude them from being used

Moreover, during storage, products should be kept in a clean and hygienic place for avoiding contamination occurring; special care should also be taken to avoid formation of molds, since they may produce aflatoxins [29]. For determination of foreign matter and storage conditions, macroscopic examination can properly be employed for determining the presence of foreign matter in whole or cut plant materials. For these, common sense and good pharmaceutical practices are used. Such common senses and good pharmaceutical practices can, even, be used after laboratory tests since the test procedures cannot take account of all possible impurities in deciding whether an unusual substance not detectable by the prescribed tests can be tolerated [29]. For instance, if a sample is found to be significantly different from the specifications in terms of color, consistency, odor, or taste, it is considered as not fulfilling the requirements. However, such examination may need further microscopic examination for either rejecting or accepting their requirements.

*Summary of distributions of medicinal plants along their major habitat categories in Ethiopia.*

*Ethiopian Common Medicinal Plants: Their Parts and Uses in Traditional Medicine - Ecology… DOI: http://dx.doi.org/10.5772/intechopen.86202*

there is no assurance that the contents of the herbs contained in the package are the same as what are stated outside the package [30]. Climatic factors (prevailing temperature, rainfall, humidity, altitude of the growing region, light), nutritional factors (nutrients, pH, cation exchange capacity), harvesting factors (age, season, collection time, plant organ), and post-harvesting factors (storage hygiene, drying process) are the major factors affecting the contents and composition of medicinal plant raw materials and their products [29, 30]. For these, some of the most important laboratory test methods (histological techniques), common sense, and good pharmaceutical practices are used [29]. Techniques such as thin-layer chromatography and microscopic and electrophoretic techniques are widely used to evaluate the quality of herbal drugs [14, 29, 31] and the content and quality of meats [32] as well. These techniques and good pharmaceutical practices are also used to support the development of national standards based on local market conditions, with due regard to existing national legislation and national and regional norms [29]. Therefore, improved and currently available pharmaceutical analytical methods led to improvements in harvesting schedules, cultivation techniques, storage, product purity, and activity and stability of active compounds [30].

### **4.2 Major quality control methods for medicinal plant materials and their products**

Among others, thin-layer chromatography, macroscopic and microscopic examinations, gas chromatography and volatile components, and electrophoretic techniques [14, 29] are the most important quality control methods for medicinal plant materials and their products, described briefly here below.

#### *4.2.1 Macroscopic and microscopic examinations*

Herbal materials are categorized based on sensory, macroscopic, and microscopic characteristics, which are the first steps toward establishing the identity and the degree of purity of such materials, and should be carried out before any further tests undertaken, according to [29]. Therefore, to establish identity, purity, and quality, visual inspection (macroscopic examination) provides the simplest and quickest means. Herbal materials should be entirely free from visible signs of contamination such as insects, molds (fungi), and other animal contamination, including animal excreta; any soil, stones, sand, dust, and other foreign inorganic matter must also be removed before herbal materials are cut or ground for testing [29]. Moreover, plant parts used for medication with abnormal odor, discoloration, slime, or signs of deterioration should be detected to exclude them from being used for medication products.

Moreover, during storage, products should be kept in a clean and hygienic place for avoiding contamination occurring; special care should also be taken to avoid formation of molds, since they may produce aflatoxins [29]. For determination of foreign matter and storage conditions, macroscopic examination can properly be employed for determining the presence of foreign matter in whole or cut plant materials. For these, common sense and good pharmaceutical practices are used. Such common senses and good pharmaceutical practices can, even, be used after laboratory tests since the test procedures cannot take account of all possible impurities in deciding whether an unusual substance not detectable by the prescribed tests can be tolerated [29]. For instance, if a sample is found to be significantly different from the specifications in terms of color, consistency, odor, or taste, it is considered as not fulfilling the requirements. However, such examination may need further microscopic examination for either rejecting or accepting their requirements.

*Plant Science - Structure, Anatomy and Physiology in Plants Cultured in Vivo and in Vitro*

protecting them where they are found, propagating them in cultivated areas and home gardens, and creating awareness to the locals. Hence, following community and research-based approach is advised to save medicinal plants from their loss and

Plant materials are used throughout developed and developing countries as home remedies, as over-the-counter drug products, and as raw materials for the pharmaceutical industry, which represent a substantial proportion of the global drug market [29]. Thus, the traditional herbal medicines and their preparations have been widely used for thousands of years in many countries. Therefore, it is so essential to overview here some modern control histological techniques or tests, suitable standards, and practical experiences used for assessing the quality of medicinal materials and their products. Quality control of herbal medicine using histological techniques and pharmaceutical practices is also very vital for avoiding the risks happened on patients and the beliefs in services provided by traditional healers. According to [30], quality control is a phrase that refers to processes involved in maintaining the quality or validity of the manufactured products. However, the quality control of herbal medicine is beyond this, meaning it is the management of medicinal plants and their products during cultivation, identification process of the plant species with their parts and localities (their being free from polluted environment causing diseases), and medicine preparation including its components, medication processes, storage standards, and dosage; all should be taken into account. This means, without proper all-round quality control,

**4. Applied plant anatomy: quality control of herbal medicine**

*Summary of distributions of medicinal plants along their major habitat categories in Ethiopia.*

**102**

extinction.

**Figure 3.**

**4.1 General overview**

#### *4.2.2 Thin-layer chromatography (TLC)*

This technique is simple, can be employed for multiple sample analysis, and so has manyfold possibilities of detection in analyzing herbal medicines [14]. The report of [29] also confirmed that TLC is used for evaluating herbal materials and their preparations; particularly, it is valuable for the qualitative determination of small amounts of impurities.

#### *4.2.3 Gas chromatography (GC) and volatile components*

Many pharmacologically active components in herbal medicines are volatile chemical compounds; thereby, the analysis of volatile compounds by gas chromatography is very important in the analysis of herbal medicines [14]. GC is a useful analytical tool in the research field of herbal medicines via analyzing their volatile oils, which have a number of advantages: (1) the GC of the volatile oil gives a reasonable "fingerprint" which can be used to identify the plant and to detect the presence of impurities in the volatile oil, and (2) the extraction of the volatile oil is relatively straightforward and can be standardized, and the components can be readily identified using GC analysis [14].

#### *4.2.4 Electrophoretic method*

It is a good tool for producing the chemical fingerprints of the herbal medicines and has similar technical characteristics of liquid chromatography [14]. Electrophoretic method, especially capillary electrophoresis (CE), used in the analysis of herbal medicines, is a versatile and powerful separation tool with a highseparation efficiency and selectivity when analyzing mixtures of low-molecularmass components [14].

### **5. Conclusions**

There are various forms of medicinal plants including trees, shrubs, climbers, and herbs; of those herbal medicinal plants are dominantly used for different human and animal treatments in Ethiopia. These plants are collected mainly from riverbanks, cultivated areas, bushlands, forest, woodlands, and grasslands, among others. They are used for treatments of stomachaches, dysentery, diarrhea, asthma, cancer, evil eyes, earaches, sores of throat and gum, cough, and so on. For such treatments, these medicinal plants have specific parts used for treatment; most of them are leaves and roots. Hence, traditional medicine plays a significant role in the healthcare of the majority of the people in developing countries, including Ethiopia, and medicinal plants provide valuable contribution to this practice. However, the vegetative resources that are unique to the country, particularly used for medication, are dwindling due to continuous exploitation and pressure on the limited resources. Hence, conservation priority should be given to such medicinal plants and their habitats besides the knowledge of traditional practice of medication via designing appropriate strategies, particularly in the rural areas of the country, where there are less accessibility to clinics and hospitals with their medicines and health experts (doctors). Community- and research-based conservation mechanisms could be an appropriate approach for mitigating the problems pertinent to the loss of medicinal plants and their habitats and for documenting medicinal plants and the knowledge of traditional healers on how to prepare and provide the traditional medication to their patients. Medicinal plants should be multiplied

**105**

provided the original work is properly cited.

\* and Yohannes Moges2

\*Address all correspondence to: mogesadmasu@gmail.com

Debre Birhan University, Debre Birhan, Ethiopia

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

2 Department of Midwifery, College of Health Sciences, Debre Birhan University,

1 Department of Biology, College of Natural and Computational Sciences,

*Ethiopian Common Medicinal Plants: Their Parts and Uses in Traditional Medicine - Ecology…*

through medicinal gardens, proper handling practices, and scientific development. Moreover, for controlling the quality of medicinal plant materials and their products, chromatography, electrophoretic, macroscopic/microscopic techniques, and

The authors would like to thank Debre Birhan University of Ethiopia for its library facilitation while writing this manuscript. We also extend our thanks to Hirut Fisiha for assisting us during editing and revising of this manuscript.

The authors declare that there is no any conflict of interest between authors and

*DOI: http://dx.doi.org/10.5772/intechopen.86202*

**Acknowledgements**

**Conflict of interest**

**Author details**

Admasu Moges1

Debre Birhan, Ethiopia

other organizations as well.

pharmaceutical practices are the most important tools.

*Ethiopian Common Medicinal Plants: Their Parts and Uses in Traditional Medicine - Ecology… DOI: http://dx.doi.org/10.5772/intechopen.86202*

through medicinal gardens, proper handling practices, and scientific development. Moreover, for controlling the quality of medicinal plant materials and their products, chromatography, electrophoretic, macroscopic/microscopic techniques, and pharmaceutical practices are the most important tools.
