Introduction of Herbal Medicine and its Important

1. INTRODUCTION:

1.1 HERBAL MEDICINE AND ITS IMPORTANT
    
     Herbal Medicine is defined as branch of science in which plant based formulations are used to alleviate the diseases. It is also known as botanical medicine or phytomedicine. In the early twentieth century herbal medicine was prime healthcare system as antibiotics or analgesics were not available. With inceasing use of allopathic system of medicine, herbal medicine gradually lost its popularity among people and it was based on the fast therapeutic actions of synthetic drugs. Almost a century has passed and it has witnessed limitations of allopathic system of medicine. Lately herbal medicine has gained momentum and it is evident from the fact that certain herbal remedies are more effective as compare to synthetic drugs.

     Substances derived from the plants remain the basis for a large proportion of the commercial medications used today for the treatment of heart disease, high blood pressure, pain, asthma, and other problems. For example, ephedra is a herb used in Traditional Chinese Medicine for more than two thousand years to treat asthma and other respiratory problems. Ephedrine, the active ingredient in ephedra, is used in the commercial pharmaceutical preparations for the relief of asthma symptoms and other respiratory problems. It helps the patient to breathe more easily.

     Another example of the use of a herbal preparation in modern medicine is the foxglove plant. This herb had been in use since 1775. At present, the powdered leaf of this plant is known as the cardiac stimulant digitalis to the millions of heart patients it keeps alive worldwide.

1.2 SCOPE OF THE HERBAL THERAPY AND INDIAN HERBAL MARKET

     Traditional Indian practice held that certain drugs should be formulated through the addition of chosen substances that enhances bioavailability of anti-TB drug RIFAMPICIN. Formulation of piperine with rifampicin will save the drug counter effects.

     Herbal oriented pharmaceutical companies are investing crores of rupees on researching, developing and popularizing OTC remedies. India can be a major player in the global market for herbal product based medicines. Exports of herbal materials and medicines can jump from just Rs. 456 crore in 2000 to Rs.3000 crore in 2005 and with a “grand strategic plan” exports can shoot to Rs.10,000 crore by 2010.

1.3 THE SIGNIFICANCE OF QUALITY FOR EFFICACY AND SAFETY OF  
    HERBALDRUGS     
                                                                                                                                     
The efficacy and safety of any pharmaceutical product is determined by the compounds (desired and undesired) which it contains. The purpose of quality control is to ensure that each dosage unit of the drug product delivers the same amount of active ingredients and is, as far as possible, free of impurities. As herbal medicinal products are complex mixtures which originate from biological sources, great efforts are necessary to guarantee a constant and adequate quality. By carefully selecting the plant material and a standardized manufacturing process the pattern and concentration of constituents of herbal medicinal products should be kept as constant as possible as this is a prerequisite for reproducible therapeutic results.

     The major problem in quality control is the batch to batch variations in the quality of medicinal plants. This is mainly due to the existence of ecotype pharmacological variations in the case of many medicinal plants. Therapeutic value of medicinal plants could differ depending on soil conditions, nutritional status, climatic conditions, seasonal variations, diurnal variations and their association with other organisms.


2. STANDARDISATION OF HERBS
     
     The World Health Assembly emphasized the need to ensure quality control of medicinal plants with appropriate moral techniques and suitable standards, as it is estimated that about 80% of the people living in developing countries mainly depend upon herbal drugs for their preliminary health care needs. So, to deliver a good quality and safe medication standardization of hers and formulations is become very important. WHO gives different quality control parameters to standardize the raw material as well as finished products.

     For the standardization and quality assurance purposes three attributes viz. authenticity, purity and assay are desirable. Authenticity corresponds to the right identity which involves many parameters like morphology, microscopy, and chemical analysis. Purity pertains to evaluating that there are no adulterants present in the plant material. It can be evaluated by pharmacognostic evaluations like qualitative and quantitative microscopy, physical constants like, ash values, extractive values etc. Assay part of standardization is chemical and biological profiling by which the chemical and biological effects could be assessed and curative values get established. Chemical assay gives the quantitative evaluation of active constituents by using different techniques like HPTLC, HPLC, and Spectroscopy etc. In biological assays the drug activity is evaluated through a pharmacological model. For example the effectiveness of hepatoprotective drugs can be evaluated by its action on liver. 

2.1 Problems in standardization:

Problems in standardization arises form the complex chemical composition of herbal drug. Standardization of certain marker compound of herbal drug in general does not serve the purpose of standardization since activity of drug does not depend upon one or few components. In most of the cases, it is the result of concerted activity of several active compounds as well as of inert accompanying substances. Though these inert components do not directly affect the activity of drug, they might influence bioavailability and excretion of active component/s. Further, these inert components may also play a role in the stability of the active component and minimize the rate of side effects. If there are several active components present in a herbal drug, they may have additive or potentiating effect. The quantity of the active constituents may influence by several factors such as age and origin, harvesting period, and so on. To eliminate at least some of the causes of inconsistency, in terms of active ingredients, it was suggested that one should use cultivated plants rather than wild plants which are often heterogeneous with respect to the above factors and consistently in their content of active principles.

2.2 Standardization of finished products:

The process of standardization of finished product starts with the standardization of the raw materials. Certain parameters have been listed in different pharmacopoeias, Including Ayurvedic pharmacopoeia of India, WHO standards are Organoleptic, Microscopic examination, Morphology, Moisture Content, Foreign Matter, Ash Values, Bitterness Values, Hemolytic Index, Foaming Index, Volatile Matter, Pesticide Residue, Microbial Contamination, Metal Analysis, Radioactive Contamination and Chromatographic Evaluation are required for maintaining the quality of herbal raw material.

After the standardization of the raw material, next step is to monitor the process of preparation of the formulation and set parameters for in house quality control testing and finally the standardization of the finished product. Quality assurance of the herbal product relies upon good manufacturing facilities with adequate batch analysis and standard methods for preparation. Various processes use in the manufacture of the herbal drugs lacks standardized methods. Large scale commercialization of herbal drugs necessitates scientifically evolved standardized methods of plant drug production.

2.3 Standardization of herbs using marker compound analysis:
Every herb has a range of chemical constituents, which are produced as a result of metabolic activity in the plant. These compounds either alone or their combination are mainly responsible for the pharmacological activities or therapeutic action in the human body. Hence it would be more practical to test for the presence of these compounds. For example, Ashwagandha (whithania somnifera) can be assayed for whethanolides, Guggul (Commifora mukul) for guggulusterones, Neem (Azadirachta indica) for azadirachtine or nimbidine, Harida (Curcuma longa) for curcuminoids. For testing purpose these compounds are refered to as bio marker compounds. On the other hand, where the chemical composition of the herbs has been worked out but it is not clearly established whether these chemical entities are responsible for some particular action, any compound which is predominantly present in the herbs can be utilized as marker compound for the purpose of standardization. This group represents compounds like aegelin in Bilva (Aegle marmelose), Shatavarine in Shatavri (Asparagus racemosus), Fistuline in Aragvadha (cassia fistul )

One of the best methods of the standardizing herbs and herbal formulation based on the modern scientific tool is using chromatography. It helps not only in the establishing the current identity but also in regulating chemical sanctity of the herbs. For quantitative work HPLC is preferred generally. This is used mainly for volatile compound like essential oils and perfumes. In the past few years, HPTLC has emerge as a potential tool for rapid and efficient analysis of extract of herbal drugs and formulations.