Pharmacognostic standardization of Aralia cachemirica: a comparative study

Aralia cachemirica Decne. is an endemic and an important medicinal plant species of Kashmir Himalaya. Despite having immense medicinal importance, little information is available on the standardization parameters of the species. For this reason, present work was carried out for providing comprehensive report on the quality control and standardization parameters of A. cachemirica. In this connection, different parts (leaves, stem, and root) of the plant were examined. Methods like microscopy and macroscopy, physicochemical parameters, extractive values, and fluorescence analysis were used to establish pharmacognostical standards. The macroscopic, microscopy, and physicochemical parameters of different parts of A. cachemirica revealed various diagnostic characteristics in the species. This is the first study providing complete pharmacognostic profile of A. cachemirica and hence will be useful for correct identification and authentication of the species for future studies.


Background
Plants happen to be serving human beings as a natural source of cure for various ailments and diseases since ages. The world has seen huge increase in plant research in recent times, and numerous evidences show vast potential of medicinal plants used in various traditional systems [1]. In Ayurveda, about 2000 plant species are labeled as source of medicinal value, while in Chinese Pharmacopoeia 5700 traditional medicines are listed [2], most of which are still used in conventional medical practice [3]. These are now getting more attention than ever because they have potential of multitude benefits to society or indeed to all mankind, especially in medicine and pharmacological studies [4]. Therefore, there is a need to evaluate phytoconstituents obtained from traditional medicines, based on various phytochemical screening and pharmacological and analytical methods [5]. The World Health Organization (WHO) supports, suggests, and encourages traditional/herbal remedies in national health care programs as these drugs are easily available at low cost, safe, and people have reliance in them [6]. Proper identification, quality assurance, and establishing pharmacognostic standards are very important parameters for evaluation of medicinal plants. Macroscopic and microscopic characters, physicochemical studies, and fluorescence analysis of these are prime steps for their evaluation. According to the WHO, the macroscopical and microscopical account of a medicinal plant is the first step towards ascertaining the identity and the degree of purity of such material [6].
Despite having great medicinal importance, little information is available on the standardization parameters of A. cachemirica. Hence, present work can only be an attempt for providing comprehensive report on the quality control and standardization parameters of A. cachemirica. In this connection, different parts (leaves, stem, and root) of the plant were examined. Methods like microscopy and macroscopy, physicochemical parameters, extractive values, and fluorescence analysis were used to establish pharmacognostical standards. These parameters in turn can facilitate the quality of the drug and be helpful for the assemblage of appropriate monograph for its proper identification.

Preparation for pharmacognostic studies
Healthy and disease-free plants of A. cachemirica were collected from Ferozpur Nallah area of Jammu and Kashmir. The collected specimens were identified and deposited in Kashmir University Herbarium (KASH) under voucher number 2689-KASH. The plant collections were made quite judiciously throughout the course of the present study. The plant materials were fragmented into different parts (leaves, stem, and root) and dried under shade at room temperature for 15-20 days. After shade drying, the plant materials were pulverized to coarse powder using grinder and stored under proper conditions for future use. The pharmacognostic studies were carried out on different parts (leaves, stem, and root) separately.

Organoleptic evaluation
It refers to the evaluation of plant material by color, odor, taste, shape, texture etc. Different dried parts of A. cachemirica were considered for macroscopical evaluation [13].

Macroscopic evaluation
Fresh and healthy plants of A. cachemirica were assessed for their external characteristics.

Microscopic evaluation Anatomy
Transverse sections of fresh materials of different parts of A. cachemirica were cut with the help of sharp blades. Peels were obtained from fresh leaves by forceps. Different sections/peels were stained with safranin and observed under microscope and photographed.

Powder microscopy
For the analysis of plant powder, pinch of fine powder is taken in a test tube and boiled in chloral hydrate solution for few minutes. A few drops of powder were smeared on a slide mounted with phloroglucinol followed by few drops of concentrated HCl [13]. The prepared slides were then observed under a microscope and photographed.

Macroscopic and organoleptic description
The macroscopic and organoleptic description of various parts of A. cachemirica is presented in Tables 1 and 2 and Fig. 1a-e.

Microscopy Anatomy
The anatomical studies of different parts of A. cachemirica revealed presence of various diagnostic features as depicted in Fig. 2a-e.

Powder microscopy
The result of powder microscopy of different parts of A. cachemirica revealed many important features which are illustrated in the Fig. 3a-h.

Physicochemical parameters
The results attained from various physicochemical parameters in different parts of A. cachemirica are presented in Table 3. The detailed results of cold extraction, hot extraction, and successive extraction values are presented in Table 4. The fluorescence characteristics of powdered leaves, stem, and root of A. cachemirica were observed in visible, short, and long UV light. The observations are presented in Tables 5, 6, and  7 showing the variation in color.

Discussion
Proper identification, quality assurance, and establishing pharmacognostic standards are very significant factors for evaluation of medicinal plants. According to the World Health Organization (WHO), the macroscopical and microscopical account of a medicinal plant is the first step towards ascertaining the identity and the degree of purity of such material and should be accomplished before any tests are undertaken [6,13]. Microscopic assessment of the plant material is crucial for the detection of source materials. The anatomical attributes are employed as a criterion for unraveling the species, genera, and even families. Also, anatomy gives the idea of diagnostic features of a plant material such as cork cells, cortex, secondary phloem, and fibers which forms the vital factors for the quality control and standardization of herbal drugs [18]. Investigations of the powdered plant material offer the comprehensive structural information of the raw drugs by discovering the identified histological characters in the drugs. The powdered examination of herbal material is based on the cytomorphological parameters, for instance collenchyma, parenchyma, trichomes, vessels, and secretory cells,  and cell inclusions, viz., pollen grains, starch grains, and calcium oxalate crystals [19,20]. Physicochemical parameters are also vital for the standardization and quality control of herbal drugs which included foreign matter analysis, loss on drying, ash content, pH, swelling index, and foaming index. Herbal materials should be devoid of any kind of contamination, so foreign matter analysis of powdered drugs can be considered as an important parameter in order to check the purity of herbal drugs [21]. Loss on drying is commonly used test procedure for determination of moisture content in a powdered sample. Moisture content of drugs should be at minimal level to discourage the growth of bacteria, yeast, or fungi during storage [22]. Ash values are used to determine quality and purity of crude drug. It indicates presence of various impurities like carbonate, oxalate, and silicate. The water soluble ash is used to estimate the amount of inorganic compound present in drugs. The acid insoluble ash consist mainly silica and indicate contamination with earthy material [22]. The pH values provide information about acidic or basic nature of the chemical constituents present in the crude drug. Foaming index is seen to be less than 100 in all the parts of the select species which reveals absence or very little amount of saponins.
Swelling index indicates the presence of gums and mucilage, hemicellulose, or pectin in the natural drug [21]. Estimation of extractive values determines the amount of the active constituents in a given amount of plant material when extracted with a particular solvent. The extractions of any crude drug with a particular solvent yield a solution containing different phytoconstituents. The compositions of these chemical constituents depend upon the nature of the drug and the solvent used. It also provides an indication whether the crude drug is exhausted or not [22,23]. Fluorescence analysis is also an important pharmacognostic parameter. Some constituents show fluorescence in the visible range in daylight. The ultraviolet light produces fluorescence in many natural products which do not visibly fluoresce in daylight. If substance themselves are not fluorescent, they may often be converted into fluorescent derivatives or decomposition products by applying different reagents. Hence, crude drugs are often assessed qualitatively in this way, and it is an important parameter for pharmacognostic evaluation of crude drugs [24,25].

Conclusion
The study may possibly provide a foundation for further undertakings towards generating understanding about medicinal plants of Kashmir Himalaya. The pharmacognostic studies are the first step towards ascertaining the identity and the degree of purity of herbal materials. The pharmacognostic analysis is not reported previously in this plant species thus making this first report which provides inclusive pharmacognostic profile of A. cachemirica and thereby will be helpful for correct identification and authentication of the species for future studies.
Abbreviations WHO: World Health Organization; KASH: Kashmir University Herbarium