Ethnobotanical Leaflets 13: 540-47 , 2009.
Histological and Physico-chemical Evaluation of Zanthoxylum nitidum Stem Bark
Sanjib Bhattacharya1*, M. Kamaruz Zaman2, Ashoke K. Ghosh1
of Pharmaceutical Sciences,
*Corresponding author: E-mail: email@example.com
Zanthoxylum nitidum (Roxb.) DC (Rutaceae), called Tez-mui in Assamese, is a large prickly shrub, and its stem bark is ethnomedicinally prescribed in North-East India for treatment of various disease conditions. Scientific parameters are not yet available to identify the exact plant material and to ascertain its quality and purity. The present investigation was therefore undertaken to determine the requisite histological and physico-chemical standards for evaluating the plant material. These studies provided referential pharmaco-botanical information for correct identification and standardization of this plant material. These information will also be helpful to differentiate Z. nitidum from the closely related other species of Zanthoxylum.
Key words: Zanthoxylum nitidum, stem bark, pharmaco-botanical, quality control.
The genus Zanthoxylum Linn
belongs to the family Rutaceae and is a large genus of aromatic prickly trees
or shrubs distributed pan-tropically and 13 species of it are found in
Materials and Methods
The fully matured entire plants of Z.
nitidum were collected during the month of November 2006 from
Reagents and chemicals
All reagents and chemicals used for
testing were analytical grade obtained from Ranbaxy Fine Chemicals Ltd.,
The transverse sections (TS) of freshly collected mature stem bark were obtained by usual techniques. Good sections were collected and observed under compound microscope. A camera lucida was attached with the microscope and the sections were suitably traced out.
Physico-chemical parameters such as the
percentage of loss on drying (
Phytochemical screening [10,11]
The dried and powdered stem bark was subjected to preliminary phytochemical screening for qualitative detection of phytoconstituents.
Preliminary phytochemical screening of methanol extract of Z. nitidum was carried out by using standard procedures described by Kokate (1994) and Khandelwal (2005).
Fluorescence analysis 
Fluorescence analysis of dried and powdered stem bark was carried out according to the procedure described by Gupta et al. (2006) by using the reagents as mentioned in Table 4 and viewed in day light, short (254 nm) and long (365 nm) ultraviolet (UV) radiations. The colours and fluorescence (if any) observed by application of different reagents in different radiations were recorded.
Results and Discussion
The TS of stem bark is shown in Fig 1. The TS exhibited a cork consisting of narrow cells. The cortex contained small starch grains, crystals of calcium oxalate, but no sclereids. After cortex there was a narrow band of pericyclic sclerenchyma. The medullary rays were numerous, mainly one cell wide. Calcium oxalate crystals were also found in the phloem. The microscopic or histological features, like presence of pericyclic sclerenchyma, absence of sclereids, etc may be useful diagnostic histological charecters.
Fig 1. Schematic diagram, TS of the stem bark.
A- cork, B- cortex, C- pericyclic sclerenchyma, D- sclerenchyma E- medullary ray.
The results of preliminary phytochemical screening are shown in Table 1. The results demonstrated presence of true alkaloids, carbohydrates and flavonoids in the stem bark extract of Z. nitidum.
Table 1. Results of phytochemical screening of methanol extract of stem bark of Z. nitidum.
+ = Present, - = Absent.
The values of all physico-chemical determinations are summarized in Table 2 and 3.Water soluble ash was found to be quite greater than acid insoluble ash value. The results showed that ethanol yielded higher extractive value. These all are important quantitative parameters for quality control of plant material.
Table 2. Loss on drying (
Table 3. Extractive values of stem bark of Z. nitidum.
The results of fluorescence analysis are summarized in Table 4. Different colours on application of different reagents on powdered stem bark were found under day light and UV light. However, no detectable fluorescence was observed.
Table 4. Fluorescence analysis of powdered stem bark of Z. nitidum.
To ensure reproducible quality of herbal products, proper control of starting material is utmost essential. Thus in recent years there have been an emphasis in standardization of medicinal plants of therapeutic potential. According to World Health Organization (WHO) the macroscopic and microscopic description of a medicinal plant is the first step towards establishing its identity and purity and should be carried out before any tests are undertaken. 
After present investigation it can be concluded that the histological and physico-chemical studies of Z. nitidum stem bark yielded a set of qualitative and quantitative pharmaco-botanical parameters or standards that can serve as an important source of information to ascertain the identity and to determine the quality and purity of the plant material in future studies. As previously mentioned, Z. nitidum being a morphologically variable species, these information will also be helpful to differentiate Z. nitidum from the closely related other species and varieties of Zanthoxylum.
The authors would like to thank Prof.
Dr. A. K. Dolui, Department of Pharmaceutical Sciences,
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