INTRODUCTION:

The use of natural gums and mucilage as important part of formulation is with the development of pharmacy and different dosage forms. As general exicipients for oral use, eg. in tablets and capsules etc. the options are limited¹. The prospects of natural polymers are brighter but even here extensive testing will be required. The synthetic polymers have certain disadvantages such as high cost, toxicity, environmental pollution during synthesis, non-renewable sources, side effects, less patient compliance, etc². While the advantages of natural plant based materials include low cost, natural origin, free from side effects, bioacceptable, renewable source, environmental-friendly processing, local availability (especially in developing countries), better patient tolerance as well as public acceptance, from edible sources, etc³.

Mucilages are polysaccharide complexes formed from sugar and uronic acid units. mucilages form slimy masses in water, are typically heterogeneous in composition. Upon hydrolysis, arabinose, galactose, glucose, mannose, xylose and various uronic acids are the most frequently observed components. Mucilages are obtained mainly from rhizomes, seeds or other plant parts.

Some are obtained from marine algae, and from selected microorganisms⁴. In present study the rhizomes of Eulophia herbacea were selected for the isolation of mucilage. The seeds of Eulophia herbacea also known as Kukad-kand in Marathi, contain a high proportion of mucilage and it also being used for different therapeutic purposes⁵. The plant exudates (Acacia, karaya, and Tragacanth) have been the traditional gums for pharmaceutical purposes and they still find significant applications. These gums are labour intensive and carry premium price and their use will probably continue to decline⁶. However there are no reports on isolation and characterization of mucilage of Eulophia herbacea Lindl. Hence, the present study is planned to isolate and characterize mucilage of Eulophia herbacea Lindl.

MATERIAL AND METHOD:

Materials:

The fresh Eulophia herbacea rhizomes were collected from plants growing in hilly region of Nandurbar, India. The plant was authenticated at the Botany Department of M. J. College, Jalgaon, India. Ethanol (95%), Acetone, trichloro acetic acid, sodium hydroxide and diethyl ether were procured from Space Lab, Nashik. All other chemicals used were of analytical grade and double distilled water was used throughout the experiments.

Extraction of mucilage:

The fresh Eulophia herbacea rhizomes were collected and washed with water. The rhizomes were crushed and soaked in water for 5–6 hours, boiled for 30 minutes and left to stand for 1 hour to allow complete release of the mucilage into the water. The mucilage was extracted using a multi-layer muslin cloth bag to remove the marc from the solution. Acetone (in the volumes of three times to the volume of filtrate) was added to precipitate the mucilage. The mucilage was separated, dried in an oven at 40°C, collected, ground, passed through a # 80 sieve and stored in desiccator at 30°C and 45% relative humidity till use ^7-9.

Table 1: Taxonomical Classification of Eulophia herbacea Lindl.

Kingdom	Plantae
Division	Magnoliophyta
Class	Liliopsida
Order	Asparagales
Family	Orchidaceae
Genus	Eulophia

Table 2. Physicochemical Characteristics of mucilage from Eulophia herbacea Lindl.

Sr. No.	Tests	Observations
1.	Description	Yellowish white powder.
2.	Solubility	Forms colloidal solution, soluble in luck warm water, Practically insoluble in ethanol, acetone, ether and chloroform.
3.	Odour	Characteristic
4.	Appearance	Amorphous
5.	*Identification* : a) Mounted in 96% ethanol b) Mounted in ruthenium red c) Mounted in Iodine solution.	Transparent angular masses. Particles stained red. Particles stained blue.
6.	Melting range	Decomposes above 2000c
7.	PH (1%w/v)	Neutral.
8.	Loss on drying	4%
9.	Ash value	3.8%
10.	Acid insoluble ash.	0%
11.	Swelling index	17
12.	Test for Carbohydrate (Mollish test)	+
14.	Test for chloride (Silver-nitrate test)	_
15.	Test for Sulphate (Barium chloride test)	_
16.	Uronic acid test	+
17.	Test for foreign matter	NMT 0.1 %
18.	Test for heavy metal as lead.	25-30 ppm.
19.	Test for Arsenic.	Less than 1 ppm.

+ Present. – Absent

Purification of the Mucilage:

The crude mucilage (1 %) was homogenized (Potter homogenizer) with cold dilute trichloro acetic acid solution (5%). The solution was centrifuged (3500 rpm for 20 min), neutralized with sodium hydroxide by drop wise addition and then dialyzed for 30 hours against distilled water. The mucilage was precipitated with ethanol (in the quantities of three times the volumes) and washed successively with ethanol, acetone and diethyl ether. The mucilage so obtained was dried under vacuum (less than 1 Torr at 25°C for 12 hour). The so obtained mucilage was passed through a # 80 sieve and stored in desiccator at 30°C and 45% relative humidity till use^{10, 11.}

Characterization of Mucilage:

Physical characterization:

The collected mucilage was evaluated for physical characteristics^{12, 13}viz., Appearance, Odour, Solubility, percentage yield, average particle size, swelling ratio, weight loss on drying, pH, Charring, density and bio burden.

Table 3. Data showing the different ash values of seeds of Eulophia herbacea Lindl.

Sr . No.	Types of Ash	Ash Value in %w/w
1	Total ash	3.8 %
2	Acid insoluble ash	0 %
3	Sulphated ash	0.83

Chemical characterization:

The extracted mucilage was tested for chemical characteristics for identification, test for Carbohydrate,btest for Tannins, test for chloride, test for sulphate, test for Uronic acid. The mucilage was also tested for unwanted chemicals^12,
13., foreign matter, heavy metal and Arsenic.

Table 4. Physicochemical characteristics of mucilage of seeds of Eulophia herbacea Lindl.

Sr. No.	Parameter	Result
1	Solubility	Soluble in warm water, Practically insoluble in ethanol, acetone, ether, and chloroform
2	Swelling index in distilled water	17.0
3	Loss on drying	4%
4	Angle of repose	27⁰
5	Bulk density	0.64 gm/cc
6	Tapped density	0.86 gm/cc
7	Carr index (%)	25.58
8	Hausner ratio	1.34

Flow properties:

The dried Eulophia herbacea rhizomes mucilage was tested for the flow properties¹⁴ viz., Angle of repose, Bulk densities, compressibility index and Hausner’s ratio. All these evaluations were carried out as per procedures describe in official books.

Fourier Transform Infrared (FTIR) Spectroscopy:

FTIR spectrums of dried mucilage were recorded on samples prepared in potassium bromide (KBr) disks using FTIR spectrophotometer 1601 PC (Shimadzu, Tokyo, Japan). Samples were prepared in KBr disks using a hydrostatic press at 6-8 tons pressure. The scanning range was 500 to 4000 cm-1.

RESULT AND DISCUSSION:

The mucilage is isolated by dissolving in water and precipitating in 90% alcohol and dried at room temperature, total yield of mucilage by alcohol precipitation was found to be 14gm % W/W. The morphological and physical evaluatory study of isolated mucilage shows, it is yellowish white powder, with characteristic odour and amorphous in nature. When dissolved in water, it gives neutral, colloidal solution; it is soluble in luck warm water, practically insoluble in ethanol, acetone, ether and chloroform. Moisture content of mucilage was found to be 4 % was found to be within official limit.. Mucilage decomposes above 2000c, which is a characteristic of most of the polysaccharide. The foreign matter in this mucilage was found to be not more than 0.1 and the heavy metal as lead were found to be25-30 ppm Arsenic was found to be Less than 1 ppm. The swelling index was found to be 17. And ash values as total ash, acid insoluble ash and sulphated ash 3.8, 0 and 0.83% respectively, the 0% of acid insoluble ash value indicate the absence of sandy material. The isolated mucilage were studied for it’s physicochemical parameters such as angle of repose, density. The angle of repose indicated that the powder was having good flow. The bulk density and tapped density of mucilage was found to be 0.64 and 0.84 gm/cc. The result of chemical test shows presence of carbohydrate, uronic acid which are general constituent of mucilage. While the absence of Tannins, chloride and sulphate, shows the purity of mucilage.

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Received on 14.07.2011 Modified on 23.07.2011

Research J. Pharm. and Tech. 4(10): Oct. 2011; Page 1615-1617