INTRODUCTION:

Medicinal plants have been a major source of cure for human diseases since time immemorial. It is no wonder that the world’s one-fourth population i.e. 1.42 billion people, are dependent on traditional medicines for the treatment of various ailments ¹. Medicinal herbs are moving from fringe to main stream use with a greater number of people seeking remedies and health approaches free from side effects caused by synthetic chemicals.

Recently considerable attention has been paid to utilize eco-friendly and bio-friendly plant based products for the prevention and cure of different human diseases. Considering the adverse effects of synthetic drugs, the Western population is looking for natural remedies, which are safe and effective. It is documented that most of the World’s population has taken in traditional medicine, particularly plant drug for the primary health care ² .The Indian flora offers a variety of plants having medicinal properties. These plants can be exploited to find out effective alternative to synthetic drugs ^3.

Mimosa pudica is a creeping annual or perennial herb often grown for its curiosity value, as the compound leaves fold inward and droop when touched and reopens within minutes. It belongs to the Mimosaceae family. Mimosa pudica is native to Brazil, but is now a pan tropical weed. The other names given to this plant are Humble plant, Shame plant, Touch me not (Germplasm Resources Information Network, 2008), Sleeping grass (Tropical Biological Association), Prayer plant, The species epithet “pudica” is a latin equivalent for “Bashful” or “Shrinking”, because of its curious nature and easy procreation. The stem is erect in young plants, but becomes creeping or trailing with age. The plant grows to a height of 1.5m (5 ft). The leaves are bipinnately compound, with one or two pinnae pairs and 10-26 leaflets per pinna. The petioles are also prickly and on close examination, it is seen that the floret petals are red in their upper part and the filaments are pink to lavender. The fruit consists of clusters of 2-8 pods of 1-2cm long each, prickly on the margins. The pods break into 2-5 segments and contain pale brown seeds 2.5mm long ⁴.

This plant has a history of use for the treatment of various ailments and the most commonly used plant part for this purpose is the root, but flowers, bark and fruit can also be utilized. Several research works have been carried out to study about the phytochemical components of Mimosa pudica ^5,6 and also about the antimicrobial activity of the plant ^7,8. The present study intends to study about the antibacterial Activity of the Plant Extracts of Mimosa pudica against selected microbes.

Materials and Methods:

Mimosa pudica was subjected to pharmacognostic study. The various methods used in the study included organoleptic study, fluorescence analysis and preliminary phytochemical studies.

Organoleptic study:

The powder of Mimosa pudica was used for studies. The colour variation and taste were the basis for this test as given by Jackson and Snowdown⁹.

The fluorescence properties were studied under UV light adopting the method described by Kokoshi, Chase and Pratt¹⁰. The behavior of the samples with different chemical reagents was studied and fluorescence characters were observed on long UV light at 254nm.

About 20 gm of the powder of Mimosa pudica was weighed accurately and mixed with 250 ml of hot water. After 1hour it was filtered and the supernatant was used as the extract. The preliminary phytochemical test of this extract was performed by specific reagents. These extracts were subjected to qualitative chemical tests for detection of various plant constituents.

Table - 1. Organoleptic study of the powder:

1.	Colour	Deep green
2.	Odour	Characteristics
3.	Taste	Slightly bitter

Table -2. The fluorescence analysis of the powder of Mimosa pudica:

S.No.	Treatment with chemical reagents	Observation
1.	Powder as such	Deep green
2.	Powder + 1N Sodium hydroxide in methanol	Light green
3.	Powder + 1N Sodium hydroxide in water	Reddish yellow
4.	Powder + 50% Hydrochloric acid	Light green
5.	Powder + 50% Sulphuric acid	Light blackish green
6.	Powder + 50% Nitric acid	Green
7.	Powder + Petroleum ether	Pale yellow
8.	Powder + Chloroform	Light yellow
9.	Powder + Picric acid	Yellowish green
10.	Powder + 5% Ferric chloride solution	Deep brown
11.	Powder + 5% Iodine solution	Green
12.	Powder + Methanol	Green
13.	Powder + (Nitric acid + Ammonia)	Light Green

Table- 3. The behaviour of the leaf powder of Mimosa pudica when treated with different chemical reagents:

S.No.	Treatment with chemical reagents	Observation
1.	Powder as such	Deep green
2.	Concentrated Hydrochloric acid	Blackish green
3.	Concentrated Sulphuric acid	Brownish yellow
4.	Concentrated Nitric acid	Light brown
5.	Glacial acetic acid	Light yellow
6.	5% Sodium hydroxide solution	Light green
7.	5% Potassium hydroxide solution	Light green
8.	5% Ferric chloride solution	Yellow
9.	Picric acid	Brownish yellow
10.	Ammonia	Reddish Brown
11.	Powder + 1N Sodium hydroxide in methanol	Deep green
12.	Powder + 1N Sodium hydroxide in water	Light green

Table- 4. Different chemical group tests of Mimosa pudica and their results:

Name of compound	Name of test	Observation	Result
Alkaloids	1.Mayer’s test	White or creamy white precipitate.	+
	2. Dragendorff’s test	Orange or orange-red color.	+
	3. Wagner's test	Brown or deep brown precipitate.	+
Glycosides	General test	Yellow color.	+
Flaavonoids	General test	A yellow colouration.	+
Terpenoids	Salkowski test	A reddish brown colouration.	+
Carbohydrates	1. Molisch Test	A red-violet layer at the interface between the acid (bottom) and aqueous (upper) layers.	_
	2.Fehling's Test	A red precipitate.	_
Steroids	General test	The color changed from violet to blue or green.	+
Tanins	General test	A blue-black coloration.	+
Phlobatanins	General test	Red precipitate	+
Saponins	Frothing test	Formation of emulsion.	+

+ = Presence; – = Absence

Results and Discussion:

The pharmacognostical characters of the aerial powders have been studied by screening the same through varying parameters.

The investigation on organoleptic study of aerial powder of Mimosa pudica indicated the characters like colour, odour and taste. The colour of the aerial powder showed deep green colour. The taste and odour of the aerial powders were also tested. The taste is slightly bitter and on analysis the aerial powder gives a characteristic odour (Table 1).

The aerial powders are treated with various chemicals exhibited various colours in the UV light. When the powder was treated with aqueous 1 N NaOH and 50% H₂SO₄ the aerial powder exhibited reddish yellow and light green in UV light and the results are depicted (Table 2).

When the leaf powders were treated with chemicals like FeCl₃, HCl, HNO₃, picric acid, NH₃, NaOH+ methanol etc various shades of yellow, Blackish green , light brown, brownish yellow, Reddish Brown , deep green, etc colours were obtained (Table 3).¹¹

Pharmaceutical preparation derived from natural resources such as vegetables often contain compounds that contribute the antimicrobial defense systems and apparently play a role in the protection against degenerative diseases.

Conclusion:

The results of organoleptic study offer a scientific basis for the traditional use of Mimosa pudica which possess characters like deep green, characteristic odour and slightly bitter taste. The leaf powders when treated with various chemicals exhibited various colours in the UV light. The aerial part of Mimosa pudica the has been tested for the identification of the chemical group present in that plant. It has been found that alkaloids, glycoloids, flavonoids, terpenoids, steroids, phlobatanins, tannins and saponins are present.

References:

1. Reddy, K.J. (2004): Medicinal plant research scenario in India, Info concepts India Inc., pp.25-28.

2. Dubey, N.K., Kumar, R. and Tripathi, P. (2004): Global promotion of herbal medicine: India’s opportunity, Current Science, 86(1), pp.37-41.

3. Gaikwadi, S.S., Vadlamudi, V.P., Waghmaee, S.P., Maral, V.J., Ranteke, V.D. and Dhok, A.P. (2003): Phytochemical analysis of aqueous extract of few medicinal plants, PKV. Res. J., 27(1), pp.91-92.

4. Shelef, L. A. 1983. Antimicrobial effects of spices. J. Food Safety 6: 29-44. U S Forest Service2008. "Mimosa pudica", Usambara Invasive Plants.

5. Deininger, R, 1984, Lectures of the Medical Congress Berlin: Firma Klosterfrau, Koln. 24–31.Germplasm Resources Information Network 2008. "Mimosa pudica L.". GRIN, United States Department of Agriculture, Agricultural Research Service, Beltsville Area.

6. Ahmad, I, and Beg, A. Z. 2001. Antimicrobial and phytochemical studies on 45 Indianmedicinal plants against multi-drug resistant human pathogens. J Ethnopharmacol 74: 113–23.

7. Palacious C, and Reyes, R. E. 1991. Antibacterial and Antimycotic of Mimosa pudica in experimental animals, Arch Invest Med. (Mex), 22(2) : 163-169.

8. Ojalla, T, Remes, S, and Hans, P. 1999. Antimicrobial activity of some coumarin containing herbal plants growing in Finland. J Ethnopharmacology, 68 (1-3): 267-274.

9. Jackson, B.P. and Snowdown, D.W. (1968): Powdered vegetable drugs, Cheer Chil Ltd., London, pp.25.

10. Kokoshi, G.J., Kokoshi, J.R. and Sharma, F.J. (1958): Fluorescence of powdered vegetable drugs under ultra violet radiation, J. Amer. Pharm. Assn., 38(10), pp.715-717.

11. Pandey, H.C., Dixit, R.S. and Sharma, H.P. (1984): Addition to the Pharmacognosy of Kalimulri (Curculigo orchioides), Bull. Med. Ethnobot. Res., 5(1-2), pp. 55-56.

Received on 02.05.2012 Accepted on 10.08.2012

Asian J. Pharm. Tech. 2(3): July-Sept. 2012; Page 101-103