INTRODUCTION:

India is endowed with a rich wealth of Medicinal Plants. The medicinal plants have made good contribution to the development of ancient Indian systems of medicine as also to local medicine among tribal etc. Our country represents as store house of genetic diversity of medicinal plants (Williams 1996).

Medicinal plants have become the focus of intense study recently in terms of conservation and as the whether their traditional uses are supported by actual pharmacological effects or mere by based on (Locher et al., 1995, Jaiger et al., 1996) with the increasing acceptance of traditional medicine as an alternative from of health care the screening of medicinal plants for active compounds is very important traditional medicine based on plants has played a key role in the health care system of many countries like India, China etc., (Sudhersan, 1998). Herbal medicine is still the main stay of about 75-80% of the world population.

Plants are rich in alkaloids and other phytochemical contents and many of them are effectively used to cure a wide range of ailments. The alkaloids and phytochemical contents may be present in all organs of the plant including roots, stems, buds, leaves, flowers and fruits. All plant parts synthesize some chemicals which metabolite their physiological activities. These phytochemicals are used to cure the disease in herbal and homeopathic medicines. Now a day most of the peoples like to use the traditional methods to cure general diseases (Mahajan et al., 1996). This worldwide interest in medicinal plants reflects recognition of the validity of many traditional claims regarding the value of natural products in health care and the development of microbial resistance to the available antibiotics has led the authors to investigate the antimicrobial activity of medicinal plants.

Coleus may lower blood sugar levels caution is advised if you are taking prescription drugs that may lower blood sugar levels patients taking oral drugs for diabetes or using insulin should be monitored closely by their health care provider while using coleus dosing adjustments may be necessary.

Medicinal Use:

1. Promotes the flow of urine.

2. For the expelling of gases flatulence and griping pairs from the stomach and bowels.

3. Promotes menstrual flow.

4. Strengthens and gives tone to the stomach.

5. For indigestion discomfort or pain.

MATERIALS AND METHODS:

Collection of plant: Fresh plant were collected in an around Kiliyur (Perambalur District) shade dried. Plants are identified and confirmed with the authentic. Plant selected for the present study was Coleus amboinicus, Phyla nodiflora and Vitex negundo. Fresh leaves and roots are collected and shade dried under room temperature and powder was used for further investigation.

Extraction: A soxhlet apparatus was used for the extraction antimicrobial active compounds from the plant leaves. The collected plant leaves were shade dried and powdered separately. 20gm of dried powder was packed with plastic cup and then subjected to extraction with the hexane, chloroform and alcohol separately. The collected extracts were concentrated by evaporation under room temperature and used for antibacterial activity. The collected extracts were then chosen for antibacterial activity.

Bacterial Inoculum Preparation: Bacterial cultures used in this study were obtained from MTCC, Chandigar. Bacterial cultures included in this study were B. cereus, B. subtilis, S.aureus, Shigella flexneri and Salmonella Paratyphi A. All the cultures were grown in Muller - Hinton broth medium. The inoculum was used for antibacterial assay.

Antibacterial Assay: The media and the test bacterial cultures were poured into dishes. [Muller - Hinton agar media]. The test strain (0.2 ml) was inoculated into the media to inoculums size (108cells/ml) when the temperature reached 40-42°C. Care was taken to ensure proper homogenization. The plant extracts were tested for antibacterial activity in the agar well diffusion assay, against Bacillus cereus, Bacillus subtilis, Staphylococcus aureus, Shigella flexneri and Salmonella Paratyphi A.

Agar Well Diffusion Method: The antibacterial activities were tested against (hexane, chloroform and alcohol) leaves Coleus amboinicus, Phyla nodiflora and Vitex negundo. The inoculum of microorganism was prepared from pure cultures (Parihar and Bohra, 2006). About 15-20 ml of Muller-Hinton agar medium was poured in the sterilized petridish and allowed to solidify. One drop of bacterial strains was spread over the medium by swab. Wells of 6nm in diameter and about 2 cm apart punctured in the culture medium using sterile Cork borers. About 100 µl of plant extract was added to the wells. Plates were incubated in air at 37°C for 24 hours. Antibacterial activities were evaluated by measuring inhibition zone diameters.

RESULTS:

Medicinally important plant species viz., Coleus amboinicus, Phyla nodiflora and Vitex negundo were selected for screening of secondary metabolites. During this investigation, an attempt has been made to decipher the effect of these secondary metabolites towards its antibacterial activities. Hexane, chloroform and alcohol extracts from the leaf of Coleus amboinicus, Phyla nodiflora and Vitex negundo exhibited antibacterial activity against Bacillus cereus, Bacillus subtilis, Staphylococcus aureus, Shigella flexneri and Salmonella Paratyphi A.

Antibacterial Activity: The effect of different extracts of three test plants on pathogens was shown in Tables 1, 2 and 3. The results clearly showed that plant extracts were specific in action against the growth of bacteria. The extracts of leaf of Coleus amboinicus and Vitex negundo exhibit relatively higher zone of inhibition followed by Phyla nodiflora.

Table 1: Effect of hexane, chloroform and alcohol extract leaf samples of Coleus amboinicus on pathogens

Name of the pathogens	Control	Hexane	Chloroform	Alcohol
Bacillus cereus	--	--	--	7
B. subtilis	--	9	--	7
S.aureus	--	8	9	--
Shigella flexneri	--	--	7	7
Salmonella P.typhi A	--	9	8	--

Tetracycline used as Standard (30 µg/disc)

Zones Measure in Millimeter (mm)

Table 2: Effect of hexane, chloroform and alcohol extract leaf samples of Phyla nodiflora on pathogens

Name of the pathogens	Control	Hexane	Chloroform	Alcohol
Bacillus cereus	--	9	9	11
B. subtilis	--	9	13	9
S.aureus	--	7	10	9
Shigella flexneri	--	9	11	9
Salmonella P.typhi A	--	9	11	8

Tetracycline used as Standard (30 µg/disc)

Zones Measure in Millimeter (mm)

Table 3: Effect of hexane, chloroform and alcohol extract leaf samples of Vitex negundo on pathogens

Name of the pathogens	Control	Hexane	Chloroform	Alcohol
Bacillus cereus	--	7	5	7
B. subtilis	--	8	7	8
S.aureus	--	11	8	7
Shigella flexneri	--	9	-	8
Salmonella P.typhi A	--	7	8	10

Tetracycline used as Standard (30 µg/disc)

Zones Measure in Millimeter (mm)

DISCUSSION:

In the present study, three medicinal plant species viz., Coleus amboinicus, Phyla nodiflora and Vitex negundo were screened to detect the presence or absence of several bioactive compounds which are reported to cure different diseases and ailments.

It was clear from this study that the solvent of extraction and method of extraction affected the degree of antimicrobial activity. Other factors such as the environmental and climatic conditions of the plants also affected the degree of antimicrobial activity.

Many substances may be antimicrobial, but only a few of them will be potential therapeutic agents for the simple reason that mammalian cells are more sensitive to chemical inhibition than microbial cells (Sivakumar and Alagesaboopathi, 2006). Moreover, emphasized the need for toxicity testing of drugs derived from medicinal plants because the crude products obtained from such cheaper sources are often associated with a large number of compounds that have discomforting abilities Ramdass et al., 2006. Hence the herbal drugs have to be subjected to extensive pharmacological, toxicological and clinical tests to conform the prescribed status. Thus the ethnobotanical approach will be like a search for molecular diversity subjecting a wide variety of new molecules from plant sources and testing them with as many different tests as possible (Muhammad and Muhammad, 2005).

REFERENCES:

1. Jaiger, A.K., A. Hutching, and J. Van Stadeb. 1996. Screening of zulimedicinal plants of prostaglandin synthesis inhibitors. Journal of ethanopharmacology, 52:95-100.

2. Locher, C.P. 1994. Antimicrobial activity and anti complement activity of extract obtained from selected Halation medicinal plants. Journal of ethanopharmacology. 49:23-32.

3. Mahajan, V., D.S. Arora, and U. Sabherwal. 1996. Antibacterial activity of some tea samples. Indian J.Microbiol. 31: 443-445.

4. Muhammad, H.S., and S. Muhammad. 2005. The use of Lawsonia inermis Linn. Henna in the management of burn wound infections. African Journal of Biotechnology. 9: 934-937.

5. Parihar, L., and A. Bohra. 2006. Antimicrobial activity of stem extracts of some spices plants. Ad. Plant Sci. 19 (II).

6. Ramdas, K., Y.L. Ramachandra, and S. Padmalatha. 2006. Antibacterial activity of the leaf extracts of Asparagus racemosus. Geobios. 33: 279-280.

7. Sivakumar, R., and C. Alagesaboopathi. 2006. Antimicrobial activity of two different forms of Abrus precatorius L. Ad. Plant Sci. 19(II): 409-413.

8. Sudhersan, C. 1998. Shoot bud regeneration from leaf explants of a medicinal plant Enicosternma oxillare. Current science. 74: 1099-1100.

9. Williams, V.L.1996. The wit water stand multi trade veld and flora. 82:12-14.

Received on 07.06.2011 Accepted on 21.06.2011

Asian J. Pharm. Tech. 1(2): April-June 2011; Page 53-55