INTRODUCTION:

The medicinal plants are of great interest to human health. Plant based medicines have been a part of traditional healthcare in most parts of the world for thousands of years ^(1). Plants contain numerous biologically active compounds, many of these have been shown to exhibit antimicrobial properties and therefore they were in use as antimicrobial drugs in traditional medicines. Plants used in traditional medicine contain a vast array of substances that can be used to treat chronic and even infectious diseases. According to a report of World Health Organization, more than 80% of world’s populations depend on traditional medicine for their primary health care needs. Knowledge of the phytochemicals is desirable not only for the discovery of healthcare products, but also in disclosing new sources of economic materials like alkaloids, tannins, oils, gums etc., ^(2). The systematic screening of plant extracts or plant derived substances still remains an interesting strategy to find new lead compounds in many plant species.

Medicinal plants have no doubt remained the major sources of traditional medicine worldwide. Accordingly, attention of scientists and researchers have been attracted towards developing new antibiotics that will curtail the increasing drug resistance among microorganisms ⁽³⁾ reported that plants used for traditional medicine generally contain a number of compounds which may be a potential natural antimicrobial combination and which may serve as an alternative, effective, cheap and safe antimicrobial agents for treatment of common microbial infections.

Diospyros virginiana is a persimmon species commonly called the American Persimmon, Common Persimmon, Eastern Persimmon, "'Simmon", "Possumwood", or "Sugar-plum". This is a well-known indigenous tree, growing in woods and fields. Persimmons have been used to lubricate the lungs and strengthen the spleen and pancreas (4). They improve energy and contain enzymes that help damaged cells and foreign microbes be broken down. Persimmons have a special affinity for the large intestines and heart. Persimmons have been used to treat bronchitis, catarrh, cough, diarrhea, dysentery, goiter, hangover, hemorrhoids and hiccoughs. The bark has been used in intermittent and both it and the unripe fruit have been beneficial in various forms of disease of the bowels, chronic dysentery, and uterine hemorrhage; used in infusion, syrup, or vinous tincture.

Seeds and fruits are generally low in crude protein, crude fat, and calcium but high in nitrogen-free extract and tannin ⁽^5). The inner bark and unripe fruit are sometimes used in treatment of fevers, diarrhea, and hemorrhage. Indelible ink is made from fruit. Persimmon is valued as an ornamental because of its hardiness, adaptability to a wide range of soils and climates, its lustrous leaves, its abundant crop of fruits, and its immunity from disease and insects ^(6). Therefore, the aim of the present work is to investigate antimicrobial activity and MIC of the leaves and bark extracts of D.virginiana.

MATERIALS AND METHODS:

D.virginiana belongs to the family Ebenaceae was collected from Coonoor, Nilgiris District, Tamil Nadu, India and identified by the special key given Cambell flora. The leaf and bark of D.virginiana were washed with sterile distilled water. After, the leaves and bark were shade dried and powdered by using pestle and mortar. 25g of powder was filled in the thimble and extracted successively with ethanol using a Soxhlet extractor for 48 h. The extracts were concentrated using rotary flash evaporator and preserved at 5°C in airtight bottle until further use. All the extracts were subjected to antimicrobial activity assay.

Determination of antimicrobial activity:

Antibacterial activity:

Antibacterial activity of the extracts was determined by disc diffusion method as described by⁽⁷⁾ with some modifications. The concentration of bacterial suspension was adjusted to 0.5 McFarland standards. The bacterial suspensions were seeded on MHA plates. In each of these plates three wells were cut out using a standard cork borer (7 mm). Using a micropipette, 100 µl of each extract and negative control was added in to different wells containing disc. A positive control antibiotic disc was placed in the plate. Plates were incubated for 24 hours at 37°C. Antibacterial activity was evaluated by measuring the zone of inhibition. Experiment was performed in triplicates⁽⁸⁾.

Antifungal activity:

Antifungal activity of the extracts was determined by agar well diffusion method as described by⁽⁹⁾ with some modifications. The fungal suspensions were seeded on SDA plates. In each of these plates three wells were cut out using a standard cork borer (7 mm). Using a micropipette, 100 µl of each extract and negative control was added in to different wells containing disc. A positive control antibiotic disc was placed in the plate. Plates were incubated for 48-72 hours at room temperature. Antifungal activity was evaluated by measuring the zone of inhibition. Experiment was performed in triplicates.

Minimum inhibitory concentration:

The MIC was evaluated on plant extract that showed antimicrobial activity. This test was performed at four concentrations of 10, 20, 30 and 40 µg/ml by the same disc diffusion method. All the experiments were conducted with a minimum of three triplicates per strain.

RESULT:

Antimicrobial activity of the methanol, chloroform and P.ether extract of the leaves and bark of D.virginiana with respective to positive and negative control (Table -1, 2). Methanol extract exhibits higher antimicrobial effect than that of chloroform and P.ether extracts. Both extracts showed high antibacterial activity against S.pyogenes, P.vulgaris than P.aeruginosa, P.fluroscence and S.aureus. In both extracts showed high significant antifungal activity against C.albicans and A. niger.

The leaf extract of D.virginiana against bacterial pathogens showed the least MIC value, that is 20 µg/ml against S.pyogenes at 10% and the bark extract showed at P.vulgaris (25 µg/ml at 10%). The antifungal activity showed least activity at leaves extract against A.niger (20 µg/ml) and bark recorded at C.albicans (23 µg/ml) respectively (Table-3, 4).

DISCUSSION:

Drug resistant in microbes become a big problem along with the emergence of new infectious diseases. Microorganism acquired resistant against the pharmaceutical drugs by the production of drug degrading enzymes, resistant plasmids, alteration of metabolic pathway etc., ⁽¹⁰^).The focus of this study was to discover a natural source of broad range antimicrobial compound. In the current study methanol, chloroform and aqueous extracts of the leaves and bark of D.virginiana was screened for antimicrobial analysis.

These local ethno-medical preparations and prescriptions of plant sources should be scientifically evaluated and then disseminated properly and the knowledge about the botanical preparation of traditional sources of medicinal plants can be extended for future investigation into the field of pharmacology, phytochemistry, ethno botany and other biological actions for drug discovery^(11,12). Hence, this clearly reveals the antibacterial nature of the plant D.virginiana suggests that this plant could be exploited in the management of diseases caused by these bacteria in human systems.

The extracts have bioactive compound which inhibits the growth of various pathogens. The spectrum of the antimicrobial compound present is found to be broad as it is inhibiting bacterial species ⁽¹³⁾. So this plant has potential to produce useful antimicrobial compounds and it must be better explored.

CONCLUSION:

In the current study methanol, chloroform and p.ether extracts of the leaves and bark of D.virginiana ware screened against a variety of Gram positive bacteria, Gram negative bacteria and fungi by disc diffusion method. Both the plant extracts showed significant antimicrobial activity and MIC against Gram negative bacteria and fungi. These studies concludes that D.virginiana is a valuable medicinal plant possessing a broad range of antimicrobial activity and can be explored for isolation of natural antimicrobial compounds.

REFERENCES:

1. Akerele O. Medicinal plants and primary health care: an agenda for action. Filoterapia, 59; 1988:355-363.

2. Khare, C.P. Indian Medicinal Plants- An Illustrated Dictionary. Springer Science, Business Media, LLC, First Edition. 2007.

3. Zaika, L.L. Spices and herbs: Their antimicrobial activity and its determination. J. Food Safety, 9; 1988:97-118.

4. Das, S., Pal, S., Mujib, A., Dey, S. Biotechnology of medicinal plants- Recent advances and potential. Ist Edition, Vol II (UK992 Publications, Hyderabad), 1999;pp. 126-139.

5. Arthur, H.R. A Phytochemical survey of some of plants of North Bornew. J. Pharm. Pharmacol., 6; 1954:66-72.

6. Getie, M., Gebre-Mariam, T., Rietz, R., Hohne, C., Huschka, C., Schmidtke, M., Abate, A. and Neubert, H. H. R. Evaluation of the anti-microbial and anti-inflammatory activities of the medicinal plants Dodonaea viscosa, Rumex nervosus and Rumex abyssinicus. Filoterapia. 74,2003:139 – 143.

7. Tagg, T.R., Dajani, A.S. and Wannamaker, L.W. Bacteriocin of Gram positive bacteria. Bacteriology Review, 40; 1976:722-756.

8. Collins, C.H. and Lyne, P.M. Microbiological methods. 3rd ed. Butterworth and Co. Ltd. 1970:p 414-427.

9. Vogel, H.G. Similarities between various systems of traditional medicine. Considerations for the future of ethnopharmacology. J.Ethnopharmacol., 35; 1991:179-190.

10. Varahalarao, V., and Chandrasheka, R.N. In vitro bioactivity of Indian medicinal plant Calotropis procera . Journal of Global Pharma Technology, 2(2); 2010: 43-45.

11. Evans, W.C., Trease and Evans’ Pharmacognosy. 14th revised. W.B. Sounders Company Limited, London, pp. 545- 546; 2006.

12. Veermuthu, D., Muniappan, A., Savarimuthu, I. Antimicrobial activity of some ethnomedicinal plants used by Paliyar tribe from Tamilnadu, India. BMC Complement. Altern. Med., 6; 2006:35.

13. Roselle, I.L. A Screening method for natural products with antimicrobial activity: A review of literature. Journal of Ethnopharmacology, 23; 1988:127-149.

Received on 21.11.2013 Modified on 11.12.2013

Res. J. Pharmacognosy & Phytochem. 6(1): Jan.-Mar. 2014; Page 16-18