Pharmacognostical and antibacterial evaluation of Murraya koenigii (L) Spreng

Our present study was aimed to detect the medicinal uses of the plant Murraya koenigii (L) Spreng belonging to the family Rutaceae by performing various studies such as Pharmacognostical, phytochemical and antibacterial activity, using seven different bacterial strains, which are harmful to human beings. The Murraya koenigii commonly known as “Curry leaf“ has been recognized in different systems of traditional medicines for the treatment of different diseases and ailments of human beings. The leaves of the plant are said to be cooling and stomachache. The study includes macroscopy, microscopy, preliminary phytochemical screening and antibacterial evaluation.


INTRODUCTION
Plants contain chemical compounds that may be in one way or another responsible for their healing properties and other functions. The chemical compounds are secondary metabolites of which at least twelve thousand have been isolated (Hasan et al., 1988). Medicinal plants, which form the backbone of traditional medicine, have in the last few decades been the subjects for very intense pharmacological studies; this has been brought about by the acknowledgement of the value of medicinal plants as potential sources of new compounds of therapeutic value and as a source of lead compounds in the drug development.
In the developing countries, it is estimated that about 80 % of the population rely on traditional medicine for their primary health care.
There arises a need and therefore to screen medicinal plants for bioactive compounds as a basis for further pharmacological studies (Shailendra Gurav et al., 2007). Up to 80 % of the population depends directly on the traditional medicine for the primary health care (Kirby, 1966).
The use of plant extracts and phytochemicals, both with known antimicrobial properties, can be of great significance in therapeutic treatments. In the last few years, a number of studies have been conducted in different countries to prove such efficiency. Many plants have been used because of their antimicrobial traits, which are chiefly due to synthesized during secondary metabolism of the plant (Prusti, 2008). The present study is aimed to investigate the pharmacognostical, phytochemical and antibacterial evaluation of the medicinal plant Murraya koenigii (L) Spreng.

1. Collection and authentification of the plant
For the present study, the fresh leaves of Murraya koenigii were collected in summer season locally from the Experimental Orchards, Faculty of Agriculture, Annamalai University, Tamil Nadu in May, 2014.
The taxonomic identification of the plant was confirmed by Dr. V. Venkatesalu, Head of the Department of Botany (DDE), Annamalai University, Voucher specimen was deposited in the Department.

Microscopic (Anatomical) Studies
The fresh leaves of Murraya koenigii was collected and fixed in FAA (Farmalin Acetic acid and alcohol mixtures). Free hand sections were taken and kept in 70 % ethanol. The sections were stained with saffranin and mounted according to the methods described by Johansen (1940), Photographs were taken by Phase contrast microscope (Olympus SP-350, digital compact camera, 8.0 mega pixels).

3. 1. Fluorescence Analysis
Fine powder and their extracts were obtained in various solvents namely petroleum ether, benzene, chloroform and ethanol. The aqueous extract was prepared by directly boiling the powder with distilled water.
They were examined under visible and UV light. These powdered material were also treated with various reagents such as 50 % HNO 3 , acetone, ethyl alcohol, 50 % H 2 SO 4 , 1 N HCL and 1 N aqueous NaOH are the various chemical and organic reagents used to perform fluorescence analysis (Kokate, 1994) and changes in colour were recorded.

3. Quantitative Determination
The percentage of total ash, water soluble ash, acid insoluble ash, sulphated ash, were obtained by employing the standard methods of analysis as described in pharmacopoeia of India (1996).

4. 1. Microbial strains
The different bacterial strains used for the study of antibacterial activities were collected from the Department of Medical Microbiology, Rajah Muthaiya Medical College & Hospital, Annamalai University, Annamalainagar. The bacterial strains were sub cultured in the Muller Hinton agar medium. The samples for bacterial strain were sub cultured in individual plates (Bauer et al., 1966).

4. Solvent used
The organic solvents such as petroleum ether, benzene, chloroform, ethanol and distilled water were used to extract bio active compounds.

RESULTS AND DISCUSSION
The macroscopical studies revealed the shape of leaves of Murraya koenigii (L) Spreng as obliquely ovate or some what rhomboid with acuminate obtuse or acute apex, bipinnately compound with exstipulate in alternate arrangement. The petiole were of 20 to 30 cm in length. The leaf had reticulate venation and dentate margin with asymmetrical base (Fig. 1 &  2).  Under the compound microscope, the stomata were found distributed on abaxial surface while the adaxial surface was without stomata. The type of stomata was noted as anomocytic one. The transverse section of leaf exposed a layer of epidermis composed of rectangular cells as outer most covering on both upper and lower layer. The upper epidermis was enveloped with deposition of cuticle. In midrib portion, epidermis was followed by 1-4 layers of collenchymatous hypodermis in continuation with 2-5 layers of chlorenchyma cells filled with chlorophyll contents. Beneath this, ground tissue portion lies. This portion is composed of oval to polygonal parenchyma cells and is transversed with vascular bundle, sandy and prismatic crystals of calcium oxalate were found in this region. Fluorescence properties of Murraya koenigii (L) Spreng, powdered leaf material obtained which is used for to analysis under ultra violet light. 50 % HNO3, acetone, ethyl alcohol, 50 % H2SO4, 1N HCL and 1 N aqueous NaOH are the various chemicals and organic reagents used to perform fluorescence analysis. The fluorescence behaviour was noted as in Table 1. The physico-chemical properties of powder exposed the moisture content (loss on drying, total ash, acid insoluble ash, water soluble ash, alcohol soluble extractives and water soluble extractives) are as shown in Table 2. The higher percentage of total ash and acid insoluble ash may be due to the presence of calcium oxalate crystals or other inorganic salts present in various metabolites.
The antibacterial activity of the leaf extracts of Murraya koenigii (L) Spreng in different solvent extracts are shown in Table 4. The antibiotic disc ampicillin showed antibacterial activity against Staphylococcus aureus, Staphylococcus epidermis, Escherichia coli, Klebsiella sps, and Enterobacter sps. It does not show any activity against Proteus vulgaris and Proteus mirabilis it had the maximum inhibitory action against almost all the bacteria used for example Staphylococcus aureus (14 mm). Therefore it should be understand that by undergoing these studies various secondary metabolites present in the plant, its importance for use as drug, its activity to fight against certain bacteria which are harmful to human beings can be easily identified. Further integrated investigation using HPLC and GC-MS will lead to purification and structural elucidation of active principle against microorganisms.