Phytochemical And Biological Screening of Tectona Grandis Leaves

Tectona grandis Linn. (TG) is commonly known as “Teak” belongs to  Lamiaceae family. Teak has been widely used in India for more than 2,000 years. It is a large deciduous tree 30-35 metre tall with light brown bark, leaves simple, opposite, broadly elliptical or acute or acuminate, with minute glandular dots, flowers are white in colour, small and have a pleasant smell [1]. The plant Tectona grandis is probably the most widely cultivated high value hardwood (HVH) in the world and is native to India and Myanmar and South- East Asian countries [2, 3]. It is now one of the most important species of tropical plantation forestry. The whole plant is medicinally important and many reports claim to cure several diseases according to Indian traditional system of medicines. The survey reveals that the plant is used in the treatment of urinary discharge, bronchitis, cold and headache, in-scabies. Also used as a laxative, sedative, diuretic, anti-diabetic, analgesic and anti-inflammatory [4-7].The various phytoconstituents isolated from Tectona grandis are Juglone, which has been reported to antimicrobial activity [8], botulin aldehyde shows antitumor activity [9], lapachol shows anti-ulcerogenic activity [10].

Plant Profile:

Table 1: Taxonomical Classification

Table 2: Other names of the plant (Tectona)

Figure. 1 (a, b, c & d): Tectona grandis plant

Collection and identification of plant material:

Tectona grandis tree consists root, flowers, fruits, long and short leaves, bark etc. The long and short leaves were procured from the backyard of Sri Venkateswara College of Pharmacy, etcherla Srikakulam, Andhra Pradesh, India.

Preparation of Tectona grandis leaf extract:

The plant leaves were collected and dried for seven days and leaves were crushed and midribs were separated then soaked in ethanol. The crushed leaves were macerated in alcohol for three days. Reflux process is conducted for one and a half hour. Then solution is filtered and the filtrate is collected and subjected to steam distillation. The solution thus obtained is concentrated till it get converted into semisolid mass and it is kept in desiccator.

Preparation of the Tectona grandis leaf extract by using Solvents (Ethanol, Benzene, Chloroform & Hexane):

• 5gm of leaf extract is dissolved in 100ml of ethanol [95%] in conical flask.
• 5gm of leaf extract is dissolved in 100ml of benzene in conical flask.
• 5gm of leaf extract is dissolved in 100ml of chloroform solution in conical flask.
• 5gm of leaf extract is dissolved in 100ml of hexane solution in conical flask.

Phytochemical Screening [11]:

Following chemical tests were carried out for different extracts of Tectonagrandis to identify the presence of various phytochemical constituents. Chemical tests for detection of organic constituents:

Evaluation Of Antioxidant Activity

Phospho-molybdenum assay:[12]

Hydroalcoholic extract of plant in different concentration ranging from 100 to 500 µg/ml were added to each test tube individually containing 3ml of distilled water and 1ml of molybdenum reagent. These test tubes were kept in incubator at 95°c for 90 minutes After incubation these test tubes were normalised to room temperature for 20-30 minutes and absorbance of reaction mixture was measured at 695nm. Mean value from three independent sample were calculated for each extract. Ascorbic acid was used as reference standard.

DPPH free Radical Scavenging Activity:[13]

The free radical scavenging activity of Tectona grandis was measured by DPPH assay following the methodology described by Blowis in 1958 where in the bleaching of the stable free radical, DPPH is monitored at characteristic wavelength in the presence of sample. In its radical form DPPH absorbs at 517nm, but upon reduction by antioxidant or radical species its absorbance decreases. Briefly, 0.1mM solution of DPPH in ethanol was prepared and 1ml of solution was added to 3ml of Tectona grandis solution in water at different concentration [25-250µg/ml] 30mins later, the absorbance was measured at 517nm. Lower absorbance of the reaction mixture indicates higher free radical scavenging activity.

The free radical scavenging activity was calculated according to the following equation

DPPH radical scavenging activity [%] = [{Ao-A1/Ao}] ×100

Where, Ao is absorbance of DPPH

A1 is absorbance of DPPH solution in presence of extract.

Hydrogen peroxide scavenging capacity assay:[14]

The hydrogen peroxide scavenging ability of Tectona grandis was determined according to the method of Ruch,1989. Solution of hydrogen peroxide [40mM] was prepared in phosphate buffer [pH7.4]. The different concentration of Tectona grandis[10-50µg/ml] in phosphate buffer was added to hydrogen peroxide solution [0.6ml, 40mM]. The absorbance value of reaction mixture was recorded at 330nm. Blank solution was containing phosphate buffer without hydrogen peroxide. The % of hydrogen peroxide scavenging of Tectona grandis and standard compound was calculated as

Hydrogen radical scavenging activity [%] = [{Ao-A1/Ao}] ×100

Where, Ao is absorbance of hydrogen peroxide

A1 is absorbance of hydrogen peroxide solution in presence of extract.

Evaluation Of Antimicrobial Activity [15, 16]:

Antimicrobial activity using nutrient broth method Firstly, the prepared nutrient broth with the standard procedure is dividing into different concentration like 25mg/ml, 50mg/ml, 75mg/ml and 100mg/ml of Tectona grandis leaves drug extract. Now few drops of the specific microorganism [Bacillus subtilis, Escherichia coli, Staphylococcus aureus, Lacto bacillus and Klebsiella pneumoniae] is added to each concentration test tubes and kept for incubation for 24 hours. Then growth of microorganism is not observed.

RESULTS AND DISCUSSION:

In the present work, leaves extracts of different solvents like ethanolic, benzene, chloroform, hexane of Tectona grandis was used for phytochemical screening and antioxidant and antimicrobial activities. Phytochemical screening of extracts of Tectona grandis leaves was carried out by employing standard conventional protocols (i.e., alkaloids, glycosides, carbohydrates, tannins, steroids)

According to this report, Tectona grandis showed the presence of alkaloids, carbohydrates, glycosides, tannins and steroids.

Evaluation Of Antioxidants Activity:

Table 6: Phosphomolybdate Method

Figure. 2: Graphical Represent of Phosphomolybdate Method

Values are mean ± SEM o triplicate determinations

Figure. 3: Graphical Represent of DPPH Free Radical Scavenging Activity

Values are mean ± SEM o triplicate determinations

Figure. 4: Graphical Represent of Hydrogen Peroxide Scavenging Activity

Figure. 5: Antimicrobial Activity of Tectona Grandis Leaves