1. INTRODUCTION:

Now a days, traditional medicine is revealed by an extensive activity of research on different plant species and their therapeutic principles all over the world^1-2. Free radicals of different forms are constantly generated for specific metabolic requirement and quenched by an effective antioxidant network in the body. When the generation of these species exceeds the levels of antioxidant mechanism, it leads to oxidative damage of tissues and bio molecules, eventually leading to disease conditions, especially degenerative diseases³.

Some of the non-nutritive antioxidants of plants are phenolic compounds, flavonoids, coumarins, benzylisothiocyanate etc⁵. Epidemiological evidence indicates an inverse relationship between the intake of food rich in phenolic compounds and the reduction of certain chronic diseases and coronary heart disease mortality⁶.

Drakshasava is a polyherbal hydroalcoholic preparation and is used to improve digestion, as blood purifier, in the treatment of anaemia and advised as a choice of remedy in respiratory problems. The chief ingredient of Drakshasava is draksha, dried fruits of Vitis vinifera⁷. The composition and properties of fruits of Vitis vinifera have been extensively investigated and it was reported that they contain large amount of phenolic compounds as catechins, epicatechin, quercetin and gallic acid, dimeric, trimeric and tetrameric procyanidins^8-9. These compounds have many favourable effects on human health such as lowering of human low density lipoproteins, reduction of heart disease and cancer because of their antioxidant property^10-17.

Therefore, we undertook the present investigation to estimate the total phenolic content as well as total flavonoids and to evaluate the antioxidant potential of Drakshasava-T and Drakshasava-M prepared by traditional and modern methods respectively and its marketed preparation on two different in vitro antioxidant activity models as super-oxide radical scavenging activity and lipid per-oxidation assay.

2. MATERIALS AND METHOD:

2.1 Preparation of Drakshasava-T:

This was prepared by the method as given in Ayurvedic Formulary of India, Part-II⁷. The ingredients were procured from local market, Jamnagar. Identification of individual plant material was done as per Ayurvedic Pharmacopoeia of India. Authentication of all these ingredients was done by Dr. G. D. Bagchi, Scientist, Department of Taxonomy and Pharmacognosy, Central Institute of Medicinal and Aromatic Plants, Lucknow. Prepared herbarium has been deposited in CIMAP for future reference.

According to this method, dried fruits of Vitis vinifera were crushed and then placed in polished vessel of brass along with prescribed quantity of water (16.384 L), and allowed to steep overnight. After overnight steeping, this material was warmed at medium flame until the water for decoction reduced to one fourth of the prescribed quantity (4.096 L), then the heating was stopped and it was filtered through unstarched muslin cloth in cleaned and fumigated vessel and after that jaggery and honey were added and mixed properly. Then dhataki flowers (Woodfordia floribunda) and prescribed quantity of coarsely powdered prakshepa dravyas as Myristica fragrans (flowers), Eugenia caryophyllus (flower bud), Cubeba officinalis (fruits), Santalum album (heart wood), Piper nigrum (fruits), Cinnamomum zeylanicum (stem bark), Eletteria cardamomum (seeds) and Cinnamomum tamala (leaves) were added and this sweet filtered fluid was placed for fermentation in incubator for fifteen days at 33ºC± 1ºC. After fifteen days, completion of fermentation was confirmed by standard tests¹⁸. The fermented preparation was filtered with unstarched muslin cloth and kept in cleaned covered vessel for further next seven days. Then, it was poured in clean amber colored glass bottles previously rinsed with ethyl alcohol, packed and labelled properly.

2.2 Preparation of Drakshasava-M:

Method of preparation was same as followed with Drakshasava-T, only dhataki flowers were replaced with yeast for inducing fermentation¹⁹.

2.3 Chemicals:

Folin-Ciocalteu and thiobarbituric acid were obtained from Loba Chemie, India. Nitroblue Tetrazolium (NBT) and gallic acid were obtained from Sigma chemicals, St. Louis, USA. Quercetin was purchased from Yucca Enterprises, Bombay. Ferrous sulphate, trichloroacetic acid, potassium dihydrogen phosphate, phenazine methosulphate, sodium carbonate, aluminium chloride, ethanol and methanol etc were of analytical grade and obtained from Ranbaxy Fine Chemicals.

2.4 Estimation of total phenolic content:

Total phenolic content was determined in both types of Drakshasava as Drakshasava-T and Drakshasava-M prepared by traditional and modern methods respectively and in its marketed preparation by using Folin Cio-calteu’s reagent²⁰. For the preparation of calibration curve, 1 ml of each of the different concentration of standard gallic acid solution in ethanol as 100, 50, 25, 10, 5, 2.5 and 1 µg/ml was mixed with 5 ml Folin-Ciocalteu reagent (diluted ten fold) and 4 ml of sodium carbonate solution (7.5 g/ml). The absorbance of the blue colored solution was measured after 30 min at 20ºC at 765 nm in Schimadzu 1700 UV-Visible spectrophotometer and the calibration curve was constructed between concentration versus absorbance.

The same procedure was applied for both types of test formulations of Drakshasava as Drakshasava-T and Drakshasava-M respectively and for its marketed preparation, 1 ml of each of the test preparation of Drakshasava as Drakshasava-T (1g/100ml), Drakshasava-M (1g/100ml) and its marketed preparation (1g/100 ml) was mixed with the same reagents as did in the construction of calibration curve and after 1 h, the absorbance of blue colored solution formed was measured for the determination of total phenolic content in both types of Drakshasava as Drakshasava-T, Drakshasava-M and in its marketed preparation. All determinations were performed in triplicate. The total phenolic content was determined in terms of gallic acid equivalent (GAE) as milligram per gram of the test formulation and expressed as percentage weight by weight (%w/w).

2.5 Estimation of total flavonoid content:

Total flavonoid content was estimated in both types of Drakshasava as Drakshasava-T and Drakshasava-M prepared by traditional and modern methods respectively and in its marketed preparation by aluminium chloride method²¹. For the preparation of calibration curve, 1 ml of each of the different concentration of standard quercetin solution in methanol as 10, 20, 40, 60, 80 and 100 µg/ml was added to the 10 ml capacity volumetric flask containing 4 ml of distilled water. To the above mixture, 0.3 ml of 5% sodium nitrite (NaNO₂) was added. After 5 min, 0.3 ml of 10% aluminium chloride (AlCl₃) was added. After 6 min, 2 ml of 1 M NaOH was added and the total volume was made up to 10 ml with distilled water. The solution was mixed well and the absorbance was measured against a separately prepared reagent blank at 510 nm.

The same procedure was applied for both of the test formulations of Drakshasava as Drakshasava-T and Drakshasava-M prepared by traditional and modern methods respectively and its marketed preparation, 1 ml of each of the test preparation of Drakshasava as Drakshasava-T (1g/10ml), Drakshasava-M (1g/10ml) and marketed Drakshasava (1g/10ml) was mixed with the same reagents as did in the construction of calibration curve, and then the absorbance was measured for the determination of total flavonoid content in both the test formulations of Drakshasava and in its marketed preparation. All determinations were performed in triplicate. The total flavonoid content was measured in terms of quercetin equivalent as milligram per gram of the test formulation and expressed as percentage weight by weight (%w/w).

2.6. In vitro determination of antioxidant activity:

2.6.1 Super-oxide radical scavenging activity:

The super-oxide radical scavenging activity of both types of Drakshasava as Drakshasava-T and Drakshasava-M prepared by traditional and modern methods respectively and marketed Drakshasava was measured by NBT method²². About 1 ml NBT solution containing 156µM NBT dissolved in 1 ml 10mM phosphate buffer, pH 7.4 and 0.1 ml of different concentration as 100, 150, 200, 250 and 300 µg/ml of each of the test preparation of Drakshasava as Drakshasava-T, Drakshasava-M and marketed Drakshasava respectively and standard antioxidant Vitamin-E was mixed and the reaction was started by adding 100 µl of phenazine methosulphate in 100 mM phosphate buffer having pH 7.4. The reaction mixture was incubated at 25ºC for 5 min, and absorbance at 560 nm was measured against control sample. Percentage inhibition was determined by comparing the results of test and control as per the formula mentioned below-

Inhibition (%) =	(Control absorbance- Test absorbance)	x 100
	Control absorbance

2.6.2 Assay of lipid per-oxidation:

The extent of lipid per-oxidation in goat liver homogenate was measured in vitro in terms of formation of thiobarbituric acid reactive substance (TBARS) by using standard method with the help of spectrophotometer²³. Goat liver was purchased from local slaughter house. Its lobes were dried between blotting paper and were cut into small pieces with a heavy duty blade. They were then homogenized in glass-teflon homogenizing tubes in cold phosphate buffer saline (pH 7.4). It was centrifuged at 2000 rpm for 10 minutes, and supernatant was diluted with phosphate buffer saline up to final concentration of protein 0.8-1.5mg/0.1ml. Protein concentration was measured by using standard method²⁴. To study the comparative response, five different concentrations as 100, 150, 200, 250 and 300 µg/ml of each of the test preparation of Drakshasava as Drakshasava-T, Drakshasava-M prepared by traditional and modern methods respectively and marketed Drakshasava were taken in this experiment. Liver homogenate was aliquoted to seventeen different glass petri dishes. The first two groups were treated as control and standard where buffer and Vitamin-E were added respectively. From the 3^rd group upto 7^th group, different concentration as (100, 150, 200, 250 and 300 µg/ml) of Drakshasava-T, from 8^th group upto 12^th group different concentration as (100, 150, 200, 250 and 300 µg/ml) of Drakshasava-M while from 13^th to 17^th group various concentration as (100, 150, 200, 250 and 300 µg/ml) of marketed Drakshasava were added.

Lipid per-oxidation was initiated by adding 100 μl of 15 mM ferrous sulphate solution to 3 ml of liver homogenate. After 30 minutes, 100 μl of this reaction mixture was taken in a tube containing 1.5 ml of 10% trichloroacetic acid. After 10 minutes, tubes were centrifuged and supernatant was separated and mixed with 1.5 ml of 0.67% thiobarbituric acid. The mixture was heated in a water bath to complete the reaction. The intensity of pink colored complex formed was measured at 535 nm. The percentage of inhibition of lipid per-oxidation was calculated by the following formula –

Inhibition (%) =	(Control absorbance- Test absorbance)	x 100
	Control absorbance

3. RESULTS:

3.1. Results of estimation of total phenolics and flavonoids

Total phenolic content and flavonoids have been estimated in both types of Drakshasava as Drakshasava-T and Drakshasava-M prepared by traditional and modern methods respectively and in its marketed preparation. The calibration curve of standard gallic acid for the estimation of total phenolics has been shown in Fig. 1 while calibration curve of standard quercetin for the quantification of total flavonoids has been shown in Fig. 2. A good linear relationship was observed between absorbance and concentration of standard gallic acid in the range of 1 to 100 µg/ml while for quercetin in the range of 10 to 100 µg/ml. Total phenolic content was measured in the terms of gallic acid equivalent (GAE) in milligram per gram of test formulation and was expressed as percentage weight by weight (% w/w) while total flavonoid content was measured in terms of quercetin equivalent in milligram per gram of the test formulation and was expressed as % w/w. Total phenolic content and flavonoids were found present in rich concentration in both types of Drakshasava as Drakshasava-T, Drakshasava-M and in its marketed preparation. Results of total phenolic content and total flavonoids in both types of Drakshasava as Drakshasava-T, M and marketed Drakshasava have been shown in Table 1.

3.2. Results of in vitro antioxidant activity:

Both types of Drakshasava as Drakshasava-T and Drakshasava-M prepared by traditional and modern methods respectively were evaluated for their antioxidant potential and showed dose dependent antioxidant activity in super oxide radical scavenging activity as well as in lipid per oxidation assay.

3.2.1. Super oxide radical scavenging activity:

Effect of both types of Drakshasava as Drakshasava-T and Drakshasava-M prepared by traditional and modern methods respectively on super-oxide radical scavenging activity has been shown in Fig.3. Both types of Drakshasava as Drakshasava-T and Drakshasava-M showed significant scavenging of super oxide radical in dose dependent manner and showed inhibitory concentration (IC₅₀) 120.63 µg/ml and 128.36 µg/ml respectively. Marketed Drakshasava also showed significant scavenging of super oxide radical in dose dependent manner and showed IC₅₀ 125.12 µg/ml.

3.2.2. Lipid per oxidation assay:

Effect of both types of Drakshasava as Drakshasava-T and Drakshasava-M prepared by traditional and modern methods respectively on lipid per oxidation assay has been shown in Fig.4. Both types of Drakshasava as Drakshasava-T and Drakshasava-M inhibited the ferrous sulphate induced lipid per oxidation in dose dependent manner and showed inhibitory concentration (IC₅₀) 212.50 µg/ml and 220.15 µg/ml respectively. Marketed Drakshasava also significantly inhibited the ferrous sulphate induced lipid per oxidation in dose dependent manner and showed IC₅₀ 216.26 µg/ml.

Fig.1. Calibration curve of standard gallic acid for the estimation of total phenolics

Fig.2. Calibration curve of standard quercetin for the estimation of total flavonoids

Fig. 3. Effect of Drakshasava-T, M and its marketed formulation on super oxide radical scavenging activity

All values are shown as mean ± SEM of three replicates

Fig. 4. Effect of Drakshasava-T, M and its marketed formulation on lipid per oxidation model

All values are shown as mean ± SEM of three replicates

Table 1. Total phenolic content and flavonoids in Drakshasava-T, M and marketed Drakshasava

Sample	Total phenolic content (%w/w)	Total flavonoids (%w/w)
Drakshasava-T	0.1045	0.01264
Drakshasava-M	0.1041	0.01214
Marketed Drakshasava	0.1043	0.01248

4. DISCUSSION:

Plants contain a large variety of phyto-nutrients, many having antioxidant properties. Antioxidant compounds include vitamins, carotenoids, flavonoids and phenolics. Among them, phenolics and flavonoids are the most important and exhibit substantial antioxidant activity^25-26. Thus, on the basis of presence of rich concentration of total phenolics and flavonoids, both of the test formulations of Drakshasava as Drakshasava-T and Drakshasava-M prepared by traditional and modern methods respectively were evaluated for their antioxidant potential on two different in vitro models as super-oxide radical scavenging activity and lipid per-oxidation assay.

In vitro superoxide radical scavenging activity:

Superoxide radical is a highly toxic species and is generated by numerous biological and photochemical reactions. Both aerobic and anaerobic organisms possess super oxide dismutase enzymes that catalyze the breakdown of super oxide radical²⁷.

Reduced phenazine methosulphate assay was used to measure the super oxide dismutase activity of Drakshasava-T, M and its marketed preparation and all these test preparations of Drakshasava exhibited dose dependent antioxidant activity.

In vitro assay of lipid per oxidation:

Lipids are widely involved in oxidative reactions and these reactions can be induced by some radicals, called reactive oxygen species (ROS). Oxidative stress caused by ROS in the living cell is associated with numerous diseases as coronary heart disease, atherosclerosis, inflammation, cancer, anaemia, age related muscular degeneration and ageing. Use of antioxidants can reduce the problems caused by reactive oxygen species and thus they retard the oxidative process²⁸.

The results presented in Fig.4, showed that both types of Drakshasava as Drakshasava-T, Drakshasava-M and its marketed preparation inhibited the ferrous sulphate induced lipid per-oxidation in a dose dependent manner. The inhibition could be caused by the absence of ferryl-perferryl complex or by changing the ratio of ferric to ferrous or by reducing the rate of conversion of ferrous to ferric or by changing the iron itself or combination thereof²⁹. Thus, Drakshasava-T, M and its marketed preparation showed potent antioxidant activity and evidenced that the free radical scavenging potential helps in ameliorating disease process. Therefore, both types of Drakshasava as Drakshasava-T, Drakshasava-M and its marketed preparation can be recommended for the in vivo pharmacological activities based on their antioxidant potential as cardioprotective activity, hepatoprotective , antidiabetic and many others. Enzyme modifying action of antioxidants could account for their pharmacological activities.

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Received on 22.01.2013 Modified on 04.02.2013

Asian J. Research Chem. 6(3): March 2013; Page 204-208