Preliminary Phytochemical Screening and Antioxidant Activity of Petroleum Ether Extract of Trichosanthes dioica Roxb (Fruits)

 

 

Yogesh Shivhare, Priya Singh, K. K. Patel and Prashant Soni

Department of Pharmacognosy, VNS Institute of Pharmacy, Bhopal (M.P.)

 

ABSTRACT:

In-vitro antioxidant activity of petroleum ether extract of Trichosanthes dioica was determined by DPPH free radical scavenging assay, Reducing power assay, Nitric oxide scavenging activity, Hydrogen peroxide radical scavenging activity using ascorbic acid as a standard. The IC50 values were calculated for all the models in order to evaluate the antioxidant efficiency of Trichosanthes dioica extract. In all the testing a significant correlation existed between concentration of the extract and % inhibition of free radicals. Obtained results clearly indicated that petroleum ether extract of Trichosanthes dioica possesses significant antioxidant potential as compared with standard.

 

KEYWORDS: Trichosanthes dioica, Nitric oxide, % Inhibition

 

 

INTRODUCTION:

Oxygen is a crucial module for the survival of humans.1 Under certain situations it has deleterious effects on the human body.2 Most of the potentially harmful effects of oxygen are due to the formation and activity of a number of chemical compounds, known as reactive oxygen species (ROS). These are highly reactive substances and are responsible for various diseases like CNS disorders, diabetes mellitus and liver diseases.3 Thus, there is the need of antioxidants to overcome these problems. Recently, interest has increased considerably in finding naturally occurring antioxidants for use in foods or medicinal materials to replace synthetic antioxidants, which are being restricted due to their side effects such as carcinogenicity.4 Herbal plants have been used for medicinal applications from earliest time, when man began caring for his body and health. The emphasis of development of new biologically active molecule has been gradually replaced by use of total herbs as medicine and food supplements. Now herbal based products have very good present and future prospects in International market.5

 

The fruits of the plant Trichosanthes dioica (family- Cucurbitaceae) commonly known as pointed gourd in English and Parwal in Hindi, native to the plains of N. India extending to Assam and E. Bengal. For centuries, Pointed gourd has been used in folk medicine to heal arrange of ailments and has been credited with many medicinal properties especially laxative, cooling, and in bilious fever, beneficial in piles, tonic etc.6, 7 By keeping this view, the present exploration of the petroleum ether extract of the fruits of Trichosanthes dioica was undertaken to evaluate its antioxidant potential.

 

MATERIALS AND METHODS:

Plant material:

The fresh fruits of Trichosanthes dioica were collected from the local market of Bhopal and authenticated by Dr. A. S. Yadav, professor, Government MVM College Bhopal. The fruits were shade dried and pulverized into moderately coarse powder and then stored in a tightly closed container for further use.


Preparation of extract:

The dried powdered plant material (125g) was extracted in soxhlet apparatus with petroleum ether (60-80şc). The extract was concentrated to a brown residue (1.9g w/w). This crude extract was used for further investigation for potential antioxidant properties.

 

Preliminary phytochemical screening:

Dried petroleum ether extract was subjected to preliminary phytochemical investigations for the identification of secondary metabolites by utilizing standard methods of qualitative test analysis.8, 9

 

EVALUATION OF ANTIOXIDANT ACTIVITY:

DPPH scavenging activity:

The procedure of Brand- Williams10 has been adapted for evaluation of the free radical scavenging capacity of the methanolic extract. Different concentrations (05-45μg/ml) of petroleum ether extract of Trichosanthes dioica were prepared and 3ml of each solution was mixed with 1 ml of a 0.1mM DPPH solution. The decrease in absorbance was measured at 515 nm after 30 minutes of incubation period at room temperature using a UV Visible spectrophotometer1700. The scavenging activity of sample extract was expressed as the inhibition of DPPH radical and calculated according to the following formula with as the control:

 

Scavenging Activity (%) = [(A control - A sample) / A control]*100, where A control (containing adequately diluted DPPH solution) and A sample   is the Absorbance with different dilutions of drug extract. Ascorbic acid was used as reference standard.

 

Reducing power assay:

Reducing power of extract of Trichosanthes dioica was estimated using the protocol reported by Oyaizu11. Different concentrations of petroleum ether extract of Trichosanthes dioica (5-25μg/ml) were prepared and 1ml of each solution was mixed with phosphate buffer (2.5ml, 0.2M, pH 6.8) and potassium ferricyanide (2.5ml, 1%). The mixture was incubated at 50˚C for 20 min. To this mixture, 2.5 ml of 10% trichloroacetic acid (TCA) was added and then centrifuged at 3000 rpm for 10 min. The upper layer of the solution (2.5 ml) was mixed with distilled water (2.5ml) and Fecl3 (0.5 ml, 0.1%) was added and the absorbance was measured at 700 nm. The percentage scavenging was calculated by using the formula (A control - A sample)/ A control ×100, where A control is the absorbance of solution without extract and A sample is the absorbance with different dilutions of drug extract. Ascorbic acid was used as standard.

 

Nitric oxide scavenging activity:

Nitric oxide scavenging activity was evaluated by the method of Gupta12. 1ml of Sodium nitroprusside (10mM) in phosphate-buffered saline (PBS) was mixed with 3.0 ml of different concentrations (20 – 120μg/ml) of the petroleum ether extract of Trichosanthes dioica dissolved in water and incubated at 25­­0 C for 180 min. The samples from the above were reacted with equal volume of Greiss reagent (1% sulphanilamide, 0.1% napthylethylenediamine hydrochloride and 3% of phosphoric acid). The absorbance of the chromophore formed during the diazotization of nitrite with sulphanilamide and subsequent coupling with napthylethylenediamine was read at 546 nm. The percentage scavenging was calculated by using the formula: (A control - A sample)/ A control ×100, where A control is the absorbance of solution without extract and   A sample is the absorbance with different dilutions of drug extract. Ascorbic acid was used as reference standard.

 

Hydrogen peroxide radical scavenging activity:

The ability of the Trichosanthes dioica extract to scavenge hydrogen peroxide was determined according to the method of Ruch13. A solution of hydrogen peroxide (40 mM) was prepared in phosphate buffer (pH 7.4). The concentration of hydrogen peroxide was determined by absorption at 230 nm using a UV Visible spectrophotometer 1700. Then hydrogen peroxide solution (0.6 ml, 40 mM) was mixed to different concentrations (30 – 180μg/ml) of the petroleum ether extract dissolved in water The absorbance of hydrogen peroxide at 230 nm was determined after ten minutes against a blank solution containing phosphate buffer without hydrogen peroxide. The percentage scavenging was calculated by using the formula:

(A control - A sample)/ A control ×100, where A control is the absorbance of solution without extract and A sample is the Absorbance with different dilutions of drug extract. Ascorbic acid was used as reference standard.

 

STATISTICAL DATA:

Data are presented as the mean ± SEM of each triplicate test. The analysis was performed by using Dunnett vs. Control test and by ANOVA. P<0.05 were considered to be statistically significant.

 

RESULTS:

Preliminary phytochemical screening:

Preliminary Phytochemical screening of the petroleum ether extract of Trichosanthes dioica showed the presence of triterpenoids and steroids.

 

DPPH scavenging activity:

The results of DPPH radical scavenging activity of the petroleum ether extract of Trichosanthes dioica with IC50 (% Inhibition) are shown in fig 1.1. The IC50 value of petroleum ether extract of Trichosanthes dioica and standard (ascorbic acid) was found to be 33µg/ml, and 11µg/ml respectively. The results showed a significant (p <0.01) decrease in the concentration of DPPH radical due to the scavenging ability of petroleum ether extract as compared to standard (ascorbic acid).

 

 

Reducing power assay:

The Reducing ability of petroleum ether extract of Trichosanthes dioica and ascorbic acid were shown in the fig 1.2. The IC50 value of petroleum ether extract of Trichosanthes dioica and standard (ascorbic acid) was found to be 34µg/ml and 12µg/ml respectively. The test material (petroleum ether extract of Trichosanthes dioica) has shown significant reducing property when compared with standard (ascorbic acid).

 

Nitric oxide scavenging activity:

The nitric oxide scavenging activity of petroleum ether extract of Trichosanthes dioica and ascorbic acid were shown in the fig 1.3 which illustrates the % inhibition of nitric oxide generation by petroleum ether extract of Trichosanthes dioica. Ascorbic acid was used as a reference. The IC50 value of petroleum ether extract and standard (ascorbic acid) was found to be 113µg/ml and 85µg/ml respectively. The results indicate significant (p <0.01) decrease in the concentration of nitric oxide radical due to the scavenging ability of petroleum ether extract as compared to standard (ascorbic acid).

 

Hydrogen peroxide radical scavenging activity:

Hydrogen peroxide scavenging activity of petroleum ether extract of Trichosanthes dioica and ascorbic acid were shown in the fig 1.4. It showed significant scavenging activity of hydroxyl radical generated from H2O2 system. The IC50 value for petroleum ether extract was 162µg/ml, whereas 167µg/ml was the value of ascorbic acid. The results indicated that petroleum ether extract possessed significant antioxidant activity (p<0.01).

 

DISCUSSION:

DPPH is a constant free radical at room temperature and accepts an electron or hydrogen radical to develop into a stable diamagnetic molecule.14 The decrease in absorbance of DPPH radical caused by antioxidants, because of the reaction between antioxidant molecules and radical, progresses, which consequences in the scavenging of the radical by hydrogen donation.15 Thus, as expected, petroleum ether extract of Trichosanthes dioica showed DPPH radical scavenging activity in a concentration dependent manner. In the reducing power assay, the reduction and consequent formation of the ferrous product is monitored coincident formation of Perl’s Prussian blue at 700 nm.16 An increasing absorbance is indicative of potent antioxidant activity. In the present work, it was observed that absorbance of the petroleum ether extract was increased with increase in concentration of test. So, petroleum ether extract of T. dioica showed concentration dependant reducing capacity. Excess concentration of NO is associated with several diseases.17, 18 Oxygen reacts with the excess nitric oxide to generate nitrite and peroxynitrite anions, which act as free radicals.19,20  In the present study, the extract competes with oxygen to react with nitric oxide and thus inhibits generation of the anions. Even though hydrogen peroxide itself is not very imprudent, it can sometimes cause cytotoxicity by giving augment to hydroxyl radicals in the cell. Thus, removing H2O2 is very important throughout food systems. Scavenging of H2O2 by antioxidants may be due to contribution of electrons to H2O2, thus neutralizing it to water.21 As the petroleum ether extract scavenged hydrogen peroxide radical similar to the standard (ascorbic acid). So it reflects that the plant extract could probably reduce the formation of hydroxyl radical in-vivo and can prevent the cellular and oxidative damage.

CONCLUSION:

Hence, the results obtained from data concludes that petroleum ether extract of Trichosanthes dioica has potent antioxidant activity which may probably be due to the phytoconstituents present in the plant or could be a function of either the individual or the additive effects of the phytoconstituents.

 

ACKNOWLEDGEMENT:

Mr. Yogesh Shivhare, corresponding author, sincerely thanks to Principal, VNS Institute of Pharmacy, Bhopal (M.P.) India, for providing necessary facilities during the course of this work.

 

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Received on 01.01.2010

Accepted on 24.03.2010   

© A&V Publication all right reserved

Research Journal of Pharmacognosy  and Phytochemistry. 2(2): March -April 2010, 155-158