Phytochemical Screening and Antioxidant Studies in the Pulp Extracts of Cucurbita maxima

 

Rangarajan Narasimhan*, Sathiyamoorthy. M

Department of Biochemistry, Sri Sankara Arts and Science College, Enathur, Kanchipuram-631561, Tamil Nadu, India. 

*Corresponding Author E-mail: n.rangarajan@yahoo.co.in

 

ABSTRACT:

Plant products have been part of phytomedicines since time immemorial. The medicinal properties of Cucurbita maxima include anti-diabetic, antioxidant, anticarcinogenic, and anti-inflammatory effects. The objective of this study was to identify the phytochemicals and antioxidants levels in the Cucurbita maxima pulp extracts. The crude ethanol and chloroform extracts of Cucurbita maxima were subjected to preliminary screening. The Phytochemical screening of the Cucurbita maxima pulp extracts revealed the presence of polyphenols, alkaloids, flavanoids, terpenoids, and glycosides. The chemical screening further showed the presence of various amino acids. The pulp homogenate of Cucurbita maxima showed the presence of reasonable levels of enzymatic and nonenzymatic antioxidants.

 

KEY WORDS: Cucurbita maxima, phytochemical, homogenate, antioxidants, oxidative stress. 

 

 


INTRODUCTION:

The plant kingdom is an important source of herbal drugs. Even in recent years, there has been an increasing awareness about the importance of medicinal plants. According to World Health Organization, medicinal plants would be the best source to synthesize drugs. Medicinal plants contain some organic compounds which provide definite physiological action on the human body1. Plant products have been part of phytomedicines since time immemorial. India is the largest producer of medicinal herbs and a rich heritage of traditional medicine constituting with its different components like ayurveda, siddha, unani and homoeopathy 2, 3.  Pumpkin is gourd-like squash belongs to genus Cucurbita and the family Cucurbitaceae.

 

Pumpkins are considered to be a fruit and it contains 90 percent water. It is monoecious plant and it has both male and female flowers on the same plant. The pulp is characteristically flat and asymmetrically oval, and light green in color.

 

Pumpkin is widely cultivated throughout India and in most warm regions of the world, for use as vegetable as well as medicine. Both of its fruits and the aerial parts are commonly consumed as vegetable. The fruits are sweet, refrigerant, emollient, diuretic, sedative and tonic and are useful in burns, scalps, inflammations, abscesses, boils, migraine and neuralgia. Fruit pulp is used as poultice and supplied on to burns, boils and inflammations. The pulp used as antihelminthic and diuretic. This plant has been traditionally used in many countries such as India, China, Brazil, Yugoslavia and America as antidiabetic and antihyperlipidemic, antitumor, antihypertensive, anti-inflammatory, immunomodulatory and antibacterial agent 4.

 

Figure 1. Cucurbita maxima

Figure 2. Cucurbita maxima Pulp

 

MATERIALS AND METHODS:

Plant source

The fresh pulp of cucurbita maxima was purchased from a super market in kanchipuram.  The plant pulp was dried in shade and ground to a uniform powder using a milling machine. The powder was kept in an airtight container for further use.

 

Preparation of solvent extracts:

Ethanol Extract:

5g of powdered pulp was used separately for the preparation of extract. Sample was packed between folds of filter paper and placed in soxhelet apparatus, run between 60-800c using ethanol as solvent.

 

Chloroform Extract:

5g of powdered pulp was used separately for the preparation of extract. Sample was packed between folds of filter paper and placed in soxhelet apparatus, run between 60-800c using chloroform as solvent.

 

Qualitative Analysis of Phytochemicals:

Chemical tests were carried out on the ethanol and chloroform extracts of the powdered pulp using standard procedures to identify the constituents as described by Harborne (1988) 5.

 

The solid part left after soxhelet extraction was digested with 6N HCl in boiling water for half an hour and used for amino acid analysis.

 

Biochemical Analyses:

100 mg of the pulp tissue was weighed, uniformly homogenized with 1.0 ml of 0.5 M phosphate buffer, pH 6.9. The homogenate was centrifuged and the supernatent was used for the following biochemical assays.

 

The total protein content was estimated by the method of Lowry et al. (1951) 6. The level of reduced glutathione was measured by the method of Moron et al. (1979) 7. The vitamin C level was estimated by the method of Omaye et al. (1979) 8. The level of vitamin E was estimated by the method of Desai, (1984)9. The activity of SOD in tissue homogenate was estimated using the method of Stefan Marklund and Gudrun Marklund,(1974)10. The activity of glutathione peroxidase in tissue homogenate was determined by the method of Rotruck et al. (1973)11. The activity of Catalase in tissue homogenate was determined by using the method of Sinha, (1972)12.

 

RESULTS AND DISCUSSION:

Table 1 shows the phytochemical compositions of the ethanol and chloroform extracts of Cucurbita maxima pulp. The results illustrate the presence of various phytochemicals in Cucurbita maxima pulp extracts. Both ethanol and chloroform extracts gave similar results for many tests.  The results show that Cucurbita maxima pulp extracts contain alkaloids, flavanoids, proteins, carbohydrates, polyphenols, phytosterols, glycosides and terpenoids as phytochemical constituents.

 

Phytochemical analysis conducted on the plant extracts revealed the presence of constituents which are known to exhibit medicinal as well as physiological activities. The phenolic compounds are one of the largest and most ubiquitous groups of plant metabolites. They     possess biological properties such as antiapoptosis, antiaging, anticarcinogen,  antiinflammation,  antiatherosclerosis, cardiovascular protection and  improvement of endothelial function. Several studies have described the antioxidant properties of medicinal plants which are rich in phenolic compounds 13.

 

Flavonoids are hydroxylated phenolic substances known to be synthesized by plants in response to microbial infection and they have been found to be antimicrobial substances against wide array of microorganisms in vitro. Their activity is probably due to their ability to complex with extracellular and soluble proteins and to complex with bacterial cell wall .They also are effective antioxidant and show strong anticancer activities. The plant extracts were also revealed to contain saponins which are known to produce inhibitory effect on inflammation. Recent research in the pharmacology of food phytochemicals, a great number of reports have established that plant phenolic compounds including flavonoids are potent antioxidants with reported antimutagenic and anticarcinogenic effects 14.

 

Table-1. Qualitative analysis of the phytochemicals in ethanol and chloroform extracts of  cucurbita maxima pulp

S.No

Phytochemicals

Ethanol

Chloroform

1

Alkaloids

+

+

2

Flavonoids

+

+

3

Carbohydrates

+

+

4

Glycosides

-

+

5

Polyphenols

+

+

6

Tanins

+

+

7

Phenols

+

+

8

Phytosteols

-

-

9

Saponins

+

+

10

Terpenoids

+

+

11

Proteins

+

+

12

Amino acid

+

+

13

Anthraquinones

-

-

(-) Indicates Absence   (+) Indicates Presence

 

Although the mammalian body has certain defence mechanisms to combat and reduce oxidative damage, epidemiological evidence indicates that the consumption of foodstuffs containing antioxidant phyto nutrients notably flavanoids and other polyphenolics is advantageous for our health. Thus, natural antioxidants function as free-radical scavengers and chain breakers, complexers of pro-oxidant metal ions and quenchers of singlet-oxygen formation15.

 

Alkaloids have been associated with medicinal uses for centuries and one of their common biological properties is their cytotoxicity. Several workers have reported the analgesic, antispasmodic and antibacterial properties of alkaloids. The results obtained in this study thus suggest the identified phytochemical compounds may be the bioactive constituents of substantial medicinal merit. In recent years, secondary plant metabolites (phytochemicals) have been extensively investigated as a source of medicinal agents. Since time immemorial, man has used various parts of plants in the treatment and prevention of various ailments.

 

Table 2 shows the profile of amino acids present in the ethanol and chloroform extracts of Cucurbita maxima pulp. It reveals that the Cucurbita maxima pulp contains essential amino acids which may provide a good source of amino acid as supplement.

 

The levels and activities of antioxidants are depicted in the Table 3. Antioxidants are compounds that can delay or inhibit the oxidation of lipids or other molecules by inhibiting the initiation or propagation of oxidative chain reactions 16. The antioxidative effect is mainly due to phenolic components, such as flavonoids, phenolic acids, and phenolic diterpenes 17. The antioxidant activity of phenolic compounds is mainly due to their redox properties, which can play an important role in absorbing and neutralizing free radicals, quenching singlet and triplet oxygen, or decomposing peroxides. The preservative effect of many plant spices and herbs suggests the presence of antioxidative and antimicrobial constituents in their tissues 18.

 

Abiotic stress results in the formation of Reactive oxygen species (ROS) in plants which creates a condition called oxidative stress that can damage cellular components. Plants have developed efficient antioxidant system that can protect plants from this disaster. The toxic effects of ROS are counteracted by enzymatic as well as non- enzymatic antioxidative system such as: superoxide dismutase (SOD), catalase (CAT), Ascorbate peroxidase (APX), glutathione reductase (GR), Ascorbic acid (AsA), Tocopherol, Glutathione and phenolic compounds.

 

Normally, each cellular compartment contains more than one enzymatic activity that detoxifies a particular ROS. For example, the cytosol contains at least three different enzymatic activities that scavenge H202. Activities of antioxidant enzymes have been directly correlated with the stress tolerance in plants and augmented ability to scavenge ROS has been observed in the plants that grow in sublethal levels of stress 19.

 

In plants over 150 genes encode for different ROS-detoxifying or ROS-producing enzymes forming well organized ROS gene 20. Considerable progress has been made in understanding how plants protect themselves against oxidative stresses and pathogens. Several genes encoding for plant antioxidant enzymes have been cloned, characterized, and used in the construction of transgenic lines.

 

Table-2. Qualitative analysis of the amino acids in ethanol and chloroform extracts of cucurbita maxima pulp

Tests

Ethanol

Chloroform

Ninhydrin

+

+

Xantho    proteic

+

+

Folin’s

+

+

Millon’s

+

+

Pauly’s

+

+

Morner’s

-

+

Hopkin’s cole

+

+

Ehrlish’s

+

-

Sakaguchi’s

-

+

Sodium plumbate

+

-

Sodium nitropruside

-

+

 (-) Indicates Absence      (+) Indicates  Presence

 

Table-3. The levels and activities of protein and antioxidants in the cucurbita maxima pulp tissue

S.No

Parameters

Values

1

Protein (mg/gm of tissue)

74

2

Vitamin-C (mg/gm of tissue)

12

3

Vitamin-E (mg/gm of tissue)

15

4

Reduced Glutathione (mg/g of tissue)

52.7

5

Catalase (µmoles of Hydrogen peroxide utilized/min/mg/of tissue)

40.8

6

SOD (µg of pyrogallol auto oxidation inhibition/min)

102

7

Glutathione peroxidase

(µmoles of GSH oxidised/min/mg of tissue)

5.7

 

CONCLUSION:

In the present study, evaluation of phytochemicals and antioxidant studies of Cucurbita maxima pulp provide valuable information regarding their identification, authentication and chemical constituents. This may be useful for the standardization and isolation of bioactive compounds from this plant. The constituents of Cucurbita maxima pulp extracts may have several medicinal properties that leading to opening up new avenues in the use of natural products for therapeutic purpose.

 

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Received on 01.01.2016          Accepted on 29.01.2016        

© Asian Pharma Press All Right Reserved

Asian J. Pharm. Res. 6(1): January -March, 2016; Page 01-04

DOI: 10.5958/2231-5691.2016.00001.0