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
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Asian J. Pharm. Res. 6(1): January -March, 2016; Page 01-04
DOI: 10.5958/2231-5691.2016.00001.0