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Research Article
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In vitro Antioxidant Activity, Phytochemical Screening, Cytotoxicity and Total Phenolic Content in Extracts of Caesalpinia pulcherrima (Caesalpiniaceae) Pods |
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M.R. Kumbhare,
T. Sivakumar,
P.B. Udavant,
A.S. Dhake
and
A.R. Surana
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ABSTRACT
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Caesalpinia pulcherrima L. Swartz (Caesalpiniaceae) is an ornamental plant also used as a common medicinal plant in India, Taiwan and South-East Asian countries. Majority of the diseases/disorders are mainly linked to oxidative stress due to free radicals. The aims of this study were to screen for phytochemical constituents, evaluate cytotoxicity, in vitro antioxidant activity and estimation of total phenolic content of extracts of pods of Caesalpinia pulcherrima. Phytochemical analysis revealed the presence of tannins, flavonoids, steroids and alkaloids. Brine Shrimp Lethality (BSL) bioassay was used to investigate the cytotoxic effects. The LC 50 (μg mL-1) values obtained for extracts as 750 μg mL-1 for petroleum ether extract, 800 μg mL-1 for chloroform extract and 900 μg mL-1 for methanol extract. The total phenolic content of the methanolic extract was 38.04% w/w, equivalent to gallic acid. Petroleum ether, chloroform and methanolic extracts of Caesalpinia pulcherrima and standard ascorbic acid were found to be scavenger of DPPH radical with an IC50 of 124.75, 112.08, 54.34 and 13.86 μg mL-1, respectively. Methanolic extract was good scavenger of DPPH radical. Petroleum ether, chloroform, ethyl acetate soluble fraction of methanolic extracts of pods of Caesalpinia pulcherrima and ascorbic acid were found to be scavenger of nitric oxide radical with an IC50 of 93.32, 65.12, 54.83 and 12.59 μg mL-1, respectively. Ethyl acetate soluble fraction was found to be good scavenger of nitric oxide radical. Our conclusion provides support that the crude extracts of C. pulcherrima is a probable source of natural antioxidants and this justified its uses in folkloric medicines.
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How
to cite this article:
M.R. Kumbhare, T. Sivakumar, P.B. Udavant, A.S. Dhake and A.R. Surana, 2012. In vitro Antioxidant Activity, Phytochemical Screening, Cytotoxicity and Total Phenolic Content in Extracts of Caesalpinia pulcherrima (Caesalpiniaceae) Pods. Pakistan Journal of Biological Sciences, 15: 325-332. DOI: 10.3923/pjbs.2012.325.332 URL: https://scialert.net/abstract/?doi=pjbs.2012.325.332
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Received: April 23, 2012;
Accepted: June 25, 2012;
Published: August 01, 2012
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INTRODUCTION
In Ayurveda, the use of herbal extracts and nutritional supplements is well
documented either as alternative or complimentary medicine to the conventional
chemotherapy for treatment of inflammatory diseases in the Indian subcontinent
for 5000 years (Dahanukar et al., 2000). The current
rising recognition of medicinal plants is due to many reasons, including escalating
faith in herbal medicine. No doubt allopathic medicine may cure a wide range
of diseases; however, its high prices and side-effects are causing many people
to return to herbal medicines which have fewer side effects (Kala,
2005). For most of the developing world, the main issue of public health
is still the acute need for basic health care which is sadly lacking even at
the most elementary level. This is true in both the rapidly growing cities and
in the rural areas. The World Health Organization (WHO) indicates that more
than half of the worlds population does not have access to adequate health
care services. Medicinal plants offer alternative remedies with tremendous opportunities.
They not only provide access and affordable medicine to poor people; they can
also generate income, employment and foreign exchange for developing countries.
Many traditional healing herbs and plant parts have been shown to have medicinal
value, especially in the rural areas and that these can be used to prevent,
alleviate or cure several human diseases. The WHO estimates that more than 80%
of the worlds population rely either solely or largely on traditional
remedies for health care. Interest in the exploitation of medicinal and aromatic
plants as pharmaceuticals, herbal remedies, flavorings, perfumes and cosmetics
and other natural products has greatly increased in the recent years (CIMAP,
2000). Caesalpinia pulcherrima L. (Caesalpiniaceae) is an attractive
plant due to its array of flowers which appear yellow, pink, off-white and red
with yellow margins (Roach et al., 2003).
Caesalpinia pulcherrima is also known as peacock flower. It is a common
medicinal plant in India, Taiwan and South-East Asian countries. In alternative
medicine, the different parts of this plant have been used as an anti-inflammatory,
abortifacient, emmenagogue, bronchitis and malarial infection while fruits are
employed to cure diarrhea and dysentery (Srinivas et
al., 2003; Chiang et al., 2003). Bark
shown Antimicrobial, Cytotoxic activity (Islam et al.,
2003). Flowers shown Antimicrobial and Antifungal activity (Sudhakar
et al., 2006), fruits shown Antiviral activity (Chiang
et al., 2003). Leaves shown Antitumor activity (Chiang
et al., 2003), Antimicrobial activity (Ragasa
et al., 2002), Antiviral activity (Chiang et
al., 2003). Its seeds have shown Antiviral activity (Chiang
et al., 2003) stem shown cytotoxic activity (McPherson
et al., 1983). The brine shrimp cytotoxicity assay was considered
as a convenient probe for preliminary assessment of toxicity developed by Meyer
et al. (1982). Since ancient times, the medicinal properties of plants
have been investigated in the recent scientific developments throughout the
world, due to their potent antioxidant activities. As antioxidants have been
reported to prevent oxidative damage caused by free radicals, it can interfere
with the oxidation process by reacting with free radicals, chelating, catalytic
metals and also by acting as oxygen scavengers (Shahidi et
al., 1992; Elzaawely and Tawata, 2012). Akond
et al. (2011) reported total polyphenol and antioxidant activity
of 29 common bean from diverse origins USA, Barzil and India. The potentially
reactive derivatives of oxygen, attributed as Reactive Oxygen Species (ROS),
are continuously generated inside the human body. ROS have been considered to
cause injury to living organisms and thus play an important role in many human
diseases such as arthritis, atherosclerosis, diabetes mellitus and cancer (Elzaawely
and Tawata, 2012; Gupta et al., 2007). The
generated ROS are detoxified by the antioxidants present in the body. Recently
there has been an increase of attention in the therapeutic potentials of medicinal
plants as antioxidants in reducing such free radical induced tissue injury.
Besides well identified and traditionally used natural antioxidants from tea,
wine, fruits, vegetables and spices, some natural antioxidant (e.g., rosemary
and sage) are already exploited commercially also as antioxidant additives or
nutritional supplements (Schuler, 1990). Also many other
plant species have been investigated in the search for novel antioxidants (Chu
et al., 2000; Koleva et al., 2002;
Mantle et al., 2000; Oke and
Hamburger, 2002) but generally there is still a demand to find more information
concerning the antioxidant potential of plant species. It has been mentioned
the antioxidant activity of plants might be due to their phenolic compounds
(Cook and Samman, 1996). Flavonoids are a group of polyphenolic
compounds with known properties which include free radical scavenging, inhibition
of hydrolytic and oxidative enzymes and anti-inflammatory action (Frankel,
1995). Some evidence suggests that the biological actions of these compounds
are related to their antioxidant activity (Gryglewski et
al., 1987). An easy, rapid and sensitive method for the antioxidant
screening of plant extracts is free radical scavenging assay using 1,1-diphenyl-2-picrylhydrazyl
(DPPH) stable radical spectrophotometrically. In the presence of an antioxidant,
DPPH radical obtains one more electron and the absorbance decreases (Koleva
et al., 2002). Phenols are a class of low molecular weight secondary
metabolites found in most land plants (Okpuzor et al.,
2009). Derived polyphenols from plants are of great importance because of
their potential antioxidant and antimicrobial properties. Phenolic compounds
exhibit a considerable free radical scavenging (antioxidant) activity which
is determined by their reactivity as hydrogen or electron-donating agents, the
stability of the resulting antioxidant derived radical, their reactivity with
other antioxidants and finally their metal chelating properties (Ang-Lee
et al., 2001; Wojdylo et al., 2007).
Phytochemicals have been of huge interest as a supply of natural antioxidants
used for health promotion, food preservation, food flavoring and cosmetics as
they are safer than synthetics (Khasawneh et al.,
2011). In this study for the first time evaluated cytotoxicity, in vitro
antioxidant activity and estimated total phenolic content of methanolic
extract of pods of Caesalpinia pulcherrima (Caesalpiniaceae).
MATERIALS AND METHODS Plant material: Pods of Caesalpinia pulcherrima was collected from local region of Nashik, India in October 2008. The plant material was identified and authenticated by Dr. P.G. Diwakar Botanical survey of India, Koregaon Park, Pune, India. (Ref No. BSI/WC/Tech/2009/370). Preparation of extract: The plant material were cleaned, dried under shade and pulverized by using grinder. 500 g of the powder of pods was in succession extracted with petroleum ether, chloroform and methanol in order of their rising polarity using Soxhlet apparatus. The yield of extracts obtained as petroleum ether as 1.21%, chloroform as 2.46%, Methanol as 13.32%. From the Preliminary Phytochemical study revealed that occurrence of sterols, glycosides, alkaloids, triterpenoids, flavonoids and tannins in the extracts.
Brine shrimp lethality (BST): The in vitro lethality in a simple
zoological organism such as BST, developed by Meyer et
al. (1982), might be used as a simple tool to guide for cytotoxic activity.
Brine shrimp eggs were collected from Fisheries Dept. Government of Maharashtra
Dapachari, Dahanu Dist-Thane, Maharashtra, India. Brine shrimp eggs were placed
in artificial sea water (3.8% w/v NaCl in distilled water) and incubated at
24-28°C. Eggs were hatched in 48 h providing large number of larvae (nauplii).
Ten numbers of nauplii were placed in 5 mL of sea water and different concentrations
were prepared and placed in vials. Alive nauplii were counted after 24 h and
lethal concentration (LC50) calculated (Ramachandran
et al., 2011).
Antioxidant activity
DPPH free radical scavenging assay: 2,2-diphenyl-1-picrylhydrazyl (DPPH)
is widely used to test the ability of compounds to act as free radical scavengers
or hydrogen donors and to evaluate antioxidant activity of phytoconstituents.
DPPH is nitrogen centered free radical. It reacts similar as peroxyl radial.
The reaction rates directly correlate with antioxidant activity. The odd electron
in DPPH free radical gives a strong absorption maximum at 517 nm and is purple
in color. The color turn from purple to yellow as the molar absorptivity of
DPPH radical at 517 nm reduces when odd electron of DPPH radical becomes paired
with hydrogen from free radical scavenging antioxidant to form the reduced DPPH-H.
The resulting decoloration is stoichiometric with respect to number of electrons
captured (Sanchez-Moreno et al., 1999).
Ascorbic acid was used as standard. Percentage inhibition was calculated using formula:
where, A is absorbance. The respective reaction is as follows:
Nitric oxide radical scavenging assay: Sodium nitroprusside in aqueous
solution at physiological pH, spontaneously produce nitric oxide which reacts
with oxygen to produce nitrite ions which can be determined by the use of the
Griess reagent. Scavengers of nitric oxide compete with oxygen and reduce the
production of nitric oxide. Nitric oxide scavenging activity was performed by
sodium nitroprusside-Griess reagent. In this method sodium nitroprusside (1
mM) in phosphate buffer saline solution was mixed with different concentration
of extracts solution in methanol and incubated at 37°C for 150 min. Blank
solution was also prepared. After incubation 0.5 mL of Griess reagent (1% sulphanilamide,
2% o-phosphoric acid add 0.1% N-(1-naphthyl)-ethylenediamine hydrochloride)
was added. The absorbance was taken at 546 nm. Ascorbic acid was used as a standard.
Percentage inhibition was calculated as per above formula. IC50 was
calculated for each extract (Viturro et al., 1999;
Garrat, 1964).
Estimation of total phenolic content: Total phenolic content of methanol
extract of pods of Caesalpinia pulcherrima by Folin-Ciocalteu method
was determined as per method described by Chandler and Dodds
(1993). The quantitative phenolic estimation was performed at max 765 nm
by change in intensity of Folin-phenolic compounds complex. Readings were taken
after 1 h at 765 nm by UV Spectrophotometer (1650 Shimadzu, Japan) against reagent
blank. With the help of calibration curve, the phenolic concentration of extract
was determined (Ravishankara et al., 2002; Chandler
and Dodds, 1993; Vicente et al., 2011).
RESULTS Phytochemical screening: The crude petroleum ether, chloroform and methanolic extract of pods of Caesalpinia pulcherrima was qualitatively tested for the presence of sterols, glycosides, alkaloids, triterpenoids, flavonoids, anthraquinones, carotenoids, tannins and the results were given in Table 1. Cytotoxicity studies: In brine shrimp lethality bioassay (Table 2), crude petroleum ether, chloroform and methanolic extract of pods of Caesalpinia pulcherrima showed lethality against the brine shrimp nauplii. It showed different mortality rate at different concentrations. The LC50 (μg mL-1) values obtained for extracts as 750 μg mL-1 for petroleum ether extract, 800 μg mL-1 for chloroform extract and 900 μg mL-1 for methanol extract.
Antioxidant activity by DPPH free radical scavenging assay: DPPH radical
scavenging ability is widely used as an index to evaluate the antioxidant potential
of medicinal plants.
Table 1: |
Preliminary phytochemical study |
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+: Positive test, -: Negative test |
Table 2: |
LC 50 values of different extracts of Caesalpinia
pulcherrima pods |
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In vitro antioxidant studies of the three extracts, the extent of DPPH
radical scavenging at different concentrations (25-100 μg mL-1)
of Caesalpinia pulcherrima extracts was measured, with ascorbic acid
as the standard/control. The radical scavenging effect was found to increase
with increasing concentrations. The control and the plant extracts showed (Table
3) their maximum activity of 91.93% (control) 76.11% (methanol) 52.58% (chloroform)
36.12% (petroleum ether), respectively with IC50 values of 13.86,
64.51, 102.88 and 144.58 μg mL-1. Methanolic extract was found
to be good scavenger of DPPH radical.
Antioxidant activity by nitrous oxide free radical scavenging assay:
Nitric oxide radical scavenging activity was determined according to the method
reported by Garrat (1964). In vitro antioxidant
studies of the three extracts; the extent of NO radical scavenging at different
concentrations (25-100 μg mL-1) of Caesalpinia pulcherrima
extracts was measured, with ascorbic acid as the standard.
Table 4: |
Nitric oxide free radical scavenging activity of different
extracts of Caesalpinia pulcherrima pods and ascorbic acid |
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Table 5: |
Calibration curve data of gallic acid |
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The radical scavenging effect was found to increase with increasing concentrations.
The control and the plant extracts showed (Table 4) their
maximum activity of 93.78% (control) 70.40% (methanol) 66.67% (chloroform) 46.13%
(petroleum ether), respectively with IC50 values of 12.59, 68.44,
73.08 and 107.59 μg mL-1.
Estimation of total phenolic content: The values obtained for absorbance at 765 nm were 0.374, 0.498, 0.567, 0.699, 0.791, 0.904, 1.005, 1.147 and 1.354, respectively for 1, 2, 3, 4, 5, 6, 7, 8 and methanolic extract of Caesalpinia pulcherrima. Total phenolics content in methanolic extract of pods of Caesalpinia pulcherrima was found to 38.04% w/w, equivalent to gallic acid. Result is shown in Table 5. DISCUSSION
The crude petroleum ether, chloroform and methanolic extracts of pods of
Caesalpinia pulcherrima was qualitatively tested for the presence of sterols,
glycosides, alkaloids, triterpenoids, flavonoids, anthraquinones, carotenoids
and tannins. Isolation of pure, pharmacologically active constituents from plants
remains an extensive and tiresome process. For this reason, it is necessary
to have methods existing which eliminate needless separation procedures. Chemical
screening is thus performed to allow localization and targeted isolation of
new or valuable constituents with possible pharmacological activities. Alkaloids
have been linked with medicinal uses for centuries and one of their common biological
properties is their cytotoxicity (Nobori et al.,
1994). The selection of todays therapy is therefore investigation
of plant drugs. However, due to the over exploitation of the medicinal plants,
several of them have become rare. The brine shrimp lethality assay represents
a quick, inexpensive and simple bioassay for testing plant extracts bioactivity
which in the majority cases correlates reasonably fit with cytotoxicity and
anti-tumor properties. Cytotoxic and antioxidant activity displayed by the plants
demonstrates presence of secondary metabolites (McLaughlin
et al., 1993). In this study, the brine shrimp lethality of extracts
of pods of Caesalpinia pulcherrima a medicinal plant used in traditional
medicine to brine shrimp was determined following the modified method of Solis
et al. (1993). Cytotoxic property by plant material is due to the
presence of antitumor compounds (Ara et al., 1999).
Cancer is the main killer disease in most developed as well as developing countries
which is induced by oxidative stress (Bandyopadhyay et
al., 1999; Gulcin, 2009). Hence antioxidants
which are very effective in combating cancer needs thorough search especially
safer compounds from plant sources. Increased oxidative stress encountered in
body due to either environmental hazard or impairment in the body metabolism
due to varying disease conditions including drugs or having insufficient amount
of dietary antioxidants, has to be limited by exogenous supply of antioxidants
as a choice of therapy or preventive measure. Natural antioxidants that are
present in herbs and spices are accountable for inhibiting or preventing the
harmful consequences of oxidative stress. Spices and herbs contain free radical
scavengers like polyphenols, flavonoids and phenolic compounds Natural antioxidants
are favored over that of allopathic drugs to overcome the side effects. The
majority of the polar compounds such as phenolic and flavonoid substances are
potent inhibitors of reactive oxygen species attack (Owen
et al., 2003; Rebiai et al., 2011).
Phenol compounds have some antioxidant activity (Leamsomrong
et al., 2009). They are able to terminate free radicals and chelate
metal ions that are capable of catalyzing formation of ROS that promote lipid
peroxidation (Muchuweti et al., 2007). There
are many studies indicated on the toxic effects of plants attributed to the
presence of bound cyanogenic glycosides (Zakaria et al.,
2006). The biological properties, including cytotoxic and antioxidant properties,
of flavonoids are considered in an evaluation of the medicinal and nutritional
values of these compounds (Harborne and Williams, 2000;
Ramachandran et al., 2011). The antioxidant activity
has correlation with total phenolic content. Methanolic, chloroform and petroleum
ether extracts at various concentrations ranging from 25-100 μg mL-1
were tested for their antioxidant activity using DPPH (1-diphenyl-2-picrylhydrazyl)
radical scavenging assay method. The DPPH is a stable free radical at room temperature
and accept an electron or hydrogen radical to become a stable diagnostic molecule
(Gupta and Sharma, 2010). This study explains antioxidant
activity of extracts. DPPH radical scavenging activity assay assesses the capacity
of the extract to donate hydrogen or to scavenge free radicals. The result revealed
that the methanolic extract of the species exhibited the highest radical scavenging
activity (%) with 76.11 followed by its chloroform extract with 52.58 and for
petroleum ether extract 36.12. The DPPH radical scavenging activities of extracts
increased gradually in a dose dependent manner. Smaller IC50 value
corresponds to a higher antioxidant activity of the plant extract (Maisuthisakul
et al., 2007). Nitric oxide is a very unstable species under the
aerobic condition. It reacts with O2 to produce the stable product
nitrates and nitrite through intermediates through NO2, N2O4
and N3O4. It is estimated by using the Griess reagent.
In the presence of test compound which is a scavenger, the amount of nitrous
acid will decrease. Free radicals are constantly produced in the living system
which can cause an extensive damage to bio-molecules and tissues thereby causing
various diseases like extensive lysis and degenerative diseases (Ames
et al., 1993). The results obtained are shown in Table
4 and it indicates that the crude methanolic extract (70.4%), chloroform
extract (66.67%) and petroleum ether extract (46.13%) of the plant possessed
moderate NO free radical scavenging activity. The NO free radical scavenging
activity was increased by increasing the concentration of the test samples.
Plant phenolics are a major group of compounds acting as primary antioxidants
or free radical scavengers. Therefore, it was reasonable to determine the total
phenolic content in the plant extract. The result shows that the phenolic content
of pods of Caesalpinia pulcherrima is higher and the radical scavenging
activity is likely to be due to the phenolics however, phenols may not be solely
responsible for the antioxidant activity. In general, extracts with high antioxidant
activity show a high phenolic content. Plant extracts with high phenolic contents
also show high flavonoid content as reported for other plant species (Makepeace
et al., 1985). The antioxidant activities of different extracts of
pods of Caesalpinia pulcherrima are in accordance with their amount of
phenolics contents.
CONCLUSION Currently there has been an increased interest worldwide to identify antioxidant compounds from plant sources which are pharmacologically potent and have small or no side effects for use in protective medicine and the food industry. Increasing acquaintance in antioxidant phytoconstituents and include them in daily uses and diet can give sufficient support to human body to fight those diseases. Brine shrimp lethality assay is very useful and inexpensive way of assessing the bioactivity of plant extracts. The promising result displayed by the plant extract in brine shrimp lethality test justified the efficacy of the plant in traditional medicine. Phytochemical analysis revealed the presence of tannins, flavonoids, steroids and alkaloids. This study affirms the in vitro antioxidant potential of crude methanolic, chloroform and petroleum ether extracts of the pods of Caesalpinia pulcherrima, with results comparable to those of the standard compounds such as ascorbic acid. ACKNOWLEDGMENTS The authors are thankful to the authorities of SMBT College of Pharmacy, Nandihills, Dhamangaon, Tal-Igatpuri, Dist.-Nashik-422403(M.S.), India for providing necessary facilities and encouragement to carry out research work.
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REFERENCES |
1: Ames, B.N., M.K. Shigenaga and T.M. Hagen, 1993. Oxidants, antioxidants and the degenerative diseases of aging. Proc. Nat. Acad. Sci. USA., 90: 7915-7922. Direct Link |
2: Ang-Lee, M.K., J. Moss and C.S. Yuan, 2001. Herbal medicines and preoperative care. J. Am. Med. Assoc., 286: 208-216. PubMed | Direct Link |
3: Ara, J., V. Sultana, S. Ehteshamul-Haque, R. Qasim and V.U. Ahmad, 1999. Cytotoxic activity of marine macroalgae on Atremia salina (brine shrimp). Phytother. Res., 13: 304-307. PubMed |
4: Bandyopadhyay, U., D. Das and R.K. Banerjee, 1999. Reactive oxygen species: Oxidative damage and pathogenesis. Curr. Sci., 77: 658-666. Direct Link |
5: Chandler, S.F. and J.H. Dodds, 1993. The effect of phosphate, nitrogen and sucrose on the production of phenolics and solasidine in callus cultures of Solanum laciniatum. Plant Cell Rep., 2: 105-110.
6: Chiang, L.C., W. Chiang, M.C. Liu and C.C. Liu, 2003. In vitro antiviral activities of Caesalpinia pulcherrima and its related flavonoids. J. Antimicrob. Chemother., 50: 194-198. CrossRef | Direct Link |
7: Chu, Y.H., C.L. Chang and H.F. Hsu, 2000. Flavonoid content of several vegetables and their antioxidant activity. J. Sci. Food Agric., 80: 561-566. Direct Link |
8: Cook, N.C. and S. Samman, 1996. Flavonoids-chemistry, metabolism, cardioprotective effects, and dietary sources. J. Nutr. Biochem., 7: 66-76. CrossRef | Direct Link |
9: Dahanukar, S.A., R.A. Kulkarni and N.N. Rege, 2000. Pharmacology of medicinal plants and natural products. Indian J. Pharmacol., 32: 81-118. Direct Link |
10: Elzaawely, A.A. and S. Tawata, 2012. Antioxidant activity of phenolic rich fraction obtained from Convolvulus arvensis L. leaves grown in Egypt. Asian J. Crop Sci., 4: 32-40. CrossRef | Direct Link |
11: Frankel, E., 1995. Nutritional benefits of flavonoids. Proceedings of the International Conference on Food Factors: Chemistry and Cancer Prevention, December 10-15, 1995, Hamamatsu, Japan -.
12: Garrat, D.C., 1964. The Quantitative Analysis of Drugs. Vol. 3, Chapman and Hall, Japan, ISBN: 8123907540, pp: 456-458.
13: Akond, A.S.M.G.M., L. Khandaker, J. Berthold, L. Cates, K. Peters, H. Delong and K. Hossain, 2011. Anthocyanin, total polyphenols and antioxidant activity of common bean. Am. J. Food Technol., 6: 385-394. CrossRef |
14: Gryglewski, R.J., R. Korbut, J. Robak and J. Swies, 1987. On the mechanism of antithrombotic action of flavonoids. Biochem. Pharmacol., 36: 317-322. CrossRef | Direct Link |
15: Gulcin, I., 2009. Antioxidant activity of L-adrenaline: A structure-activity insight. Chem. Biol. Interact., 179: 71-80.
16: Gupta, M., U.K. Mazumder and P. Gomathi, 2007. Antioxidant and antimicrobial properties of galega purpurea root. Asian J. Plant Sci., 6: 533-537. CrossRef | Direct Link |
17: Gupta, V.K. and S.K. Sharma, 2010. In vitro antioxidant activities of aqueous extract of Ficus bangalensis Linn. Root. Int. J. Biol. Chem., 4: 134-140. CrossRef | Direct Link |
18: Kala, C.P., 2005. Current status of medicinal plants used by traditional Vaidyas in Uttaranchal state of India. Ethnobot. Res. Applied, 3: 267-278. Direct Link |
19: Koleva, I.I., T.A. van Beek, J.P.H. Linssen, A. de Groot and L.N. Evstatieva, 2002. Screening of plant extracts for antioxidant activity: A comparative study on three testing methods. Phytochem. Anal., 13: 8-17. CrossRef | Direct Link |
20: Kumar, S., S.A. Hassan, S. Dwivedi, A.K. Kukreja and A. Sharma et al., 2000. Proceedings of the National Seminar on the Frontiers of Research and Development in Medicinal Plants: September 16-18, 2000. Central Institute of Medicinal and Aromatic Plants, Lucknow, India, Pages: 711.
21: Leamsomrong, K., M. Suttajit and P. Chantiratikul, 2009. Flow injection analysis system for the determination of total phenolic compounds by using folin-ciocalteu assay. Asian J. Applied Sci., 2: 184-190. CrossRef | Direct Link |
22: Maisuthisakul, P., M. Suttajit and R. Pongsawatmanit, 2007. Assessment of phenolic content and free radical-scavenging capacity of some thai indigenous plants. Food Chem., 100: 1409-1418. CrossRef | Direct Link |
23: Makepeace, W., A.T. Dobson and D. Scott, 1985. Interference phenomena due to mouse ear and king devil hawkweed. New Zealand J. Bot., 23: 79-90. CrossRef |
24: Mantle, D., F. Eddeb and A.T. Pickering, 2000. Comparison of relative antioxidant activities of British medicinal plant species in vitro. J. Ethnopharmacol., 72: 47-51. CrossRef | Direct Link |
25: McLaughlin, J.L., C.J. Chang and D.L. Smith, 1993. Simple bench-top bioassays (brine shrimp and potato discs) for the discovery of plant antitumor compounds. Am. Chem. Soc. Sympos. Ser., 534: 112-134. CrossRef |
26: Meyer, B.N., N.R. Ferrigni, J.E. Putnam, L.B. Jacobsen, D.E. Nichols and J.L. McLaughlin, 1982. Brine shrimp: A convenient general bioassay for active plant constituents. Planta Med., 45: 31-34. CrossRef | PubMed | Direct Link |
27: Khasawneh, M.A., H.M. Elwy, N.M. Fawzi, A.A. Hamza, A.R. Chevidenkandy and A.H. Hassan, 2011. Antioxidant activity, lipoxygenase inhibitory effect and polyphenolic compounds from Calotropis procera (Ait.) R. Br. Res. J. Phytochem., 5: 80-88. CrossRef | Direct Link |
28: Muchuweti, M., E. Kativu, C.H. Mupure, C. Chidewe, A.R. Ndhlala and M.A.N. Benhura, 2007. Phenolic composition and antioxidant properties of some spices. Am. J. Food Technol., 2: 414-420. CrossRef | Direct Link |
29: Islam, A.K.M.N., M.A. Ali, A. Sayeed, S.M.A. Salam and A. Islam et al., 2003. An antimicrobial terpenoid from Caesalpinia pulcherrima swartz.: Its characterization, antimicrobial and cytotoxic activities. Asian J. Plant Sci., 2: 1162-1165. CrossRef | Direct Link |
30: Nobori, T., K. Miura, D.J. Wu, A. Lois, K. Takabayashi and D.A. Carson, 1994. Deletions of the cyclin-dependent kinase-4 inhibitor gene in multiple human cancers. Nature, 368: 753-756. CrossRef | PubMed | Direct Link |
31: Okpuzor, J., H. Ogbunugafor, G.K. Kareem and M.N. Igwo-Ezikpe, 2009. In vitro investigation of antioxidant phenolic compounds in extracts of Senna alata Res. J. Phytochem., 3: 68-76. CrossRef | Direct Link |
32: Owen, R.W., R. Haubner, W. Mier, A. Giacosa, W.E. Hull, B. Spiegelhalder and H. Bartsch, 2003. Isolation, structure elucidation and antioxidant potential of the major phenolic and flavonoid compounds in brined olive drupes. Food Chem. Toxicol., 41: 703-717. CrossRef |
33: McPherson, D.D., G.A. Cordell, D.D. Soejarto, J.M. Pizzuto and H.H.S. Fong, 1983. Peltogynoids and homoisoflavonoids from Caesalpinia pulcherrima. Phytochemistry, 22: 2835-2838. CrossRef | Direct Link |
34: Ragasa, C.Y., J.G. Hofilena and J.A. Rideout, 2002. New furanoid diterpenes from Caesalpinia pulcherrima. J. Nat. Prod., 65: 1107-1110. PubMed |
35: Ramachandran, S., M. Vamsikrishna, K.V. Gowthami, B. Heera and M.D. Dhanaraju, 2011. Assessment of cytotoxic activity of agave cantula using brine shrimp (Artemia salina) lethality bioassay. Asian J. Sci. Res., 4: 90-94. CrossRef |
36: Ravishankara, M.N., N. Shrivastava, H. Padh and M. Rajani, 2002. Evaluation of Antioxidants properties of root bark of Hemidesmus Indicus R.Br. (Anantmul). Phytomedicine, 9: 153-160. PubMed |
37: Rebiai, A., T. Lanez and M.L. Belfar, 2011. In vitro evaluation of antioxidant capacity of Algerian propolis by spectrophotometrical and electrochemical assays. Int. J. Pharmacol., 7: 113-118. CrossRef | Direct Link |
38: Roach, J.S., S. McLean, W.F. Reynolds and W.F. Tinto, 2003. Cassane diterpenoids of Caesalpinia pulcherrima. J. Nat. Prod., 66: 1378-1381. CrossRef | Direct Link |
39: Sanchez-Moreno, C., J.A. Larrauri and F. Saura-Calixto, 1999. Free radical scavenging capacity and inhibition of lipid oxidation of wines, grape juices and related polyphenolic constituents. Food Res. Int., 32: 407-412. CrossRef | Direct Link |
40: Schuler, P., 1990. Natural Antioxidants Exploited Commercially. In: Food Antioxidants, Hudson, B.J.F. (Ed.). Elsevier, London, UK., pp: 99-170.
41: Shahidi, F., P.K. Janitha and P.D. Wanasundara, 1992. Phenolic antioxidants. Crit. Rev. Food Sci. Nutr., 32: 67-103. CrossRef | Direct Link |
42: Solis, P.N., C.W. Wright, M.M. Anderson, M.P. Gupta and J.D. Phillipson, 1993. A microwell cytotoxicity assay using Artemia salina (brine shrimp). Planta Med., 59: 250-252. CrossRef | Direct Link |
43: Srinivas, K.V.N.S., Y.K. Rao, I. Mahender, B. Das, K.V.S.R. Krishna, K.H. Kishore and U.S.N. Murty, 2003. Flavanoids from Caesalpinia pulcherrima. Phytochemistry, 63: 789-793. CrossRef |
44: Sudhakar, M., C.V. Rao, P.M. Rao, D.B. Raju and Y. Venkateswarlu, 2006. Antimicrobial activity of Caesalpinia pulcherrima, Euphorbia hirta and Asystasia gangeticum. Fitoterapia, 77: 378-380. CrossRef | Direct Link |
45: Vicente, C.D., F.C. de Abreu, M.O.F. Goulart and J. N. de Vasconcelos, 2011. Phenolic constituents, furfuraldehyde and antioxidant capacity of sugar cane spirit aged in woods casks. Am. J. Food Technol., 6: 631-646. CrossRef | Direct Link |
46: Viturro, C., A. Molina and G. Schmeda-Hirschmann, 1999. Free radical scavengers from Mutisia friesiana (Asteraceae) and Sanicula graveolens (Apiaceae). Phytother. Res., 13: 422-424. Direct Link |
47: Wojdylo, A., J. Oszmianski and R. Czemerys, 2007. Antioxidant activity and phenolic compounds in 32 selected herbs. Food Chem., 105: 940-949. CrossRef | Direct Link |
48: Zakaria, Z.A., H.M. Khairi, M.N. Somchit, M.R. Sulaiman and A.M.M. Jais et al., 2006. The in vitro antibacterial activity and brine shrimp toxicity of Manihot esculenta var. Sri Pontian (Euphorbiacea) extract. Int. J. Phamacol., 2: 216-220. CrossRef | Direct Link |
49: Oke, J.M. and M.O. Hamburger, 2002. Screening of some Nigerian medicinal plants for antioxidant activity using 2,2-diphenyl-picryl-hydrazyl radical. Afr. J. Biomed. Res., 5: 77-79. Direct Link |
50: Harborne, J.B. and C.A. Williams, 2000. Advances in flavonoid research since 1992. Phytochemistry, 55: 481-504. CrossRef | PubMed | Direct Link |
|
|
|
 |