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Effect of Extraction Solvents on Phenolic, Flavonoid and Antioxidant activities of Three Nigerian Medicinal Plants

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Effect of Extraction Solvents on Phenolic, Flavonoid and Antioxidant activities of Three Nigerian Medicinal Plants

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The effect of extracting solvents (absolute methanol, ethanol, acetone and ethyl acetate) on the phenolic, flavonoid contents and antioxidant activities of the bark of Azadirachta indica, leaves of Acalypha wilkesiana, and Solanum scabrum were studied. The total phenolic content (TPC) was determined using folin-ciocalteu method while total flavonoid content (TFC) was determined using aluminum chloride method. Antioxidant activity was determined using 2, 2-diphenyl-1-picryl hydrazine (DPPH) free radical scavenging and inhibition of lipid peroxidation. Acetone extract of S. scabrum recorded the highest phenolic content (34.2g GAE/100g) while methanol extract of A. indica recorded the lowest (3.77g GAE/100g). Ethanol extract of A. indica recorded the highest flavonoid content (8.7 g QE/100g) while acetone extract of A. wilkesiana recorded the lowest (3.41 g QE/100g). Methanol extract of A. wilkesiana recorded the highest DPPH free radical scavenging activity (85.65%) while ethyl acetate extract of A. indica recorded the highest inhibition of lipid peroxidation (41.57%). The result of this study showed that the activity of antioxidant of different plants is dependent on extracting solvents. Nature and Science
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Nature and Science, 2011;9(7) http://www.sciencepub.net/nature
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Effect of Extraction Solvents on Phenolic, Flavonoid and Antioxidant activities of Three Nigerian Medicinal
Plants
*Anokwuru, C.P. 1, Anyasor, G.N.1, Ajibaye O.2, Fakoya O.1, Okebugwu P.1
1. Department of Chemical and Environmental Sciences, School of Science and Technology, Babcock University,
Ilisan-Remo, Ogun State, P.M.B. 21244 Ikeja, Nigeria
2. Malaria research laboratory, Biochemistry division, Nigerian Institute of Medical Research (NIMR), Yaba,
Nigeria.
* Corresponding author: Email: anokwuruc@babcockuni.edu.ng; Mobile: +2348025493477
Abstract: The effect of extracting solvents (absolute methanol, ethanol, acetone and ethyl acetate) on the phenolic,
flavonoid contents and antioxidant activities of the bark of Azadirachta indica, leaves of Acalypha wilkesiana, and
Solanum scabrum were studied. The total phenolic content (TPC) was determined using folin-ciocalteu method
while total flavonoid content (TFC) was determined using aluminum chloride method. Antioxidant activity was
determined using 2, 2-diphenyl-1-picryl hydrazine (DPPH) free radical scavenging and inhibition of lipid
peroxidation. Acetone extract of S. scabrum recorded the highest phenolic content (34.2g GAE/100g) while
methanol extract of A. indica recorded the lowest (3.77g GAE/100g). Ethanol extract of A. indica recorded the
highest flavonoid content (8.7 g QE/100g) while acetone extract of A. wilkesiana recorded the lowest (3.41 g
QE/100g). Methanol extract of A. wilkesiana recorded the highest DPPH free radical scavenging activity (85.65%)
while ethyl acetate extract of A. indica recorded the highest inhibition of lipid peroxidation (41.57%). The result of
this study showed that the activity of antioxidant of different plants is dependent on extracting solvents.
Nature and Science 2011;9(7):53-61]. (ISSN: 1545-0740). http://www.sciencepub.net.
Keywords: Polyphenols, Antioxidant activity, Medicinal plants, Extracts, solvents
INTRODUCTION
Plants have been a source of medicine in the past
centuries and today scientists and the general public
recognize their value as a source of new or
complimentary medicinal products (Premanath &
Lakshmidevi, 2010). The medicinal value of these
plants lies in some chemical active substances that
produce definite physiological action on the human
body (Aiyelaagbe & Osamudiamen, 2009). Medicinal
plants are used by 80% of the world population as the
only available medicines especially in developing
countries (EL-Kamali & EL-amir, 2010). Nigeria has a
great variety of natural vegetation, which is used in
trado-medicine to cure various ailments, some plants
are also useful for ornamental purposes, while many
due to their odoriferous nature are used in flavoring or
as food additives and preservatives (Egwaikhinde &
Gimba, 2007). Practically, every part of the A. indica
(leaves, bark, fruit, flowers, oil and gum) has been
reported to be associated with various remedial
properties such as the treatment of general body pain
after child delivery, pyorrhea, intestinal worms,
antimicrobial effects, storage behavior, in vitro
antiviral activity and antibacterial agent (Biu et al.,
2009; Taha et al., 2008). Acalypha species are
popularly used for the treatment of malaria,
dermatological and gastro-intestinal disorders. Seeds
from A. wilkensiana (Euphorbiaceae) are essential
components of a complex plant mixture used by
traditional healers in southwest Nigeria in the treatment
of breast tumors and inflammation (Udobang et al.,
2010).
Most of the physiological impairment, tissues
damages, pathological events or diseases affecting
humans have been attributed by recent scientific
studies to be caused by unstable and extremely reactive
chemical species called free radicals and/or reactive
oxygen species (Tawaha et al., 2007; Sathishkumar et
al., 2009; Subhasree et al., 2009; Jang et al., 2006).
The imbalance between the production of bodily
antioxidant defense system and free radical formation
results in oxidative stress. Oxidative stress has been
implicated in the alteration of genetic material,
inducing oxidation that causes membrane lipid
peroxidation, decreased membrane fluidity and
inducing metabolic injury and death. This may lead to
accelerated aging, cancer, cardiovascular diseases,
neurodegenerative diseases, and inflammation
(Neergheen et al., 2006; Prakash et al., 2007; Wong et
al., 2006; Kubola & Siriamornpun, 2008; Subhasree et
al., 2009).
Lipid peroxidation is one of the major causes of
deterioration in foods that results in the formation of
potentially toxic compounds. This has led to the use of
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synthetic antioxidants, such as butylated
hydroxyanisole (BHA), butylated hydroxytoluene
(BHT), tert-butyl hydroquinone (TBHQ) and
propylgallate (PG) as food additives to preserve against
deterioration; however, their use is increasingly
restricted, due to their potential health risks and
toxicity (Tawaha et al., 2007). Hence, scientists are
now searching for naturally occurring antioxidants in
plant sources for food or medicinal materials as
alternative for synthetic antioxidants (D’Abrosca et al.,
2007; Loo et al., 2007; Stanojević et al., 2009).
Antioxidants protective effect against lipoperoxidative
damage depends on the hydroxyl group in each
molecule; however, the effectiveness of antioxidants
has been found to be related also to their incorporation
rate into cells and their orientation in the
biomembranes (Saija et al., 1994). Natural antioxidants
endogenous to food of plant origin can scavenge
reactive oxygen and nitrogen species (RONS);
evidence suggests that these may be of great
importance in preventing the onset of oxidative
diseases in the human body (Amarowicz et al., 2010).
Plants are a major source of phenolic compounds,
which are synthesized as secondary metabolites during
normal development in response to stress conditions,
such as wounding and UV radiation among others.
Plants may contain simple phenolics, phenolic
acids, coumarins, flavonoids, stilbenes, hydrolysable
and condensed tannins, lignins and lignans.
Distribution of phenolics in plants at the tissue, cellular
and subcellular levels is not uniform. Insoluble
phenolics are found in cell walls, while soluble
phenolics are present within the plant cell vacuoles.
Cell wall phenolics may be linked to various cell
components such as sugars. Therefore, the nature of
polyphenol compounds in plants is complex
(Maisuthisakul et al., 2008). The beneficial effects of
plant phenolics are related to their antioxidant activity,
particularly their ability to scavenge free radicals, to
donate hydrogen atoms or electrons, or to chelate metal
cations. Besides, phenolic compounds contribute
largely to the colour and sensory characteristics of
fruits and vegetables. In addition, phenols participate in
growth and reproduction processes, and provide
protection against pathogens and predators. At the
cellular level, it participate in cell protection against the
harmful action of reactive oxygen species (ROS),
mainly oxygen free radicals, produced in response to
environmental stresses such as salinity, drought, high
light intensity or mineral nutrient deficiency, because
of the imbalance between the production and
scavenging of ROS in chloroplasts. These cytotoxic-
activated oxygen species can seriously disrupt normal
metabolism through oxidative damage to lipids,
proteins and nucleic acids. Accordingly, plants
containing high concentrations of antioxidants show
considerable resistance to the oxidative damage caused
by the ROS, as shown in the case of salt stressed plants
(Meot-Duros & Magne, 2009).
Recovery of antioxidant compounds from plant
materials is typically accomplished through different
extraction techniques taking into account their
chemistry and uneven distribution in the plant matrix.
Solvent extraction is most frequently used technique
for isolation of plant antioxidant compounds (Sultana
et al., 2009). However, the extract yields, polyphenolic
contents, and resulting antioxidant activities of the
plant materials are strongly dependent on the nature of
extracting solvent and method, due to the presence of
different antioxidant compounds of varied chemical
characteristics and polarities that may or may not be
soluble in a particular solvent (Sultana et al., 2009;
Jakopic et al ., 2009). Polar solvents are frequently
employed for the recovery of polyphenols from a plant
matrix. The most suitable of these solvents are (hot or
cold) aqueous mixtures containing ethanol, methanol,
acetone, and ethyl acetate (Sultana et al., 2009).
Sultana et al. (2009) reported that aqueous,
ethanolic and methanolic extracts of barks of
Azadirachta indica, Acacia nilotica, Eugenia
jambolana, Terminalia arjuna, leaves and roots of
Moringa oleifera, fruit of Ficus religiosa, and leaves of
Aloe barbadensis exhibited better antioxidant activities
and phenolic contents compared to absolute methanol
and ethanol. Fifty percent (50%) aqueous solvent
extracts from black tea at 2, 8 and 18 h gave markedly
higher amounts of total polyphenol and antioxidant
activity as compared to absolute ones (Turkmen et al.,
2007). Among aqueous solvents, acetone or N, N-
dimethylformamide (DMF) was the most efficient
solvent with respect to the three parameters measured.
In the case of absolute solvent extracts, DMF and
methanol were much more efficient than ethanol and
acetone. Jakopic at al., (2009) reported that methanol
extract of wallnut fruits extracts yielded higher total
phenolic contents compared to the ethanolic extract.
According to koffi et al. (2010) ethanolic extract of
Ivorian plants extracted higher phenolics compared
with acetone, water, and methanol. Therefore, the
present study was aimed to determine the effect of
different extracting solvents on the total phenolic,
flavonoid content, and antioxidant acitivities of the
plants under study.
MATERIALS AND METHODS
Chemicals
Methanol, ethanol, ethyl acetate and acetone
were Analar grade (Sigma-Aldrich). Thiobarbituric
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acid (TBA), FeCl3, 2,2-diphenyl-1-picrylhydrazyl
(DPPH), Folin–Ciocalteu reagent, aluminium chloride,
quercetin, were obtained from Sigma–Aldrich S.p.A.
(Milan, Italy).
Preparation of plant samples
Acalypha wilkesiana leaf and Azadirachta indica
stem back were obtained from the horticultural garden
in December 2009 at Babcock University, Ilisan Remo,
Ogun State, Nigeria. Solanum scrabrum leaf was
purchased in Ilisan Remo market. The fresh samples
were washed and air-dried for one week. All dried
plant materials were ground to powder and sieved to
obtain fine particles. 20 g of each sample was soaked
with methanol, ethanol, ethylacetate and acetone for 72
h. The filtrates were concentrated using rotary
evaporator at 40oC. The dried extracts were weighed
and store at -4oC.
Determination of plant yield
The percentage yield was obtained using this
formula W2-W1/W0× 100. Where W2is the weight of
the extract and the container, W1the weight of the
container alone and W0the weight of the initial dried
sample
Determination of Total Phenolic Content (TPC)
This was estimated as described by Singleton
and Rossi (1965) and modified by Gulcin et al. (2003).
One ml aliquot of extracts or standard solution of gallic
acid (10, 20, 30, 40 and 50 µg/ml) was added in a
volumetric flask containing 9 ml of water. One
milliliter of Folin-Ciocalteu’s reagent was added to the
mixture and vortexed. After 5 min, 10 ml of 7%
sodium carbonate was added to the mixture, and then
incubated for 90 min at room temperature. After
incubation, the absorbance against the reagent blank
was determined at 750 nm. A reagent blank was
prepared using distilled water instead of the plant
extract. The amount of phenolic compound in the
extract was determined from the standard curve
produced with varying concentrations (10, 20, 30, 40,
50 µg/ml) of gallic acid (R2=0.9986). The total
phenolic content of the plant was expressed as g Gallic
acid equivalent (GAE)/100g dry weight. All samples
were analyzed in triplicates
Determination of Total Flavonoid Content (TFC)
The TFC was measured following a
spectrophotometric method by Dewanto et al. (2002).
Briefly, extract of each plant material (1 ml containing
100 µg/ml) were diluted with water (4 ml) in a 10 ml
volumetric flask. Initially, 5% NaN02solution (0.3 ml)
was added to each volumetric flask at 5 min, 10%
AlCl3(0.3 ml) was added and at 6 min. 1M NaOH (2
ml) was added. Water (2.4 ml) was then added to the
reaction flask and mixed well. Absorbance of the
reaction mixture was read at 510 nm. Total Flavonoid
Content was determined as quercetin equivalents
(g/100g of dry weight). Triplicate reading were taken
for each sample and the result averaged.
Determination of DPPH Radical Scavenging
Activity
This was carried out according to the 2,2-
diphenyl-2-picrylhydrazyl (DPPH) assay system by
Mensor et al. (2001). One ml of a 0.3 mM DPPH
methanol solution was added to 2.5 ml solution of the
extract or standard (100 µg/ml, 200 µg/ml, 300 µg/ml)
and allowed to react at room temperature for 30 min.
The absorbance of resulting mixture was measured at
518 nm and converted to percentage antioxidant
activity (AA %), using the formula:
AA% = [(Absblank – Abssample) × 100]/ Abs blank
Abs = Absorbance.
Methanol (1.0 ml) plus extract solution (2.5 ml) was
used as blank. 1ml of 0.3 mM DPPH plus methanol
(2.5 ml) was used as a negative control. Solution of
gallic acid served as positive control. This assay was
carried out in triplicates for each concentration.
Determination of Inhibition of Lipid Peroxidation
A modified thiobarbituric acid reactive
substances assay was used to measure the lipid
peroxide formed, using egg yolk homogenate as lipid-
rich media (Ruberto et al., 2000). Egg homogenate (0.5
ml, 10 % v/v) and 0.1 ml of each extract were added to
a test tube and made up to 1 ml with distilled water.
0.05 ml of FeSO4(0.07 M) was added to induce lipid
peroxidation and incubated for 30 min. Then 1.5 ml of
20% acetic acid (pH adjusted to 3.5 with NaOH) and
1.5 ml of 0.8% (w/v) TBA in 1.1% sodium dodecyl
sulphate and 20% TCA were added and the resulting
mixtures were vortexed and then heated at 95°C for 60
min. After cooling, 5.0 ml of butan-1-ol was added to
each tube and centrifuged at 3000 rpm for 10 min. The
absorbance of the organic layer was measures at 532
nm. Percentage inhibition of lipid peroxide formed by
the extracts were calculated according to
(1 – E/C) x 100.
Where C = is the absorbance value of the fully oxidized
control and E absorbance in the presence of extract.
(Abs532+TBA-Abs532-TBA).
RESULTS
Table 1 showed the percentage yield of extracts of A.
wikesiana leaf, A. indica bark, and S. scabrum leaf in
acetone, ethanol, ethylacetate and methanol as solvents.
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In A. wilkesiana, the methanolic extract gave the
highest yield (14.67%) while the ethylacetate extract
gave the least yield (2.73%). In A. indica, acetone
extract gave the highest yield (11.7%) while
ethylacetate extract gave the lowest yield (3.43%). In S.
scrabrum, methanolic extract gave the highest yield
(17.23%) while ethyl acetate extract gave the lowest
yield (4.13).
Table 2 showed the total phenolic content of A.
wilkesiana leaf, A. indica stem bark and S. scabrum
leaf in four different solvents. The total phenolic
content of the three samples were determined as gallic
acid equivalent (GAE) in g per 100 g dry weight. In
A.wikesiana, the methanolic extract recorded the
highest TPC (13.77 g GAE/100g) followed by
ethylacetate (12.83 g GAE/100g), acetone (10.8 g
GAE/100g) and ethanol (5.87g GAE/100g) in A.indica,
acetone recorded the highest TPC (15.1g GAE/100g),
followed by ethylacetate (13.5 g GAE/100g), ethanol
(7.47 g GAE/100g) and methanol extract (3.77 g
GAE/100g). In S.scabrum, acetone extract recorded the
highest TPC ( 34.2 g GAE/100g), followed by ethanol
extract (29 g GAE/100g), ethylacetate extract (13.5 g
GAE/100g) and methanol (13.4 g GAE/100g).
Results also showed an increased magnitude in TFC in
the order of methanol extract (4.05 g QE/100 g) >
ethanol extract (3.69 g QE/100 g) > ethylacetate
extract (3.67 g QE/100 g) > acetone extract (3.41 g
QE/100 g) of A. wilkesiana. A. indica bark extracts
indicated ethanol extract (8.7 g QE/ 100 g) >
ethylacetate extract (5.32g QE/100g) > acetone extract
(5.15g QE/100g) > methanol extract (5.14g QE/100g).
In S. scabrum extract, ethylacetate extract (5.26g
QE/100g)> methanol extract (5.20g QE/100g)> ethanol
extract (3.81g QE/100g) > acetone (3.51g QE/100g)
(Table 2).
DPPH scavenging activity
The magnitude of DPPH scavenging power of
different solvents of A. wilkesiana was in the order of
methanol extract (85.65%) > acetone extract (84.90%)
> ethylacetate extract (83.99%)> ethanol extract
(70.17%). A. indica showed acetone extract (85.52%) >
methanol extract (84.13%) > ethylacetate extract
(82.10%) > ethanol (81.49%), S. scabrum showed
ethanol extract (72.33%) > methanol extract (70.39%)
> ethylacetate extract (68.94%) > acetone extract
(52.84%) (Figure 1).
Inhibition of lipid peroxidation
Result of the percentage inhibition of lipid
peroxidation of egg homogenate showed A. wilkesiana,
A. indica and S. scabrum in acetone, ethanol,
ethylacetate and methanol are in the range of 24.1% to
40.27%. In A. wilkesiana, acetone extract (40.27%) and
methanol extract (25%) recorded the highest and
lowest inhibitions respectively. In A. indica stem bark,
ethylacetate extract (41.57%) and acetone (32.27%)
extract recorded the highest and lowest inhibition
respectively. S.scabrum acetone (27.6%) and
ethylacetate (27.6%) extracts recorded the highest
inhibition while methanol extract (24.1%) showed the
lowest inhibition of lipid peroxide (Figure 2).
Percentage yield
Table 1: Percentage yield of plant extracts in different solvents
Plant used
Yield (%)
Acetone Ethanol Ethylacetate Methanol
A. wilkesiana 4.34 ± 0.23
ab
5.37 ± 0.19
ab
2.73 ± 0.26
b
14.67 ± 0.88
a
A. indica 11.7 ± 0.12
a
6.8 ± 0.12
ac
3.43 ± 0.19
b
9.77 ± 0.12
ab
S. scabrum 15.47 ± 0.18
ab
4.77 ± 0.15
ac
4.13 ± 0.15
b
17.23 ± 0.18
a
a-Highest yield and significantly different (p <0.05) from other yields (ab, ac & b) of each row.
ab- significantly different (p <0.05) from b only.
ac- significantly different (p <0.05) from b only.
Extract yields with identical alphabets show no significant difference (p <0.05).
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Total Phenolic Content (TPC)
Table 2: Total phenolic content (g GAE/100 gdw) and total flavonoid contents (g QE/100 gdw)
Extract TPC TFC
AWL AIB SSL AWL AIB SSL
Acetone
Ethanol
Ethylacetate
Methanol
10.80±0.4
a
5.87±0.12b
12.83±0.82c
13.77±0.01c
15.10±0.04
a
7.47±0.07b
13.5±0.1c
3.77±0.03d
34.2±0.26
a
29±1.51b
13.37±0.12c
13.40±0.2c
3.41±0.03
3.69±0.03f
3.67±0.01f
4.05±0.06g
5.15±0.03
8.70±0.04f
5.32±0.06g
5.14±0.02e
3.51±0.01
3.81±0.02f
5.26±0.02g
5.20±0.03g
Data are expressed as the average of three determinations ± S.E
Data with different lower case letters on individual solvent extracts of each plant are significantly different (p<0.05)
AWL: acalypha wilkesiana leaf
AIB: azadiractha indica stem bark
SSL: solanum scabrum leaf
Dw- dry weight
Figure 1: Graph of percentage inhibition of DPPH free radical of the plant extracts.
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Figure 2: Graph of percentage inhibition of lipid peroxidation of three plant extracts in four different solvents.
Discussion
The result of the percentage yield suggested that
absolute methanol was a better solvent for the
extraction of A. wikesiana and S. scabrum, while
acetone was a better solvent for the extraction of A.
indica.
In a study by Nahak and Sahu (2010) on
antioxidant activity of A. indica leaf, methanol gave the
least yield compared to water and ethanol. In another
study of phenolic compounds and antioxidant activity
of Henna leaves extract (Lawsonia inermis) by Hosien
and Zinab (2007), water gave higher yield compared to
methanol. Stanojevic et al. (2009) showed that the
magnitude of extract yield of Hieracium pilosella leaf
was ethanol>methanol>water. Sultana et al (2009),
reported that absolute ethanol gave the highest yield of
A. indica bark compared to absolute methanol, aqueous
methanol and ethanol. Although acetone and ethyl
acetate were not used in that study, the values of the
extract yields were higher than the values in this study.
Methanol extract of A. wilkesiana had high total
phenolic content while acetone extract of A. indica and
S. scabrum showed high total phenolic content
suggesting that methanol and acetone could serve as
better solvents for phenolic compound extraction.
Result also showed that the A. wilkesiana and A. indica
with the highest extract yield also had the highest
phenolic content (Tables 1 & 2). Previous findings had
shown that the efficiency of the phenolics extraction
depends on the type of the plant and kind of solvent
used (Jang et al., 2007; Jakopic et al. 2009). The study
conducted by Koffi et al. (2010) concluded that ethanol
was found to be the best solvent for the extraction of
phenolics of 26 Ivorian plants. The phenolic content of
methanol and ethyl acetate extract of A. indica bark in
this study was lower than the phenolic content of
methanol and ethyl acetate of A. indica bark reported
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by Ghimeray et al., 2009. This trend could be as a
result of the different geographical location of the
plants.
Many flavonoids are found to be strong
antioxidants capable of effectively scavenging the
reactive oxygen species because of their phenolic
hydroxyl groups (Cao et al., 1997; Miller & Ruiz-
Larrea, 2002; Subhasree et al., 2009). This study
showed methanol, ethyl acetate and ethanol had a
significantly high (P<0.05) flavonoid content in A.
wilkesiana, S. scabrum and A. indica respectively than
other extracts of each plant. This indicates that
methanol was the best solvent for the extraction of
flavonoid in A. wilkesiana, ethyl acetate for the
extraction of flavonoid in S.scabrum and ethanol for
flavonoid extraction in A. indica.
Comparing the flavonoid content of A.
wilkesiana with the phenolic content, methanol also
extracted the highest phenol. However, this trend did
not result into a strong linear correlation (r = 0.4) at p<
0.01 between phenolic contents and flavonoid contents
of A. wilkesiana. In A. indica, ethanol extracts showed
significantly high flavonoid content than the other
extracts (Table 2). In S. scabrum, ethyl acetate extract
gave the highest flavonoid content which was higher
than acetone and ethanol extract. This suggests that
ethyl acetate and methanol are better solvents for the
extraction of flavonoids compared to acetone and
ethanol in S. scabrum. In general, A. indica contained
more flavonoids compared to A. wilkesiana and S.
scabrum, since the least flavonoid content in A. indica
was higher than the highest flavonoid content in A.
wilkesiana and close to the highest flavonoid content in
S. scabrum. This could be because the A. indica bark
sample was woody and is the external part of the plant
compared to the leaves of the other samples. According
to Miller & Ruize-Laurrea (2002) flavonoids are found
particularly at the woody and external parts of plants.
This result showed that. A. indica had highest content
of flavonoids in ethanol extract than all the extracts of
A. wilkesiana and S. scabrum. The flavonoid content of
methanol and ethyl acetate extract of A. indica bark in
this study was higher than the flavonoid content of
methanol and ethyl acetate of A. indica bark reported
by Ghimeray et al., 2009. The difference in the
geographical location could be responsible for this
observation.
The strong negative correlation (r = -0.998)
between TPC and TFC of S. scabrum suggests that the
extract that gave the highest phenolic content gave the
lowest flavonoid content. Contrary to the relationship
between phenolics and extract yield, there were strong
correlation between extract yield and flavonoid for A.
wilkesiana (r = 0.801), and S. scabrum (r = 0.981) but a
negative correlation for A. indica (r = -0.229).
Study showed that methanol, acetone and
ethanol exhibited high free radical inhibition in A.
wilkesiana, S. scabrum and A. indica respectively than
other extracts (Figure 1). This suggests that these
solvents are better for the extraction of plant
antioxidants in the studied plants. Study had also
shown that antioxidant activity of extracts is strongly
dependents on the extraction solvent (Jang et al.,
2007). The linear correlation between TPC and
percentage inhibition of DPPH radical showed that
phenolics in various extracts had a strong correlation
with DPPH radical scavenging activity. The phenolic
contents of A. indica and S. scabrum did not show any
correlation with inhibition of DPPH free radicals.
Several studies have shown a positive correlation
between the total content of phenolic compounds and
the antioxidant activity in plants (Kim et al., 2003;
Deridane et al., 2006; Bouayed et al., 2007; Lim &
Quah, 2007; Tawaha et al., 2007).
Lipid peroxidative activity showed that acetone
extract was significantly high compared to methanol,
ethanol and ethylacetate extracts of A. wikesiana leaf.
In A. indica stem back, ethylacetate extract was
significantly high compared to methanol, ethanol and
acetone extract while there was no significant
difference in all extracts in S. scabrum. Generally, the
inhibition of lipid peroxidation of all extracts was
lower than their respective antioxidant activity against
DPPH free radicals. There was a strong negative
correlation (r = -0.980) that was significantly different
at p<0.05 between inhibition of lipid peroxidation and
total flavonoid content of A. wilkesiana. This suggests
that the extract with the least flavonoid content exerted
the highest inhibition of lipid peroxidation. There was
also linear correlation (r = 0.6) at p<0.05 between
inhibition of lipid peroxidation and flavonoid content
of A. indica. There was no correlation between
inhibition of lipid peroxidation and total phenolic
content of all the plants under study.
Conclusion
The result of this study showed that acetone
extract of S. scabrum gave the highest TPC while
ethanol extract of A. indica gave the highest TFC.
Methanol extract of A. wilkesiana gave the highest
inhibition of DPPH free radicals activity while ethyl
acetate extract of A. indica gave the highest inhibition
of lipid peroxidation. This present study supports the
view that the amount of flavonoid, phenols and extent
of antioxidant activity is dependent on the type of plant
part and solvent used for extraction.
Nature and Science, 2011;9(7) http://www.sciencepub.net/nature
60
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Date Submitted: 31st May, 2011
... In agreement with Anokwuru et al. (2011);Owoyele et. al. (2011);Borokini and Omotayo (2012) respectively, A. wilkesiana was reportedly used in the treatment of stomach ache, and gastro-intestinal disorders from the days of old. ...
... Our study however, validates the safety claims by previous authors earlier mentioned after a mixed method of administration of A. wilkesiana leaf extract in this study did not reveal neither gross nor histological effects on stomach of experimental rats. The safety of the gastrointestinal tract and stomach of rats are guaranteed in this study, which supports the report that administration of A. wilkesiana leaf extract via oral consumption for gastro-intestinal disorders is safe for human consumption and is not injurious to the stomach (Anokwuru et al., 2011;Owoyele et. al., 2011;Borokini and Omotayo, 2012). ...
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Background: Acalypha wilkesianafamily (Euphobiaceae), common name (copperleaf), leaf’s juice is robbed on fungal skin infections while oral consumption mitigates stomach disorder claimed by traditionalists. However, there are little or no scientific information in support of these claims. Aim: This study assessed integument and stomach morphology of rats after a sub-chronic exposure to A. wilkesiana leaf extract by mixed-routes of administration. Materials and Methods: Twenty-five (25) Sprague-Dawley rats, both sexes, mean weight (204.34g) assigned (n=5) labeled (A-E) and polypropylene caged with coconut husks as bedding. Animals were housed in a well-ventilated, neat and hygienic environment, adaptation (14days); temperature (23-25.5°C), humidity (55-60%), and periodicity (12:12hr) while water and feeds were provided regularly. Plant material was identified, authenticated and extracted conventionally. Grouping/administration (A=100mg/kg, B=200mg/kg, C=300mg/kg, D=400mg/kg body weight and E=untreated). Animals were treated via mixed-routes of administration orally (mornings) and subcutaneously (evenings) for 45days at 2days interval. Stool dropping was collected and investigated for fecal occult blood testusing guaiac slide kits. Acute toxicity testing was doneusing anentirely new method.Empirical and physical measurements were conducted before and after extract administration. At the end, all animals were sacrificed by cervical dislocation. Skin and stomach were excised, grossed, fixed and preserved in 10% formalin. Cut tissues (3-5mm) were processed histologically, sectioned (3-5microns), stained (H&E) and examined microscopically. Data were analyzed using IBM SPSS Version 25.0. Groups were compared using ANOVA and presented as Mean ± S.E.M. while p-value≤0.05 were significant. Results: Morphologically (gross/histology), adverse changes were not observed, though,rats presented with varying degrees of weight losses particularly marked in group E. Conclusions And Recommendations: This study suggests that A. wilkesiana leaf extract administered via mixed-routes do not have harmful effects on the morphology of target organs, thereby validating the existing safety claims by herbal practitioners
... The percentage yield of plant extract was calculated by the following formula as described by Anokwuru et al., (2011). ...
... The dialyzed solution was freeze-dried to obtain collagen. The percentage yield of extracted collagen was determined using the following formula [26]. ...
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Physical trauma caused by burn injuries can be life-threatening and poses financial hardship for the patient too. Treatment of wounds is a major clinical challenge in burn therapy. The purpose of this study was to devise a phyto nanoparticle-loaded dressing for burn management. The triad of nanotechnology, phytochemistry and skin tissue engineering forms an innovative concept for the management of burn wounds. Our marine biosphere is blessed with numerous natural resources of biopolymers, and marine-derived collagen is one of the major polymers that exhibit biocompatible and biomimetic properties. For fabricating the phyto-nano impregnated collagen sponge construct, fish collagen was extracted from Red Snapper (Lutjanus argentimaculatus) and incorporated with green synthesized silver nanoparticles (MJSN) biosynthesized from Mirabilis jalapa tuber extract (MJTE). Finally, the biofuntionalized collagen was freeze-dried to yield sponges. MJSN and collagen sponge were characterized separately and as a combination product, by different methods like UV–vis/FTIR spectroscopy, XRD, DLS, Zeta potential, SEM and TEM. Furthermore, an optimum dose concentration of MJSN was assessed by carrying out a direct contact test with L929 mouse fibroblasts, followed by MTT and LDH assays to assess cytotoxicity, viability and cytocompatibility. From the findings of this study, MJSN incorporated collagen sponges were non-cytotoxic and cytocompatible and may be proposed for dual applications of sustained drug delivery and tissue regeneration in the healing of burn wounds that still remains an unmet clinical need in tissue reconstruction. Graphical abstract
... Soquetta et al. [19], Altemimi et al. [24] and Truong et al. [40] reported that different solvents had different polarities and therefore different abilities to dissolve and extract different bioactive compounds from the compact matrix of plant tissues and fibre materials. Ethyl acetate having both a polar and non-polar properties is able to dissolve and extract both polar and non-polar bioactive compounds [41,42]. ...
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... The percentage yield of Desmodium velutinum stem obtained in this present study was lower than the percentage yield of methanol extract of Azadirachta indica stem (9.77%) reported by Anokwuru et al. [15] . Also, Odey et al . ...
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... Soquetta et al. [19], Altemimi et al. [24] and Truong et al. [40] reported that different solvents had different polarities and therefore different abilities to dissolve and extract different bioactive compounds from the compact matrix of plant tissues and fibre materials. Ethyl acetate having both a polar and non-polar properties is able to dissolve and extract both polar and non-polar bioactive compounds [41,42]. ...
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Methanolic extracts of six cultivars of Portulaca oleracea were analyzed for their total phenol content (TPC) using the Folin–Ciocalteu method. The antioxidant activity was measured using the 1,1-diphenyl-2-picrylhydrazyl, ferric-reducing antioxidant power (FRAP) and β-carotene bleaching (BCB) assays. The iodine titration method was used to determine the ascorbic acid content (AAC). The TPC of the cultivars of P. oleracea ranged from 127±13 to 478±45mg GAE/100g of fresh weight of plant. There was good correlation between the TPC value and its AEAC, IC50 and FRAP values (r2>0.9) for all the cultivars. The AAC for the cultivars ranged from 38.5±0.6 to 73.0±17.5mg/100g. The TPC value of the common variety PO1, was the lowest compared to the ornamental cultivars (PO2–PO6). The BCB assay showed that all cultivars were capable of inhibiting lipid peroxidation and the inhibition power did not correlate with TPC value.