96
International Journal of Tropical Medicine and Public Health
Volume 1, Issue 1, 2011
Crosshouse books
Original Research Paper
NUTRITIONAL AND CHEMICAL EVALUATION OF SOLANUMINCANUM (BITTER GARDEN
EGG)
AUTA, R. and Ali, I.
Department of Biochemistry, Kaduna State University, Kaduna, Nigeria
Abstract
Objectives: Solanumincanum was evaluated for its nutritional and chemical values
using standard analytical methods.forits proximate composition, phytonutrient
components, vitamin and mineral constituents. The result showed that Solanumincanum
has high moisture content (91.4 ± 0.56%). The concentration of estimated crude protein
and available carbohydrate were 8.31 ± 0.63 and 51.74% respectively. It also had high
ash (21.2 ± 0.42%) and crude lipid (12.53 ± 0.74%) contents, while its crude fibre (6.22 ±
0.36) and caloric values (308.9Kcal/100g) were low. The study revealed the presence of
bioactive constituents comprising saponin (14.4%), alkaloid (0.6%), flavonoid (26.7%),
oxalate (2295mg/100g) and cyanogenic glycoside (5.71 mg/100g). Solanumincanum
contained vitamins such as riboflavin, ascorbic acid and tocopherol. The results of the
mineral composition per 100 g (DW) were as follows: P (1085.00 mg), Mg (39.14 mg), K
(216.89 mg), Mn (147.78 mg), Cu (256.17 mg), Na (149.34 mg), Fe (326.50 mg) and Ca
(15.29 mg). The significance of the findings is thus discussed.
Keywords: Solanumincanum, vitamins, Phytochemical and mineral elements
Introduction
The human body composition shows that
it requires some nutrients which are
substances in food that will nourish
them. These nutrients must be supplied
in sufficient quantities and in proper
combinations to permit optimum growth,
maintenance and repairs of tissues and
reproduction. Daily allowance of each
nutrient for different ages of human
population has been recommended by
Food and Agriculture Organization
(FAO)/World
Health
Organization
(WHO) (Ifeolu, 1999).
The chemical composition of a food is of
utmost
importance
from
many
standpoints, including nutrition and
health, toxicology and safety, and
stability to microbiological, chemical or
physical changes. Many of the local
vegetable materials are under-exploited
because
of inadequate scientific
knowledge of their nutritional potentials
(Akubugwo et al., 2007).
Solanumincanum commonly known as
bitter garden egg and locally called
gautandaacii (Hausa Language) belongs
to the family Solanaceae. It is a delicate
perennial often cultivated as an annual
crop. It is a shrub, growing 1 – 3m high.
The leaves are simple, ovate, elliptic, 2.5
– 12 cm long and 2.5 – 8 cm wide. The
fruit is fleshy, less than 3 cm in diameter
on wild plants but much larger in
cultivated forms (Denston, 1951). The
97
fruit is botanically classified as a berry
and contains numerous small, soft seeds
which are edible, but are bitter because
they contain an insignificant amount of
nicotinoid alkaloids (Aliyu, 2006). The
raw fruit have a bitter taste but becomes
tender when cooked and develops a rich
complex flavor. Salting and then rinsing
the sliced, per boiled fruit (degorging)
can soften and remove much of the
bitterness. As native plant in the
Northern Nigeria, it is a cheap source of
vegetable, particularly during its
cultivation season and can be eaten fresh
(raw), dried or boiled along with other
foods.
Despite
the
use
of
Solanumincanum, it has not been given
due research attention in terms of its
nutritional content. It is against this
background that this work is initiated to
provide information on the proximate,
phytochemicals, vitamins and minerals
content of the plant.
Materials and Methods
Sample collections
Solanumincanum used in this study was
obtained at Bakin-dogo, central market
in Kaduna State, Nigeria in August
2009. The sample was identified by a
taxonomist at the Department of
Biological Sciences, Ahmadu Bello
University, Zaria.
Sample treatment
Solanumincanum was washed with
distilled water and residual moisture
evaporated at room temperature before
sun drying for 5-6 days on a clean paper
with constant turning over to avoid
fungal growth. The sample was ground
into fine powder using pestle and mortar
and sieved through 20-mesh sieve. The
dried powdered sample was used for all
the analyses except for moisture content
determination where fresh samples were
used.
Proximate analysis
The recommended methods of the
Association of Official Analytical
Chemists (AOAC, 1999) were used for
the determination of moisture, ash, crude
lipid, crude fibre and nitrogen content.
Determination of moisture content
Exactly 5g of fresh sample in triplicate
were transferred into a dried weighed
flat crucible. The weight of the crucible
and their contents were recorded after
which they were transferred into an air
oven at 1050C to dry for 8 hour, at the
end of which the crucibles were
transferred into a desiccator and allowed
to cool then weighed and returned to the
oven for another 30 minutes and again
cooled in a desiccator and weighed. The
process was repeated until a constant
weight was obtained at the fifth round.
The percentage loss in weight was
expressed as percentage moisture
content. Similar determination was
carried out on 2 g dry sample so as to
evaluate the residual moisture content,
which was used later to convert other
parameters on 100% dry weight (DW)
basis.
Determination of ash content
Exactly 2g of sample was transferred
into a dried weighed platinum dish, the
weight of the dish and the samples were
taken and the dishes were transferred
into a furnace at 5500C degrees and left
for 2 hours. The dishes were removed,
cooled in a desiccator and weighed. The
ashes were moistened with a few drop of
distilled water and those that showed
black particles were evaporated and
returned to the furnace until completely
ashed. The percentage residue weighed
was expressed as ash content.
98
Determination of crude lipid and crude
fibre content
Crude lipid and crude fibre was determined
as described by the method of Hassan and
Umar (2006). Exactly 2g (in triplicate) of
dried sample were weighed into porous preweighed thimble and its mouth plugged with
cotton. The thimble was placed in an
extraction chamber, which was suspended
above weighed receiving flask containing
petroleum ether (B.P. 40-60oC) and below a
condenser. The flask was heated on heating
mantle for eight hours to extract the crude
lipid. After the extraction, the thimble was
removed from the Soxhlet and the apparatus
reassembled and heated over water bath for
the solvent recovery. The flask containing
the crude lipid was disconnected, cleaned
with dry cloth, oven dried at 100oC for 30
minutes, cooled in a desiccator and weighed.
The difference in weight is expressed as
percentage crude lipid content.
Crude fibre was estimated by acid-base
digestion with 1.25% H2SO4 (w/v) and
1.25% NaOH (w/v) solutions. The residue
after crude lipid extraction was put into a
600cm3 beaker and 200cm3 of boiling 1.25%
H2SO4 added. The content was boiled for 30
minutes, cooled, filtered through a filter
paper and residue washed with three 50cm3
portions of boiling water. The drained
residue was returned to the original beaker
and 200cm3 of boiling 1.25% NaOH added.
The content was boiled for 30 minutes,
filtered, washed as above, residue drained
and washed with 25cm3 ethanol. The filter
paper containing the residue was dried in an
oven at 130oC to constant weight and cooled
in a desiccator. The residue was scrapped
into pre-weighed porcelain crucible,
weighed, ashed at 550oC for two hours,
cooled in a desiccator and reweighed. Crude
fibre content was expressed as percentage
loss in weigh on ignition.
Determination of nitrogen content
Micro-Kjeldahl method was used to
determine the nitrogen content of the
sample. Two grams dried powdered sample
was placed into a 100ml Kjeldahl digestion
flask. A Kjeldahl digestion tablet and 10ml
of concentrated tetraoxosulphate (VI) acid
were added and the sample digested gently
until frothing stopped. The mixture was
boiled until the digest become clear. The
content was filtered into a 100ml volumetric
flask and made up to 100ml with distilled
water. 10ml of the aliquot solution and
20cm3 of 45% sodium hydroxide solution
were put into a distillation flask and steam
distilled. The ammonia liberated was
collected over 50ml 20% boric acid mixed
indicator solution, cooled and titrated with
standard 0.01M HCl solution. Blank
determination was carried out in a similar
manner.
Estimation of crude protein and
available carbohydrate
Crude protein was estimated by multiplying
the sample percentage nitrogen content by a
factor 6.25. Available carbohydrate was
calculated by difference by subtracting total
sum of crude protein, crude lipid, crude fibre
and ash from 100% DW sample (AOAC,
1999).
Estimation of energy value
The sample calorific value was estimated (in
kcal.) by multiplying the percentages of
crude protein, crude lipid and carbohydrate
by the recommended factors (2.44, 8.37 and
3.57 respectively) used in vegetables
analysis (Asibey-Berko and Tayie, 1999).
Mineral analysis
The sample mineral elements (K, Ca, Mn,
Fe, Cu, Na, Mg and K) contents were
analyzed using Shimadzu automated atomic
absorption spectrophotometer at the
National Research Institute on Chemical
Technology (N.A.R.I.C.T), Zaria.
The plant sample was digested with
concentrated HNO3 and HCl at 1000C for 2
99
hours to ensure complete digestion in a fume
cupboard. Elemental filters were used to
select the appropriate wavelength for each
element. Standard preparation was carried
out using standard solutions of the various
elements as provided by shimadzu. The
digested sample was loaded on the AAS
sample holder and the analysis was run. The
concentration of the unknown was expressed
as parts per million (ppm).
Determination of Saponin
A gravimetric method of AOAC (1984)
employing the use of a soxhlet extractor and
two different organic solvents was used. 2g
of the sample was weigh into a thimble and
put in a soxhlet extractor with a condenser
fitted on top. Extraction was done with
acetone in a 250ml round bottom flask for
3hrs, after which another weighed 250ml
round bottom flask containing methanol was
fitted to the same extractor and extraction
continued for another 3hrs. At the end of
second extraction, the methanol was
recovered by distillation and the flask oven
dried to remove the remaining solvent in the
flask. The flask was allowed to cool in a
desiccator and then weigh. The saponin
content was calculated in percentage.
Determination of oxalate
Oxalate was determined by using the
method of Oke (1969). 2g of the sample was
digested with 10ml 6 M HCL for one hour
and made up to 250 ml in a volumetric flask.
The pH of the filtrate was adjusted with
conc. NH4OH solution until the colour of
solution changed from salmon pink colour to
a faint yellow colour. Thereafter the solution
was heated on a water bath to 90oC and the
oxalate was precipitated with 10ml of 5%
CaCl2 solution. The solution was allowed to
stand overnight and the suspension was
centrifuged at 2500 rpm after which the
supernatant was decanted and precipitate
completely dissolved in 10ml of hot 20%
(v/v) H2SO4. The total filtrate resulting from
the dissolution in H2SO4 was made up to
300 ml. an aliquot of 125ml of the filtrate
was heated until near boiling point and then
titrated against 0.05 M of standardized
KMnO4 solution to a faint pink colour which
persisted for about 30s after which the
burette reading was taken. The oxalate
content was evaluated from the titre value.
Determination of alkaloid
The gravimetric method of Harbone (1973)
was adopted. 5g of the sample was weighed
into a 250ml beaker and 200ml of 10%
acetic acid in ethanol was added and
allowed to stand for 4hrs. The extract was
filtered and concentrated on a waterbath to
one-quarter of the original volume.
Concentrated ammonium hydroxide was
added drop-wise to the extract until
precipitation was completed. The whole
solution was allowed to settle, and then the
precipitation was filtered in a weighed filter
paper and was washed with 1% NH4OH.
The precipitate in the filter paper was dried
in the oven at 60oC for 30m and reweighed.
The alkaloid content was calculated in
percentage.
Determination of cyanogenic glycoside
(HCN)
Cyanogenic glycoside determination was
carried out using alkaline picrate method of
Onwuka (2005). 5g of powdered sample was
weighed and dissolved in 50ml distilled
water in a corked conical flask. Cyanide
extraction was allowed to stay overnight and
then was filtered. Different concentrations of
KCN solution containing 0.1 to 1.0 mg/ml
cyanide was prepared for cyanide standard
curve. To 1ml of the filtered sample and
standard cyanide solution in test tubes, 4ml
of alkaline picrate solution was added and
incubated in a water bath for 15min. after
colourdevelopment; the absorbance was
taken at 490nm against a blank containing
only 1ml distilled water and 4ml alkaline
picrate solution. The cyanide content was
extrapolated from the cyanide standard
curve.
100
Determination of flavonoid
Flavonoid was determined by the method
described by Boham and Kocipai-Abyazan
(1974). Ten grammes of the dried sample
was extracted thrice with 100ml each of
80% aqueous methanol at room temperature.
The whole solution was filtered through
whatman filter paper No 42 (125mm). The
filtrate was later transferred into a crucible
and evaporated into dryness over a water
bath and weighed to a constant weight. The
flavonoid content was calculated in
percentage.
Determination of tannins
Tannin was estimated according to the
procedure of Makkar et al., (1993). 50 µL of
tannins extract was taken in a test tube and
the volume made up to 1.0ml with distilled
water. Then, 0.5ml FolinCiocalteu solution
added and mixed. Then 2.5ml 20% sodium
carbonate solution was added and mixed and
kept for 40min at room temperature. Optical
density was taken at 725nm in
spectrophotometer and concentration was
estimated from the standard curve.
Determination of riboflavin (vitamin
B2)
Determination of riboflavin was carried out
using the method described by Poornima
and Ravishankar (2009). 5 g of the sample
was extracted with 100 ml of 50% ethanol
solution and shaken for 1 hr. This was
filtered into a 100 ml of the extract that was
pipette into a 50 ml volumetric flask. 10 ml
of 5% potassium permanganate and 10 ml of
30% H2O2 were added and allowed to stand
over a hot water bath for about 30 min. 2 ml
of 40% sodium sulphate was added. This
was made up to 50 ml mark and the
absorbance measured at 510 nm in a
spectrophotometer.
Determination of vitamin E
Vitamin
E
was
determined
spectrophotometrically using the method as
described by AOAC (1999).
Determination
of
ascorbic
acid
(vitamin C)
5 g of the sample was weighed into a bottle
and 100 ml of EDTA/TCA (2:1) extracting
solution were mixed and the mixture shaken
for 30 min. This was transferred into a
centrifuge tube and centrifuged at 3000 rpm
for about 20 min. It was transferred into a
100 ml volumetric flask and 1% starch
indicator was added. These were added and
titrated with 20% CuSO4 solution to get a
dark end point (Barakat et al., 1993).
Results and Discussions
Proximate analysis
The
proximate
composition
of
solanumincanum is summarized in table 1.
The result shows that solanumincanumhave
a very high moisture content (91.4%) higher
than that reported in some leafy vegetables
consumed in Nigeria (Hassan and Umar,
2006; Akubugwo et al., 2007).
The ash content which is an index of mineral
content (21.2%) is higher than of a bitter
leaves (15.86%) commonly used by
lactating mother and Moringaoleifera leaves
(15.09%) (Lockett et al, 2000). This shows
that solanumincanum may be a very good
source of mineral element.
The result of this work showed that
inadequate
protein
is
present
in
Solanumincanum(8.31%) compared to that
of commonly eaten leafy vegetables in
Nigeria and Swaziland (Lockett et al., 2000;
Hassan and Umar, 2006; Isong and Idiong,
1997; Ogle and Grivetti, 1985). However,
the value is higher than 2.5% and 3.3 %
obtained in Solanum melanogaster and
Voandzeasubteranea respectively (Taiga et
al., 2008). According to Pearson (1976),
plant foods that provide more than 12% of
its caloric value from protein are considered
to be good sources of protein.
Solanumincanum does not provide this
requirement and is therefore considered not
to be a good source of protein.
101
When compared with the values of other
subteranea (89.42%) (Taiga et al., 2008),
leafy vegetables (Hassan and Umar, 2006;
but higher than the reported values for
Agbo, 2004; Sena et al., 1998; Akubugwo et
Amaranthusincurvatus (23.7%) (Asibeyal., 2007; Ifon and Bassir, 1980),
Berko
and
Tayie,
1999)
and
Solanumincanum have a higher content of
Mormodicabalsamina (39.05%) (Hassan and
crude lipid (12.53%).
Umar, 2006). However, the value is in
The crude fibre content of solanumincanum
agreement with that of Amaranthushybridisu
(6.22%) is low when compared with
(52.18%) reported by Akubugwo et al.,
amaranthushybridus (8.61%) (Akubugwo
2007. The recommended dietary allowance,
etal., 2007), Mormodicabalsamina (29%)
RDA values for children, adults, pregnant
(Hassan and Umar, 2006),but higher than
and lactating mothers are 130g, 130g, 175g
5.4% of Solanum melanogaster (Taiga et al.,
and 210g respectively. When 100g of dried
2008).Solanumincanum is not a valuable
Solanumincanum is consumed, it will be
source of dietary fibre in human nutrition
capable of contributing 40%, 40%, 30% and
since it does not provide the RDA of fibre
25% of their respective daily requirement.
for children (19-25%), adults (21-38%),
The
estimated
calorific
value
of
pregnant (28%) and lactating mothers
Solanumincanum (308.9 Kcal/100g) is
(29%).
higher than that reported for most leafy
The available carbohydrate content of
vegetables (Isong et al., 1999; Akubugwo et
Solanumincanum (51.74%) is lower than
al., 2007; Hassan and Umar, 2006).
that of Solanum melanogaster (87.57%), V.
TABLE 1: proximate composition of Solanumincanum
PARAMETERS
Concentration (%DW)*
a
MOISTURE
91.4 ± 0.56
ASH
21.2± 0.42
CRUDE LIPID
12.5±0.07
CRUDE PROTEIN
8.31 ± O.63
CRUDE FIBRE
6.22 ± 0.36
AVAILABLE CARBOHYDRATE
51.74 ± 0.32
ESTIMATED CALORIC VALUE
308.9 Kcal
The data are mean value ± standard
hemolytic activity, formation of foams in
deviation (SD) of three replicatesaValue
aqueous solution, cholesterol binding
expressed as % wet weight.
properties and bitterness (Sodipo et al., 200;
Table 2 summarizes the quantitative
Okwu, 2004). These properties show that the
determination of phytochemical constituents
extract of Solanumincanum may have very
of Solanumincanum. High quantity of
high medicinal activities. It has been
flavonoids, tannins, saponins, oxalate and
documented that plant saponins help human
cyanogenic glycoside were detected. The
to combat microbes and viruses, fight fungal
saponin content of 14.40 mg/100g is lower
infections, knock out some kind of tumor
than that reported by Poornima and
cells, particularly lung and blood cancers
Ravishankar (2009) in Dioscoreabelophylla
and also boost the effectiveness of certain
(wild yam), 18.46 mg/100g but higher than
vaccines (Barakat et al., 1993).
that reported by Akubugwo et al, 2007 in
The flavonoids concentration detected
Amaranthushybridus, 1.68 mg/100g. The
(26.70 mg/100g) in solanumincanumis
high content of saponin in solanumincanum
higher than that of bryophylumpinnatum (a
gives it a very good property which includes
medicinal plant- 1.72 mg/100g) and
102
Dioscoreabelophylla (8.82 mg/100g) as
reported by Okwu and Josiah (2006) and
Poornima
and
Ravishankar
(2009)
respectively. Flavonoids are potent water
soluble antioxidants and free radical
scavengers which prevent oxidative cell
damage and have anticancer activity (DelRio et al., 1997; Salah et al., 1995; Okwu,
2004). The high content of flavonoids in
solanumincanumsuggests its use for
medicinal purpose.
The tannin contents (2.45 mg/ml) is higher
than
that
of
Amaranthushybridus
(Akubugwo et al, 2007) and a number of
medicinal plant (Okwu and Josiah, 2006;
Edeogaetal, 2005). The bitter property of
Solanumincanum may be due to the
presence of tannin in them. Tannins also
have the property of hastening the healing of
wounds and inflamed mucous membrane.
Tannin as an antinutrient have been
implicated in having the capability of
lowering available protein by antagonistic
competition and therefore eliciting protein
deficiency syndrome, marasmus and
kwarshiokor. However, the antinutrient
present in Solanumincanum is within the
tolerable limits and can easily be detoxified
by soaking or boiling (Ekop and Eddy,
2005; Ekop et al., 2004; Eka and Osagie,
1998).
When isolated, pure alkaloids are used as
basic medicinal agents for their analgesic,
antispasmodic and bactericidal effects
(Stray, 1998; Okwu and Okwu, 2008). The
alkaloid content of Solanumincanum (0.6
mg/100g) is lower than values reported for
some of the leafy vegetables consumed in
Nigeria (Akubugwo et al., 2007; Okwu and
Josiah, 2006).
Phytochemicals are natural constituents of
plants that have nutritional and therapeutic
activities (Olaleye and Akindahunsi, 2004a;
Akindahunsi and Olaleye, 2003; Salawu and
Akindahunsi, 2007). Solanumincanum in
addition to alkaloids, flavanoids, tannins and
saponins also contain oxalate (22.95
mg/100g) and cyanogenic glycoside (5.71
mg/100g).
TABLE 2: Phytochemical composition of Solanumincanum
Phytochemical
Composition (mg/100g)
Alkaloids
0.60
Flavonoids
26.70
Tannins
2.45
Saponins
14.40
Oxalate
22.95
Cyanogenic glycosides
5.7
Results are mean of triplicate determinations
103
TABLE 3: Mineral composition of Solanumincanum:
Mineral element
Concentration (mg/100g DW)
Phosphorus
1085.00
Magnesium
39.14
Potassium
216.89
Manganese
147.78
Copper
256.17
Sodium
149.34
Iron
326.50
Calcium
15.29
Ca/P
0.01
K/Na
1.45
Results are mean values of two replicates.
TABLE 4: Vitamin composition of Solanumincanum
Vitamin
Concentration (mg/100g DW)
Riboflavin (Vitamin B2)
0.036
Ascorbic acid (Vitamin C)
6.273
a-Tochopherol (Vitamin E)
0.140
Results are mean of triplicate determinations
Vitamin content
Table 4 shows the results of the vitamin
composition of Solanumincanum. The
sample has low amount of riboflavin (0.036
mg/100g)
when
compared
with
Amaranthushybridus,
Aspillaafricana,
Bryophylumpinnatumand
Dioscoreabelophylla (Akubugwo et al.,
2007; Okwu and Josiah, 2006; Poornima
and Ravishankar, 2009). The RDA of
riboflavin is 1.1 to 1.3 mg/day (0.25 – 0.27
mg/100g). Deficiency results in angular
somatitis, magenta tongue, vascularization
of cornea, epithelial keratitis, scrotal
dermatitis and vulvitis (Gordon, 2003;
Ifeolu, 1999). Solanumincanum does not
meet the RDA for riboflavin, thus the need
to consume other food sources with
riboflavin.
Vitamin E is a major lipid soluble
antioxidant, and is the most effective chain
breaking antioxidant within the cell
membrane where it protects membrane fatty
acids from lipid peroxidation (Afolabi,
2009). If vitamin E is not available to do its
job, free radicals can pull electrons from cell
membranes, DNA and other electron-dense
cell components. This either alters the cell
DNA, which may increase the risk for
cancer or injures cell membrane, possibly
causing the cell to die (Gordon, 2003). The
vitamin E level in Solanumincanum (0.14
mg/100g) is lower than value (0.5 mg/100g)
reported by Akubugwo et al., (2007) in
Amaranthushybridus but could still be a
source of vitamin when consumed with
other valuable sources of dietary vitamin E
in human nutrition.
Vitamin C is considered the most important
water soluble antioxidant in extracellular
fluids, as it is capable of neutralizing
Reactive Oxygen Species (ROS) in aqueous
phase before lipid peroxidation is initiated
(Afolabi, 2009). The vitamin C content of
Solanumincanum (6.273 mg/100g) is higher
than 1.67 mg/100g of Dioscoreabelophylla
(Poornima and Ravishankar, 2009) but
lower than values (25.4 – 44.03 mg/100g)
reported in some leafy vegetables in Nigeria
104
(Akubugwo et al., 2007; Okwu and Josiah,
2006). Man has lost the ability to synthesize
vitamin C and so require it in his diets. A
deficiency of this vitamin results in scurvy
characterized by swollen bleeding gums,
poor
wound
healing,
subcutaneous
haemorrhage and swelling of joints (Ifeolu,
1999).
The mineral contents of Solanumincanum
are shown on table 3. Phosphorus was the
most abundant macro element present with a
value of 1085.00 mg/100g. The value is by
far higher than the values reported for most
leafy vegetables in Nigeria and other parts
of Africa, which falls within the range of
0.18 – 640 mg/100g (Ladan et al., 1996;
Hassan and Umar, 2006; Akubugwo et al.,
2007; Okwu and Josiah, 2006).
The calcium content (15.29 mg/100g) was
lower than the values reported for
Mormodicabalsamina
(941
mg/100g),
Amaranthushybridus
(44.15
mg/100g)
(Hassan and Umar, 2006; Akubugwo et al.,
2007), but higher than that reported for two
medicinal plant (1.04 and 0.32 mg/100g) for
A. Africana and B. pinnatum respectively (;
Okwu and Josiah, 2006). For a good Ca to P
intestinal absorption, Ca/P ratio should be
close to unity (Guil-Guerrero et al., 1998).
The ratio is quite low, though suggests high
phosphorus content in Solanumincanum.
Potassium content was 216.89 mg/100g, a
value
lower
than
that
of
Mormodicabalsamina (1320.00 mg/100g)
(Hassan and Umar, 2006). Solanumincanum
has a low amount of sodium (149.34
mg/100g). It has been documented that a
K/Na ratio in a diet is an important factor in
prevention
of
hypertension
and
arterosclerosis, since potassium depresses
and sodium enhances blood pressure
(Yoshimura et al., 1991). A K/Na ratio of 34 is considered the most adequate for the
normal retention of protein during growth
stage (Guil-Guerrero et al., 1998). The
calculated K/Na ratio in the sample was
below the range, but other food sources rich
in potassium when prepared with
Solanumincanum will bring the ratio within
the range.
The iron content of Solanumincanum
(326.50 mg/100g) was higher than
amaranthushybridus (13.58 mg/100g) and
balsam apple (60.3 mg/100g) as reported by
Akubugwo et al. (2007) and Hassan and
Umar (2006) respectively. Iron is an
essential component of haemoglobin in
blood, myoglobin of muscles and certain
proteins such as ferritin, hemosiderin and
cytochromes found in the body. It is also a
cofactor for cytochrome oxido-reductase,
catalase, peroxidase, xanthine oxidase,
tryptophan oxidase and phenylalanine
hydrolase (Ifeolu, 1999). Since iron in the
body is derived from the diet,
Solanumincanum could be a very good
source.
The copper content of the sample (256.17
mg/100g) is quiet high when compared with
other leafy vegetables common in Northern
Nigeria (Hassan and Umar, 2006; Ibrahim et
al., 2001). Nutritional anaemia in infants has
been treated with copper and iron. Copper
probably plays a role in iron absorption and
mobilization of stored iron (Ifeolu, 1999).
Manganese is required in human nutrition
for bone formation and growth. The
manganese content of Solanumincanum
(147.78 mg/100g) is comparable with the
values reported in some leafy vegetables in
southern Nigeria (Ifon and Bassir, 1979) but
higher than the values of some leafy
vegetables common in the northern part of
Nigeria (Ibrahim et al., 2001; Hassan and
Umar, 2006; Turan et al., 2003).
The magnesium content of Solanumincanum
(39.14 mg/100g) was low when compared
with
that
of
amaranthushybridus
(Akubugwo et al., 2007) and balsam apple
(Hassan and Umar, 2006).
Conclusion
105
This study has revealed and provided some
biochemical information on the nutritional
content ofSolanumincanum. As rich source
of minerals, phytochemicals and some
vitamins, Solanumincanum could be a
potential source of useful drugs and can also
complement other conventional vegetables.
A further study on the amino acid profile,
nutritive, chemical or physical changes
during processing is in progress.
References
1. Afolabi, A.A. (2009). Biochemistry:
Consequent
seemingly
inconsequential. Inaugural lecture
series 56, FUT Akure. 29 – 30.
2. Agbo, J.T. (2004). Proximate
nutrient composition of sickle pod.
(Cassia obtusfolia) leaves and seeds.
Plant Prod. Res. J., 8: 13 -17.
3. Akubugwo, I.E.; Obasi, N.A.;
Chinyere, G.C. and Ugbogu, A.E.
(2007). Nutritional and Chemical
value of
Amaranthushybridus
leaves from Afikpo, Nigeria. African
Journal of Biotechnology. 6: 2833 –
2839.
4. Aliyu, H.M. (2006). Proximate
analysis of some leafy vegetables
(Roselle Jute and Bitter leaf).
International J. Food Agric. Res.
3(1): 11 – 12.
5. AOAC (1984). Official Methods of
Analysis of the Association of
Official Analytical Chemists. 14th
(Edn.). Washington, DC.
6. AOAC (1999). Methods of Analysis
of Association of Official of
Analytical Chemists (16th edition).
Washington D.C.1:600 – 792.
7. Asibey-Berko, E. and Taiye, F.A.K.
(1999). Proximate analysis of some
underutilized Ghanian Vegetables.
Ghana J. Sci., 39: 91 -92.
8. Barakat, M.Z.; Shahab, S.K.;
Darwin, N. and Zahemy, E.I. (1993).
Determination of ascorbic acid from
plants. Anal. Biochem. 53: 225 –
245.
9. Boham, A.B. and Kocipai, A.C.
(1994). Flavonoid and condensed
tannins from leaves of Hawaiian
vacinninumvaticulum
and
vicalycinium. Pacific Sci. 48: 458 –
463.
10. Del-Rio, A.; Obdululio, B.G.;
Casfillo, J.F. Marin, F.G. and
Ortuno, A. (1997). Uses and
Properties of citrus flavonoids. J.
Agric Food Chem. 45:4505- 4515.
11. Denston, T.C. (1951). A textbook of
Pharmacology, 5th edition, medicinal
plants of West Africa. London
Oxford Press. 147 – 149.
12. Edeoga, H.O.; Okwu, D.E. and
Mbaebie,
B.O.
(2005).
Photochemical constituents of some
Nigerian Medicinal plants. Afr. J.
Biotechnol. 4 (7): 685 – 688.
13. Eka, O.U. and Osagie, A.U. (1998).
Nutritional quality of plant food.
Post harvest publishers, University
of Benin, Nigeria. 38 – 54.
14. Ekop, A.S. and Eddy, N.O. (2005).
Comparative studies of the level of
toxicants in the seed of Indian
Almond(Terminaliacatappa)
and
African walnut (Coulaedulis). Chem.
Class J. 2: 74 – 76.
15. Ekop, A.S.; Eddy, N.O. and Udofia,
P.G. (2004). Effect of processing on
the elemental composition of beans.
Proceedings of 28th annual Conf. of
Nig. Inst. Of food and Sci. Tec.
(NIFEST), Ibadan. 217 – 218.
16. Gordon, M.W. (2003). Vitamins and
Minerals.
In:
Contemporary
th
Nutrition. 5 Ed. McGraw-Hill, NY.
239 – 289.
17. Guil-Guerrero,
J.L.;
GimenezGimenez, A.; Rodriguez-Garcia, I
and Torija-Isasa, M.E. (1998).
106
Nutritional composition of Sonchus
species (S. asperL, S.oleraceusL and
S. tenerrimusL). J. Sci. Food Agri.,
76: 628-632.
18. Harbone, J.B. (1973). Phytochemical
Methods, Chapman and Hall,
London. P. 113.
19. Hassan, L.G. and Umar, K.J. (2006).
Nutritional value of Balsam Apple
(Momordicabalsamina L.) leaves.
Pakistan Journal of Nutrition, 5 (6):
522 – 529.
20. Hassan, L.G. and Umar, K.J. (2006).
Nutritional value of Balsam Apple
(Momordicabalsamina L.) leaves.
Pak. J. Nutr. 5(6): 522-529.
21. Ibrahim, N.D.G.; Abdurahhman,
E.M. and
Ibrahim, G. (2001).
Elemental analysis of the leaves of
Verniniaamygdalinaand
its
biological evaluation in rats. Nig. J.
Natural Prod. Med., 5: 13-16.
22. IfeoluAkinwande (1999). Mineral
Metabolism.
In:
Nutritional
Biochemistry. University of Lagos
press, Nigeria. P178-189.
23. Ifon, E.T. and Bassir, O. (1979). The
nutritive value of some Nigerian
leafy green vegetables – part 1:
Vitamin and Mineral contents. Food
Chem., 4: 263 -267.
24. Ifon, E.T. and Bassir, O. (1980). The
nutritive value of some Nigerian
leafy green vegetables – part 2: The
distribution of protein, carbohydrates
(including ethanol-soluble simple
sugars), crude fat, fibre and ash.
Food Chem., 5: 231 – 235.
25. Isong, E.U. and Idiong, U.I. (1997).
Comparative
studies
on
the
nutritional and toxic composition of
three
varieties
of
Lesiantheraafricana. Plant foods for
Human Nutr., 51: 79 – 84.
26. Isong, E.U.; Adewusi, S.A.R.;
Nkanga, E.U.; Umoh, E.E. and
Offiong, E.E. (1999). Nutritional and
phytogeriatological studies in three
varieties
of
Gnetumafricanum
(afang). Food Chem., 64: 489 – 493.
27. Ladan, M.J.; Bilbils, L.S. and Lawal,
M. (1996). Nutrient composition of
some
green
leafy
vegetable
consumed in Sokoto. Niger. J. Basic
Appl. Sci. 5: 39-44.
28. Lockeett, C.T., Calvert, C.C. and
Grivetti, L.E. (2000). Energy and
micronutrient composition of dietary
and medicinal wild plants consumed
during drought: Study of rural
Fulani, Northeastern Nigeria. Int. J.
Food Sci. Nutr., 51: 195 – 208.
29. Makkar, H.P.S.; Blummel, M.;
Borowy, N.K. and Becker, K.
(1993). Gravimetric determinations
of tannins and their correlations with
chemical and protein precipitation
methods. J. Sc. Food Agric. 61: 161
– 165.
30. Ogle B.M. and Grivetti, L.E. (1985).
Legacy of the chameleon: Edible
wild plants in the kingdom of
Swaziland, Southern Africa. A
cultural, ecological nutritional study.
Part IV – Nutritional analysis and
conclution. Ecol. Food Nutr., 17: 41
– 64.
31. Oke, O.L. (1969). Chemical studies
on some Nigerian foodstuffs. West
African J. Bio. Applied Chem. 8: 53
– 56.
32. Okwu, D.E. (2004). Phytochemicals
and vitamin content of indigenous
spices of South Eastern Nigeria. J.
Sustain. Agric. Environ. 6: 30-34.
33. Okwu, D.E. and Josiah, C. (2006).
Evaluation
of
the
chemical
composition of two Nigerian
Medical plants. Afr. J. Biotechnol.
5(4): 357-361
34. Okwu, D.E. and Okwu, M.E. (2004).
Chemical
composition
of
107
Spondiasmombinlinn plant parts. J.
sustain Agric. Environ. 6(2): 140 –
147.
35. Olaleye, M.T. and Akindahunsi,
A.A.
(2003).
Phytotochemical
investigation
and
antimicrobial
activities of extracts of the leaves of
Viscum album. Nigerian Journal of
Biochemistry
and
Molecular
Biology, 18(2), 77 – 79.
36. Olaleye, M.T. and Akindahunsi,
A.A. (2004). Hypotensive activity of
methanolic extract of the Calyces of
Hibiscus
sabdariffa
L.
on
Normotensive
rats.
In:
plant
Bioactives in Traditional Medicine,
recent progress in medicinal plants
series (D.K. Majumdar, J.N. Govil,
V.K. Singh and Rajeev Kumar
Sharma, Eds.). Studium press LLC.
USA. 9: 283 -288.
37. Onwuka, G.I. (2005). Food analysis
and instrumentation (theory and
practice). 1stEdn. Napthali prints,
Surulere, Lagos-Nigeria. 140 – 160.
38. Pearson, D. (1976). Chemical
analysis of foods. (7th ed)
churchchill, Livingstone, London,
pp. 218-336.
39. Poornima, G.N. and Ravishankar,
R.V.
(2009).
Evaluation
of
Phytonutrients and vitamin contents
in a wild yam, Dioscoreabelophylla
(Prain) Haines. African Journal of
Biotechnology. Vol. 8(6): 971 – 973.
40. Salah, N.; Miller, N.J.; Pagange, G.;
Tijburg, L.; Bolwell, G.P.; Rice, E.
and
Evans,
C.(1995).
Polyphenolicflavonoils as scavenger
of aqueous phase radicals as chain
breaking antioxidant. Arch Biochem.
Broph. 2: 339-346.
41. Salawu, S.O. and Akindahunsi, A.A.
(2007). Protective effect of some
tropical vegetables against CC14-
induced hepatic damage. J. Med
Food. 10(2): 350 – 355.
42. Sena, L.P.; Vanderjagt, D.J.; Rivera,
C.; Tsin, A.T.C.; Muhammadu, I.;
Mahamadou, O.; Milson, M.;
Pastosyn, A. and Glew, R.H. (1998).
Analysis of nutritional components
of eight famine foods of the republic
of Niger. Plant Foods Human Nutr.
52: 17 – 30.
43. Sodipo,
O.A.;Akiniyi,
J.A.
andOgunbamosu,
J.U.
(2000).
Studies on certain Characteristics of
extracts
of
bark
of
pansinystaliamacruceras (K schemp)
pierreExbeille. Global J. Pure Appl.
Sci. 6: 83-87.
44. Stray, F.(1998). The Natural Guide
to Medicinal Herbs, and Plants.
Tiger Books International, London.
pp. 12-16.
45. Taiga, A.; Suleiman, M.N.; Aina,
D.O.; Sule, W.F. and Alege, G.O.
(2008). Proximate analysis of some
dry season vegetables in Anyigba,
Kogi State, Nigeria. Vol. 7 (10):
1588 – 1590.
46. Turan, M.S.; Kordali, H.; Zengin,
A.D. and Sezen, Y. (2003). Macro
and micro mineral content of some
wild edible leaves consumed in
Eastern
Anatolia.
ActaAgriculturaeScandinavica,
Section B, plant soil Science, 53: 129
– 137.
47. Yoshimura, M.; Takahashi, H. and
Nakanishi, T. (1991).Role of sodium,
potassium, calcium, and magnesium
on blood pressure regulation and
antihypertensive dietary therapy.
Japanese J. Nutr., 49: 53-62.
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