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European Scientific Journal June 2014 edition vol.10, No.18 ISSN: 1857 – 7881 (Print) e - ISSN 1857- 7431
247
DETERMINATION OF PHYSICAL AND
PHYTOCHEMICAL CONSTITUENTS OF SOME
TROPICAL TIMBERS INDIGENOUS TO NIGER
DELTA AREA OF NIGERIA
Chigozie M. Ejikeme, PhD
Department of Chemical Sciences, Godfrey Okoye University,
Thinkers Corner, Enugu, Nigeria
Chukwuma S. Ezeonu, PhD
Department of Biochemistry, Federal University Wukari,
Taraba State, Nigeria
Augustine N. Eboatu, PhD
Department of Pure and Industrial Chemistry,
Nnamdi Azikiwe University, Awka, Anambra State, Nigeria
Abstract
Selected timbers indigenous to Niger delta area of Nigeria were
identified and their physical properties and phytochemical constituent
(qualitative and quantitative determination) check conducted. The result of
the physical properties showed that: the highest porosity index was 1.75 %
from Phyllanthus discoideus, the highest specific gravity recorded was 0.54
for Sacoglottis gabonensis, the highest charring temperature of 97-110
o
C
was recorded for Pycnanthus angolensis. Moisture contents of the range 16
% in Cassipourea barteria was the lowest while 33 % was the highest in
Bombax brevicuspe. All the timber samples were acidic with the exception of
Glyphaea brevis which is neutral with a pH of 7.18. All the timbers were
soluble in hot conc. H
2
SO
4
. Qualitative phytochemical studies showed that
almost all the phytochemicals except phlobatannins are present in varied
form in almost all the timber samples examined. Quantitative determination
of the pytochemical constituents showed that: Cola laurifolia and Bridelia
micrantha with contents of 1180mg/g and 1160mg/g had the highest tannin,
while the least recorded was 620mg/100g found in Lovoa trichiliode, 80 %
of the timber samples analysed had above 6 % of flavonoids in them,
cynogenic glycoside recorded in each of the wood samples was less than
1000 mg/g with the highest contents of 891 mg/g, 859 mg/g and 810 mg/g
found in Phyllanthus discoideus, Cassipourea barteri and Bridelia
micrantha. Bridelia micrantha and Homalinum letestui with values of 5.84
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g/100g and 5.34 g/100g respectively contain the highest quantity of oxalate,
Phyllanthus discoideus and Rhizophora racemosa with values of 11.6 % and
12.2 % had the highest quantity of alkaloids and saponin respectively. These
qualities possessed by the examined timbers shows that apart from their
properties in building and other constructions, they are good sources for dye
production, agro-chemicals and pharmaceuticals due to their phytochemical
constituents.
Keywords: Niger delta, timbers, Physical, Phytochemicals, constituents
Introduction
The ubiquitous nature of wood has made it a valuable material in
every stage of human development. This is well captured in the words of
Fuwape (2000) that at the early age, the baby rests in wooden cot, plays with
wooden toys, and learns to write on wooden slate and paper when he is of
school age. On graduating from school he receives a paper certificate, if he is
lucky to secure employment his salary is paid in paper currency. When he is
old he uses a wooden walking stick, sleeps on wooden bed and when he dies
the body is laid in wooden coffin. Wood is very important in the world today
so much so that its importance is innumerable.
Niger delta area of Nigeria is a densely populated region in Nigeria
which in the past was referred to as “oil rivers” because it was once the
major producer of palm oil in the glorious days of agricultural boom in
Nigeria before the discovery of crude oil. The area was the British Oil
Rivers Protectorate from 1885 until 1893 when it was expanded and became
the Niger Coast Protectorate (Hogan, 2013). The region covers about 70,000
km
2
, making up 7.5% of Nigeria’s land mass. Present day delta area of
Nigeria is made up of 9 states viz: Bayelsa, Delta, Rivers, Abia, Akwa Ibom,
Cross River, Imo, Edo and Ondo States. Niger delta is associated with
regions in Nigeria where crude oil is produced (crude oil producing states).
This area is made up of mangrove swamp vegetation with diverse species of
both plants and animals. It is the hub of timber logging in Nigeria as well as
center of herbal drug sources.
Wood has been used for centuries for needs varying from farming
tools to building materials, from fuel to weapons of hunting and warfare. It
remained virtually the most predominant material used for construction of
houses, barns, fences, bridges, furniture items, musical instruments and
energy generation (Douglas 1995). Wood and wood products have
contributed significantly to developments in education, communication,
entertainment, sports and industrialization.
In Nigeria, over four thousand six hundred (4600) plant species and
three hundred and fifty (350) timbers have been identified (Eboatu et al.,
European Scientific Journal June 2014 edition vol.10, No.18 ISSN: 1857 – 7881 (Print) e - ISSN 1857- 7431
249
1990 and Akindele and Lemay 2006), but this is without investigation of
their chemical constituent like those of the timbers in developed countries.
Akharaiyi et al. (2012) studied the antibacterial, phytochemical and
antioxidant activities of the leaf extracts of Gliricidia sepium and Spathodea
campanulata, and noted the differences in the chemical components of the
plants’ extracts such as tannins, alkaloids, phenols, flavonoids and saponins.
Compaore et al. (2011) carried out a comparative study on the composition
and antioxidative properties of seeds of Moringa oleifera and the pulps of
Parkia biglobosa and Adansonia digitata commonly used in food
fortification in Burkina Faso. From the literature, lots of work has been done
on the chemical constituents of the seeds, leaves and parts of plants of
tropical timbers, but it appears there is limited/no records on the physical
properties and phytochemical constituents of woods of these tropical timbers
especially those of Niger delta area of Nigeria, hence the need of a work in
this direction. This therefore, is the reason for carrying out this work to
determine the physical and phytochemical constituents of some timbers
indigenous to Niger delta area of Nigeria as this will help to establish facts
about their biochemical and pharmaceutical applications.
Materials and methods
Materials
The wood samples were obtained from timber markets in Enugu
(Enugu State), Abakaliki (Ebonyi State), Okada (Edo State), and Nnewi
(Anambra State) all in Nigeria. These wood samples were carefully selected
from sawed healthy timbers identified and their local names obtained from
timber dealers, confirmed by botanist and literature (Keay et al., 1964). The
timber dealers were able to give the local or common names of the timbers
while the botanical names were obtained with the aid of Forest Officers and
the literature (Keay et al., 1964).
Wood Sample Preparation
Fourteen well grounded fine powdered timber samples were obtained
using Angle grinder/polisher (Siemens, Germany). The powdered samples
were kept in air- tight polyurethane bags in cool dry cabinets until required.
Methods
Determination of Physical Constituents of woods
pH Determination
The hydrogen ion concentration (pH) of the powdered woods were
determined as described elsewhere by Amadi et al., 2004; and TAPPI, 1983,
using electrical pH meter PHS-25 made by Life Care England.
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Moisture Content
The moisture content was determined by weighing two grams of each
wood powder into a pre-heated, cooled and weighed crucible. The wood
sample in each crucible was dried in an oven for 24 hours at a regulated
temperature of 85
0
C to a constant weight. Each crucible and its content were
cooled in desiccators before weighing in accordance to the method described
by Amadi et al. (2004).
The moisture content was determined as the percentage moisture,
given as:
% =
×
100
Specific Gravity
The specific gravity was determined gravimetrically by measuring
the oven-dried wood powder using specific gravity bottle.
Charring Temperature
The charring temperature was determined by placing 0.50g of each
wood powder inside an ignition tube into which a thermometer (0 - 360
0
C)
was inserted. The combustion tube was then clamped and heated on a
heating mantle regulated at constant heating point. As the materials were
heated to char point, the exact char temperatures were recorded.
Wood Solubility
The wood solubility was determined by placing 1g of each wood
powder into nine different 250cm
3
Kjeldahl flasks. 20cm
3
of different
solvents, viz: cold water, hot water, 1.0M dilute tetraoxosulphate (VI) acid,
1.0M dilute hydrochloric acid, concentrated tetraoxosulphate (VI) acid,
concentrated hydrochloric acid, 1% sodium hydroxide, ether and ethanol
were added separately to each wood sample group. The mixture was allowed
to stand for 2 hours and the entire mixture in the Kjeldah flask was boiled
gently in a fume cupboard for 1 hour to determine their solubility properties.
Distilled water (100 cm
3
) was added to each mixture in the Kjeldahl flask,
the solution was filtered through a Whatman filter paper No 42 (125 mm),
the residues washed with distilled water, dried in an oven for 3 hours at a
regulated temperature of 80
o
C, cooled in a desiccator before weighing to
determine their final weight and solubility properties.
Determination of Porosity Index
One gram of cold water starch was prepared with 5cm
3
of water. The
starch which serves as an adhesive was mixed with 1.03g of the wood
European Scientific Journal June 2014 edition vol.10, No.18 ISSN: 1857 – 7881 (Print) e - ISSN 1857- 7431
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powder. The mixture (slurry mixture) was moulded into ring shape and
allowed to dry on exposure to air for 15 hours. The moulded dry wood
sample was weighed using an electronic weighing balance Model B218 and
dry weight was determined. The dry wood sample was soaked in 75cm
3
paraffin oil for 24 hours. The soaked dry wood sample was weighed and the
weight noted.
Mathematically, Porosity index was calculated thus:
=
Determination of Colour
The colours of the wood powder were determined using physical
visual identification compared with a colour chart. The colours of the wood
samples were matched with Chemistry Colour Chart and respective colours
were obtained (http://www.rfs.org.uk/learning/what-wood).
Phytochemical constituents of the wood samples
The following constituent of various wood samples were determined
using standard methods as described by Edeoga et al. (2005).
Qualitative Analyses of the Phytochemicals of the wood Sample
Test for Tannins
Weighed 0.30g of each wood powder was boiled in 30cm
3
of water in
a water bath for 10m and then filtered using Whatman filter paper No 42
(125mm). Three drops of 0.1% ferric chloride was added to 5cm
3
of the
filtrate and observed for brownish green or a blue black colouration.
Test for Phlobatannins
Some 30cm
3
of distilled water was added to 0.30g of each wood
powder weighed into a beaker. The mixture was allowed to stand for 24
hours. Measured 10cm
3
of the aqueous extract of each wood sample was
boiled with 5cm
3
of 1% aqueous hydrochloric acid and observed for deposit
of red precipitate.
Test for Saponin
To 0.30g of the wood powder was added 30cm
3
of distilled water,
boiled for 10 minutes in a water bath and filtered using Whatman filter paper
No 42 (125mm). The filtrate (10 cm
3
) was mixed with 5cm
3
of distilled
water and shaken vigorously for a stable persistent froth. The frothing was
mixed with three drops of olive oil and shaken vigorously, then observed for
the formation of emulsion.
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Test for Steroid
Some 20cm
3
of ethanol was added to 0.30g each wood powder
weighed into a beaker, the mixture was allowed to stand for 2 hours. Acetic
anhydride (2 cm
3
) was added to 5 cm
3
of the ethanolic extract of each sample
following with addition of 2cm
3
of concentrated tetraoxosulphate (VI) acid.
The colour changed from violet to blue or green in some samples indicating
the presence of steroids.
Test for Terpenoids
Distilled water (30cm
3
) was added to 0.30g of each wood powder
weighed into a beaker and the mixture was allowed to stand for 2 hours.
Measured 5cm
3
of each extract was mixed in 2cm
3
of chloroform and 3cm
3
of concentrated tetraoxosulphate (VI) acid was added to form a layer. If a
reddish brown colouration at the interface was formed, that shows positive
results for the presence of terpenoids.
Test for Flavonoids (Sofowara, 1993; Harborne, 1973).
Distilled water (30 cm
3
) was added to 0.30 g of the wood powder
weighed into a beaker, the mixture was allowed to stand for 2 hours and
filtered using Whatman filter paper No 42 (125mm). Some 5cm
3
of 1.0M
dilute ammonia solution was added to 10cm
3
of the aqueous filtrate of each
wood extract followed by the addition of 5cm
3
of concentrated
tetraoxosulphate (VI) acid. Observation of yellow colouration which
disappeared on standing indicates the presence of flavonoids.
Test for Alkaloids (Hikino et al., 1984).
Two grams of each wood powder was placed in a 250 cm
3
conical
flask and 20cm
3
of 5% tetraoxosulphate (VI) acid (H
2
SO
4
) in 50% ethanol
was added. The mixture was boiled for 2 minutes and filtered through
Whatman filter paper No 42 (125 mm). The filtrate was placed in a
separating funnel and made alkaline with 5cm
3
of 28% ammonia solution
(NH
3
). The solution was extracted with equal volume of chloroform
(5.0cm
3
). The chloroform solution was extracted with two 5cm
3
portion of
1.0M dilute tetraoxosulphate (VI) acid, the final acid extract was then used to
carry out the following test:-
To 2cm
3
of acid extract was added 0.5cm
3
of Dragennorff’s reagent
(Bismuth potassium iodide solution) and observed for orange coloured
precipitation indicating the presence of alkaloid.
European Scientific Journal June 2014 edition vol.10, No.18 ISSN: 1857 – 7881 (Print) e - ISSN 1857- 7431
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Test for Glycoside (Hikino et al., 1984).
Some 20cm
3
of water was added to 2.00 g of each wood sample. The
mixture was heated on a water bath for 5 minutes and filtered through Gem
filter paper (12.5cm). The filtrate was used for the following test:-
(a) 5cm
3
of the filtrate was added 0.2cm
3
of Fehlings solutions A and B
until it turned alkaline (tested with litmus paper) and heated on a
water bath for a brick-red colouration.
(b) Using 15cm
3
of 1.0M sulphuric acid instead of water, the above test
was repeated and the amount of precipitate formed compared with
that of (a) above. If the precipitate formed is high it indicates the
presence of glycoside, if low it indicates the absence of glycoside.
Quantitative determination of phytochemical constituents of woods
Tannin
The Folin-Denis reagent was prepared by dissolving 50g of sodium
tungstate (Na
2
WO
4
) in 37cm
3
of distilled water, followed by adding 10g of
phosphomolybdic acid (H
3
PMo
12
O
40
) and 25cm
3
of orthophosphoric acid
(H
3
PO
4
). The mixture was refluxed for 2 hours, cooled and diluted to 500cm
3
with distilled water. The method used was as reported by Amadi et al.,
(2004). One gram of each wood powder was weighed into a conical flask and
100 cm
3
of distilled water added. This was boiled gently on an electric hot
plate for 1 hour and filtered through Whatman filter paper No 42 (125 mm)
into a 100 cm
3
volumetric flask. For colour development, 50cm
3
of distilled
water and 10cm
3
of diluted extract (aliquot volume) were pipetted into a 100
cm
3
conical flask, followed by the addition of 5.0cm
3
Folin-Denis reagent
and 10cm
3
of saturated Na
2
CO
3
solution.
After thorough mixing, the solution was allowed to stand for 30
minutes in a water bath at a temperature of 25
o
C. Optical density was
measured at 700 nm with the aid of a Spectrum Lab23A spectrophotometer
and optical density (absorbance) compared on a standard tannic acid curve.
The tannic standard curve was prepared by dissolving 0.20 g of tannic acid in
distilled water and diluted to 200 cm
3
mark (1 mg/cm
3
). Varying
concentrations (0.2 - 1.0 mg/cm
3
) of the standard tannic acid solution were
pipetted into five different test tubes. 5cm
3
of Folin-Denis reagent and 10cm
3
of saturated Na
2
CO
3
solution were pipetted into the test tube, and was made
up to the 100 cm
3
mark with distilled water. The solution was left to stand
for 30 minutes in a water bath at a temperature of 25
o
C. Optical density was
measured at 700 nm with the aid of a Spectrum Lab23A spectrophotometer.
A plot of optical density (absorbance) versus tannic acid concentration was
made.
=
× ×
×
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254
Where C = concentration of tannic acid read off the graph.
Determination of Alkaloids (Harborne, 1973).
Some 2.50 g of each wood powder was weighed into a 250 cm
3
beaker and 200 cm
3
of 10 % acetic acid in ethanol was added to each wood
powder and allowed to stand for 4 hours. This was filtered and the extract
was concentrated on a water bath to one - quarter of the original volume
followed by addition of 15 drops of concentrated ammonium hydroxide drop
wise to the extract until the precipitation was complete. The whole mixture
was allowed to settle for 3 hours, the supernatant was discarded and the
precipitates washed with 20cm
3
of 0.1M of ammonium hydroxide and then
filtered using Gem fitter paper (12.5cm). The residue was dried in an oven
and weighed using electronic weighing balance Model B-218.
The percentage of alkaloid can be expressed mathematically as:-
% =
× 100
Determination of flavonoid
Each wood powder weighing 2.50 g was placed in a 250 cm
3
beaker
and 50 cm
3
of 80% aqueous methanol added, covered and allowed to stand
for 24 hours at room temperature. The supernatant was discarded and the
residue re-extracted three times with the same volume of ethanol. The whole
solution of each wood sample was filtered through Whatman filter paper No
42 (125 mm). The filtrate of each wood sample was later transferred into a
crucible and evaporated to dryness over a water bath. The crucible and its
content was cooled in a desiccator and weighed until constant weight was
obtained (Boham and Kocipai- Abyazan, 1994).
The percentage of flavonoid is expressed mathematically as:-
% =
× 100
Determination of Saponin
Five gram of each wood powder was put into a 250 cm
3
conical flask
and 100 cm
3
of 20% aqueous ethanol was added. The mixture was heated
over a hot water bath for 4 hours with continuous stirring at a temperature of
55
o
C. The mixture was filtered and the residue re-extracted with another
100cm
3
of 20% aqueous ethanol, heated for 4 hours at a constant temperature
of 55
o
C with constant stirring. The combined extract was reduced to 40 cm
3
over water bath at a temperature of 90
o
C. The concentrate was transferred
into a 250cm
3
separator funnel and 20cm
3
of diethyl ether was added and
shaken vigorously. The aqueous layer was recovered while the ether layer
was discarded. The purification process was repeated twice. 60cm
3
of n-
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255
butanol was added and the butanol extract was washed twice with 10cm
3
of 5
% sodium chloride. The sodium chloride layer was discarded and the
remaining solution heated in a water bath for 30 minutes, after which the
solution was transferred into a crucible and was dried in an oven to a
constant weight (Obdoni and Ochuko, 2001).
The saponin content was calculated as a percentage:
% =
× 100
Determination of Oxalate
Some 2.50g of each wood powder was weighed into a 250cm
3
beaker
and the wood powder extracted three (3) times by warming with 20cm
3
of
0.3M HCl at a temperature of 50
o
C with constant stirring using a magnetic
stirrer for 1 hour.
For oxalate estimation, 5.0 cm
3
of extract was made alkaline by
adding 1.0cm
3
of 5M ammonium hydroxide. This was made acidic by adding
2 drops of phenolphthalein indicator, 3 drops of glacial acetic acid and
1.0cm
3
of 5% calcium chloride and the mixture was allowed to stand for 3
hours after which it was then centrifuged at 3000 rpm for 15 minutes. The
supernatant was discarded and the precipitate washed three times with hot
water by thorough mixing each time followed by centrifugation. Then to
each tube, 2.0cm
3
of 3M tetraoxosulphate (VI) acid was added and the
precipitate dissolved by warming in a water bath at a temperature of 70
0
C.
The content of each tube was then titrated with freshly prepared 0.01M
potassium permanganate (KMnO
4
) at room temperature until the first pink
colour appears throughout the solution. However, when solution was allowed
to stand returns to colourless after which it was warmed on an electric hot
plate at a temperature of 70
o
C for 3 minutes, re-titrated again until a pink
colour appears and persists for at least 30 seconds (Munro and Bassir, 1969).
Oxalate in sample was calculated as Titration Reaction
C
2
O
2-
4
+ 8H
+
+ MnO
2-
4
= 2CO
2
+ 4H
2
O + Mn
2+
Ratio of reacting ions = 1:1
From M
1
V
1
= M
2
V
2
Where
M
1
= molarity of KM
n
O
4
M
2
= molarity of extract (oxalate)
V
1
= Volume of extract (oxalate)
V
2
= Volume of KMnO
4
(Titre Value)
Molecular Weight of CaCO
3
= 100
Weight of oxalate in titre = M
2
× molecular weight = Xg
2
=
× 2 =
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100
=
.
× 100 =
% /100 =
.
Determination of Cyanogenic Glycoside
One gram of each dry wood powder was weighed into a 250cm
3
round botton flask and 200cm
3
of distilled water was added and allowed to
stand for 2 hours for autolysis to occur. An antifoaming agent (tannic acid)
was added and full distillation carried out in a 250cm
3
conical flask
containing 20cm
3
of 2.5% NaOH (sodium hydroxide). To 100cm
3
of each
distillate containing cyanogenic glycoside, 8cm
3
of 6M NH
4
OH (ammonium
hydroxide) and 2cm
3
of 5% KI (Potassium Iodide) was added, mixed and
titrated with 0.02M AgNO
3
(silver nitrate) using a micro-burette against a
black background. Permanent turbidity indicates the end point (Amadi et al.
2004).
Cyanogenic glycoside content of the sample was calculated as:
100
=
(
)
× 1.08 ×
(
)
× ()
× 100
Result and discussion
Table 1 shows the various timbers indigenous to Niger delta area of
Nigeria. Most of them are domiciled in Port Harcourt, Calabar, Ikom, Eket
and parts of Rivers state. Here they are mainly used as sources of timbers
and their roots and leaves used for medical purposes. Most of these timbers
are part of the mangrove rainforest where they constitute good percentage of
trees in the niger delta forest vegetation of Nigeria. They have been
identified and are well known to timber dealers in Nigeria. Their indigenous
names as well as botanical names are written in table 1 below.
Table 1: Names and areas of location of wood /timbers (samples) from Niger Delta Area of
Nigeria.
S/N
Wood Sample
(Botanical
Name)
Botanical
families
Igbo
Names
Yoruba
Names
Hausa Names
Areas of
Location
1
Monodara
tenuifolia
Annonaceae
Ehuru ofia
Lakesin
Guyiyadanmiya
Port
Harcourt
2
Pycnanthus
angolensis
Myisticaceae Akwa-mili Akomu Akujaadi Calabar,
3
Rhizophora
racemosa
Rhizophoraceae Ngala
Eku, eso
roro
Loko Calabar
4
Allanblackia
floribunda
Guttiferae Egba Orogbo Guthiferae eku
Calabar,
Ikom
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5 Glyphaea brevis Tiliaceae Anyasu alo Eso, shishi
Bolukonu
kanana
Calabar
6
Cola laurifolia
Stericuliaceae
Ufa
Awori
Karanga
Calabar
7
Bombax
brevicuspe
Bombacaceae Akpudele Ida odan Kurya Ikom
8
Bridelia
micrantha
Euphorbiaceae Ogaofia Ira odan Kirni
Calabar,
Ikom
9
Lovoa
trichiliodes
Meliaceae Sida Akoko igbo Epo-ipa Calabar
10
Phyllanthus
discoideus
Euphorbiaceae Isinkpi Ashasha Baushe Ikom
11
Sacoglottis
gabonensis
Rhizophoraceae Nche Atala Chediya Rivers
12
Cassipourea
barteri
Lecythidaceae Itobo Itobo Odu Eket
13
Homalinum
letestui
Boraginaceae Akpurukwu Akpurukwu -
Ikom,
Calabar
14 Khaya ivorensis Bignoniaceae Ono
Oganwo
Madachi Calabar
The significance of the physical properties of wood generally is as
means used in placing them into various categories as ways of assessing their
usefulness. Some of the uses to which timbers are subjected to include their
usefulness in: buildings (houses, doors, bridges, and fences), furniture
production and varieties of wood work (carvings, equipment construction
such as drums and lorry carriages). The knowledge of their moisture content
can help in knowing if they are suitable for various outdoor uses as well as
chemical and pharmaceutical application. pH content enable their application
in corrosive prone areas. Porosity gives a good estimate of their particle
compactness or otherwise and thus shows where they are needed. Colour
type is an easy way of identifying them visually. Apart from Glyphaea brevis
which is neutral with a pH of 7.18, all the wood samples investigated were
acidic with Allanblackia floribunda having the lowest pH value of 4.53, an
indication of being the most acidic. Other woods examined have pH in the
range of 5.31 to 6.95. The implication being that the soil in the niger delta
environment is suitable for their growth and thus the trees are acidic as a
means of adaptability to such environment. It also gave insight into their
survivability mainly in the Niger delta region of Nigeria and similar
environments in the tropics. The percentage porosity index of the woods are
generally low showing that most of them have high compact grain particles
suitable for all types of wood uses. Porosity in woods shows empty spaces
‘voids’ prevalent in them which are normally occupied by water, mineral
salts and air, bearing in mind that the wood was formerly part of a live tree
where porosity was required for translocation and conduction in vessels. The
lowest porosity index was 1.14 % recorded for Homalinum letestui while the
European Scientific Journal June 2014 edition vol.10, No.18 ISSN: 1857 – 7881 (Print) e - ISSN 1857- 7431
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highest porosity index was 1.75 % by Phyllanthus discoideus. Most wood
with higher pore spaces are softwood while those of lower pore spaces are
hardwood. The highest specific gravity recorded was 0.54 by Sacoglottis
gabonensis. These woods generally have good specific gravity which is a
measure of their density and weight. According to Panshin and Dezeeuw
(1964), decrease in specific gravity affects the strength of the wood. As
specific gravity increases, strength properties increase, because, internal
stresses are distributed among more molecular material. Thus it can be
deduced that wood with high specific gravity has high wood strength and as
such their physical and mechanical properties will not be affected, because,
high wood strength increases the physical and mechanical properties of
wood. While those with low specific gravity will have low wood strength
and their physical and mechanical properties will be affected because of
decrease in the wood strength. David et al. (1999) explained that specific
gravity of wood is based on oven-dry weight of the wood. Thus specific
gravity is an excellent index of the amount of wood substance contained in a
piece of wood; it is a good index of mechanical properties as long as the
wood is clear, straight grained and free from defects. Specific gravity values
also reflect the presence of gums, resins and extractives, which contribute
little to mechanical properties (David et al., 1999). They have high charring
temperatures in the range of 63 – 110
o
C. The highest charring temperature
of 97 - 110
o
C was recorded for Pycnanthus angolensis and the least value of
83
o
C recorded for Khaya ivorensis (Table 2). Since wood charring is a
primary factor that determines the load-carrying capacity of structural wood
members in a fire, it therefore means that woods with high rate of charring
temperature will have high ability of load-carrying capacity than woods of
low charring rate. Charring temperatures assists in estimating their
usefulness in high temperature environments. The Moisture contents are
moderate, of the range 16 % in Cassipourea barteria as the lowest and 33 %
in Bombax brevicuspe being the highest. Most of the woods fall in the
moisture content percentage categories of above 20%. This result agrees with
the work by Arntzen (1994) in which research discovered that the fibre
saturation point usually varies between 21 and 28%. An indication of the
pliability of these woods in buildings and various construction works.
Moderate water content as seen in table 2 below prevents their breakage and
dryness respectively and at the same time improves their strength, showing
they are of good quality. Decrease in moisture content can also lead to wood
shrinkage and loss of usage/value.
European Scientific Journal June 2014 edition vol.10, No.18 ISSN: 1857 – 7881 (Print) e - ISSN 1857- 7431
259
Table 2: Physical properties of the wood samples
Table 3 illustrates qualitative presence of phytochemicals present in
the woods examined. That though flavanoids are present in all the timber
samples examined, they are not heavily present. Also flavanoid has slightly
good presence in: Bombax brevicuspe and Bridelia micrantha, the same
could be said of Alkaloids except for Bridelia micrantha where alkaloids are
absent. Good presence of alkaloid was recorded for Monodara tenuifolia and
Cola laurifolia. Rhizophora racemosa, Bombax brevicuspe. Bridelia
micrantha, Sacoglottis gabonensis and Khaya ivorensis showed heavy
presence of tannins. Phloba tannins are present only in Bridelia micrantha.
Heavy presence of saponin was found in: Rhizophora racemosa, Bombax
brevicuspe, Sacaglottis gabonensis, Khaya ivorensis. Moreover, Bridelia
micrantha and Pycnanthus angolensis recorded heavy presence of glycoside
and terpenoids respectively. Additionally, heavy presence of steroids was
found in Pycnanthus angolensis, Allanblackia floribunda, Cola laurifolia,
Lovoa trichiliodes, Phyllanthus discoideus, Cassipourea barteri, Homalinum
letestui. The presence and quantity of the phytochemicals in the various
woods is as shown on table 3.
S/N
Wood Sample
(Botanic names)
pH
Values
Moistur
e
Content
(%)
Specifi
c
Gravit
y
Charring
Temperatur
e (
0
C)
Porosity
index
(%)
Colour
1
Monodara tenuifolia
5.85
27.0
0.43
90 – 101
1.38
Cornsilk
2
Pycnanthus
angolensis
6.09 25.0 0.36 97 – 110 1.56 Chocolate
3
Rhizophora
racemosa
6.25 27.0 0.32
64 – 81
1.32 Tan
4
Allanblackia
floribunda
4.53 25.0 0.37 95 – 121 1.23 Cornsilk
5
Glyphaea brevis
7.18
27.0
0.39
94 – 101
1.38
Burly wood
6
Cola laurifolia
6.6
25.0
0.34
64 – 90
1.17
Chocolate
7 Bombax brevicuspe 6.0 33.0 0.23 81 – 92 1.25
Sandy
Brown
8
Bridelia micrantha
6.65
29.0
0.23
75 – 95
1.32
Tan
9
Lovoa trichilioides
6.55
26.0
0.19
90 – 115
1.18
Burly Wood
10
Phyllanthus
discoideus
6.51 25.0 0.29 92 – 115 1.75 Khaki
11
Sacoglottis
gabonensis
6.37 27.0 0.54 89 – 104 1.41 Tan
12
Cassipourea
barteria
6.95 16.0 0.44 97 – 114 1.70 Peru
13 Homalinum letestui 6.48 20.0 0.45 65 – 82 1.14
Navajowhit
e
14
Khaya ivorensis
5.31
29.0
0.32
63 – 85
1.39
Cornsilk
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260
Table 3: Result on the qualitative analyses of the phytochemicals of the wood samples
Key
Table 4 shows that the wood solubility in the Niger delta timbers are similar to each other. They are insoluble in
both cold and hot water, dilute and concentrated HCl, Ethanol, dilute NaOH and diethyl ether. The result as seen in Table
4 indicates that all the woods are slightly soluble in Conc. HCl when heated, and in both concentrated and diluted H
2
SO
4.
They are all soluble in concentrated H
2
SO
4
when heated.
The solubility result shows that they are resilient (resistant) to
polar, organic and corrosive substances except perhaps highly corrosive hot acids.
S/N
Wood Sample
(Botanic names)
Flavonoids Alkaloids Saponins Tannins Glycoside Steroids
Terpenoids
Phloba
Tannins
1
Monodara tenuifolia
+
++
+
++
++
++
+
-
2
Pycnanthus
angolensis
+ + + + + +++ +++ -
3
Rhizophora racemosa
+
+
+++
++
++
-
+
-
4
Allanblackia
floribunda
+ + ++ + ++ +++ ++ -
5
Glyphea brevis
+
+
+
+++
++
+
+
-
6
Cola laurifolia
+
++
+
+++
+
+++
++
-
7
Bombax brevicuspe
++
+
+++
++
-
-
++
-
8
Bridelia micrantha
++
-
+++
+++
+++
++
+
+
9
Lovoa trichiliodes
+
+
+
-
-
+++
+
-
10
Phyllanthus
discoideus
+ + + - ++ +++ - -
11
Sacoglottis
gabonensis
+ + +++ + ++ - + -
12
Cassipourea barteri
+
+
+
-
++
+++
-
-
13
Homalinum letestui
+
+
+
-
++
+++
-
-
14
Khaya ivorensis
+
+
+++
+
++
-
+
-
Heavily present
......................+++
Slightly present
........................++
Present
...........................+
Absent
.......................... _
European Scientific Journal June 2014 edition vol.10, No.18 ISSN: 1857 – 7881 (Print) e - ISSN 1857- 7431
261
Table 4: Result of the solubility property of the wood samples
S/N
Wood Sample
(Botanic
names)
Hot and
cold water
1.0M
Dilute HCl
Concentrated
HCl
Concentrated
HCl + heat
1.0M
Dilute
H
2
SO
4
Concentrated
H
2
SO
4
Concentrated
H
2
SO
4
+ heat
1%
NaOH
Ethanol
Diethyl
ether
1
Monodara
tenuifolia
Insoluble Insoluble Insoluble
Slightly
Soluble
Slightly
Soluble
Slightly
Soluble
Soluble Insoluble Insoluble Insoluble
2
Pycnanthus
angolensis
Insoluble Insoluble Insoluble
Slightly
Soluble
Slightly
Soluble
Slightly
Soluble
Soluble Insoluble Insoluble Insoluble
3
Rhizophora
racemosa
Insoluble Insoluble Insoluble
Slightly
Soluble
Slightly
Soluble
Slightly
Soluble
Soluble Insoluble Insoluble Insoluble
4
Allanblackia
floribunda
Insoluble Insoluble Insoluble
Slightly
Soluble
Slightly
Soluble
Slightly
Soluble
Soluble Insoluble Insoluble Insoluble
5
Glyphaea
brevis
Insoluble Insoluble Insoluble
Slightly
Soluble
Slightly
Soluble
Slightly
Soluble
Soluble Insoluble Insoluble Insoluble
6 Cola laurifolia Insoluble Insoluble Insoluble
Slightly
Soluble
Slightly
Soluble
Slightly
Soluble
Soluble Insoluble Insoluble Insoluble
7
Bombax
brevicuspe
Insoluble Insoluble Insoluble
Slightly
Soluble
Slightly
Soluble
Slightly
Soluble
Soluble Insoluble Insoluble Insoluble
8
Bridelia
micrantha
Insoluble Insoluble Insoluble
Slightly
Soluble
Slightly
Soluble
Slightly
Soluble
Soluble Insoluble Insoluble Insoluble
9
Lovoa
trichilioides
Insoluble Insoluble Insoluble
Slightly
Soluble
Slightly
Soluble
Slightly
Soluble
Soluble Insoluble Insoluble Insoluble
10
Phyllanthus
discoideus
Insoluble Insoluble Insoluble
Slightly
Soluble
Slightly
Soluble
Slightly
Soluble
Soluble Insoluble Insoluble Insoluble
11
Sacoglottis
gabonensis
Insoluble Insoluble Insoluble
Slightly
Soluble
Slightly
Soluble
Slightly
Soluble
Soluble Insoluble Insoluble Insoluble
12
Cassipourea
barteria
Insoluble Insoluble Insoluble
Slightly
Soluble
Slightly
Soluble
Slightly
Soluble
Soluble Insoluble Insoluble Insoluble
13
Homalinum
letestui
Insoluble Insoluble Insoluble
Slightly
Soluble
Slightly
Soluble
Slightly
Soluble
Soluble Insoluble Insoluble Insoluble
14
Khaya
ivorensis
Insoluble Insoluble Insoluble
Slightly
Soluble
Slightly
Soluble
Slightly
Soluble
Soluble Insoluble Insoluble Insoluble
European Scientific Journal June 2014 edition vol.10, No.18 ISSN: 1857 – 7881 (Print) e - ISSN 1857- 7431
262
Figures of the Quantitative Determination of the phytochemical
constituents of the Wood Sample
.
Fig. 1: Quantity of Tannin in Wood Samples
The tannin content in the various woods is shown in fig. 1. The
various wood sample examined have appreciable quantities of tannin. Cola
laurifolia with tannin content of 1180mg/100g and Bridelia micrantha
having 1160mg/100g of tannin as seen in fig. 1 above, has the highest
quantity of tannin. The least content of tannin with value of 620mg/100g was
found in Lovoa trichiliodes. The range of the quantity of tannin present in the
wood samples was between 620 to 1180mg/100g indicating the fact that
though the tannin quantity may seem low being a phytochemical, yet, the
quantity is appreciable in these Niger delta indigenous timbers. Tannin, also
called tannic acid, is any of a group of pale-yellow to light-brown amorphous
substances in the form of powder, flakes, or a spongy mass, widely
distributed in many species of plants, where they play a role in protection
from predation, as pesticides, and in plant growth regulation (Katie and
Thorington, 2006). Tannins are classified as ergastic substances, i.e., non-
protoplasm materials found in cells. They are also found in leaf, bud, seed,
root, and stem tissues. In addition to their principal applications in leather
manufacture and dyeing, tannins are used in the clarification of wine and
beer, as a constituent to reduce viscosity of drilling mud for oil wells, and in
boiler water to prevent scale formation. Because of its styptic and astringent
properties, tannin has been used to treat tonsillitis, pharyngitis, hemorrhoids,
and skin eruptions; it has been administered internally to check diarrhea and
intestinal bleeding and as an antidote for metallic, alkaloidal, and glycosidic
0
200
400
600
800
1000
1200
1400
Tannin Content (mg/100g)
Wood Sample
European Scientific Journal June 2014 edition vol.10, No.18 ISSN: 1857 – 7881 (Print) e - ISSN 1857- 7431
263
poisons, with which it forms insoluble precipitates. Soluble in water, tannins
form dark blue or dark green solutions with iron salts, a property utilized in
the manufacture of ink ( http://www.britannica.com / Ebchecked / topic /
582701 / tannin). The implication in this study is that those timber among
the following samples investigated that have high content of tannin such as
Cola laurifolia and Bridelia micrantha, may have their tannins extracted
and used for medical purposes (treatment of tonsillitis, pharyngitis,
hemorrhoids, and skin eruptions as well as diarrhea and intestinal bleeding);
for commercial usage (protective anti-predator substances, pesticides, plant
growth regulator, leather manufacture and dyeing, clarification of wine and
beer, anti-viscous agent in drilling mud for oil wells, and in boiler water for
the prevention of scale formation). Tannins are dietary anti-nutrients that are
responsible for the astringent taste of food and drinks. They are also anti-
oxidants.
.
Fig. 2: Quantity of Flavonoid Present in Wood Samples.
Flavonoid content present in most of the wood samples (fig. 2) such
as Homalinum letestui, Sacoglottis gabonensis, Khaya ivorensis, Phyllanthus
discoideus, Lovoa trichiloides, Bridelia micrantha, Bombax brevicuspe,
Glyphea brevis and Monodara tenuifolia were above 6%. This shows that
flavonoid content is appreciable in the wood samples investigated.
Flavonoids are plant nutrients that when consumed in the form of fruits and
vegetables are non-toxic as well as potentially beneficial to the human body
(http://www.wisegeek.com/what-are-flavonoids.htm). Flavonoids are widely
0
1
2
3
4
5
6
7
8
9
Flavonoid Content (%)
Wood Sample
European Scientific Journal June 2014 edition vol.10, No.18 ISSN: 1857 – 7881 (Print) e - ISSN 1857- 7431
264
distributed throughout plants, and together with carotenes are responsible for
the colouring of fruits, flowers, vegetables and herbs. They also play a role in
protecting the plants from microbes and insect attacks. In higher plants,
flavonoids are involved in UV filtration, symbiotic nitrogen fixation and
floral pigmentation. More importantly, the consumption of foods containing
flavonoids has been linked to numerous health benefits. Though research
shows flavonoids alone provide minimal antioxidant benefit due to slow
absorption by the body, there is indication that they biologically trigger the
production of natural enzymes that fight diseases that reduce the risk of
certain cancers, heart disease, and age-related degenerative diseases. Some
research also indicates flavonoids may help prevent tooth decay and reduce
the occurrence of common ailments such as the flu
(http://www.wisegeek.com/what-are-flavonoids.htm). Thus the implication
of appreciable flavonoid in tibers of niger delta area of Nigeria investigated
is that most of these woods, apart from timber usage in which they are
currently applied can also be used in health and nutritional industries
especially for herbal purposes.
Fig. 3: Quantity of Cyanogenic glycoside present in the wood samples.
In fig. 3, the quantity of cynogenic glycoside recorded in each of the
wood samples was less than 1000 mg/g with the highest contents of 891
mg/g, 859 mg/g and 810 mg/g found in Phyllanthus discoideus, Cassipourea
barteri and Bridelia micrantha. Glycosides are compounds containing a
carbohydrate and a non-carbohydrate residue in the same molecule. The
0
100
200
300
400
500
600
700
800
900
1000
Cyanogenic Glycoside (mg/100g)
Wood Sample
European Scientific Journal June 2014 edition vol.10, No.18 ISSN: 1857 – 7881 (Print) e - ISSN 1857- 7431
265
carbohydrate residue is attached by an acetal linkage at carbon atom 1 to a
non-carbohydrate residue or aglycone. The non-sugar component is known
as the aglycone and sugar component glycone. Thus, a glycoside is a
molecule in which a sugar is bound to a non-carbohydrate moiety, usually a
small organic molecule. In plants, aglycone in cyanogenic glycosides
contains a cyanide group which when plants are attacked are released and
become activated by enzymes in the cytoplasm. These remove the sugar part
of the molecule and release toxic hydrogen cyanide, storing them in inactive
forms in the cytoplasm preventing them from damaging the plant under
normal conditions. In humans, glycosides increase capillary resistance and
decrease vitamin C deficiency. They are recommended in the treatment of
thrombopenia (blood coagulation), influenza, fever, gastric ulcer and have
cortisone like action in rheumatic arthritis and other inflammatory diseases.
Cyanogenic glycosides are anti–nutrient glycosides that contain the cyanide
(-CN) group.
Fig. 4: Quantity of Oxalate present in the wood samples
Bridelia micrantha and Homalinum letestui with Oxalate content of
5.84 g/100g and 5.34 g/100g respectively contain the highest quantity of this
phytochemical among the wood samples analysed in this work. The least
Oxalate value of 0.21 g/100g was found in Sacoglottis gabonensis. The rest
of the result of oxalate content is as shown in fig. 4. The reason for the
higher content of oxalate in some of the woods is not known but may be
attributed to plants age, season, climate and the soil type (Mahmut, 2000).
From literature, foods high in oxalate causes inflammation, pain and burning,
irritation of tissues and mucous membranes, and contribute to the formation
of calcium oxalate kidney stones (http://alwayswellwithin.Com
/2010/04/27/high-oxalata-foods-can-trigger-pain-and-information). Oxalates
0
1
2
3
4
5
6
7
Oxalate Content (g/100g)
Wood Sample
European Scientific Journal June 2014 edition vol.10, No.18 ISSN: 1857 – 7881 (Print) e - ISSN 1857- 7431
266
are dietary anti-nutrients that chelate dietary calcium. Therefore, the lower
the rate of oxalates in wood samples as seen above the better for the
nutritional and medical properties of the wood.
Fig. 5: Quantity of Alkaloid present in Wood Samples.
Fig. 5 is detailed illustration of the content of Alkaloid present in the
samples analyzed. In ascending order of alkaloid content, the wood content
of same phytochemical is as shown: Allenblackia floribunda (1.6%), Bridelia
micrantha (2.0%), Glyphea brevis (4.8%), Homalinum letestui (4.8%),
Bombax brevicuspe (5.6%), Rhizophora racemosa (6.0%), Lovoa
trichilioides (7.2%), Pycnanthus angolensis (7.6%), Sacoglottis gabonensis
(8.0%), Monodara tenuifolia (8.6%), Cassipourea barteri (9.0%), Khaya
ivorensis (9.4%), Cola laurifolia (10.4%), Phyllanthus discoideus (11.6%).
Alkaloids are produced by a large variety of organisms, including
bacteria, fungi, plants, and animals, and are part of the group of natural
products. In addition to carbon, hydrogen and nitrogen, alkaloids may also
contain oxygen, sulphur and more rarely other elements such as chlorine,
bromine, and phosphorus. Current research demonstrates not only that
alkaloids participate in plant metabolism over the long term, it has been
suggested that alkaloids may have a role in the defense of the plant against
singlet oxygen, which is damaging to all living organisms and is produced in
plant tissues in the presence of light. Of fifteen alkaloids tested, most showed
a good ability to quench singlet oxygen, with brucine and strychnine being
especially efficient. In human, they often have pharmacological effects and
are used as medications, as recreational drugs, or in entheogenic rituals.
0
2
4
6
8
10
12
14
Alkaloid Content (%)
Wood Sample
European Scientific Journal June 2014 edition vol.10, No.18 ISSN: 1857 – 7881 (Print) e - ISSN 1857- 7431
267
Although alkaloids act on a diversity of metabolic systems in humans and
other animals, they almost uniformly invoke a bitter taste (http://
www.us.elsevierhealth.com/ media/us/sample,chapters / 9780702029332 /
9780702029332_2.pdf ).
Fig. 6: Quantity of Saponin present in Wood Samples
From the bar chart in fig. 6 of the result of the percentage saponin
content of the various Niger delta indigenous timbers examined, the saponin
content range is between 2.8 to 12 %. The saponin contents in decreasing
order are as follows: Rhizophora racemosa (12.2 %), Bridelia micrantha
(10.6 %), Bombax brevicuspe (10.2 %), Sacoglottis gabonensis (6.6 %),
Allanblackia floribunda (5.2 %), Homalinum letestui (4.8 %), Cola laurifolia
(4.6 %), Monodara tenuifolia (4.4 %), Glyphea brevis (4.4 %), Lovoa
trichiliodes (4.4 %), Phyllanthus discoideus (4.2 %), Cassipourea barteri
(3.8 %), Pycnanthus angolensis (2.8 %), Khaya ivorensis (2.8%).
Saponins are basically phytochemicals which are found in most of the
herbs, beans and vegetables. They are glycosides with distinctive foaming
characteristics. Saponin protects plants against microbes and fungi; they are
natural pesticides, as they are good insect repellent. Some plant saponins
may enhance nutrient absorption and aid in animal digestion. However,
saponins are often bitter to taste, and so can reduce plant palatability.
Saponins are found to have numerous health benefits. Recent studies have
illustrated saponins effects which have been beneficial on the treatment of
allergies, eczema, malaria, and control of blood cholesterol levels, bone
health, cancer, and building up of the immune system.
(http://www.herbs 2000.com /h_menu/saponins.htm).
0
2
4
6
8
10
12
14
Saponin Content (%)
Wood Sample
European Scientific Journal June 2014 edition vol.10, No.18 ISSN: 1857 – 7881 (Print) e - ISSN 1857- 7431
268
Conclusion
The results of the physical properties and phytochemical constituents
of the wood samples from Niger delta area of Nigeria indicated that these
phytochemical constituents are present on the wood samples. However, these
constituents are more concentrated in some woods than the others. Fig. 1 – 5
clearly illustrates various phytochemical contents in these woods. Some of
the benefits derivable from this research as regards these woods showed that
tannins can be harnessed for leather, dye, wood adhesives and
pharmaceutical industries. The presence of Alkaloids signified the
possession of antimicrobial properties within the woods while the presence
of flavonoid shows possession of antioxidant, anti- inflammatory and
antiviral infection activities. Flavonoids was said to have the ability to lower
the cholesterol level. Saponins are found to have numerous health benefits.
Recent studies have illustrated saponin effects which have been beneficial on
the control of blood cholesterol levels, bone health, cancer, and building up
of the immune system. This work is therefore a basis establishing the
presence of these phytochemicals in these woods. Thus niger delta timbers
can also be used for other purposes (wooden doors, wood works, boat
contruction, paper production etc) due to their physical qualities, apart from
timber usages for construction of house roofs as they are currently employed
in Nigeria.
Acknowledgment
The kind gesture of the management of Godfrey Okoye University,
Enugu, Nigeria in permitting the researchers to carry out this project using
their facilities is hereby gratefully acknowledged.
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