Abstract: Nauclea latifolia has been found to lower blood pressure of both normotensive and hypertensive rats. The chloroform fractrion of this plant was subjected to column chromatography and five fractions were obtained, CF1-CF5. All the fractions were active in lowering blood pressure of normotensive rabbits. Fraction CF1, CF3 ,CF4 and CF5 were active at a dose range of 2.5 -10 mg/kg. At 10 mg/kg, CF1 reduced the Mean Arterial Pressure (MAP) from 97.6 ± 5.6 to 61.6 ± 8.6 mmHg , CF3 reduced the MAP from 95.3 ±5.1 to 68.3 ±3. mmHg, CF4 reduced the MAP from 84.8 ± 4.7 to 58.6 ± 5.0 mmHg while CF5 reduced the MAP from 78.6 ± 7.5 to 53.0 ± 4.6 mmHg. CF2 was effective at the dose range of 0.2 -0.6 mg/kg. At 0.6 mg/kg CF2 reduced the MAP from 79.0 ± 3.1 to 48.4 ± 3.7. It was thus concluded that Nauclea latifolia can be partitioned into 5 major fractions all of which are active in lowering blood pressure, but CF2 was most poten

A E Eferakeya

A J Afolayan

B A Ayinde

D N Onwukaeme

F C A Meachina

Z A M Nworgu

CiteSeerX

Journal of Applied Sciences Research, 5(12): 2208-2212, 2009
© 2009, INSInet Publication
Corresponding Author: Z.A.M. Nworgu, Dept. of pharmacology, Faculty of pharmacy, University of Benin, Benin city, Nigeria.
E-mail: zamnworgu@yahoo.com
2208
The Effect of Active Fractions of the Roots of Nauclea Latifolia Smith (Rubiaceae) on
Blood Pressure of Normotensive Rabbits
 
Z.a.m.nworgu, A.e.eferakeya D.n.onwukaeme, A.j. Afolayan, F.C. A meachina, B.A. Ayinde1 1 2 3 1 2
Department of Pharmacology and Toxicology Faculty of Pharmacy, University of Benin1
Department of Pharmacognosy, Faculty of Pharmacy, University of Benin, Benin City, Nigeria.2
Dept of Botany, Faculty of Science, University of Fort Hare, Alice, South Africa3
Abstract: Nauclea latifolia has been found to lower blood pressure of both normotensive and hypertensive
rats. The chloroform fractrion of this plant was subjected to column chromatography and five fractions
were obtained, CF1- CF5. All the fractions were active in lowering blood pressure of normotensive
rabbits. Fraction CF1, CF3 ,CF4 and CF5  were active  at a dose range of 2.5 -10 mg/kg. At 10 mg/kg,
CF1 reduced the Mean Arterial Pressure (MAP) from 97.6 ± 5.6 to 61.6 ± 8.6 mmHg , CF3 reduced the
MAP from 95.3 ±5.1 to 68.3 ±3. mmHg, CF4 reduced the MAP from 84.8 ± 4.7 to 58.6 ± 5.0 mmHg
while CF5 reduced the MAP from 78.6 ± 7.5  to 53.0 ± 4.6 mmHg. CF2 was effective at the dose range
of 0.2 – 0.6 mg/kg. At 0.6 mg/kg CF2 reduced the MAP from 79.0 ± 3.1  to 48.4 ± 3.7. It was thus
concluded that Nauclea latifolia can be partitioned into 5 major fractions all of which are active in
lowering blood pressure, but CF2 was most potent 
Key words: Hypertension,  active column fractions, Nauclear latifolia, rabbits
INTRODUCTION
Nauclea latifolia is from the family Rubiaceae, the
plant is commonly known as Pincushion tree. It is a
strangling shrub or small tree native to Tropical Africa
and Asia. It has sweet scented flower heads. It
produces red fruits that resemble a large, rather hard
strawberry, with many seeds which have a pleasant
taste but act as emetic if eaten in excess . Nauclea[1]
latifolia is used profusely by traditional medicine
practitioners.  The bark and root of Nauclea latifolia
are used in the treatment of malaria in Ghana . The[2]
leaves are also used for the treatment of malaria in
East Africa  and in Nigeria . The roots are also used[3] [4]
to induce abortion and as a purgative . The bark is[5]
used in the treatment of wounds, coughs and
gonorrhoea in Nigeria . The crude extract of the roots[6]
have been shown to have antihypertensive effect . The[7]
aim of this work is to fractionate the crude extract and
find which of the fraction is active.
MATERIAL AND METHODS 
Collection of Plant Material: Roots of  Nauclea
latifolia wERE collected around Ugbowo campus of
University of Benin, in March.  The plant was initially
identified by the Chief technologist of Department of
Pharmacognosy, Faculty of Pharmacy, University of
Benin and later authenticated at Forest Research
Institute of Nigeria, Ibadan where a herbarium
specimen No FHI16938 was deposited. 
The plant material was washed and dried at room
temperature first, then put in an oven at 50 ºC for 48
hours before the sample was reduced to coarse powder
and then stored in airtight containers.
Extraction and Isolation: The powdered plant material
(500 g) was extracted with 2 litres of 70 % ethanol for
48 hours using Soxhlet extractor.
The ethanolic extract of Nauclea latifolia was
evaporated to ¼ of the original volume and was then
exhaustively partitioned with aliquots of 250 ml
chloroform. Both the ethanol and chloroform soluble
fractions were concentrated to dryness using a rotary
evaporator. A column was packed with 40 g of silica
254gel G 60 F  made into slurry with n-hexane. After
equilibration with 100 ml of n-hexane, 10 g of
chloroform fraction earlier adsorbed on silica gel G 60
was loaded on to the column. This was eluted with
hexane with increasing concentrations of chloroform
until 100% chloroform was reached. Thereafter
increasing concentrations of methanol were introduced
until chloroform – methanol 65: 35 was reached to
complete elution. A total of 70 fractions were obtained.
Each fraction was examined using analytical thin-layer
chromatography (TLC) and those fractions with similar
spots were pooled together resulting in 5 fractions
coded CF1, CF2, CF3, CF4 and CF5.
J. Appl. Sci. Res., 5(12): 2208-2212, 2009
2209
Laboratory Animals: Matured male rabbits were
obtained from the Animal House of the Department of
Pharmacology and Toxicology of University of Benin.
They were maintained with rat chow (Bendel Feeds
and Flour mills Plc) and water ad libitum . The rabbits
were housed, two in a cage. The animals were exposed
to 12 hour light-dark cycle and were handled according
to standard protocol.
Blood Pressure Measurements: Five male rabbits (1.5
– 2.2 Kg) were anaesthetised with pentobarbitone
sodium (40 mg/kg) intraperitoneally. The trachea was
exposed and cannulated to facilitate spontaneous
respiration. The ear vein was cannulated for
administration of drugs, while the carotid artery was
cannulated and connected via a Bentley Physiological
Pressure Transducer to a twin channel Ugo Basil
(Gemini 7070) recorder for recording of blood pressure
and heart rate. Both cannulas were filled with normal
saline but the one connected to the pressure transducer
was heparinised (20 U/ml). Calibration was done using
mercury sphygmomanometer. The animal’s body
temperatures were kept constant by a 100 watt bulb
from an overhead lamp and were allowed 20 minutes
to stabilize before starting the experiments. The initial
systolic (SBP) and diastolic (DBP) blood pressures
before addition of any drugs (basal blood pressures)
were noted. The chloroform fractions were dissolved in
50 % dimethyl sulfoxide (DMSO) before administering
to the rats. The effects of 50 % DMSO) followed by
graded doses (2.5 – 10 mg/kg) of CF1, CF3, CF4 and
CF5 on the basal blood pressures were investigate.
Doses of CF2 used were 0.2 – 0.6 mg/kg.
Statistical Analysis: All data were expressed as mean
± SEM (standard error of the mean) and n represents
the number of animals used. Data were compared using
one way analysis of variance (ANOVA), Graph Pad
InstantR version 2.05 software (UK) was used for all
data analysis. P < 0.05 was regarded as indicating
significant difference in all cases.
RESULTS AND DISCUSSION
All the chloroform fractions reduced the blood
pressure of normotensive rabbits in a dose dependant
manner.  Chloroform fraction 1 (CF1) at 10 mg/kg
reduced the systolic blood pressure from 113.1 ± 7.1 to
71.0 ± 6.8 mm Hg. It also reduced the diastolic
pressure from 91.2 ± 4.9 to 57.0 ± 10 and MAP from
97.6 ± 5.6 to 61.6 ± 8.6 mm Hg. These changes were
significant at p< 0.01 compared to the basal values
(Fig 1).  The actual decrease in systolic pressure  was
of 42.1 mm Hg (37.2 %), was greater than the
decrease in diastolic pressure (34.2 mm Hg, 37.5 %)
and mean arterial pressure ( 35.6 mm Hg, 36.4 %).
Chloroform fraction 2 (CF2) was most potent. At
0.6 mg/kg reduced the systolic pressure from 101.8 ±
4.9 to 64.8 ± 6.2 mm Hg. It also reduced the diastolic
pressure from 67.8 ± 3.4 to 40.0 ± 3.0 mm Hg and
MAP from 79.0 ± 3.1 to 48.4 ± 3.7 mm Hg. These
changes were significant at p< 0.01 compared to the
basal values (Fig. 2). This fraction like fraction 1
caused a greater decrease in actual systolic pressures
(37 mm Hg, 36.3 %), compared to diastolic (27.8 mm
Hg, 41.0 %) and mean arterial pressures (30.6, 38.7 %)
The effect of chloroform fraction 3 (CF3) at 10
mg/Kg was reduction of the systolic pressure from
107.0 ±  4.6 to 77.6 ± 3.9 mm Hg. Similar  effect
occurred on the diastolic and MAP pressures, where it
reduced them from 91.0 ± 6.5 to 63.4 ± 3.5 and  from
95.3 ± 5.1 to 68.3 ± 3.6 mm Hg respectively (Fig. 3).
These changes were significant at p < 0.01. The
difference in the decrease in systolic pressure caused
by this fraction (33.8 mm Hg, 31.5 %) is slightly more
compared to that caused in diastolic  (27.6 mm Hg,
30.0 %) and mean arterial pressures (27.0 mm Hg,
28.3 %).
Chloroform fraction 4 (CF4) at 10 mg/Kg reduced
the systolic pressure from 100.0 ± 5.2 to 69.4 ± 5.5
mm Hg. It also reduced the diastolic pressure from
77.6 ± 4.9 to 53.2 ± 5.2 and MAP from 84.8 ± 4.7 to
58.6 ± 5.0 mm Hg (Fig. 4). These changes were
significant at p< 0.01 compared to the basal values.
There is just a slight difference in the actual decrease
in systolic (30.6 mm Hg, 30.6 %), diastolic (24.4 mm
Hg (31.8 %) and mean arterial pressure (25.5, 30.0 %)
caused by this fraction.
Chloroform fraction 5 (CF5) at 10 mg/kg reduced
the systolic pressure from 104.5 ±2.6 to 77.2 ± 6.0 mm
Hg (p < 0.01). It also reduced the diastolic pressure
from 64.5 ± 6.6 to 45.5 ± 4.9 mm Hg (p < 0.05 )and
MAP from 78.0 ± 7.5 to 53.0 ± 4.6 mm Hg (p < 0.05,
Fig. 5). This fraction is the least potent in lowering
blood pressures, but it caused a greater decrease in
systolic pressure ( 27.3 mm Hg, 26.1 %), compared to
diastolic pressure (19 mm Hg, 29.4 %). There was no
difference between the actual decrease in systolic and
mean arterial pressures (25.0 mm Hg 32.0 %).
Discussion: Plant extracts are partitioned into organic
solvents with the sole aim of narrowing down the
active constituents into a particular fraction. This
ensures separation of the inactive from active
constituents. Chromatographic separation of chloroform
fraction of Nauclea latifolia gave five fractions CF1 to
CF5 all of which were effective in lowering blood
pressure. It is unique that all fractions from this plant
are active. These fractions from Nauclea latifolia do
fnot contain the same constituents according to their R
values.
J. Appl. Sci. Res., 5(12): 2208-2212, 2009
2210
Fig. 1: Effects of chloroform fraction 1 (CF1) of Nauclea latifolia on blood pressure (mean ± SEM mm Hg) of
normotensive rabbits. n = 5, ap < 0.01, compared to the respective basal values for the three curves
Fig. 2: Effects of chloroform fraction 2 (CF2) of Nauclea latifolia on blood pressure (mean ± SEM mm Hg)  of
normotensive rabbits. n = 5, ap < 0.01, bp < 0.05 compared to the respective basal values for the three
curves
J. Appl. Sci. Res., 5(12): 2208-2212, 2009
2211
Fig. 3: Effects of chloroform fraction 3 (CF3) of Nauclea latifolia on blood pressure (mean ± SEM mm Hg)  of
normotensive rabbits. n = 5, ap < 0.01, compared to the respective basal pressure for the three curves
Fig. 4: Effects of chloroform fraction 4 (CF4) of Nauclea latifolia on blood pressure (mean ± SEM mm Hg)  of
normotensive rabbits. n = 5, ap < 0.01, compared to the respective basal pressure for the three curves
CF2 which was most potent produced its effect at
a dose range of 0.2 - 0.6 mg/kg it also produces a
much greater decrease in systolic pressure than
diastolic pressure.  CFI, CF3, CF4 and CF5 produced
their effect at a dose range of 2.5 -10mg/kg. Even
though these four fractions had the same dose range
the extent of blood pressure lowering effect differed.
For example at 10 mg/kg CF1 caused a reduction in
systolic blood pressure of 42 mmHg compared to 33.8,
30.6 and 27.3 mmHg caused by CF3. CF4 and CF5
respectively. The changes in diastolic pressures
followed a similar pattern. CF1 caused a reduction of
34.2 mmHg compared to 27.6, 24.4, and 19.2 caused
by CF3 CF4 and CF5 respectively. This shows that in
terms of potency CF2 is most potent followed by CFI,
CF3, CF4.and CF5.
J. Appl. Sci. Res., 5(12): 2208-2212, 2009
2212
Fig. 5: Effects of chloroform fraction 5 (CF5) of Nauclea latifolia on blood pressure (mean ± SEM mm Hg)  of
normotensive rabbits. n = 5, ap < 0.01, bp < 0.05 compared to the respective basal pressure for the three
curves
All the fractions reduced the systolic blood
pressure more than they did the diastolic pressure.
Epidemiological evidence has shown that the
cardiovascular risk of hypertensive patients relates,
probably to a greater extent, to systolic blood pressure
values than diastolic blood pressure values (Grassi,
2003). A reduction in systolic blood pressure is
accompanied by a clear-cut decrease in cardiovascular
morbidity and mortality. This indicates that these
fractions will be usefull in reducing cardiovascular risk
associated with hypertension as they decrease the
systolic pressure.
Conclusion: This study has shown that Nauclea
latifolia has 5 fractions all of which are active in
lowering blood pressure.and that  chloroform fractrion
2 was most potent
REFERENCES
1. Oliver, B., 1960. Medicinal plants in Nigeria.
Published by Department of the Nigerian college
of Arts, Science and Technology, Ibadan p: 81.
2. oye, G.L., 1990. Studies on antimalarial action of
Cryptolepis sanguinolenta extract. Proc. Int. Symp.
On East- West Med, Seoul, Korea Oct 10-11: 243-
251.
3. Kokwaro, J.O., 1976. Medicinal plants of E.
Africa. East Africa Literature bureau, Nairobi p 35.
4. Akubue, P.I., G.C. Mittal, 1982. Clinical
evaluation of a traditional herbal practice in
Nigeria: preliminary report.  J. Ethnopharmacol
6(3): 355-359.
5. Vasileva, B., 1969. plants medicinales de Guinea.
Conakry. Republic de Guinea. pp: 24-25.
6. Madibunyi, I.I., 1995. Antihepatotoxic of ethanolic
extract of Nauclea latifolia root bark. J. Herbs
Spices & Med. Plants., 3(2): 23-25.
7. Nworgu, et al., 2008. Preliminary studies of blood
pressure lowering effect of Nauclea latifolia in
rats, Afr. J. pharm. Pharmacol., 2(2): 37-41. 
8. Grassi, G., 2003. Systolic blood pressure,
cardiovascular risk and effects of antihypertensive
treatment. E-journal of Cardiology practice Volume
1.May 4.


The Effect of Active Fractions of the Roots of Nauclea Latifolia Smith (Rubiaceae) on Blood Pressure of Normotensive Rabbits

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The Effect of Active Fractions of the Roots of Nauclea Latifolia Smith (Rubiaceae) on Blood Pressure of Normotensive Rabbits

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