Cola nut is a
caffeine-containing nut of evergreen trees of the genus Cola, primarily
of the species Cola acuminata and Cola nitida. It is one of the
most common chewable nut in Nigeria. It is a central nervous system stimulant
used in folk medicine as an aphrodisiac, an appetite suppressant, to treat
migraine headache and indigestion. The aim of the present study was to
investigate the possible effects of Cola nitida extracts on the cerebral
cortex, hippocampus and some biochemical parameters. Forty (40) adult Long
Evans rats of both sexes, with average weight of 210-230grams were randomly
divided into four groups: A (control) = four rats (administered normal feed and
distilled water);B= caffeine fraction group containing three sub groups of four
rats each, B1, B2 and B3 were administered with di-chloromethane caffeine
fractionof 19.2, 38.4 and 57.6mg/kg body weight, respectively; C= aqueous
extract group containing three sub groups of four rats each, C1, C2 and C3 and
were administered cola nut aqueous extract orally at the concentration of 300,
600 and 900 mg/kg body weight respectively; D= cola nut supplement group
containing three sub groups of four rats each, D1, D2 and D3 were administered
10%, 20% and 30% w/w cola nut supplemented feed, respectively. The
administration lasted for a period of 21 days (3 weeks). Behavioural test for
spatial learning and memory was carried out using Morris water maze and
anxiety-like behaviours using Elevated Plus Maze. Blood was collected via
cardiac puncture for determination of haematological indices, Brain tissues
used for determination of oxidative stress parameters were homogenised in cold
saline thoseused for histological studies were fixed in Bouin‟s fluid processed
and stained using Haematoxylin and Eosin (H and E) and toluidine blue stains.
The Morris water maze test showed a non-significant decrease (P˃0.05) in time
to find the platform in all the treatment groups. A non- significant increase
(P˃0.05) in the meantime spent in the open arm, number of entriesinto the open
arm, rearing and number of head dips in the elevated plus maze test
compared with the control was observed. The result of the oxidative stress
markers showedstatistical significant decrease insuperoxide dismutase (SOD) of
the aqueous and caffeine fraction groups when compared with the control.No
significant difference was observed with the other markers. The results of the
haematological indices revealed a statistical significant increase(p˃0.05)
anddecrease (P˃0.05) in lymphocytes and neutrophils counts respectively in the
caffeine and aqueous extract groups. The histology results revealed
neurodegenerative changes in the cerebral cortex and hippocampus of the treated
groups, which range from neuronal degeneration, pyknosis and clumping of
pyramidal cells in the hippocampus. It was concluded that ingestion of cola nut
and its constituent by Long Evans rats caused no significant effect on learning
and memory, decreased anxiety-like behaviours, anti-inflammatory effect by
increasing lymphocytes and decreasing neutrophils level, non-antioxidant effect
by significantly decreasing the level of superoxide dismutase (SOD) and
Plants have been an important source of medicine for
thousands of years. The world health organization (WHO) estimated that 80% of
people still rely on traditional remedies such as herbs for their medicines
(WHO, 2000; Tripathi and Tripathi, 2003). Plants are also a source of modern
medicines. It is estimated that approximately a quarter of processed drugs
contain plant extracts or active ingredients obtained from or modelled on plant
substances (Tripathi and Tripathi, 2003). Plant-derived substances have recently
become of great interest due to their versatile applications. Medicinal plants
are the richest resource of drugs of traditional system of medicine, modern
medicines, food supplements, folk medicines, pharmaceutical intermediates and
chemical entities for synthetic drugs (Ncube et al.,2008).
Medicinal plants were used by
people from different cultures without the knowledge of their active
ingredients. This is common practice which is laden with hazards as the extract
may contain some toxic constituents (Lown, 1993).
Cola nitida commonly called
cola nut in English, “Goro” in Hausa, “Obi” in
Yoruba, “Oji” in Igbo, “Irevu” in Ebira and “Ebi” in Nupe is a genus of
125 species of trees native to tropical rainforest of Africa. Cola is one of
the major tree crop grown in Nigeria today, and the tree on which it grows is
believed among some Nigerian tribes to be the first tree on the earth(Lowor,
2010). It is a smooth fruit consisting two cotyledons of the family
Sterculoideae. It is cultivated in the tropical West Africa. Some species are
also cultivated for their nuts in Madagascar, Brazil, Jamaica and other humid
tropics. The seed contains caffeine and is bitter. The first taste of Cola
nitida is bitter, but it
sweetens upon chewing (Lovejoy et
al., 1980). It isan important part of the traditional spiritual practice of
culture and religion in West Africa, particularly in Nigeria.Cola nut has been
reportedly used in folk medicine as an aphrodisiac, an appetite suppressant, to
treat migraine headache and indigestion (Esimone et al., 2007).
Statement of Research Problem
Cola nitida has
neurodegenerative effects on the cerebellum of Wistar rats(Buraimoh et al., 2014).
Memory and cognition
enhancement procedure is not well understood in the field of neuroscience and
due to high consumption of Cola nitida by Nigerians, especially students
to increase alertness and probably memory, there is need to investigate and
compile empirical evidence to either proof or disprove this belief.
Furthermore, considering the
use of the fruit by people in West Africa, especially Nigeria, who believe that
it has a divine power of curing some diseases, there is need to investigate the
effects of Cola nitida on neurobehavioral activities and vital tissues
of the body such as cerebrum and hippocampus at microscopic level.
Justification of the Study
Despite reported evidence of
neurodegeneration that Cola nitida has on the cerebellum (Buraimoh et
al., 2014), traditional, cultural and social use in our environment is
still on the rise. Therefore, there is need to investigate further; the effect
of Cola nitida on other parts of the nervous system, such as the
cerebral cortex and hippocampus.
Significance of the Study
The study could be of great importance inidentifying and
evaluating the regions of the brain that may be affected by Cola nitida,
give insight to people, especially students on the effect of the plant on
memory, cognition, anxiety-like behaviours and its relationship with
1.4 Aim and Objectives of the study
1.4.1 Aim of the Study
The aim of the study was to
investigate the extraction and study
the effect of heat on caffeine extracted from kolanut.
1.4.2 Objectives of the Study
The objectives of this study were
Investigate the effect of Cola
nitida on spatiallearningand memory, andanxiety-like behaviour using Morris
water maze and elevated plus maze, respectively.
Investigate the effect of Cola
nitida on haematological indices (PCV, WBC, Hb, and differential cell
counts) of Long Evans rats.
Evaluate the comparative effect ofCola
nitida on the oxidative stress markers(GSH, MDA, CAT and SOD) of the
cerebrum of Long Evans rats.
the effect of Cola nitida on the histology of cerebral cortex and
hippocampus of Long Evans rats.
nitida has no effect on the histology of the cerebrum and
hippocampus of adult Long Evans rats.
Cola nitida has effect
on neurobehavioursof adult Long Evans rats.
1.6 Scope of
This work would be limited to the effects of Cola nitida
and its active ingredient caffeine on the histology of cerebral cortex and
hippocampus, neurobehaviours, haematological indices and some biochemical
1.7 Limitations of the Study
microscopy was not done to show the detailed structure of the cerebral cortex
and hippocampus due to lack of electron microscope.
Neurotransmitters were not assayed
due to lack of fund.