Nigerian scientists have confirmed in clinical
settings and in animal models that eating
moderate quantities of bitter cola does not
just enhance sexual activity but have
clinically significant analgesic/anti-
inflammatory effects in knee osteoarthritis
patients. CHUKWUMA MUANYA writes.
CAN eating at least a piece of bitter kola
(Garcinia kola) daily be the treatment for low
libido, low sperm count, erectile dysfunction
and knee osteoarthritis?
Results of a study published in African
Journal of Pharmacy and Pharmacology have
confirmed that bitter kola possesses sexual
enhancing effects on male rats as evidenced
by the increased mounting (MF) and
intromission (IF) frequencies with increased
number of subsequent ejaculations over the
20 min observation period.
The study is titled "Effects of ethanolic
extract of Garcinia kola on sexual behaviour
and sperm parameters in male Wistar rats."
Another study published in Journal of
Orthopaedic Surgery and Research by
medical doctors, pharmacists and nurses at
Obafemi Awolowo University Teaching
Hospital (OAUTH) concluded: "Garcinia kola
appeared to have clinically significant
analgesic/anti-inflammatory effects in knee
osteoarthritis patients. Garcinia kola is a
potential osteoarthritis disease activity
modifier with good mid term outcome.
Further studies are required for
standardization of dosages and to determine
The study is titled "Clinical effects of Garcinia
kola in knee osteoarthritis."
Botanically known as Garcinia kola, bitter kola
belongs to the plant family Guttifereae. In
Nigeria it is called oje in Bokyi, edun or efiari
in Efik, efrie in Ejagham-Ekin, cida goro in
Hausa, efiat in Ibibio, emiale in Icheve, igoligo
in Idoma, aku-ilu or ugolo in Ibo, akaan in Ijo-
Izon, okain in Isekiri, and orogbo in Yoruba.
Yet another study on bitter kola published
recently in Science Journal of Microbiology
showed that seed and leaf of bitter kola have
antibacterial activity on clinical isolates of
Staphylococcus aureus, Escherichia coli,
Salmonella typhi and Streptococcus
Phytochemical screening of the extracts
revealed the presence of some bioactive
components like alkaloids, saponins, tannins,
anthraquinones and cardiac glycosides.
These components determine the
antibacterial activity of the seed and leaf
extracts. The results from this study, provides
scientific evidence that Garcinia kola has the
capability of inhibiting the growth of
pathogenic micro-organisms; thus it will be
useful in tropical medicine for the treatment
of microbial infections.
The researchers wrote: "G. kola has been
shown to be a popular treatment for diarrhea
and fever. The seed extract is antiseptic and
is active mostly against gram-positive
bacteria. While the leaf, is active mostly
against gram-negative bacteria. It is also very
efficacious for hepatitis.
"In West Africa, is now being harnessed as a
cure for the Ebola virus infections and also
against flu. The stem, bark and the seeds are
used for acute fever, inflammation of the
respiratory tract and throat infections.
Historically, Nigerians used Garcinia kola as an
"The seeds are also chewed to relieve
hoarseness of voice, sore throat and cough.
In folk medicine the seed is used for the
treatment of liver disorder. It is also used in
the treatment of dysentery and diarrhea. The
leaves are used for stomachache and pains
and is also anti helmithic. They also serve as
good remedy for typhoid fever."
Erectile dysfunction (ED) is defined as the
difficulty in achieving or maintaining an
erection sufficient for sexual activity or
penetration at least 50 per cent of the time
for the last six months.
Unfortunately, it is a problem often neglected
by the health practitioners as they strive to
deal with life threatening complications of
disease. Successful treatment of ED may
improve not only sexual relationships, but
also the overall quality of life.
Osteoarthritis is the most common form of
joint disease, affecting the knee more than
other joints. Several factors play a role in
osteoarthritis risk; these include age, gender,
genetics, behavioral influences and ethnicity.
Trauma is a recognised predisposing factor
to development of osteoarthritis of the knee
(KOA) associated with raised intra osseous
pressure and death of the chondrocytes.
Osteoarthritis of the knees reduces the ability
to avoid obstacles and supporting
epidemiologic studies have found
osteoarthritis to be a risk factor for falls. The
pain associated with osteoarthritis of the
knees increased the propensity to trip on an
obstacle and underscores the importance of
treating pain associated with osteoarthritis.
The South African researchers from Walter
Sisulu University, Mthatha, South Africa
investigated the effects of oral
administration of ethanolic extract of G. kola
on male sexual behaviour, testosterone levels
and sperm parameters.
A 70 per cent ethanolic extract of G. kola
seeds was prepared and used for treating
male Wistar rats in a group of eight; two
doses of G. kola (200 and 400 mg/kg body
weight) were used for the treatment group,
while distilled water was administered to the
All the treatments were orally administered
daily for 28 days. On day 28, mounting
frequency (MF), intromission frequency (IF)
and ejaculation frequency (EF) were
quantified during sexual behaviour tests.
At termination, body and organ weights,
gastric ulceration and cauda epididymal
sperm counts were determined. Serum was
collected for determination of testosterone
levels. Both doses (200 and 400 mg/kg)
showed marked aphrodisiac activity with
significantly increased sexual behaviour
parameters compared to controls.
However, lower dose of G. kola was more
effective than the higher dose. Testosterone
levels were higher in both treatment groups
compared to controls. Sperm counts were
similar to controls however testes weights
were higher in G. kola treated rats compared
to controls. Thus these results show that G.
kola enhances sexual activity in normal male
Meanwhile, the OAUTH researchers used
prospective randomized, placebo controlled,
double blind, clinical trial approved by the
institutional medical ethics review board and
written informed consent obtained from
All KOA patients presenting at the OAUTH
complex were recruited into the study. The
patients were grouped into four (A = Placebo,
B = Naproxen, C = Garcinia kola, D = Celebrex).
The drugs and placebo were given twice a
day per oral route. Each dose consisted of
200 mg of G. kola, Naproxen (500 mg),
Celebrex (200 mg) and Ascorbic acid (100
mg). The primary outcome measure over six
weeks study period was the change in mean
WOMAC pain visual analogue scales (VAS).
Secondary outcome measures included the
mean change in joint stiffness and physical
The South African researchers wrote: "The
present study confirmed that G. kola
possesses sexual enhancing effects on male
rats as evidenced by the increased MF and
intromission IF frequencies with increased
number of subsequent ejaculations over the
20 min observation period. These parameters
are considered to be a measure of both libido
and potency and indicative of improved
sexual arousal and performance. Thus our
results show that G. kola treatment increases
both libido and potency in normal rats."
It has been shown that drugs, which enhance
sexual function may act via an increase in
circulating testosterone levels, the male sex
hormone responsible, among other functions,
in enhancing sexual function via central and
Indeed testosterone supplementation has
been shown to improve libido and
intensifying orgasm and ejaculation.
The researchers noted: "In this study, G. kola
treatment resulted in increased testosterone
levels, which may account for the enhanced
sexual activity. The mechanisms for
increased total testosterone levels may be via
central influences to increase gonadotropins
or locally via increase in the number of
Leydig cells or their sensitivity to luteinising
hormone (LH). Further studies to elucidate
mechanisms are required.
"There was a significant increase in testicular
weights with no change in the weights of
accessory reproductive organs and
epididymal sperm count. Increase in
spermatogenesis is usually accompanied by
increased testicular weight since the bulk of
testicular weight is made up of seminiferous
tubules that house spermatids and
"Despite the increased testosterone levels
there was maintenance of accessory organ
weights. Normal accessory organ structure
and function is maintained by circulating
androgens. The actual duration of increase in
the levels of testosterone was not
determined in our study; therefore, the
accessory organs may have not experienced
the increased testosterone long enough for
weight change. Threshold levels of required
testosterone might be different for the
different accessory organ functions.
"Furthermore, despite the increased testicular
weight, G. kola had no effect on epididymal
sperm count after 28 days of treatment. One
complete spermatogenic cycle takes 58 days
in the rat. Since our study was less than 58
days, spermatogonia exposed to G. kola
treatment had not been deposited into the
epididymis for observation. A longer study is
therefore necessary to make meaningful
observations on the effects of treatment on
epididymal sperm counts.
"The body and vital organ weights were not
altered after treatment with G. kola extract.
Monitoring of organ weights gives
information on general wellbeing of the
According to the researchers, these results
show that G. kola treatment over 28 days did
not affect organ weights, since they
remained similar to those of the controls.
"Furthermore, acute toxicity and
ulcerogenicity studies confirm nontoxic
effects of G. kola," they noted.
The researchers concluded: "G. kola treatment
at two doses showed enhanced libido and
potency in male rats after treatment for 28
days. Furthermore, G. kola treatment
enhances testosterone secretion and
increases testicular weights."
According to the OAUTH study, the efficacy of
G. kola, naproxen and celebrex was apparent
for the KOA patients within the six weeks of
therapy. G. kola's onset of action was
relatively fast with better improvement when
compared with the placebo. The Garcinia kola
positive analgesic/anti-inflammatory effect
were significant in KOA patients.
The researchers said this may be a useful
alternative in patients with osteoarthritis
who have not responded to first-line
treatment with acetaminophen and in whom
non steroidal anti-inflammatory drugs
(NSAIDs) are contraindicated, ineffective, or
poorly tolerated. "As serious adverse effects
are associated with oral NSAIDs, only limited
use can be recommended."
The researchers wrote: "G. kola is known to
contain high content of bioflavonoid
compounds with a general anecdotal effect in
folk medicine in Africa. Active oxygen and
free radicals are related to various
physiological and pathological events, such
as inflammation. There is always a
relationship between oxidation, infections,
inflammatory reactions, and biological
membrane of cells.
"It has been reported to prevent
accumulation of lipid per oxidation products
and protect biomembranes against oxidative
damage by acting as antioxidant. It also acts
as scavenger of free radicals and reactive
oxygen species which are not treated by
traditional NSAIDs drugs or selective COX-2
inhibitors. When free radicals and reactive
oxygen species accumulate in the joint could
trigger additional inflammatory processes in
"The scavenging activity of flavonoids of G.
kola seeds on super oxide anion radicals (O2)
generated non-enzymically was comparable
with butylated hydroxytoluene. The reducing
power shows that flavonoids of G. kola seeds
are electron donors and could react with free
radicals to convert them to stable products
thereby terminating radical chain reaction
involved in knee osteoarthritis inflammatory
"Garcinia kola may be acting as antioxidant
to either inhibit or slow down the
progression of symptomatic knee
osteoarthritis. It could also act as a scavenger
to remove the particles that have been
observed on the surfaces of human articular
cartilage following trauma and osteoarthritis.
The particles contained calcium and
phosphorus, which were identified only in
structurally abnormal cartilage.
"Bitter kola has been known to protect
against the oxidation of lipoprotein,
presumably through the mechanisms
involving metal chelating and antioxidant
activity. The relief of pain experienced by
subjects on G. kola could be associated with
either removal of the free radicals and or
revascularization of the subchondria bone
through the anti-atherogenic effect. This
pathway is not clear at this stage of the
study. It may be through activation of the
cytokines selective inhibition of inducible
nitric oxide synthase, which has been shown
to reduce the progression of experimental
osteoarthritis in vivo.
"The bitter kola is believed to have
aphrodisiac properties probably related to its
vasodilator effects on the genitalia smooth
muscles. Reduction of intraosseous/
subchondria pressures could be the other
pathway for the reduction of knee pain
experienced by patients on G. kola. The ability
to lower intraocular pressure was earlier
noted in glaucoma patients.
"The preliminary crude observation was
confirmed scientifically in animals and human
glaucoma's patients. The vasodilatation
induced could improve the subchondria
blood circulation in knee osteoarthritis. The G.
kola extract has been shown to have
antithrombotic activities. The effect of G. kola
on chondrocyte nutrition is not clearly
elucidated at present. This will form the
fulcrum of future studies."
According to the Useful Plants of West
Tropical Africa by H. M. Bukhill, its principal
application is for chew-sticks. In Liberia they
are said to whiten the teeth. In Ghana it is the
smaller trees, which tend to be felled for this
purpose and the wood is cut and split into
pencil-sized pieces. It is bundles of these,
which are a common market commodity
throughout the Region, for the chew-sticks of
this species are considered superior to any
The roots are also used, sometimes in
preference, and in the Ibadan area of S
Nigeria they are thought to prevent dental
caries. Tests have, however, shown no anti-
biotic activity. In Sierra Leone the root is
chewed to clean the mouth.
In Igbo (Nigeria) pharmacology extracts of
stems, roots and seeds have shown strong
anti-hepatotoxic and hepatotropic activity.
Petroleum ether and acetone extracts were
found to be markedly anti-microbial.
The powdered bark is applied in Nigeria to
malignant tumours, cancers, etc., and the gum
is taken internally for gonorrhoea, and
externally to seal new wounds. In Congo a
bark-decoction is taken for female sterility
and to ease child-birth, the intake being daily
till conception is certain and then at half
quantity throughout the term.
The bark is added to that of Sarcocephalus
latifolius (Rubiaceae), a tisane of which has a
strong reputation as a diuretic, urinary
decongestant and for chronic urethral
discharge. The bark is also thought to be
galactogenic, whilst in Ghana the bark is used
with Piper guineense (Piperaceae) and sap
from a plantain stalk (Musaceae) to
embrocate the breast for mastitis.
In Ivory Coast a decoction of the bark is
taken to induce the expulsion of a dead
foetus, and seed and bark are taken to treat
stomach-pains. Bark and leaves are used in
Congo for pulmonary and gastro-intestinal
troubles. Root and bark are administered in
Sierra Leone as a tonic to men 'to make their
organs work well' and in that country too
bark is added to palm-wine to improve its
Bark is administered in Ivory Coast as an
aphrodisiac. In S Nigeria a cold-water extract
of root-bark with salt administered to cases
of ukwala (cough) and agboor (vomiting),
identified as bronchial asthma or cough, and
vomiting, is said to promote improvement.
The bark is used in tanning in Ghana, and
during the 1939–45 War thousands of tons
were exported as a tanning material.
Tannins, a reducing sugar and traces of an
alkaloid have been detected in the bark;
flavonins are also present, the whole being
extremely bitter, resinous and astringent. The
leaves have a bitter taste. They are used in
Congo as a deterrant to fleas.
A leaf-infusion is purgative. The fruits are
edible, orange-sized, and contain a yellow
pulp surrounding four seeds. The fruits are
eaten in Nigeria as a cure for general aches in
the head, back, etc., and as a vermifuge.
Igbo medicine-men prescribe the fruit for
arthritic conditions. Wild animals go for them
and the elephant is particularly partial,
coming from afar to trees in season. The
residue after chewing is white. They are
eaten raw and not in prepared food. They
have medicinal attributes. Mastication will
relieve coughs, hoarseness, and bronchial
and throat troubles. They are taken dry as a
remedy for dysentery. They are said to
provide an antidote against Strophanthus
poisoning. They are vermifugal.
In Senegal, on Mt. Nimba, Liberia, in Ivory
Coast and in Congo they are considered
aphrodisiac. In Liberia the seeds are chopped
up and steeped in water or better still in beer,
while in Congo they enter into many medico-
magical remedies taken with palm-wine 'to
cleanse the stomach and to give strength in
In Nigeria the simple act of mastication of the
seeds is held to be as effective. The active
principle, or principles, in the nut remain
enigmatic. Caffeine, which is present in the
true kola, is absent. A trace of alkaloid has
been reported in Nigerian materials, but
absent in other samples. Tannins are present
which may contain the anti-bacterials
morellin and guttiferin. The seeds have been
shown to have four fluorescent substances
of an undetermined nature. Activity may also
lie in resins, which are as yet unidentified.
BY CHUKWUMA MUANYA