Received: 23 March 2020
Accepted for publication: 24 November 2020
Slov Vet Res 2021: 58 (2): 63 – 75
DOI 10.26873/SVR-1072-2020
UDC 616.379-008.64:633.88: 599.323.45
Original Research Article
Introduction
Diabetes mellitus (DM) is an important world 
health challenge and is associated with elevated 
level of blood glucose. This condition is orchestrated 
by total or relative lack of insulin or inability of 
the cells to respond to insulin produced by the β−
cells of the islets of Langerhans in the pancreas, 
manifesting as hyperglycemia and abnormalities 
in carbohydrate, protein and fat metabolism (1, 
2). The use of animal models is one of the best 
methods for the elucidation of the disordered 
physiological processes of any ailment in order to 
ANTI-DIABETIC EFFECT OF ETHANOL EXTRACT OF Copaifera 
salikounda (HECKEL) AGAINST ALLOXAN-INDUCED DIABETES 
IN RATS
Chinyere Aloke1*, Emmanuel Sunday Igwe1, Nwogo Ajuka Obasi1, Pascal Anyaegbunam Amu2, Egwu Chinedu Ogbonnia1
1Department of Medical Biochemistry, Alex Ekwueme Federal University Ndufu-Alike, Ebonyi State, 2Department Science Laboratory 
Technology, Institute of Management and Technology, Enugu, Enugu State, Nigeria
*Corresponding author, E-mail: alokec2002@yahoo.com
Abstract: Accumulating evidences have reinforced the use of medicinal plants in the treatment of various ailments as a result of 
negative side effects associated with conventional drugs. Plant components such as phenols and flavonoids with antioxidant po-
tential have confirmed protective roles against oxidative stress-induced degenerative diseases like diabetes mellitus (DM). The 
current study was carried out to investigate the effect of seed pod ethanol extract from Copaifera salikounda (SPEECS) in alloxan-in-
duced diabetic rats. SPEECS was obtained by maceration of seed pod powder in absolute ethanol for 72 h, filtered, concentrated 
and dried in-vacuo. Gas chromatography-mass spectrometry (GC–MS) technique was used to quantitatively elucidate the chemical 
constituents of SPEECS. Twenty-four male albino rats were randomly allocated into four groups (n=6): normal control, DM control, 
DM + 200 mg/kg SPEECS and DM + 400 mg/kg SPEECS groups. DM was induced in the Wistar albino rats through intraperitoneal 
injection of 200 mg/kg body weight of alloxan. After 14 days of treatment, the body weight changes and the fasting blood glucose 
level were determined in the different groups. Also, serum biochemical parameters such as alanine aminotransferase (ALT), aspar-
tate aminotransferase (AST), alkaline phosphatase (ALP), albumin (ALB), total protein (TP), malondialdehyde (MDA), superoxide 
dismutase (SOD) and catalase (CAT) were estimated. The GC-MS results confirm nine bioactive compounds with 9-octadecenoic 
acid (55.75%) being most abundant. SPEECS (200 and 400 mg/kg) administration significantly (P < 0.05) caused gain in weight, de-
creased fasting blood glucose and reversed the elevated liver function enzymes (ALT, AST, ALP) while total TP and ALB were mark-
edly elevated relative to DM control group. Furthermore, SPEECS attenuated the activities of SOD and CAT while the level of MDA was 
significantly (P < 0.05) decreased in dose dependent manner in comparison to the DM control. This study indicated that SPEECS can 
alleviate hyperglyceamia of DM.
Key words: Copaifera salikounda; oxidative stress; medicinal plants; diabetes mellitus; phytochemicals; orthodox
draw a blueprint for the manufacture of drugs 
for its treatment (3). Alloxan has been widely 
acknowledged to selectively damage the pancreatic 
insulin-producing β-cells, thus employed for DM 
induction in experimental animals. It produces 
injurious effect on the β-cells of the pancreas by 
the oxidation of sulphydryl group (SH-group), 
production of free radicals; glucokinase enzyme 
inhibition and interference in the intracellular 
calcium balance (4). Thus, it induces oxidative 
The mitochondria serve as the primary source 
of reactive oxygen species (ROS) in cells resulting 
from imperfectly coupled electron transport. 
It has been reported that oxidative stress 
contributes substantially in the development and 
continuation of DM and its complications, as a 
result of elevated formation of free radicals and 
64 C. Aloke, E.S. Igwe, N.A. Obasi, P.A. Amu, E.C. Ogbonnia
compromised antioxidant defenses (6). Oxidative 
stress in diabetic subjects is mediated by different 
mechanisms particularly chronic exposure to 
elevated blood glucose.  Previous studies reported 
that hyperglycemia can elicit the generation of 
ROS and reactive nitrogen species (RNS) by the 
mitochondrial respiratory system (7), autoxidation 
of glucose (8), polyol pathway activation (9), 
production of advanced glycation end products 
(AGEs) (10), compromised enzyme antioxidant 
system (11) and disproportionate glutathione 
reduction/oxidation status (12). Also, high blood 
glucose can promote an important oxidative 
disparity, favoring the production of free radicals 
and the reduction of antioxidant defenses. Increased 
concentrations of ROS/RNS can culminate in the 
impairment of major components of the cellular 
structure, nucleic acids, proteins, amino acids, 
and lipids (13). These oxidative alterations in the 
DM condition would impact several cell functions, 
metabolism, and gene expression, which will 
consequently bring about other disease conditions 
(14). 
The use of folklore medicine in the management 
of DM is of immense importance due to their relative 
safety and low cost (2). Scientific exploration into 
the use of these herbal medicines demonstrated 
that they enhance secretion of insulin, facilitate 
the intake of glucose by adipose or muscle tissues 
and prevent the absorption of glucose from the 
intestine and its production by the hepatocyte 
(15). A nutritional diet rich in antioxidants is 
helpful to circumvent oxidative stress-induced 
diabetes mellitus (16). Some synthetic drugs 
with the potential to lower blood glucose such 
as metformin, rosiglitazone, sulphonylureas and 
thiazolidinediones are available for the management 
of DM (17). However, prolonged usage of these 
orthodox anti-diabetic agents poses potential 
negative side effects. The high cost and negative 
side effects associated with these drugs limit their 
usage in developing countries including Nigeria in 
the management of DM (18). Thus, identification of 
novel, potent and efficacious natural remedies for 
treatment of DM has drawn the attention of many 
researchers (19).
Copaifera salikounda (C. salikounda) (Heckel) is 
a deciduous medium-sized to large tall tree (up to 
50 m tall) that belongs to the family Caesalpiniaceae 
(Leguminosae - Fabaceae). The plant has seed pod 
which contains only one seed. It is a timber tree of 
commercial importance which is limited because of 
its restricted distribution and scattered occurrence. 
It is distributed from Guinea Bissau eastward to 
Ghana. The wood is used in production of veneer 
and in furniture making. Aromatic resin obtained 
from the wood and bark is used locally in making 
a scented unguent for cosmetic use. The pounded 
bark is applied on the body as a perfume in Liberia. 
The pulped leaves of C. salikounda have been 
reported to be employed in treatment of sores or as 
hot poultice while the dried leaves and bark blended 
with baked and powdered clay are employed in 
ulcer management. Furthermore, an infusion of the 
fruit valve is employed as blood cleanser whereas a 
cold extract of the seed is used in vertigo treatment 
(20). The seed pod of C. salikounda is used as food 
ingredient and in treatment of rheumatoid arthritis 
(21). Aloke et al. (21) had reported the presence 
of the following phytochemicals in the seed pod 
of C. salikounda in order of their abundance as 
follows: total phenolics > alkaloids> terpenoids> 
carbohydrates> flavonoids> reducing sugar> 
tannins> glycosides> steroids. There is paucity 
of scientific information on the use of the seed 
pod ethanol extract from Copaifera salikounda 
(SPEECS) for the management of DM. The current 
study was done based on personal communications 
and interviews from different traditional medicine 
practitioners that affirm the ethno-medicinal use 
of SPEECS in treating hyperglycemia. This work 
therefore, is the first documented proof of the anti-
diabetic potential of SPEECS.  
This study investigated the ability of SPEECS 
produced in a process similar to the practice of 
folklore medicine practitioners, to alleviate hyper-
glycemia and oxidative stress in diabetic rats. The 
findings are anticipated to support the traditional 
usage and claim of efficacy and scientifically ratio-
nalize the traditional therapy in the management 
of diabetic conditions.
Materials and methods
Materials 
Dried samples of seed pods of C. salikounda 
were collected in a farmland at Umuigboke 
Ugwulangwu in Ohaozara Local Government of 
Ebonyi State, Nigeria. The plant was identified and 
authenticated by a taxonomist, Mr. Alfred Ozioko 
at the International Centre for Ethnomedicine 
and Drug Development Nsukka, Enugu State 
with voucher specimen no:InterCEDD/16281. 
65Anti-diabetic effect of ethanol extract of Copaifera salikounda (Heckel) against alloxan-induced diabetes in rats
All chemicals used were of analytical grade and 
were purchased from Sigma Aldrich, Saint Louis, 
U.S.A. 
Seed pod extract preparation
The seed pods of C. salikounda were further 
dried in the shade after washing with water. They 
were then ground using mortar and pestle. The 
ground seed pods obtained were passed through 
the sieve to obtain its powdered form. The ethanol 
extract was prepared by maceration of 103.3 g of 
seed pod powder in 500 ml of absolute ethanol 
for 72 hours. Then, the extract was filtered, 
concentrated, and dried in-vacuo. The percentage 
yield of the extract was 38.9%. See Figure 1 for 
the plate showing the seed pod C. salikounda.
Seven weeks old male Wistar albino rats (110 – 
150 g) obtained from Faculty of Veterinary Medicine, 
University of Nigeria, Nsukka, Enugu State, Nigeria 
were used for this study. The rats were housed 
in the Animal House, Alex Ekwueme Federal 
University Ndufu-Alike, Ikwo, Ebonyi State, 
Nigeria. They were kept in well-ventilated cages at 
room temperature. The rats were fed a standard 
rat pellet (Vital Feed Nig., Ltd) and water. The rats 
were acclimatized for a period of seven days prior 
to the induction of experimental diabetes mellitus. 
The present study was performed according to 
international, national and institutional rules 
considering animal experiments, clinical studies 
and biodiversity rights. Approval for this study 
was given by the Academic Board of Department 
of Medical Biochemistry and Institutional Animal 
Ethical Committee of Alex Ekwueme Federal 
University Ndufu-Alike Ikwo, Nigeria with 
ethical code no: FBMS/EC/AE/2352 prior to the 
commencement of the experiments in line with the 
National Institute of Health’s ethical guidelines for 
the care and usage of laboratory animals.
Gas Chromatography – Mass spectrometry 
(GC – MS) analysis
Using gas chromatographic mass spectrometry, 
the phytochemical compounds of seed pod ethanol 
extract from C. salikounda were determined using 
GC-MSQP2010 Shimadzu system linked with a 
GC column (2010) coated with polymethyl silicon 
(0.25nm x 50m). Using programmed temperature 
from 80 to 200oC and held for 80oC for 1 min 
at rate of 5oC/min and 200oC for 20 mins, the 
detector and injector were set to a temperature 
of 300oC and 220oC respectively while the flow 
rate of the nitrogen carrier gas was 1 ml/min and 
the split ratio 1:75. Gas chromatography mass 
spectrum was performed using GC-MS QP 2010 
in conjunction with Shimadzu Japan with the 
injector temperature of 220oC and pressure of the 
carrier gas at 116.9 kpa while the column length 
and diameter were 30m and 0.25mm respectively 
and the flow rate was 50ml/min. The elutes were 
accordingly run into a mass spectrometer with a 
dictator voltage set at 1.5kv and sampling rate of 
0.2 sec. The mass spectrum was also furnished 
with a computer fed mass spectra data bank. 
Hermlez 233 M-Zcentrifuge (Germany) was used. 
Components identification was verified based on 
the relative retention time and mass spectra with 
computer Wiley Libraries and thus confirmed by 
mass spectra comparison of the peaks and those 
from literature (22). 
Acute toxicity test
The acute toxicity test was conducted to 
determine the median lethal dose (LD50) of SPEECS 
and to choose the safe dose for the treatment. 
Acute toxicity study of SPEECS was carried out 
based on Lorke method with slight modifications 
(23). Thirty-six (36) rats were used for the acute 
toxicity test. Prior to the acute toxicity study, the 
rats were weighed and fasted overnight and were 
assigned into two experimental groups, A and 
B. Group A with four rats served as the normal 
control group and was administered normal 
saline. The Group B received SPEECS.  Group B 
was further sub-divided into eight groups with 
Figure 1: Plate showing the seed pod of C. salikounda 
with some seeds
66 C. Aloke, E.S. Igwe, N.A. Obasi, P.A. Amu, E.C. Ogbonnia
each group having four rats. The sub-groups 
were orally given SPEECS at 200, 400, 800, 1200, 
1800, 2000, 3000 and 5000 mg/kg body weight 
respectively and the test animals were observed 
for 24 hours. Furthermore, the rats in the different 
groups were monitored for the first 2 hours for 
behavioral changes and morbidity and up to 72 
hours for mortality. 
Experimental design
Induction of DM
DM was induced in the Wistar albino rats after 
depriving them food overnight by intraperitoneal 
(IP) injection of 200 mg/kg body weight of freshly 
prepared alloxan dissolved in normal saline (24). 
Thereafter, the rats were fasted overnight after 
three days of injection of alloxan and their blood 
glucose determined using glucometer (Accu-Chek, 
Boerhinger Mannheim, Germany). Rats with 
fasting blood glucose ≥ 200 mg/dl on the third 
day after injection of alloxan were selected for the 
study.
Experimental groups.
A total of 24 male Wistar albino rats were used. 
The rats were randomly allocated into 4 groups of 
6 rats each as follows:
 – Normal Control = Normal control (received only 
normal saline 1.0mL/kg body weight).
 – DM = Diabetic rats not treated, received only 
normal saline 1.0mL/kg body weight.
 – DM + SPEECS (200 mg/kg) = Diabetic rats 
treated with 200mg/kg body weight SPEECS 
per os daily for 14 consecutive days
 – DM + SPEECS (400 mg/kg) = Diabetic rats 
treated with 400mg/kg body weight SPEECS 
per os daily for 14 consecutive days
Body weight determination
The rats were weighed at three different 
times using a digital weighing balance. These 
measurements were done before induction of 
experimental DM, 72 hours after induction of DM 
and after the 14 days of SPEECS administration.
Collection of blood sample 
Fourteen days after administration of SPEECS, 
the rats were fasted overnight and five rats from 
each group were humanely euthanized by cervical 
dislocation and their blood samples were collected 
through cardiac puncture into labeled plain 
sample tubes. The samples were centrifuged using 
a standard centrifuge at 4000 x g for 10 minutes 
and the sera were obtained for biochemical 
analysis.
Determination of fasting blood glucose 
The fasting blood glucose levels of the rats were 
determined using “Accu-Chek Active Glucometer” 
and blood glucose test strips (Roche Diagnostics, 
Mannheim, Germany) before induction of experi-
mental DM and 72 hours after induction of DM. 
The fasting blood glucose levels were also mea-
sured after the 14-day administration of SPEECS 
before the rats were sacrificed.
Determination of biochemical parameters
The serum activities of ALT and AST were 
determined spectrophotometrically (25) while 
ALP activity was determined using previously 
established method (26). The level of total protein 
was determined using colorimetric Biuret method 
(27) while serum albumin was determined using 
bromcresol green method (28).  
Assessment of lipid peroxidation and anti-
oxidant status.
Malondialdehyde (MDA) in serum was deter-
mined spectrophotometrically by measuring thi-
obarbituric acid reactive substance (TBARS) (29). 
Serum activities of superoxide dismutase (SOD) 
was assessed by the method outlined by Fridovich 
and Mc-Cord (30) and catalase (CAT) was deter-
mined by colorimetric method (31)
Statistical analysis
All the data were expressed as mean ± standard 
deviation. The means were compared using one-
way analysis of variance (ANOVA) and significant 
variation were determined by Duncan multiple range 
test using SPSS software version 20. Value of p < 
0.05 was considered to be statistically significant.
67Anti-diabetic effect of ethanol extract of Copaifera salikounda (Heckel) against alloxan-induced diabetes in rats
Results
GC-MS analysis of SPEECS
The results of GC-MS analysis of SPEECS gave 
nine bioactive constituents: n-hexadecanoic acid 
(8.97%), 7-octadecanoic acid methy ester (4.73 %), 
9-octadecenoic acid (55.75 %), Octadecanoic acid 
(4.43 %), Phenol, 2-methyl (8.72 %), (E) 8- methyl-
7-dodecen-1-ol acetate (3.62 %), Phthanic acid 
(1.81 %), Cyclopropaneundecanal, 2-Nonyl (4.82 %) 
and 1,4-benzenediol, 2-methyl (7.15 %) as shown 
in Table 1.
Table 1: Results from GC-MS analysis of SPEECS
S. NO Retention Time Name of com-
pound
Molecular for-
mula
Molecular weight 
(g/mol)
Area %
1 17.320 n-hexadecanoic acid
C16H32O2 257.422 8.97
2 38.290 7-octadecanoic acid methy ester
C19H36O2 296.495 4.73
3 38.534 9-octadecenoic acid
C18H34O2 282.468 55.75
4 38.659 Octadecanoic acid
CH3(CH2)16COOH 284.48 4.43
5 40.254 Phenol, 2-methyl C7H8O 108.14 8.72
6
40.461 (E) 8- methyl-7-
dodecen-1-ol 
acetate
C15H28O2 240.382 3.62
7 40.723 Phthanic acid C8H6O4 166.14 1.81
8 41.812 Cyclopropaneun-decanal, 2-Nonyl
C23H44O 336.595 4.82
9 42.675 1,4-benzenediol, 2-methyl
C7H8O2 124.13 7.15
Acute toxicity study
In acute toxicity testing, no abnormal behavior 
and mortality were recorded. This indicated that the 
LD50 was greater than 5000 mg/kg. This formed the 
basis for the selection of the doses of the extracts 
administered.
Effect of SPEECS on body weight of al-
loxan-induced diabetic rats
The results of alteration in body weight of the 
experimental rat groups are presented in Table 2. 
The average weight of the normal control group was 
found to be relatively stable but that of DM control 
group showed significant (p< 0.05) reduction in 
body weight during the 14 days. The results showed 
that injection of alloxan caused sharp reduction in 
body weight of diabetic rats which was reversed by 
the administration of SPEECS at 200 and 400 mg/
kg after 14 days of treatment. The weight gain in 
rats after 14 days treatment was higher in group fed 
with 400 mg/kg of SPEECS compared to those fed 
with 200 mg/kg of SPEECS as shown in Table 2.
Effect of SPEECS on liver function markers 
of alloxan-induced diabetic rats
The serum concentrations of ALB and TP 
were low and the activities of ALT, AST and ALP 
were significantly higher in the DM rats group in 
comparison with the normal control group. TP 
level was significantly (p< 0.05) elevated in DM 
group treated with 200 mg/kg while there was 
non-signification elevation of ALB concentration 
when compared with DM control group. The serum 
activities of ALT, AST and ALP were significantly 
(p< 0.05) lower while the levels of ALB and TP were 
significantly (p< 0.05) higher in DM group treated 
with 400 mg/kg relative to DM model rats (Table 3). 
However, there was significant increase (p< 0.05) 
in the levels of ALB, TP and significant reduction 
in the actions of AST and ALP in DM + SPEECS 
(400 mg/kg) when compared with DM + SPEECS 
(200 mg/kg) while the activity of ALT reduced but 
not statistically significant (Table 3).
68 C. Aloke, E.S. Igwe, N.A. Obasi, P.A. Amu, E.C. Ogbonnia
Table 2: Effect of SPEECS on body weight of alloxan-induced diabetic rats
Groups ALT (U/L) AST (U/L) ALP (U/L) ALB (g/L) TP (g/L)
Normal Control 37.5 ± 0.69 59.6 ± 0.86 31.5 ± 0.86 3.47 ± 0.17 5.3 ± 0.11
DM 42.8 ± 1.72* 75.4 ± 0.77* 57.7 ± 1.11* 3.19 ± 0.21 5.1 ± 0.08
DM + SPEECS (200 mg/kg) 33.4 ± 1.22# 61.6 ± 0.82# 45.9 ± 0.60# 3.22 ± 0.11 5.5 ± 0.09#
DM + SPEECS (400 mg/kg) 30.5 ± 0.56# 51.6 ± 1.11#& 38.8 ± 0.84#& 3.91 ± 0.10#& 5.9 ± 0.06#&
Results are expressed as mean ± SEM (n=5). DM: Diabetes mellitus; P< 0.05 was considered significant. *p< 0.05: the difference is significant 
compared to control group in the same column; #p < 0.05: the difference is significant compared to DM group in the same column; &p< 0.05: the 
difference is significant compared to DM + SPEECS (200 mg/kg) group in the same column. DM + SPEECS (200 mg/kg): Diabetic rats treated 
with 200mg/kg b.w seed pod ethanol extract from C. salikounda; DM + SPEECS (400 mg/kg): Diabetic rats treated with 400mg/kg b.w seed 
pod ethanol extract from C. salikounda; SPEECS: Seed pod ethamol extract from C. salikounda.  ALT: alanine aminotransferase; AST: aspartate 
aminotransferase; ALP: alkaline phosphatase; TP: total protein; ALB: albumin. 
Effect of SPEECS on liver function markers 
of alloxan-induced diabetic rats
The serum concentrations of ALB and TP 
were low and the activities of ALT, AST and ALP 
were significantly higher in the DM rats group in 
comparison with the normal control group. TP 
level was significantly (p< 0.05) elevated in DM 
group treated with 200 mg/kg while there was 
non-signification elevation of ALB concentration 
when compared with DM control group. The serum 
Group Body weight (g)
Day 1 Day 7 Day 14
Control 137.9 ± 1.87 147.7 ± 2.30 148.1 ± 2.42
DM 125.2 ± 3.22* 115.4 ± 2.71* 116.1 ± 2.69*
DM + SPEECS (200 mg/kg) 125.7 ± 4.82# 128.5 ± 2.78# 128.5 ± 2.78#
DM + SPEECS (400 mg/kg) 120.6 ± 2.10& 133.9 ± 1.43# 134.1 ± 1.45#
Table 3: Effect of SPEECS on biochemical parameters of alloxan-induced diabetic rats
Results are expressed as mean ± SEM (n=5). DM: Diabetes mellitus; P< 0.05 was considered significant. *p< 0.05: the difference is significant 
compared to control group in the same column; #p < 0.05: the difference is significant compared to DM group in the same column; &p< 0.05: the 
difference is significant compared to DM + SPEECS (200 mg/kg) group in the same column. DM + SPEECS (200 mg/kg): Diabetic rats treated 
with 200mg/kg b.w seed pod ethanol extract from C. salikounda; DM + SPEECS (400 mg/kg): Diabetic rats treated with 400mg/kg b.w seed pod 
ethanol extract from C. salikounda; SPEECS: Seed pod ethamol extract from C. salikounda
activities of ALT, AST and ALP were significantly 
(p< 0.05) lower while the levels of ALB and TP 
were significantly (p< 0.05) higher in DM group 
treated with 400 mg/kg relative to DM model rats 
(Table 3). However, there was significant increase 
(p< 0.05) in the levels of ALB, TP and significant 
reduction in the actions of AST and ALP in DM + 
SPEECS  (400 mg/kg) when compared with DM 
+ SPEECS (200 mg/kg) while the activity of ALT 
reduced but not statistically significant (Table 3).
Effect of SPEECS on fasting blood glucose 
level of alloxan-induced diabetic rats
The glucose lowering effect of the ethanol 
extract of seed pod C. salikounda is shown in 
Figure 2. The fasting blood glucose of alloxan-
induced diabetic rats three days after injection 
of alloxan were significantly increased (p< 0.05) 
in comparison with the normal control rats. The 
blood glucose level of the groups treated with 200 
and 400 mg/kg of the ethanol extracts seed pod 
of C. salikounda decreased significantly (p< 0.05) 
after 14 days of treatment in comparison to the 
DM control group. However, there was significant 
blood glucose level reduction in the group treated 
with 400 mg/kg of the extract in comparison to 
the group treated with 200 mg/kg. This showed 
that the effect of the extract was dose dependent.
69Anti-diabetic effect of ethanol extract of Copaifera salikounda (Heckel) against alloxan-induced diabetes in rats
Figure 3: (A-B) Effect of SPEECS on antioxidant status in alloxan-induced diabetic rats (n=5)
SPEECS: seed pod ethanol extract from C. salikounda; DM: Diabetes mellitus group without any treatment. DM + E 200: Diabetic rats treated with 
200 mg/kg b.w SPEECS; DM + E 400: Diabetic rats treated with 400mg/kg b.w SPEECS.
Effect of SPEECS on antioxidant status of 
alloxan-induced diabetic rats
The serum activities of SOD and CAT were 
markedly (p< 0.05) higher in DM control group 
compared to the normal control group (Figure 3 A-B). 
The activities of SOD and CAT were significantly 
Figure 2: Effect of SPEECS on blood glucose 
level of alloxan-induced diabetic rats
(p< 0.05) lower in diabetic groups treated with 200 
and 400 mg/kg SPEECS. Besides, the activities of 
SOD and CAT were significantly lower in diabetic 
rats treated with 400 mg/kg when compared with 
those treated with 200 mg/kg. This is an indication 
that 400 mg/kg of the extract is more potent and 
efficacious (Figure 3 A-B)
SPEECS: seed pod ethanol extract from Copaifera salikounda; p<0.05 was considered significant. *p<0.05: the difference is significant compared to 
control group; #p<0.05: the difference is significant compared to DM group; &p<0.05: the difference is significant compared to DM + Extract (200 
mg/kg) group; DM: Diabetes mellitus group without any treatment; DM + E 200: Diabetic rats treated with 200 mg/kg b.w SPEECS; DM + E 400: 
Diabetic rats treated with 400mg/kg b.w SPEECS; SOD: Superoxide dismutase; CAT: Catalase.
Group Body weight (g)
Day 1 Day 7 Day 14
Control 137.9 ± 1.87 147.7 ± 2.30 148.1 ± 2.42
DM 125.2 ± 3.22* 115.4 ± 2.71* 116.1 ± 2.69*
DM + SPEECS (200 mg/kg) 125.7 ± 4.82# 128.5 ± 2.78# 128.5 ± 2.78#
DM + SPEECS (400 mg/kg) 120.6 ± 2.10& 133.9 ± 1.43# 134.1 ± 1.45#
70 C. Aloke, E.S. Igwe, N.A. Obasi, P.A. Amu, E.C. Ogbonnia
Effect of SPEECS on serum MDA level in 
alloxan-induced diabetic rats
The serum concentration of MDA at the end 
of the experiment in the DM model rats was 
significantly (p<0.05) higher in comparison with 
the normal control group.  However, this effect was 
reversed following 14 days treatment with 200 and 
400 mg/kg of the extract in the treated groups. 
Additionally, the MDA level was significantly lower 
in the group treated with 400 mg/kg of the extract 
in comparison to diabetic rats that received 200 
mg/kg of the extract (Figure 4) showing that the 
extract is more effective at 400 mg/kg dose.
Figure 4: Effect of SPEECS on serum MDA level in 
alloxan-induced diabetic rats (n=5).
SPEECS: seed pod ethanol extract from Copaifera salikounda; DM: 
Diabetes mellitus; p<0.05 was considered significant. *p<0.05: the 
difference is significant compared to control group; #p<0.05: the 
difference is significant compared to DM group; &p<0.05: the difference is 
significant compared to DM + Extract (200 mg/kg) group; DM: Diabetes 
mellitus group without any treatment; DM + E 200: Diabetic rats treated 
with 200 mg/kg b.w SPEECS; DM + E 400: Diabetic rats treated with 
400mg/kg b.w SPEECS; MDA: Malondialdehyde
Discussion
Robust evidence has shown that plants are 
exemplary source of drugs. Currently, several 
available drugs have been produced from 
medicinal plants either directly or indirectly (32). 
Some studies have shown that a wide variety of 
plant extracts profoundly lowered blood glucose 
level in alloxan-induced diabetic animals (32, 33, 
34, 35). The results of this study showed that 
SPEECS has antihyperglycemic effect on alloxan-
induced DM in Wistar albino rats
Report on the quantification of the chemical 
components in the seed pod of C. salikounda 
indicated that it is predominantly rich in total 
phenolics, alkaloids, terpenoids, flavonoids, 
tannins, steroids, glycosides, reducing sugar and 
carbohydrates (21). In this study, the GC-MS 
analysis of SPEECS revealed the presence of known 
α-glucosidase inhibitors such as 9-octadecenoic 
acid and octadecanoic acid in the ethanol extracts. 
The inhibition of α-glucosidase has been reported 
to be a possible mechanism in treating DM by 
enzyme inhibition (36) and this affirms possible 
anti-hyperglycemic effects of SPEECS in this 
study. Other reports have shown the anti-diabetic 
property as well as release of insulin stimulation 
potential of hexadeconoic acid and octadecenoic 
(37, 38). Thus, the GC-MS identified compounds 
in this study: 9-octadecenoic acid, octadecanoic 
acid and hexadecanoic acid may be the potential 
anti-diabetic agents in the extract which may 
have exerted their effect via stimulation of 
insulin release and α-glucosidase inhibition. 
The findings in this study revealed that SPEECS 
contains bioactive compounds which mitigated 
hyperglyceamia and oxidative stress in alloxan-
induced diabetic rats and restored the alteration 
in their body weights. The administration of 
alloxan produced a significant oxidative impact as 
evidenced by elevation of lipid peroxidation (MDA) 
and disturbances in antioxidant enzymes status. 
The ability of alloxan to induce weight loss in 
untreated rats (DM control group) mimics what is 
commonly seen in clinical diabetes mellitus (39). 
This loss in weight could be as result of destruction 
of the pancreatic cells by alloxan leading to insulin 
deficiency which causes increased ketone bodies 
production. Consequently, elevated ketone bodies 
with increased lipolysis result in loss of body 
weight (40). The gain in body weight observed 
in diabetic rats treated with SPEECS could be 
attributed to better modulation of hyperglycemia 
in the diabetic rats and reduction in fasting blood 
glucose which could improve body weight in 
alloxan-induced diabetic rats (41). Additionally, 
the ability of SPEECS to improve body weight may 
be due to its ability to lower the elevated blood 
glucose via increased glucose metabolism, and 
this may be attributed to the protective effect of 
the extract in preventing muscle wasting (42).
The results of this study have shown that 
SPEECS at a dosage of 200 and 400 mg/kg body 
weight significantly (P< 0.0001) decreased the 
elevated blood glucose levels compared to normal 
rats. The glucose lowering effect of SPEECS (Figure 2) 
may be attributed to the enhanced secretion of insulin 
from the beta cells of pancreas or may be due to 
increased tissue uptake of glucose by enhancement 
71Anti-diabetic effect of ethanol extract of Copaifera salikounda (Heckel) against alloxan-induced diabetes in rats
of insulin sensitivity (43). Additionally, other 
mechanisms that could have accounted for 
reduction in blood glucose level include: 1) the 
ability of the extract to function as an astringent 
enhancing the precipitation of intestinal mucus 
membrane protein and formation of a bilayer that 
shield the intestine and prevent glucose uptake, 
2) the ability of the extract to speed up glucose 
liberation from circulation by promoting its 
filtration and renal excretion, and 3) promotion of 
glucose liberation via enhanced metabolism and 
inclusion into fats depots, an action requiring the 
pancreas to make insulin (44). Flavonoids have 
been reported as strong bioactive antioxidant 
and anti-diabetic agents that can regulate insulin 
secretion. Flavonoid hinders the action of hepatic 
glucose-6-phosphatase thereby preventing 
gluconeogenesis and breakdown of glycogen and 
consequently brings down elevated blood glucose 
(45). The presence of flavonoids and saponins in 
SPEECS (21) could have led to the revival of the 
non-functional beta cells by the flavonoid and 
prevention of the glucose transport by inhibiting 
intestinal sodium glucose co-transporter-1(S-
GLUT-1) by the saponins (46, 47). Also, saponins 
have been shown to exhibit blood glucose lowering 
potential (48). The blood glucose lowering 
potential of SPEECS may be due to the synergy of 
its phytochemical constituents.
Additionally, hyperglycemia increases the 
generation of free radicals by glucose auto-
oxidation and the increment of free radicals may 
lead to liver damage (49). The liver is necrotized 
in diabetic rats. This leads to increased activities 
of ALT, AST and ALP enzymes as they leak from 
the liver membrane into the blood stream and as 
such serves as indicators of the hepatotoxicity of 
alloxan (50). The significant (P< 0.05) elevation 
of serum enzymes such as ALT, AST and ALP 
observed in diabetic mellitus control rats as 
compared to normal control rats might be due 
to the leakage of these enzymes from the liver 
membrane into the blood stream (51). However, 
the oral administration of SPEECS significantly 
(P< 0.0001) decreased the elevated serum enzymes 
and implied heptato-protective effects (Table 3).
The functional capacity of the hepatocyte is 
measured by total protein content as the liver 
is provided with mechanism for the production 
of serum protein excluding γ-globulins. Hence, 
injury to the liver is marked by decrease in the 
level of protein in the blood and reduced Alb which 
can affect the body functions of animals (52). 
Disruption of protein synthesis is a consequence 
of decline in liver function (53). The observed 
decrease in Alb level in diabetes mellitus control 
group in this study could be a result of a decline in 
the number of cells responsible for Alb synthesis in 
the liver through necrosis by diabetogenic agent, 
alloxan.  However, treatment with SPEECS at 
doses 200 and 400 mg/kg significantly (P < 0.05) 
increased serum TP and Alb in a dose dependent 
manner suggesting increased protein synthesis 
probably due to the regeneration of the damaged 
liver cells by the SPEECS. 
Physiochemical processes in the body produce 
ROS which can participate in various reactions 
that when not controlled will lead to some clinical 
signs (54). Oxidative stress caused by excessive 
production of superoxide and compromised 
antioxidant enzymes has been associated with 
development of clinical conditions attributed to 
DM. DM is one of the disease conditions that is 
linked with immoderate generation of ROS like 
hydrogen peroxide (H2O2), hydroxyl radical (HO-) 
and superoxide anions (O2-). Consequently, cells 
must be safeguarded from this oxidative damage 
by antioxidant enzymes (52). This study found 
a significantly elevated activity of SOD and CAT 
in diabetic rats when compared with the normal 
control. Excessive generation of ROS particularly 
in DM cannot be completely mopped up by 
antioxidant enzymes. Thus, when oxidative stress 
occurs as a result of disease condition, the body 
system enhances the induction or up regulation 
of these enzymes (55). The alteration in the 
activity of these enzymes might be due to altered 
metabolism occasioned by induction of DM 
with alloxan. However, treatment with SPEECS 
attenuated the activity of SOD and CAT at the 
tested concentrations.
MDA is a breakdown product of lipid peroxidation 
of polyunsaturated fatty acid in the membrane 
of cells. In this study, the presence of elevated 
level of MDA in diabetic rats when compared with 
control is suggestive of induced peroxidation of 
lipid and oxidative stress which has been revealed 
to be implicated in DM (56). Treatment with the 
SPEECS significantly reduced the MDA level 
relative to the DM control group (Figure 4). The 
total anti-diabetic effect of SPEECS may be due 
to the combined action of their phytcomponents 
irrespective of their amount. Consequently, the 
significant antidiabetic action of SPEECS in this 
72 C. Aloke, E.S. Igwe, N.A. Obasi, P.A. Amu, E.C. Ogbonnia
work may be ascribed to the presence of alkaloids, 
flavonoids, phenols, steroids or terpenoids and 
other constituents that could act independently 
or in synergy to scavenge free radicals, hence 
safeguarding the islet of Langerhans from injury 
and death.
This study, however, has limitations due to 
financial constraints as the experiment leading to 
the exact mechanism of the extract could not be 
done. We did not include a reference drug in the 
study to compare its effect on the diabetic rats 
with that of the extract. Besides, a longer period 
of three weeks would have been better to evaluate 
the efficacy of the extract.
In conclusion the results of this study indicated 
that SPEECS has anti-diabetic and anti-oxidative 
potentials. These findings corroborate its usage in 
the management of diabetes mellitus in traditional 
medicine and advocate for more research to 
harness fully the potentials of C. salikounda for 
treatment of DM. 
Acknowledgements
The authors declare there is no conflict of 
interest.
We declare that this work was fully funded 
by the authors and no grant was received by the 
authors. 
The authors are grateful to Prof. Ejike C.E.C.C. 
for his invaluable comments and contributions to 
this work.
References
1. Ionut V, Amorin RP.  Epidemiology of diabe-
tes mellitus: a current review. Rom J Diabetes Nutr 
Metab Dis 2012; 19(4): 433–40.  doi: 10.2478/
v10255-012-0050-0 
2. Osadebe PO, Uzor PF, Omeje E O, Agbo MO, 
Obonga WO. Hypoglycemic activity of the extract 
and fractions of Anthocleista vogelii (Planch) stem 
bark.  Trop J Pharm Res 2014; 13: 1437–43. doi: 
10.4314/tjpr.v13i9.9
3. Chatzigeorgiou A, Halapas A, Kalafatakis K, 
Kamper E. The use of animal models in the study 
of diabetes mellitus. In Vivo 2009; 23: 245–58. 
4. Dhanesha N, Joharapurkar A, Shah G, et al. 
Exendin-4 ameliorates diabetic symptoms through 
activation of glucokinase. J Diabetes 2012; 4(4): 
369–77. doi: 10.1111/j.1753-0407.2012.00193.x
5. Bhat AH, Dar KB,  Zargar MA,  Masood A, 
Ganie SA. Modulation of oxidative stress and hy-
perglycemia by Rheum spiciformis in alloxan in-
duced diabetic rats and characterization of isolated 
compound. Drug Res (Stuttg). 2018; 69(4): 218–26. 
doi: 10.1055/a-0665-4291
6. Ceriello A. New insights on oxidative stress 
and diabetic complications may lead to a “causal” 
antioxidant therapy. Diabetes Care 2003; 26(5): 
1589–96. doi:10.2337/diacare.26.5.1589
7. Nishikawa T, Araki E. Impact of mitochon-
drial ROS production in the pathogenesis of di-
abetes mellitus and its complications. Antioxid 
Redox Sign 2007; 9(3): 343–53. doi:10.1089/
ars.2007.9.ft-19
8. Yorek MA. The role of oxidative stress in dia-
betic vascular and neural disease. Free Radic Res 
2003; 37(5): 471–80.
9. Cameron NE, Cotter MA, Hohman TC. Inter-
actions between essential fatty acid, prostanoid, 
polyol pathway and nitric oxide mechanisms in the 
neurovascular deficit of diabetic rats. Diabetologia 
1996; 39(2): 172–82. doi: 10.1007/BF00403960
10. Monnier VM. Intervention against the Mail-
lard reaction in vivo. Arch Biochem Biophys 2003; 
419(1): 1–15.
11. Maritim AC, Sanders RA, Watkins JB. Di-
abetes, oxidative stress, and antioxidants: a re-
view. J Biochem Mol Toxicol 2003; 17(1): 24–38. 
doi:10.1002/jbt.10058
12. Kaneto H, Fujii J, Suzuki K, et el. DNA 
cleavage induced by glycation of Cu,Zn-superoxide 
dismutase. Biochem J 1994; 304(1): 219–25. doi: 
10.1042/bj3040219
13. Valko M, Leibfritz D, Moncol J, et al. Free 
radicals and antioxidants in normal physiologi-
cal functions and human disease. Int J Biochem 
Cell Biol 2007; 39(1): 44–84. doi:10.1016/j.bio-
cel.2006.07.001
14. Young IS, Woodside JV. Antioxidants in 
health and disease. J Clin Pathol 2001; 54(3): 
176–86. doi:10.1136/jcp.54.3.176
15. Hui H, Tang G, Go VLW. Hypoglycemic 
herbs and their action mechanisms.  Chin Med 
2009; 4: e11. doi: 10.1186/1749-8546-4-11
16. Berraaouan A, Abid S, Bnouham M, Ber-
raaouan A. Antidiabetic oils. Curr Diabetes Rev 
2013; 9: 499–505.
17. Nathan DM, Buse JB, Davidson MB,  et 
al. Medical management of hyperglycemia in type 
2 diabetes: a consensus algorithm for the initi-
ation and adjustment of therapy: a consensus 
73Anti-diabetic effect of ethanol extract of Copaifera salikounda (Heckel) against alloxan-induced diabetes in rats
statement of the American Diabetes Association 
and the European Association for the Study of 
Diabetes. Diabetes Care 2009; 32: 193–203. doi: 
10.2337/dc08-9025.
18. Gupta RC, Chang D, Nammi S, Bensous-
san A, Bilinski K, Roufogalis BD. Interactions be-
tween antidiabetic drugs and herbs: an overview 
of mechanisms of action and clinical implications. 
Diabetol Metab Syndr 2017; 9: e59. doi:10.1186/
s13098-017-0254-9
19. Xu X, Shan B, Liao CH, Xie JH, Wen P 
W, Shi JY. Antidiabetic properties of Momordica 
charantia L. polysaccharide in alloxan-induced 
diabetic mice. Int J Biol Macromol 2015; 81: 538–
543. doi: 10.1016/j.ijbiomac.2015.08.049
20. Oteng-Amoako AA, Obeng EA. Copaifera 
salikounda Heckel. Record from PROTA4U. In: 
Lemmens RHMJ, Louppe D, Oteng-Amoako AA, 
eds. PROTA (Plant Resources of Tropical Africa / 
Ressources végétales de l’Afriqutropicale), Wagen-
ingen, Netherlands: Wageningen University, 
2012. https://prota4u.org/database/protav8.as-
p?g=pe&p=Copaifera+salikounda+Heckel  (Febru-
ary, 2021)
21. Aloke C, Ibiam UA, Obasi NA, et al. Effect 
of ethanol and aqueous extracts of seed pod of Co-
paifera salikounda (Heckel) on complete Freund’s 
adjuvant induced rheumatoid arthritis in rats. J 
Food Biochem 2019; 43(7): e12912. doi: 10.1111/
jfbc.12912
22. Okwu ED, Ighodaro UB. GC-MS evaluation 
of bioactive compounds and antibacterial activity 
of the oil fraction from the leaves of Alstonia boonei 
De Wild.  Pharma Chem 2010; 2(1): 261–2. 
23. Lorke D. A new approach to practical acute 
toxicity tests. Arch Toxicol 1983; 54(4): 275–87. 
24. Bell RH,  Hye RJ. Animal models of diabe-
tes mellitus: physiology and pathology. J Surg Res 
1983; 35: 433–60. 
25. Reitman S, Frankel S. A colorimetric method 
for the determination of serum glutamate oxaloac-
etate and pyruvate transaminase. Am J Clin Pathol 
1957; 28: 56–63. doi:10.1093/ajcp/28.1.56
26. Englehardt VA. Measurement of alkaline 
phosphatase. Aerztl Labour 1970; 16: 42–3.
27. Weichselbaum TE. An accurate and rapid 
method for the determination of protein in small 
amount of blood, serum and plasma. Am J Clin 
Pathol 1946; 10: 40–9. 
28. Doumas BT, Watson WA, Biggs HG. Albu-
min standard and measurement of albumin with 
bromcresol green. Clin Chem Acta 1971; 31(1): 
87–96.
29. Buege JA, Aust SD. Microsomal lipid perox-
idation. In: Flesicher S, Packer L, eds. Methods in 
enzymology. Vol. 52. New York : Academic Press, 
1978: 302–10.
30. Fridovich I, Mc-Cord JM. Superoxide dis-
mutase: an enzymatic function for erythrocuperin. 
J Biol Chem 1969; 244(22): 6045–55. 
31. Sinha AK. Colorimetric assay of catalase. 
Anal Biochem 1972; 47(2): 389–94. 
32. Yakubu MT, Akanji MA, Nafiu MO. Antidi-
abetic activity of aqueous of Cochlospermum plan-
chonii root in alloxan-induced diabetic. Cameroon 
J Exp Biol 2010; 6: 91–100.
33. Ananda PK, Kumarappan CT, Sunil C, Kala-
ichelvan VK. Effect of Biophytum sensitivum on 
streptozotocin and nicotinamideinduced diabetic 
rats. Asian Pac J Tropical Biomed 2012; 11: 31–5.
34. Alamgeer, Rashid M, Bashir S, et al. Com-
parative hypoglycemic activity of different extracts 
of Teucrium stocksianum in diabetic rabbits. Ban-
gladesh J Pharmacol 2013; 8: 186–93.
35. Nagappa AN, Thakurdesai PA, Venkat RN, 
Singh J. Antidiabetic activity of Terminalia catappa 
Linn fruits. J Ethnopharmacol 2003; 88: 45–50.
36. Channabasava GM, Chandrappa CP, 
Sadananda TS. In Vitro antidiabetic activity of 
three fractions of methanol extracts of Loranthus 
Micranthus, identification of phytoconstituents 
by GC-MS and possible mechanism identified by 
GEMDOCK method. Asian J Biomed Pharm Sci 
2014; 4 (34): 34–41.
37. Parker SM, Moore PC, Johnson LM, Poitout 
V. Palmitate potentiation of glucose-induced insu-
lin release: a study using 2-bromopalmitate. Me-
tabolism 2003; 52 (10): 1367–71. 
38. Zuraini A, Zamhuri KF, Yaacob A, et al. In 
vitro anti-diabetic activities and chemical analysis 
of polypeptide-k and oil isolated from seeds of Mo-
mordica charantia (Bitter gourd). Molecules 2012; 
17(8): 9631–40. doi:10.3390/molecules17089631
39. World Health Organisation. Diet, nutrition, and 
the prevention of chronic diseases. World Health Or-
ganisationTechnical Report Series 2003; 916: 1-149. 
40. Singh SK, Kesari AN, Gupta RK, Jaiswal 
D, Watal G. Assessment of antidiabetic potential 
of Cynodon dactylon extract in streptozotocin di-
abetic rats. J Ethnopharmacol 2007; 114: 174–9. 
doi:10.1016/j.jep.2007.07.039
41. Ebong PE, Atangwho IJ, Eyong EU, Egbung 
GE. The antidiabetic efficacy of combined extracts 
from two continental plants: Azadirachta indica (A. 
74 C. Aloke, E.S. Igwe, N.A. Obasi, P.A. Amu, E.C. Ogbonnia
Juss) (Neem) and Vernonia amygdalina Del. (Afri-
can bitter leaf). Am J Biochem Biotechnol 2008; 
4(3): 239–44. doi: 10.3844/ajbbsp.2008.239.244
42. Ezejiofor AN, Okorie A, Orisakwe OE. Hy-
poglycaemic and tissue-protective effects of the 
aqueous extract of Persea americana seeds on al-
loxan-induced albino rats. Malays J Med Sci 2013; 
20(5): 31–9. 
43. Maniyar Y, Bhixavatimath P. Antihypergly-
cemic and hypolipidemic activities of aqueous ex-
tract of Carica papaya Linn. leaves in alloxan-in-
duced diabetic rats. J Ayurveda Integr Med 2012; 
3(2): 70–4. doi: 10.4103/0975-9476.96519
44. Muhtadia M, Primariantia AU, Sujonoa TA. 
Antidiabetic activity of durian (Durio zibethinus 
Murr.) and rambutan (Nephelium lappaceum L.) fruit 
peels in alloxan diabetic rats. Procedia Food Sci 
2015; 3: 255–61. doi: 10.1016/j.profoo.2015.01.028
45. Chen PY, Csutora P, Veyna-Burke NA, Mar-
chase RB.  Glucose-6 phos-phate and Ca2+se-
questration are mutually enhanced in microsomes 
from liver, brain, and heart. Diabetes 1998; 4 (6): 
874–81. doi:10.2337/diabetes.47.6.874
46. Hakkim FL, Girija S, Kumar RS, Jalalud-
deen MD. Effect of aqueous and ethanol extracts of 
Cassia auriculata L. flowers on diabetes using al-
loxan – induced diabetic rats. Int J Diabetes Metab 
2007; 15: 100–6. 
47. Tiwari AK, Rao JM. Diabetes mellitus and multi-
ple therapeutic approaches of phytochemicals: present 
status and future prospects. Curr Sci 2002; 83: 30–8. 
48. Patel DK, Prasad SK, Kumar R, Hemalatha 
S. An overview on antidiabetic medicinal plants 
having insulin mimetic property. Asian Pac J Trop 
Biomed 2012; 2(4): 320–30. doi: 10.1016/S2221-
1691(12)60032-X.
49. Singh R, Seherawat A, Sharma P. Hypogly-
cemic, antidiabetic and toxicological evaluation of 
Momordica dioica fruit extracts in alloxan-induced 
rats. J Pharmacol Toxicol 2011; 6(5): 454–67. doi: 
10.3923/jpt.2011.454.467
50. Saeed MK, Deng Y, Dai R. Attenuation of 
biochemical parameters in streptozotocin-induced 
diabetic rats by oral administration of extracts and 
fractions of Cephalotaxus sinensis. J Clin Biochem 
Nutr 2008; 42: 21–8.  doi: 10.3164/jcbn2008004
51. Mansour HA, Newairy AS, Yousef MI, She-
weita SA. Biochemical study on the effects of some 
Egyptian herbs in alloxan-induced diabetic rats. 
Toxicology 2002; 170: 221–8. 
52. Kanchana N, Mohamed AS. Hepatoprotec-
tive effect of Plumbago zeylanica on paracetamol 
induced liver toxicity in rats. Int J Pharm Pharm 
Sci 2011; 3: 151–4. 
53. Afaf A, Faras EI, Elsawaf AL. Hepatoprotec-
tive activity of quercetin against paracetamol-in-
duced liver toxicity in rats. Tanta Med J 2017; 45: 
92–8. doi: 10.4103/tmj.tmj_43_16
54. Kesavulu MM, Giri R, Kameswara-Rao B, 
Apparao C. Lipid peroxidation and antioxidant en-
zyme levels in type 2 diabetics with microvascular 
complications. Diabetes Metab 2000; 26: 387–92.
55. Qujeq D, Rezvani T. Catalase (antioxidant 
enzyme) activity in streptozotocin-induced diabetic 
rats. Int J Diabetes Metab 2007; 15: 22–4. 
56. Ceriello A. Oxidative stress and glycaemic 
regulation. Metabolism 2000; 49(2 suppl 1): 27–9.
75Anti-diabetic effect of ethanol extract of Copaifera salikounda (Heckel) against alloxan-induced diabetes in rats
ANTIDIABETIČNI UČINEK EKSTRAKTA ETANOLA Copaifera salikounda (HECKEL) NA 
SLADKORNO BOLEZEN, SPROŽENO Z ALLOXAN-om, PRI PODGANAH
C. Aloke, E. S. Igwe, N. A. Obasi, P. A. Amu, E. C. Ogbonnia
Izvleček: Obstaja vedno več dokazov, ki poudarjajo uporabnost zdravilnih rastlin pri zdravljenju različnih bolezni, tudi zaradi 
različnih negativnih stranskih učinkov, povezanih s konvencionalnimi zdravili. Rastlinske sestavine kot so fenoli in flavonoidi z 
antioksidativnim potencialom, imajo po nekaterih raziskavah zaščitno vlogo pred degenerativnimi boleznimi, ki jih povzroča 
oksidativni stres, kot je sladkorna bolezen diabetes mellitus (DM). Študija je bila izvedena z namenom raziskovanja učinka 
etanolnega semenskega ekstrakta iz rastline Copaifera salikounda (SPEECS) pri podganah s sladkorno boleznijo, ki jo je pov-
zročil alloxan. SPEECS je bil pridobljen z maceracijo praška semen v prahu v absolutnem etanolu 72 ur ter nadaljnjo filtracijo, 
koncentracijo in sušenjem v vakuumu. Za kvantitativno ugotavljanje kemijskih sestavin SPEECS je bila uporabljena tehnika 
plinske kromatografije in masne spektrometrije (GC-MS). Štiriindvajset samcev podgan Wistar je bilo naključno razporejenih 
v štiri skupine (n=6): normalna kontrola, kontrola DM, DM + 200 mg/kg SPEECS in DM + 400 mg/kg SPEECS. DM je bil pri pod-
ganah sprožen z intraperitonealno injekcijo 200 mg/kg telesne mase alloxana. Po 14 dneh zdravljenja so bile pri različnih sk-
upinah določene spremembe telesne teže in nivo glukoze v krvi (na tešče). Poleg tega so avtorji raziskave izmerili še nekatere 
serumske biokemične parametre kot so ravni alaninske aminotransferaze (ALT), aspartatne aminotransferaze (AST), alkalne 
fosfataze (ALP), albumina (ALB), skupnih proteinov (TP), malondialdehida (MDA), superoksiddismutaze (SOD) in katalaze 
(CAT). Rezultati GC-MS so v izvlečku SPEECS pokazali devet bioaktivnih spojin, v katerih je največ 9-oktadecenojske kisline 
(55,75%). SPEECS (200 in 400 mg/kg) je povzročil znatno (P <0,05) povečanje telesne mase, znižanje glukoze v krvi na tešče in 
znižal raven encimov pokazateljev jetrne funkcije (ALT, AST, ALP), medtem ko je bila raven TP in ALB pri podganah, ki so preje-
male SPEECS izrazito povišana v primerjavi z DM kontrolno skupino. Zdravljenje s  SPEECS je tudi oslabilo aktivnosti SOD in 
CAT, medtem ko se je raven MDA znatno zmanjšala (P <0,05) v primerjavi s kontrolno skupino DM. Ta študija je pokazala, da 
lahko SPEECS ublaži hiperglikemijo pri sladkorni bolezni pri podganah.
Ključne besede: Copaifera salikounda; oksidativni stres; zdravilne rastline; sladkorna bolezen; fitokemikalije; ortodoksni