The Antidiabetic and Antioxidant Activities of Hydrolyzed Virgin

Coconut Oil in Streptozotocin-induced Diabetic Rats

Linda Margata

, Jansen Silalahi

, Urip Harahap

, Dwi Suryanto

and Denny Satria

Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Universitas Sumatera Utara, Medan, Indonesia

Department of Pharmacology, Faculty of Pharmacy, Universitas Sumatera Utara, Medan, Indonesia

Department of Biology, Faculty of Mathematics and Natural Sciences, Universitas Sumatera Utara, Medan, Indonesia

Department of Pharmaceutical Biology, Faculty of Pharmacy, Universitas Sumatera Utara, Medan, Indonesia

Keywords: Virgin coconut oil, Enzymatic hydrolysis, Blood glucose, Haemoglobin A1c, Superoxide dismutase

Abstract: The aim of this study was to examine the antidiabetic and antioxidant effect of enzymatically hydrolyzed

virgin coconut oil (HVCO) in streptozotocin (STZ) induced rats. VCO was hydrolyzed enzymatically using

lipase from Rhizomucor miehei (active on sn-1,3 position). Thirty male rats were induced with 40 mg/kg

body weight (BW) STZ. Rats with blood glucose level ≥ 250 mg/dl were divided into six groups which

were given with sodium carboxymethylcellulose (CMC Na) 0.5%, metformin 45 mg/kgBW, VCO (4 and 6

ml/kgBW) and HVCO (4 and 6 ml/kgBW). Blood glucose, Haemoglobin A1c (HbA1c), superoxide

dismutase (SOD), soluble receptor advanced glycosylation end-product (sRAGE) levels, and

immunihistochemistry assay on pancreas were analyzed after 30 days of treatment. It is shown that HVCO 4

ml/kgBW and metformin were not significantly different in lowering blood glucose level. Blood glucose

level in groups treated with HVCO 4 ml/kgBW and metformin were 409.2 and 364.40 mg/dl. HVCO also

lowered HbA1c and sRAGE levels (55.50 ng/ml and 148.40 pg/ml, respectively), while increased SOD

level (76.96 pg/ml). Insulin expression of rats treated with 4 ml/kgBW HVCO and metformin also did not

differ significantly which were 11.40% and 11.70%, respectively. HVCO exerted higher antidiabetic and

antioxidant effects that VCO did.

1 INTRODUCTION

Diabetes Mellitus (DM) lowers life’s quality,

productivity and increases mortality rate in either

developing or developed countries. DM is metabolic

syndrome which is marked by the occurence of

hyperglycemia. Hyperglycemia in DM could trigger

oxidative stress which then causes microvascular

complications (retinopathy, nephropathy and

neuropathy) and also macrovascular complications

(heart attack, stroke and peripheral blood vessel

disease). Risk of heart attack and stroke happen two

to four times more in diabetic patients, 50% diabetic

patients died because of cardiovascular disease

(Vassalotti, 2006; Paliyath, et al., 2011).

Insulin plays an important role in controlling

blood glucose. Insulin is a hormon produced by β-

cell which is located in Langerhans islet of pancreas.

Insulin stimulates the uptake of blood glucose by

cell, hence lowers blood glucose level. DM which is

caused by the low secretion of insulin from β-cell

pancreas is classified as Type I DM, while DM

which is caused by insulin resistance is classified as

Type II DM (Joshi, et al., 2007; Triplitt, et al.,

2005).

Hyperglycemia stimulates protein glycosylation

which is a reaction between aldehyde group in

glucose and amino group in protein. This reaction

produces schiff base via Amadori process. Amadori

product then undergoes further autooxidation

becomes advanced glycosylation end-product

(AGE). Crosslinking protein causes AGE

accumulation in extracellular matrix. AGE in

diabetic patient causes erythrocyte dysfunction

because haemoglobin is glycated. This erythrocyte

will bound to receptor of advanced glycosylation

end-product (RAGE) in endothelium and causes

endothelium dysfunction (Baynes and

Domonickzak, 2003; McKee and McKee, 2003;

Rayfield and Valentine, 2006; Mechanick, 2006).

Virgin coconut oil (VCO) is one of the sources

of medium chain triglyceride (MCT) oil. MCT has

152

Margata, L., Silalahi, J., Harahap, U., Suryanto, D. and Satria, D.

The Antidiabetic and Antioxidant Activities of Hydrolyzed Virgin Coconut Oil in Streptozotocin-induced Diabetic Rats.

DOI: 10.5220/0009862301520159

In Proceedings of the 2nd International Conference on Tropical Medicine and Infectious Disease (ICTROMI 2019), pages 152-159

ISBN: 978-989-758-469-5

been known to have benefits in glycemic control and

insulin secretion. MCT helps in the effectiveness of

glucose usage (Vala and Kapadiya, 2014; Bach and

Babayan, 1982; Fife, 2004). Studies about the

antidiabetic and antioxidant effects of VCO has been

reported (Siddalingaswamy, et al., 2011;

Mohammed and Luka, 2013; Iranloye, et al., 2013;

Akinnuga, et al., 2014; Kolondam, et al., 2008;

Elsayed, et al., 2015; Essien, et al., 2014;

Dalmacion, et al., 2012; Dewi and Aryadi, 2010).

However, study about the effect of hydrolyzed VCO

(HVCO) on blood glucose level and its antioxidant

effect have never been reported. The objective of

this study was to determine the antidiabetic and

antioxidant effects of HVCO in STZ-induced

diabetic rats.

2 MATERIALS AND METHODS

Apparatus used in this study were analytical balance,

hot plate, magnetic stirrer, thermometer, oven, water

bath, separating funnel, Easytouch test strips,

microtube, centrifugator, microplate reader,

incubator, micro pipette and laboratory glassware.

Chemicals used were lipase from Rhizomucor

miehei (≥ 20000 U/g, Sigma Aldrich), Tris-HCl

(molecular biology grade, Vivantis), distilled water

(Bratachem), n-hexane (Macron Chemicals).

Calcium chloride and sodium sulfate anhydrous

were the products of Merck. All reagents used in this

work were of analytical grade unless otherwise

stated. VCO used was the product of Palem Mustika,

Indonesia. STZ used to induce diabetic in rats was

from Nacalai Tesque. Metformin 500 mg tablets

were purchased from the local pharmacy. Rat

HbA1c, SOD and sRAGE ELISA kits were the

products of FineTest.

2.1 Enzymatic Hydrolysis of Virgin

Coconut Oil

Thirty (30) g of VCO, 30 ml of distilled water, 12.5

ml of 0.063 M calcium chloride, 25 ml of buffer

Tris-HCl 1 M pH 8 and 3 ml of lipase from R.

miehei were transferred into 250 ml Erlenmeyer

flask, respectively. The mixture was incubated for

10 hours at 50°C and stirred at 200 rpm for 10

minutes every 1 hour. After 10 hours, the mixture

was transferred into the separating funnel and

extracted with 50 ml of n-hexane. The extract was

allowed to stand for a while until two layers were

formed. The upper layer (n-hexane fraction) was

separated (filtrate I), while the bottom layer (water

fraction) was extracted again with 50 ml of n-

hexane. The second extract was allowed to stand for

a while and then the upper layer formed was

separated (filtrate II). Filtrate I and II were mixed

and then 250 g of sodium sulfate anhydrous was

added and allowed to stand for 15 minutes to absorb

the water residue. The mixture was filtered, then n-

hexane was evaporated using water bath to obtain

HVCO (Margata, et al., 2018).

2.2 Preparation of Diabetic Rats

Thirty male rats which had been acclimatized for

one week were fasted for 18 hours and water was

given ad libitum during fasting period. Blood

glucose level was measured using Easytouch test

strips. Rats were given STZ 40 mg/kgBW i.p. and

then 10% sucrose ad libitium for one day. After 10

days, blood glucose level was measured and rats

with blood glucose level ≥ 250 mg/dl were used as

experimental animals (Furman, 2015).

2.3 Experimental Design

Diabetic rats were divided into six groups (five

animals each) and were given orally: (1) CMC Na

0.5% (control group), (2) 45 mg/kgBW metformin,

(3) 4 ml/kgBW VCO, (4) 6 ml/kgBW VCO, (5) 4

ml/kgBW HVCO, and (6) 6 ml/kgBW HVCO, for

30 days. Blood glucose level was measured every

three days during experimental period. After the end

of treatment, rats were fasted for 18 h and

anesthetized with 70 mg/kgBW ketamine i.p. Blood

was collected directly from the heart and centrifuged

for 10 min at 3000 rpm to obtain serum. Serum

collected was then analyzed for HbA1c, SOD and

sRAGE levels using ELISA (Afriadi, 2010; Silalahi,

et al., 2016).

2.4 HbA1c, SOD and sRAGE Analysis

HbA1c, SOD and sRAGE were measured

enzymatically using ELISA kit. Absorbance of color

intensity was read using microplate reader at 450 nm

(Ashraf, et al., 2015).

2.5 Immunohistochemical Staining of

Pancreas

Insulin expression in pancreas was done using IHC

technique. Pancreas tissue which had been sectioned

into 3-4 µm was soaked intu xylol, ethanol 100, 90,

80, 70 and 50%, respectively, each was done 2 times

for 90 min. Peroxidase blocking was done using

The Antidiabetic and Antioxidant Activities of Hydrolyzed Virgin Coconut Oil in Streptozotocin-induced Diabetic Rats

153

0.3% H

in methanol for 20 min, washed with

10% phosphat buffer saline (PBS) 3 times for 5 min.

Non-specific blocking was done using 10% normal

serum for 30 min and then tissue was incubated with

primary antibody at 4°C for 18-22 hrs, washed with

10% PBS 3 times for 5 min. Tissue was given with

some drops of secondary (universal) antibody and

allowed to stand for 30 min and then washed with

10% PBS 3 times for 5 min. Tissue was given with

some drops of chromogen 3,3-diaminobenzidine and

allowed to stand for 5-10 sec, then washed with

distilled water, counterstained with Hematoxylin

Mayer for 5-10 sec and then with running tap water

for 10-15 min. Dehydration was done using ethanol

80, 90% and xylol (each for 2 times). Mounting was

done using E. Z mount (Lab Vision, Cat#MS-1378-

PO)

2.6 Statistical Analysis

All data were statistically analyzed using one-way

ANOVA followed by Tukey’s test using

computerized SPSS package program (SPSS 17.0

software for Windows). Results are expressed as

mean±standar deviation and considered significantly

different at p<0.05.

3 RESULTS

The effect of VCO and HVCO on blood glucose

level during 30 days of treatment can be seen in

Table 1 and Figure 1.

Figure 1: Changes in blood glucose level during 30 days

of treatment.

Table 1: Changes in blood glucose level during 30 days of treatment

Treat-

ment

Blood glucose level (mg/dl) day-

0 3 6 9 12 15 18 21 24 27 30

Negati

control

528.40

18.56

519.80

14.79

514.60

19.86

521.60

12.10

516.20

17.51

510.40

14.93

515.40

11.30

522.40

11.01

520.80

14.86

516.40

15.65

510.60

15.95

Metfor

-min

536.00

47.72

530.60

46.77

525.80

45.50

508.00

32.44

490.20

29.16

476.20

23.81

458.60

26.75

439.00

19.34

415.20

16.39

377.80

16.90

364.40

11.50

VCO 4

ml/kg

529.40

31.93

526.00

31.46

522.00

32.02

517.40

30.01

512.20

30.43

505.20

31.33

499.80

34.13

495.00

33.59

489.80

33.81

483.00

33.13

476.20

32.84

VCO 6

ml/kg

539.60

30.76

529.20

31.54

521.00

33.58

510.00

32.27

499.80

31.32

490.00

33.66

479.00

31.02

468.60

32.36

b,c

458.40

32.12

446.40

27.52

463.40

29.37

HVCO

ml/kg

533.60

36.58

523.00

36.82

514.00

34.16

503.40

38.04

474.60

41.60

463.20

41.79

452.80

40.31

444.20

39.13

435.60

38.47

422.00

40.85

409.20

46.15

HVCO

ml/kg

525.20

29.45

508.40

27.05

490.40

29.52

472.80

29.66

463.00

29.80

448.40

35.83

- - - - -

Means ± SD in each column with different superscript letters differ significantly at p<0.05 (n=5).

300

350

400

450

500

550

600

036912151821242730

Blood glucose level (mg/dl)

Day-

Negative control Metformin

VCO 4 ml/kgBW VCO 6 ml/kgBW

HVCO 4 ml/kgBW HVCO 6 ml/kgBW

ICTROMI 2019 - The 2nd International Conference on Tropical Medicine and Infectious Disease

154

In Table 1 and Figure 1, it can be seen that at day

0, all rats in each group had blood glucose level ≥

250 mg/dl. Blood glucose levels at day 0 in all rats

were not significantly different. From day 3 to 30,

blood glucose levels in all groups, except negative

control, were gradually decreasing. In negative

control group, blood glucose level was stable until

day 30. From day 3 to 12, all all groups had

significantly different blood glucose level (p>0.05).

At day 15, blood glucose levels in rats given with

metformin and HVCO 6 ml/kgBW were 476.20 and

448.40 mg/dl, respectively. Those values were

significantly different with blood glucose level in

negative control group which was 510.40 mg/dl. At

day 18, HVCO 4 ml/kgBW was shown to have a

significant decrease in blood glucose level compared

to negative control group. At day 30, blood glucose

level in rats fed with 4 ml/kgBW VCO did not differ

significantly (p<0.05) compared to blood glucose

level in rats fed with metformin which were 409.20

and 364.40 mg/dl.

The effect of VCO and HVCO on HbA1c, SOD

and sRAGE levels in diabetic rats can be seen on

Table 2 and Figure 2.

Table 2: The effect VCO and HVCO on HbA1c, SOD and sRAGE levels in diabetic rats

Treatment HbA1c (ng/ml) SOD (pg/ml) sRAGE (pg/ml)

Negative control

92.45 ± 1.44

43.95 ± 0.58

193.49 ± 2.53

Metformin

45.75 ± 0.77

82.15 ± 0.39

133.82 ± 1.63

VCO 4 ml/kgBW

68.38 ± 0.73

52.82 ± 0.22

167.55 ± 2.53

VCO 6 ml/kgBW

64.88 ± 1.41

61.49 ± 0.50

159.30 ± 1.93

HVCO 4 ml/kgBW

55.50 ± 1.59

76.96 ± 0.32

148.80 ± 1.99

Means ± SD in each column with different superscript letters differ significantly at p<0.05 (n=5).

Figure 2: The effect of VCO and HVCO on HbA1c,

SOD and sRAGE levels in diabetic rats.

As seen in Table 2 and Figure 2, HbA1c levels in

all groups were significantly different (p<0.05). The

highest to the lowest HbA1c levels started from

negative control, 4 ml/kgBW VCO, 6 ml/kgBW

VCO, 4 ml/kgBW HVCO to metformin,

respectively. SOD levels in all groups were also

significantly different (p<0.05). The lowest SOD

level was in negative control group which was 43.95

pg/ml, while the highest was in metformin group

which was 82.15 pg/ml. SOD level in rats fed with 4

ml/kgBW HVCO (52.82 pg/ml) was significantly

higher than those in 4 and 6 ml/kgBW VCO (52.82

and 61.49 pg/ml). All groups also had significantly

different sRAGE levels (p<0.05). The highest

sRAGE level was in negative control group, while

sRAGE level in groups fed with metformin, 4

ml/kgBW HVCO, 4 and 6 ml/kgBW VCO were

shown to decrease significantly compared to

negative control group.

The effect of VCO and HVCO on insulin

expression in pancreas of diabetic rats can be seen

on Figure 3 and Table 3.

Table 3: The effect VCO and HVCO on insulin expression

in diabetic rats

Treatment Mean insulin

expression ±

Insulin

expression

(%)

Negative control 6,40 ± 1,82

3.20

Metformin 23,40 ± 1,14

11.70

VCO 4 ml/kgBW 10,60 ± 1,82

5.30

VCO 6 ml/kgBW 15,60 ± 1,67

7.80

HVCO 4

ml/kgBW

22,80 ± 1,48

11.40

Means ± SD in each column with different superscript

letters differ significantly at p<0.05 (n=5). Percentage of

insulin expression was calculated from 200 cells which

was counted using Image Raster

100

150

200

250

HbA1c (ng/ml) SOD (pg/ml) sRAGE (pg/ml)

Negative control Metformin

VCO 4 ml/kgBW VCO 6 ml/kgBW

HVCO 4 ml/kgBW

The Antidiabetic and Antioxidant Activities of Hydrolyzed Virgin Coconut Oil in Streptozotocin-induced Diabetic Rats

155

Figure 3: The effect of VCO and HVCO on insulin expression in diabetic rats. A = negative control, B = metformin 45

mg/kgBW, C = VCO 4 ml/kgBW, D = VCO 6 ml/kgBW, E = HVCO 4 ml/kgBW, (→) = show positive reaction between

antigen and insulin antibody on β-cell which is marked by brown color; magnificent 10 x 40.

Based on Figure 3, it can be seen that rats from

negative control had the least brown color expressed

compared to other groups. In addition, it is also

shown that rats treated with metformin and 4

ml/kgBW HVCO showed highest insulin expression.

From Table 3, it can be seen that insulin expression

in negative control group was the lowest insulin

expression with score 6.40 (3.20%). Insulin

expression in each group differs significantly at

p<0.05, except groups treated with metformin and

HVCO 4 ml/kgBW with insulin expression of 27,60

(13,80%) and 22.80 (11.40%), respectively.

4 DISCUSSION

In this study, 40 mg/kgBW STZ was shown to give

uniform response of blood glucose levels in all

groups. STZ is a broad spectrum antibiotic which is

toxic to insulin producing β-cell in pancreas

Langerhans islet. STZ is uptaken via glucose

transporter GLUT2 and causes DNA alkylation, and

eventually causes β-cell death (Szkudelski, 2011;

Deeds, et al., 2011). β-cell damage was shown to be

stable until day 30 in this study. Blood glucose level

ICTROMI 2019 - The 2nd International Conference on Tropical Medicine and Infectious Disease

156

was not return to normal during experiment period if

intervention was not done. Structural changes in β-

cell pancreas (total granulation) occur 48 hours after

STZ administration and continue for 4 months. The

low rate of β-cell regeneration in diabetic individual

causes the importance of finding a way to increase

its regeneration rate (Eleazu, et al., 2013; Yin, et al.,

2006).

Blood glucose level was decrease after 15 day of

treatment in groups fed with metformin and 6

ml/kgBW. It shows that the bioavailability of

metformin and 6 ml/kgBW HVCO were enough to

decrease blood glucose level in diabetic rats after 15

days. After day 15, blood glucose level in group fed

with 6 ml/kgBW was not recorded because all rats in

those group did not survive until day 18. Therefore,

HbA1c, SOD and sRAGE levels in that group were

not available.

VCO was shown to have antidiabetic effect and

the effect increasing as the dosage increasing. This

study corresponds to the studies reported before

which showed that antidiabetic effect of VCO is

dose dependant (Iranloye, et al., 2013; Afriadi, 2010;

Handajani and Dharmawan, 2009). At day 30, group

fed with 4 ml/kgBW and metformin were shown to

have a decrease in blood glucose level. It might be

because those groups undergo β-cell recovery at day

30. MCFA contained in HVCO is suspected to have

important role in the recovery of β-cell pancreas. In

addition, lauric acid also has the ability to stimulate

insulin secretion (Vala and Kapadiya, 2014).

Metformin is an antihyperglycemic commonly

used in the treatment of Type II DM. Metformin

increases hepatic and peripheral insulin sensitivity

by inhibiting hepatic glucose production and

increasing the uptake of glucose in skeletal muscle

and adipose. Although metformin was not

commonly recommended as adjunct therapy in Type

I DM (Beysel, et al., 2018), this study shows that

metformin was able to lower blood glucose level in

single dose STZ induced diabetic and this finding

corresponds to the works reported before (Silalahi,

et al., 2016; Erehywa, et al., 2011; Han, et al., 2017).

This might be because diabetic type induced by STZ

has similarity either with Type I or Type II DM

(Eleazu, et al., 2013).

VCO enzymatic hydrolysis using lipase from

Rhizomucor miehei which is active on sn-1 and sn-3

position in triglyceride molecule produces two

MFAs (especially lauric acid) and one molecule 2-

monoglyceride (especially 2-monolaurin) (Aehle,

2004). MCFA is known to help blood glucose

control, increase insulin secretion and help in

glucose usage, hence MCFA can be used in diabetic

prevention and treatment (8,10). In β-cell, MCFA

activates fatty acid 1 receptor (FFAE1/GPR40) and

induces mitochondira ketogenesis, hence increases

β-cell function (Pujol, et al., 2018).

VCO and HVCO was shown to decrease HbA1c

levels although the decrease were not more effective

than that of metformin. HVCO lowered HbA1c

levels better than VCO. HbA1c is an indicator used

to monitor diabetic condition and hyperglycemia.

Glycemic control helps in decreasing the risks of

heart failure, myocardial infarction, etc. Recent

study shows that high HbA1c involved in the

increase risk of cardiovascular disease mortality in

diabetic patients (Wong, et al., 2018).

HVCO was shown to helps in decreasing

excessive oxidative stress condition in diabetic rats,

hence, it prevented the occurence of DM

complications. This result corresponds to the studies

reported before that VCO increases SOD level in

diabetic rats (Siddalingaswamy, et al, 2011;

Iranloye, et al., 2013). Oxidative stress is known to

be the key role of diabetic complications

pathogenesis. Human body is constantly protected

from excessive oxidative stress by a complex system

of enzymatic and non-enzymatic antioxidant.

Enzymatic antioxidant SOD involves in reactive

oxygen species (ROS) metabolsim. Superoxide

anion is highly reactive ROS which is converted by

SOD into hydrogen peroxide which is then reduced

to water by catalase and gluthation peroxidase

(Wong, et al., 2018; Ng, et al., 2013).

HVCO and VCO decreased sRAGE in diabetic

rats, although it was not more effective than

metformin. RAGE is a cell surface type receptor

from immunoglobulin superfamily which binds to

various ligands, including AGE. Soluble RAGE

(sRAGE) is a RAGE isoform found in blood

circulation. The binding of ligand and sRAGE

prevents the condition of oxidative stress,

inflammation and apoptosis which occur from the

interaction between RAGE and ligand. In

hyperglycemia condition, ROS and AGE induces

metalloproteinase-9 matrix which cleaves the cell

surface receptor which produces sRAGE, hence

increasing sRAGE levels in DM patients (Wong, et

al., 2018).

Antidiabetic drug metformin is known to

ameliorates oxidative stress status in DM.

Metformin prevents SOD inhibition caused by

aldehyde modification and increase its antioxidant

The Antidiabetic and Antioxidant Activities of Hydrolyzed Virgin Coconut Oil in Streptozotocin-induced Diabetic Rats

157

activity in diabetic patient. In addition, metformin

also prevents oxidative stress by decreasing ROS

and increasing enzymatic antioxidant. DM condition

causes proteins to undergo non-enzymatic glycation

with reducing sugar and produces AGE. Production

of AGE is followed by oxidative reaction which

produces radical compounds. The interaction

between AGE and its receptor (RAGE) involves in

the development of microvascular and

macrovascular complication (Ng, et al., 2013).

In this study, it was found that rats given with

VCO showed increased insulin expression compared

to rats in control group, although the score was not

higher than in metformin group. However, HVCO

showed insulin expression which was not

significantly different from metformin. This finding

corresponds to the work reported before which VCO

was able to increase β-cell and serum insulin in

diabetic rats (Iranloye, et al., 2013).

VCO and HVCO had the ability to inhibit the

continuous damage of β-cell in Langerhans islet.

This might be caused by their abilities to decrease

oxidative stress which happens in diabetic condition.

MCFAs like lauric, palmitic and capric acid which

contained in VCO and HVCO are able to increase

insulin secretion by releasing intracellular calcium

from calcium channel in β-cell membrane plasma.

Increase in insulin secretion causes lower production

of free radicals, hence decrease β-cell damage. In

addition, VCO also contains vitamin E and

antioxidants which are able to neutralize free

radicals accumulatted in diabetic condition

(Supriatna, et al., 2018).

5 CONCLUSION

HVCO is more effective than VCO in lowering

blood glucose, HbA1c and sRAGE levels, while

increasing SOD level and insulin expression in

diabetic rats. Blood glucose, HbA1c, SOD, sRAGE

levels and insulin expression in metformin and 4

ml/kgBW HVCO groups were not significantly

different after 30 days of treatment, hence, HVCO is

effective as antidiabetic and antioxidant in STZ-

induced diabetic rats.

ACKNOWLEDGEMENTS

If any, should be placed before the references

section without numbering.

REFERENCES

Aehle, W., 2004. Enzyme in Industry, Wiley-VCH.

Weinheim.

Afriadi, A., 2010. Uji Efek Virgin Coconut Oil (VCO)

terhaap Berat Badan dan Penurunan Kadar Gula

Darah (KGD) Tikus Putih Diabetes yang diinduksi

Streptozotocin (STZ). Tesis. Program Studi Magister

dan Doktor Ilmu Farmasi. Fakultas Farmasi.

Universitas Sumatera Utara.

Akinnuga, A.M., Jeje, S.O., Bamidele, O. and Sunday,

V.E., 2014. Dietary consumption of virgin coconut oil

ameliorates lipid profiles in diabetic rats. Physiology

Journal, 2014.

Ashraf, J.M., Ahmad, S., Choi, I., Ahmad, N., Farhan, M.,

Tatyana, G. And Shahab, U., 2015. Recent advances

in detection of AGEs: Immunochemical, bioanalytical

and biochemical approaches. IUBMB Life, 67(12),

pp.897-913.

Bach, A.C. and Babayan, V.K., 1982. Medium-chain

triglycerides: an update. The American Journal of

Clinical Nutrition, 36(5), pp.950-965.

Baynes, J. and Domonickzak, M.H. 2003. Medical

Biochemistry, Elsevier Science Mosby. London.

Beysel, S., Unsal, I.O., Kizilgul, M., Caliskan, M., Ucan,

B. and Cakal, E., 2018. The effects of metformin in

type 1 diabetes mellitus. BMC Endocrine Disorders,

18(1), p.1.

Dalmacion, G.V., Ortega, A.R., Pena, I.G. and Ang, C.F.,

2012. Preliminary study on the in-vitro susceptibility

of Mycobacterium tuberculosis isolates to virgin

coconut oil. Functional Foods in Health and Disease,

2(8), pp.290-299.

Deeds, M.C., Anderson, J.M., Armstrong, A.S., Gastineau,

D.A., Hiddinga, H.J., Jahangir, A., Eberhardt, N.L.

and Kudva, Y.C., 2011. Single dose streptozotocin-

induced diabetes: considerations for study design in

islet transplantation models. Laboratory Animals,

45(3), pp.131-140.

Dewi, S.S. and Aryadi,T., 2010. Efektifitas virgin coconut

oil (VCO) terhadap kandidiasis secara in vitro. In

Prosiding Seminar Nasional & Internasional.

Eleazu, C.O., Eleazu, K.C., Chukwuma, S. and Essien,

U.N., 2013. Review of the mechanism of cell death

resulting from streptozotocin challenge in

experimental animals, its practical use and potential

risk to humans. Journal of Diabetes and Metabolic

Disorders, 12(1), p.60.

Elsayed, H.H., Elrahman, M.K.A., Emara, A.H. and El-

Hafez, A., 2015. Compare effect of fatty acid

composition (olive, coconut oil and butter) on adipose

liver tissue, and serum lipid profile in albino rats.

IOSR-JBB, 1, pp.28-38.

Erejuwa, O.O., Sulaiman, S.A., Ab Wahab, M.S.,

Sirajudeen, K.N.S., Salleh, M.S.M. and Gurtu, S.,

2011. Glibenclamide or metformin combined with

honey improves glycemic control in streptozotocin-

induced diabetic rats. International Journal of

Biological Sciences, 7(2), pp.244.

ICTROMI 2019 - The 2nd International Conference on Tropical Medicine and Infectious Disease

158

Essien, N.M., Bassey, S.C., Nna, V.U. and Ofem, O.E.,

2014. Comparative effect of chronic consumption of

some edible vegetable oils on lipid profile and some

haematological parameters in rats. Annals of

Biological Research, 5(7), pp.16-21.

Fife, B., 2004. The Coconut Oil Miracle, Penguin Group.

USA.

Furman, B.L., 2015. Streptozotocin-induced diabetic

models in mice and rats. Current Protocols in

Pharmacology, 70(1), pp.5-47.

Han, X., Tao, Y.L., Deng, Y.P., Yu, J.W., Cai, J., Ren,

G.F., Sun, Y.N. and Jiang, G.J., 2017. Metformin

ameliorates insulitis in STZ-induced diabetic mice.

PeerJ, 5, p.e3155.

Handajani, N.S. and Dharmawan, R., 2009. Effect of VCO

to leucocyte differential count, glucose levels and

blood creatinine of hyperglycemic and ovalbumin

sensitized Mus musculus Balb/c. Bioscience, 1(1),

pp.1-8.

Iranloye, B., Oludare, G and, Olubiyi, M., 2013. Anti-

diabetic and antioxidant effects of virgin coconut oil in

alloxan induced diabetic male sprague dawley rats.

Journal of Diabetes Mellitus, 3(4), p.221-226.

Joshi, S.R., Parikh, R.M. and Das, A.K., 2007. Insulin –

history, biochemistry, physiology and pharmacology.

Supplement of JAPI, 55, p.19-25.

Kolondam, B.J., Pokatong, W. And Tallei, T., 2008. Kadar

trigliserida dan kolesterol tikus wistar (Rattus

novergicus) setelah konsumsi virgin coconut oil.

Biosaintifika, 1, pp.35-44.

Margata, L., Silalahi, J., Harahap, U. and Satria, D., 2018.

The effect of dietary oils and hydrolyzed coconut oil

on minerals absorption in rats. Asian Journal of

Pharmaceutical and Clinical Research, 11(1), p.185-

190.

McKee, T. and McKee, J.R., 2003. Biochemistry: The

Molecular Basis of Life, McGraw-Hill. New York, 3

edition.

Mechanick, J.I., 2006. The rational use of dietary

supplements, nutraceuticals, and functional foods for

the diabetic and prediabetic patients. In: Mechanick

and Brett, editors. Nutritional Strategies for the

Diabetic and Prediabetic Patient, Taylor & Francis,

CRC. New York, p.265-296.

Mohammed, A. and Luka, C.D., 2013. Effect of coconut

oil, coconut water and palm kernel oil on some

biochemical parameters in albino rats. Journal of

Pharmacy and Biological Sciences, 6(3), pp.56-59.

Ng, Z., Chua, K., Iqbal, T. And Kuppusamy, U., 2013.

Soluble receptor for advanced glycation end-product

(sRAGE)/pentosidine ratio: a potential risk factor

determinant for type 2 diabetic retinopathy.

International Journal of Molecular Sciences, 14(4),

pp.7480-7491.

Paliyath, G., Bakovic, M. and Shetty, K., 2011. Functional

Foods, Nutraceuticals and Degenerative Disease

Prevention, Wiley-Blackwell. UK.

Pujol, J., Christinat, N., Ratinaud, Y., Savoia, C., Mitchel,

S. and Dioum, E., 2018. Coordination of gpr40 and

ketogenesis signaling by medium chain fatty acids

regulates beta cell function. Nutrients, 10(4), p.473.

Rayfield, E.J. and Valentine, M.V., 2006. Pathophysiology

and clinical management of diabetes and prediabetes.

In: Mechanick and Brett, editors. Nutritional

Strategies for the Diabetic and Prediabetic Patient,

Taylor & Francis, CRC. New York, p.16-44.

Siddalingaswamy, M., Rayaorth, A. and Khanum, F.,

2011. Anti-diabetic effects of cold and hot extracted

virgin coconut oil. Journal of Diabetes Mellitus, 1(4),

pp.118-123.

Silalahi, J., Rosida, R., Putra, E.D.L. and Satria, D., 2016.

Hypoglycemic effect of hydrolyzed palm kernel oil in

rats. Der Pharma Chemica, 8(20), p.182-186.

Supriatna, D., Uray, A.D., Astawan, M., Muchtadi, D.

And Wresdiyati, T., 2018. The effect of VCO

processing method on blood glucose, cholesterol and

pancreatic profile of diabetic mellitus rats (Sprague

Dawley). Warta IHP, 35(2), p.91-98.

Szkudelski, T., 2001. The mechanism of alloxan and

streptozotocin action in B cells of the rat pancreas.

Physiological Research, 50(6), pp.537-546.

Triplitt, C.L., Reasner, C.A. and Isley, W.L., 2005.

Diabetes mellitus. In: DiPiro, J.T., Talbert, R.L., Yee,

G.C., Wells, B.G. and Posey, L.M. Pharmacotherapy:

A Patophysiologic Approach, The McGraw-Hill

Companies, Inc. USA, 6

edition.

Vala, G.S. and Kapadiya, P.K., 2014. Medicinal benefits

of coconut oil. International Journal of Life Sciences

Research, 2(4), pp.124-126.

Vassalotti, J.A., 2006. Nutritional strategies for the patient

with diabetic nephropathy. In: Mechanick and Brett,

editors. Nutritional Strategies for the Diabetic and

Prediabetic Patient, Taylor & Francis, CRC. New

York, p.149-169.

Yin, D., Tao, J., Lee, D.D., Shen, J., Hara, M., Lopez, J.,

Kuznetsov, A., Philipson, L.H. and Chong, A.S., 2006.

Recovery of islet β-cell function in streptozotocin-

induced diabetic mice: an indirect role for the spleen.

Diabetes, 55(12), p.3256-3263.

Wong, F.N., Chua, K.H., Tan, J.A.M.A., Wong, C.M. and

Kuppusamy, U.R., 2018. Glycaemic control in type 2

diabetic patients with chronic kidney disease: the

impacts on enzymatic antioxidants and soluble RAGE.

PeerJ, 6, p.e4421.

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