Effects Of Ethanolic Extract Of Cocoa On Blood Glucoseand Lipid Profile In Streptozotocin-Induced Diabetic Rats
This study aims to investigate the hypoglycaemic and hypocholesterolaemic properties of Malaysian cocoa (Theobroma cacao) polyphenols extract in-vivo and in-vitro. Cocoa extract (contained 190 - 286 mg total polyphenol per g of extract) was prepared from fermented and roasted (140 "C, 20 min...
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| Format: | Thesis |
| Language: | English English |
| Published: |
2005
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| Online Access: | http://psasir.upm.edu.my/id/eprint/6382/1/FPSK%28M%29_2005_27.pdf |
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| Summary: | This study aims to investigate the hypoglycaemic and hypocholesterolaemic
properties of Malaysian cocoa (Theobroma cacao) polyphenols extract in-vivo and
in-vitro. Cocoa extract (contained 190 - 286 mg total polyphenol per g of extract)
was prepared from fermented and roasted (140 "C, 20 min) beans by extracting with
80% ethanol in the ratio of 1 to 10. The total phenolic content was estimated
according to the Folin-Ciocalteu reagent method. The eluted individual polyphenol
was monitored by using a normal-phase HPLC. Monomer is the predominant
polyphenols present in cocoa extract (CE) followed by dimer and tetramer. To study
the effect of CE on plasma glucose levels and lipid profiles in normal and diabetic
rats, two different batches of animal (in-vivo) studies were performed. In the first
batch, rats were given free excess to diet containing CE in the form of powder, while
in the second batch, rats were force-fed with CE suspended in normal saline daily.
The CE was given in three dosages (100, 200 and 300 mg per kg body weight) to
both batches for a period of 4 weeks. The result showed that 100 mgkg and 300
mgkg CE significantly reduced (p < 0.05) the plasma glucose levels in the diabetic
rats of both the first and second batch of studies. In the first batch, supplementation
of 100 mgkg and 300 mglkg CE had significantly reduced (p < 0.05) the level of
total cholesterol in diabetic rats. In addition, 100, 200 and 300 mgkg CE diets had
significantly lowered (p < 0.05) the total triglycerides. Interestingly, this study found
that plasma HDL-cholesterol had increased significantly (p < 0.05) in diabetic rats
fed with 200 mgkg CE, while the LDL-cholesterol had decreased significantly (p <
0.05) in group treated with 100 mgkg CE. In the second batch, plasma cholesterol,
HDL-cholesterol and LDL-cholesterol levels showed no siginificant difference in
both normal and diabetic rats. Meanwhile, there was a significant decrease (p < 0.05)
in plasma triglyceride level in diabetic rats. In another study, rats were pretreated
with CE to investigate the protective effect of CE against streptozotocin diabetogenic
action. In 200 mglkg CE pretreated rats, there was a 163% increase in plasma
glucose levels, compared with a 226% increase in diabetic control rats. There were
no protective effects on plasma lipid profiles in CE pretreated rats. Results also
exhibited CE could normalize the body weight loss caused by STZ. BRIN-BD11 cell
lines (in-vitro) were used to evaluate the effect of CE on insulin secretion. This invitro
study demonstrated that CE at a concentration of 0.1 mglrnl significantly
increase (p < 0.05) insulin secretion compared to control. In conclusion, the study
shows that Malaysian cocoa polyphenol extract may possess potential
hypoglycaernic and hypochlosterolaernic properties. Further studies are needed to
elucidate the exact mechanism by which polyphenols present in CE can lower the
plasma glucose levels and improved lipid profiles in diabetic rats, and stimulate
insulin secretion in BRIN-BDl1 cell lines. |
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