| Summary: | Obesity is characterised by excessive fat accumulation in the body thereby
contributing to cardiovascular disease particularly hyperlipidaemia, hypertension and
atherosclerosis. Bee bread is a natural product used traditionally to maintain and
improve general health. However, its possible protective effect on cardiovascular
parameters in high-fat diet (HFD) induced obese rats has not yet established. The
objectives of this study were (1) to evaluate and analyse nutritional, phytochemical
and antioxidant activity of bee bread of stingless bee (Heterotrigona itama) from
three different regions in Malaysia namely Kelantan, Selangor and Perak (Phase 1
Study), (2) to establish animal model of obesity and to determine the best dose of bee
bread (Phase 2 Study), and (3) to determine the effects of bee bread on
cardiovascular parameters in HFD induced obese rats (Phase 3 Study). In Phase 2
study, different doses of bee bread (0.5, 1.0 and 1.5 g/kg/day) were administered to
HFD-induced obese rats via oral gavage for 6 week. In Phase 3 study,
cardioprotective and antioxidative effects of bee bread (0.5 g/kg/day) and orlistat (10
mg/kg/day) were determined in HFD-induced obese rats. At the end of the
experiment, rats were sacrificed to assess cardiovascular parameters such as Lee
obesity index, food and calorie intake, lipid profiles, adiposity and atherogenic index,
antioxidative status, and histology of aortic arch, adipose tissue and myocardium. All
bee bread samples had relatively high nutritional value, amino acids, phytochemical
and in-vitro antioxidant activities. Highest total phenolic and flavonoid contents were
found in bee bread sample from Perak whereby highest free radical scavenging activity was found in sample from Selangor. Bee bread at the dose of 0.5 g/kg/day
was chosen as the best dose as it reduced the Lee obesity index, total cholesterol, and
low-density lipoprotein (LDL) in HFD-induced obese rats. Bee bread exerts
protective effects against the risk of cardiovascular disease as it significantly reduced
Lee obesity index and levels of total cholesterol, LDL, oxidised-LDL and
malondialdehyde, as well as significantly increased the antioxidant activities such as
superoxide dismutase and glutathione peroxidase in aortic tissues. Bee bread also
significantly reduced fatty acid synthase activity, size of adipocytes and area of
necrotic patch in myocardium compared to HFD group. There was an absence of
atherosclerotic plaque in aortic arch segment in rats supplemented with bee bread.
This study suggests that bee bread supplementation at 0.5 g/kg/day for 6 weeks
significantly protects against obesity, hyperlipidaemia, oxidative stress and
atherosclerotic plaque formation possibly by increasing antioxidant enzymes
activities and decreasing fatty acid synthase activity in HFD-induced obese rats.
These beneficial effects could be attributed to the presence of phytochemical
compounds such as apigenin, caffeic acids, ferulic acids, isorhamnetin and
kaempferol in bee bread. These findings may indicate the potential use of bee bread
in reducing the risk of cardiovascular disease which needs further study to determine
its exact molecular mechanism of action.
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