Available online 11 December 2015
Open Access
Abstract
The
aim of this study is to report the antidiabetic properties of a
beverage developed from roselle calyx and selected fruits in male albino
rats. The beverage was designed to contain 30% pawpaw (Carica papaya L.), 10% grapefruit (Citrus paradisi), 20% guava leaves (Psidium guajava
L.) and 40% roselle calyx aqueous extracts. Four groups of five rats
each were acclimatized on pelletized mouse chow for seven days, after
which diabetes was induced by a single ip injection of alloxan in all
groups except group 1, which served as control. Group 2 served as
negative control while groups 3 and 4 were treated with the beverage at
2.5 and 5 ml/kg bw respectively. Food intake, body weight, and blood
glucose levels were monitored. They were sacrificed by cervical
dislocation after a 2 week treatment. Blood serum was analysed to
evaluate insulin levels, β cell function, insulin resistance and lipid
profile. Histological studies were carried out on pancreatic tissues.
Treatment with both doses of the beverage led to a significant reduction
(p < 0.05) in blood glucose, total cholesterol triglyceride, LDL and
increased HDL levels. It also improved serum insulin levels, β cell
function, reduced insulin resistance and restored pancreatic beta cells
compared to the diabetic group. These antidiabetic properties may be as a
consequence of modulation of the β-cell function, reduction of insulin
resistance and preservation/restoration of β-cell integrity. However,
treatment with the single dose showed signs of hyperinsulinaemia.
Keywords
- Atherogenic indices;
- Antidyslipidaemic;
- Beta cell function;
- Hypoglycaemic;
- Insulin sensitivity
1. Introduction
The rising bane of diabetes especially in most developing countries has become a major global health issue (Erukainure et al., 2013). In 2010, 12.1 million people were estimated to be diabetic in Africa, and this is expected to rise to 23.9 million by 2030 (Sicree et al., 2009).
Though it is mostly common among the elderly in most populations,
prevalence rates have been predicted to significantly rise among the
young and productive populations in the developing world (Gomes et al., 2006). Characterized by hyperglycaemia, diabetes is a metabolic disorder that affects carbohydrate, protein and lipid metabolism (Maritimi et al., 2003). This may be due to inadequate insulin release as seen in type 1 diabetes or insulin resistance resulting to type 2 diabetes (Meral et al., 2004). It increases the risk of several complications such as nephropathy, microangiopathy and retinopathy (Barar, 2000).
Increasing
interests in complementary and alternative medicine have led to the
development and search of novel therapy for diabetes (Yeh et al., 2002). Over the years, plants have been used in the treatment and management of diabetes (Gupta et al., 2005). This has been attributed to the presence of phytochemicals which are remedial against diabetes and other ailments.
Fruits
have been well documented to be medicinal. This has been attributed to
their antioxidant properties owing to the integrated action of oxygen
radical scavengers such as β-carotene and ascorbic acid, calcium and
dietary fibre (Bhardwaj and Pandey, 2011). Their daily consumption has been linked with reduced risk of cancer, cardiovascular disease, diabetes, stress and fatigue (Erukainure et al., 2012). Of particular interests are pawpaw (Carica papaya L.) and grape (Citrus paradisi) fruits. Their antidiabetic properties have been documented in several studies ( Erukainure et al, 2012 and Lans, 2006).
Due to their perishable nature and poor storage facilities, the
post-harvest shelf life of these fruits is very limited thereby leading
to wastage ( Bhardwaj, Pandey, 2011 and Nwachukwu et al, 2010).
Development of ready-to-serve beverage from blends of these fruits is a
convenient option for their utilization and reduces postharvest losses (Bhardwaj and Pandey, 2011). Blending juices with other medicinal plants such roselle calyx (Hibiscus sabdariffa) and guava leaves (Psidium guajava L.) improves the medicinal properties ( Erukainure et al., 2012).
The protective effect of these plants against diabetes has been
reported. Guava leaves have been shown to inhibit increases in plasma
glucose level in diabetic rats (Mazumdara et al., 2015).
Aqueous extract of roselle calyx has been demonstrated as having
beneficial effects on anti-oxidation and lipid lowering in experimental
diabetic studies (Wang et al., 2011).
A blend of the aforementioned fruits and medicinal plants to form a
natural health drink suitable for the treatment and/or management of
diabetes and its related complication has been reported ( Erukainure et al, 2012 and Okafor et al, 2010). Erukainure et al. (2012)
reported the protective role of these blends against
hyperglycaemia-induced oxidative stress in testicular tissues and sperm
cells in rats.
This
paper aims to assess the anti-diabetic and/or hypoglycaemic effect of
blends of pawpaw and grape fruits with aqueous extracts of guava leaves
and roselle calyx in male albino rats.
