Characterization of the Antidiabetic Role of Parkinsonia aculeata (Caesalpineaceae)

Abstract

This paper reports the characterization of the antidiabetic role of a hydroethanolic extract from Parkinsonia aerial parts (HEPA), in normal and alloxan-induced diabetic rats, treated with HEPA (125 and 250 mg/kg; p.o.). Oral glucose tolerance test, acute oral toxicity test and preliminary phytochemical analyses were performed. The diabetic rats treated with HEPA showed a significant reduction in serum and urinary glucose, urinary urea and triglyceride levels, as compared to the diabetic untreated group. However, in the normal treated groups, a significant reduction was found only in serum triglyceride levels. In all treated diabetic groups, an improvement in hepatic glycogen was observed, as well as a decrease in liquid intake and urinary volume, and an enhancement in the weight of skeletal muscles (soleus and extensor digitorum longus), kidneys and epididymal adipose tissue. Nevertheless, body and liver weights were ameliorated only in the diabetic group treated with HEPA (250 mg/kg). Moreover, oral glucose tolerance was higher in animals treated with HEPA, while results also showed that HEPA could be considered toxicologically safe. Phytochemical analysis revealed the presence of tanins, flavonoids and steroids in HEPA. In conclusion, P. aculeata presents an antidiabetic activity and other beneficial effects that ameliorate diabetes and associated complications.

Figure 1

Fasting serum glucose (a) and urinary glucose (b) levels in diabetic rats after subchronic treatment with HEPA. DC: diabetic control (vehicle); DT125: diabetic-treated with HEPA (125 mg/Kg); DT250: diabetic treated with HEPA (250 mg/Kg); DTI: diabetic treated with insulin. All values expressed as mean ± S.E.M. (n = 6). One-way ANOVA with Tukey's post hoc test was applied. *P < .05 versus DC group.

Figure 2

Hepatic glycogen content from diabetic and normal rats after subchronic treatment with HEPA. NC: nondiabetic control (vehicle); NT125: nondiabetic treated with HEPA (125 mg/Kg); NT250: nondiabetic treated with HEPA (250 mg/Kg); DC: diabetic control (vehicle); DT125: diabetic treated with HEPA (125 mg/Kg); DT250: diabetic treated with HEPA (250 mg/Kg); DTI: diabetic treated with insulin. All values represent mean ± S.E.M. (n = 6). One-way ANOVA with Tukey's post hoc test. ^a P < .001 versus NC; *P < .01 versus DC.

Figure 3

Urinary urea level from animals after 16 days of treatment with HEPA. NC: nondiabetic control (vehicle); NT125: nondiabetic treated with HEPA (125 mg/Kg); NT250: nondiabetic treated with HEPA (250 mg/Kg); DC: diabetic control (vehicle); DT125: diabetic treated with HEPA (125 mg/Kg); DT250: diabetic treated with HEPA (250 mg/Kg); DTI: diabetic treated with insulin. The values represent the mean ± S.E.M. (n = 6). One-way ANOVA with Tukey's post hoc test. *P < .05 versus DC.

Figure 4

Oral glucose tolerance test (OGTT) in normal (a) and diabetic (b) rats treated with HEPA. NC: nondiabetic control (vehicle); NT125: nondiabetic treated with HEPA (125 mg/Kg); NT250: nondiabetic treated with HEPA (250 mg/Kg); DC: diabetic control (vehicle); DT125: diabetic treated with HEPA (125 mg/Kg); DT250: diabetic treated with HEPA (250 mg/Kg). Each value is expressed as the mean ± S.E.M. (n = 6). For statistical analysis was employing one-way ANOVA with Tukey's post hoc test. *P < .05 versus respective control group (NC or DC). Arrows indicate the time of administration of extract or glucose.

Figure 5

Schematic representation of the proposed effects of the HEPA treatment in alloxan-induced diabetic rats. The group of diabetic rats which were treated with the HEPA showed a significant reduction in serum and urinary glucose, urinary urea, and triglyceride levels. Also, an improvement in hepatic glycogen was observed as well as a decrease in liquid intake and urinary volume, and an enhancement in the weight of skeletal muscles, kidneys, liver, and adipose tissue. Indeed, oral glucose tolerance was higher in diabetic animals treated with HEPA. Together, all observed changes in some of the measured parameters, suggests a reduction on the gluconeogenesis process.