Hypoglycemic and Hypolipidemic Properties of Leaf Extracts from Phyllanthus acidus (L.) Skeels., Leucaena leucocephala (Lam.) de Wit. and Psidium guajava (L.) in Streptozotocin- Induced Diabetic Rats

Abstract

Star gooseberry Phyllanthus acidus (L.) Skeels, lead
tree Leucaena leucocephala (Lam.) de Wit. and guava Psidium
guajava (L.) are commonly well known plants and have been
widely used in folk medicine for the treatment of many diseases
in Thailand. Some pharmacological activities of leaf extracts
from the plants in animal model of diabetes have been studied.
To increase the pharmacological document of the plants, the
present study was therefore carried out to investigate
hypoglycemic and hypolipidemic properties of leaf extracts from
P. acidus, L. leucocephala and P. guajava. The extracts at a dose
of 250 mg/kg were administered to streptozotocin (65 mg/kg)-
induced diabetic rats orally and daily for eight weeks. Blood
glucose level, body weight, hematological values, lipid profiles,
blood chemistry, and serum insulin in the rats were examined.
Antioxidant activity of the extracts was also assessed by using
1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging assay.
Moreover, to see whether the extracts have acute toxicity, once
oral administration of the extracts at a dose of 1000, 1500 and
2000 mg/kg was performed in healthy rats. The results revealed
that the extracts significantly (p<0.05) decreased blood glucose
level, total cholesterol (TC), triglyceride, (TG), low density
lipoprotein (LDL), blood urea nitrogen (BUN), and creatinine
but increased high density lipoprotein (HDL) and serum insulin
in the diabetic treated rats. However, hematological values
including white blood cell (WBC), red blood cell (RBC),
hemoglobin (Hb), hematocrit (Hct) in both normal and diabetic
rats were not affected by the extracts. DPPH assay revealed that
the leaf extracts from P. acidus, L. leucocephala and P. guajava
possessed the antioxidant activity with EC50 values of
232.37+15.27, 296.10+16.40 and 39.40+3.82 μg/ml respectively
which was less potent than ascorbic acid (1.48+0.86 μg/ml).
Moreover, the extracts at a dose up to 2000 mg/kg did not exhibit
sign of acute toxicity as well as mortality of the rats within a
period of observation.