ANTIDIABETIC ACTIVITY OF EXTRACT, FRACTIONS, AND ASIATICOSIDE COMPOUND ISOLATED FROM CENTELLA ASIATICA LINN. LEAVES IN ALLOXAN-INDUCED DIABETIC MICE

摘要

Objective: Centella asiatica Linn. is known and used as traditional antidiabetic drug especially in ayurvedic traditional system in some countries. The main objective of this study was to evaluate antidiabetic activity of ethanolic extract, saponin-rich fraction (SRF), nonsaponin fraction (NSF), and asiaticoside compound isolated from C. asiatica Linn. leaves in alloxan-induced diabetic mice. Methods: Diabetes was induced in albino mice by administration of alloxan monohydrate (60 mg/kg i.v). Extract was administrated orally each in doses of 125, 250 and 500 mg/kg, the SRF and NSF were in doses of 75, 150 and 300 mg/kg, while the asiaticoside was administrated in doses of 1.4, 2.8 and 5.6 mg/kg for 21 days. Blood fasting glucose level, insulin level, and glycosylated hemoglobin level were measured, and histopathology of pancreas was observed to determine antidiabetic activity of each sample. Results: Decreased blood fasting glucose level, increased insulin, and decreased glycosylated hemoglobin were observed in diabetic mice treated with extract, SRF and asiaticoside. On 21st day, extract at dose 500 mg/kg, SRF at dose 300 mg/kg, and asiaticoside at dose 5.6 mg/kg gave lowest blood glucose level in their each group which were 239±8.0, 254±10.4, and 217±8.1 mg/dl, respectively, compared to control group at 290±14.8 mg/dl. Insulin level of these three groups was 19.4±0.59, 24.8±0.99, and 27.8±0.77 μIU/ml, respectively, the highest value in their each group compared to 7.28±0.34 μIU/ml in control group. Meanwhile glycated hemoglobin level of these groups was 2.040±0.08, 2.010±0.04, and 2.11±0.07 ng/ml, respectively, lowest value in their each group compared to control group at 2.76±0.06 ng/ml. However, histopathology study in these groups did not show any improvements in regeneration of β-cells of pancreas. In the other side, NSF treatment did not affect any the parameters mentioned above. Conclusions: It can be concluded that extract, SRF and asiaticoside isolated from C. asiatica Linn. possess significant antidiabetic activity in diabetic mice. Based on increased levels of insulin and histopathology studies of pancreatic tissue, antidiabetic activity of those samples was believed to occur through the mechanism of increasing secretion of healthy pancreatic β-cells without any ability to regenerate β-cells that were damaged by alloxan.