Effects of methanolic and butanolic fractions of Allium elburzense Wendelbo bulbs on blood glucose level of normal and STZ-induced diabetic rats

Abstract

Allium elburzense (A. elborzense, Alliaceae), a plant rich in saponins, is an edible vegetable in northern Iran with a folk background use as antidiabetic which has not yet been examined for this indication. To evaluate the antidiabetic potential of A. elburzense, its hydroalcoholic (HdAE) and butanolic extracts (BuE) were examined. The acute (1, 2, 3, 4, 8 h) and sub-acute (11 days) effects of oral (p.o.) and intraperitoneal (i.p.) administration of HdAE and BuE of A. elburzense bulbs in different doses were evaluated on blood glucose levels of normal and streptozotocin (STZ, 55 mg/kg body weight)-induced diabetic rats. Glibenclamide (1 mg/kg b.w.) was used as reference drug. Sub-acute treatment with HdAE for 11 days reduced significantly blood glucose levels in diabetic rats (at least P<0.05), while BuE was effective only following i.p. administration (P<0.01). Acute administration did not reduce blood glucose level in normal and diabetic animals. It is concluded that HdAE of A. elburzense exhibited a significant antihyperglycemic activity following chronic administration. These results provide evidence for potential use of A. elburzense in diabetes mellitus considering the fact that this plant is endemic to a location of Iran where diabetes is a high prevalence disorder.

Keywords: Allium elburzenses; Antidiabetic; Diabetes mellitus; Plant extract; Streptozotocin.

Fig. 1

Elburzensosides (R=H, Glc or triGlc; R’= H or OH). The saponin steroids have been previously isolated from A. elburzense with the rare moiety of OH at C-5 (16).

Fig. 2

Effect of Hydroalcoholic extract (HdAE) of A. elburzense on blood glucose levels of normall rats at different doses of 100, 300 or 600 mg/kg given p.o. or 300 mg/kg administered i.p. within 0-8 h after extract administration. Glibenclamide (GBC, 1 mg/kg) and normal saline (5 ml/kg) have been used as positive and negative controls, respectively (n=6). * P<0.05: significant difference compared to normal saline group.

Fig. 3

Effect of A. elburzense butanolic extract (BuE) on blood glucose levels of normal rats at different doses of 5, 25 or 50 mg/kg given p.o. or 25 mg/kg given i.p.within 0-8 h after administration of the extract. Glibenclamide (GBC, 1 mg/kg) and normal saline (5 ml/kg) have been used as positive and negative controls, respectively (n=6). * P<0.05: significant difference compared to normal saline group.

Fig. 4

Effect of Hydroalcoholic extract (HdAE) of A. elburzense on blood glucose levels of STZ-induced diabetic rats at different doses of 100, 300 or 600 mg/kg given p.o. or 300 mg/kg administered i.p. within 0-8 h after extract administration. Glibenclamide (GBC, 1 mg/kg) and normal saline (5 ml/kg) have been used as positive and negative controls, respectively (n=6). * P<0.05, **P<0.01: significant difference compared to normal saline group.

Fig. 5

Effect of A. elburzense butanolic extract (BuE) on blood glucose levels of STZ-induced diabetic rats at different doses of 5, 25 or 50 mg/kg given p.o. or 25 mg/kg given i.p.within 0-8 h after administration of the extract. Glibenclamide (GBC, 1 mg/kg) and normal saline (5 ml/kg) have been used as positive and negative controls, respectively (n=6). * P<0.05, **P<0.01: significant difference compared to normal saline group.