TY - JOUR

T1 - Effects of Teucrium polium spp. capitatum flavonoids on the lipid and carbohydrate metabolism in rats

AU - Stefkov, Gjoshe

AU - Kulevanova, Svetlana

AU - Miova, Biljana

AU - Dinevska-Kjovkarovska, Suzana

AU - Mølgaard, Per

AU - Jäger, Anna K

AU - Josefsen, Knud

N1 - Keywords: golden germander, plant extract, INS-1E cells, STZ-rats, diabetes, insulinotropic, hypoglycemic, R. Macedonia

PY - 2011/9/1

Y1 - 2011/9/1

N2 - Context: The main objective of the study was to investigate the biochemical mechanism of the antidiabetic activities of the dry extracts of Teucrium polium L. ssp. capitatum (L.) Arcangeli (Lamiaceae), from Republic of Macedonia, traditionally used to treat diabetes. Materials and methods: Aerial parts of the plant were extracted in alcohol and freeze- or spray-dried, analyzed by high performance liquid chromatography (HPLC) and examined for insulinotropic effect in INS-1E cells in vitro. Their effect on blood glucose, lipids and carbohydrate-related enzymes was tested in normo- and streptozotocin hyperglycemic rats. Results and discussion: HPLC analyses revealed several flavonoids: luteolin, apigenin, cirsiliol, diosmetin, cirsimaritin and cirsilineol as both free aglycons and glycosides. The extract and mixture of commercial flavonoids showed a distinct insulinotropic effect on INS-1E cells at 500 µg/ml. Intragastric (i.g.) administration of identical doses of the extract (125¿mg/kg) in both normo- and hyperglycemic rats was more efficient in lowering the blood glucose than intraperitoneal injection (35% vs. 24% reduction) with highest effect (50% reduction) 8¿h after administration. After 10 days of treatment, the magnitude of the effect was comparable to i.g. administration of 2.5¿mg/kg of glibenclamide (38% reduction). No effect was seen on blood lipid profiles. In OGTT (oral glucose tolerance test), the extract lowered blood glucose levels by ~35%. The treatment reduced hepatic glycogen and tended to normalize the activity of gluconeogenic enzymes. Conclusion: The results demonstrate that examined plant extracts contain flavonoids with insulinotropic and antihyperglycemic effects.

AB - Context: The main objective of the study was to investigate the biochemical mechanism of the antidiabetic activities of the dry extracts of Teucrium polium L. ssp. capitatum (L.) Arcangeli (Lamiaceae), from Republic of Macedonia, traditionally used to treat diabetes. Materials and methods: Aerial parts of the plant were extracted in alcohol and freeze- or spray-dried, analyzed by high performance liquid chromatography (HPLC) and examined for insulinotropic effect in INS-1E cells in vitro. Their effect on blood glucose, lipids and carbohydrate-related enzymes was tested in normo- and streptozotocin hyperglycemic rats. Results and discussion: HPLC analyses revealed several flavonoids: luteolin, apigenin, cirsiliol, diosmetin, cirsimaritin and cirsilineol as both free aglycons and glycosides. The extract and mixture of commercial flavonoids showed a distinct insulinotropic effect on INS-1E cells at 500 µg/ml. Intragastric (i.g.) administration of identical doses of the extract (125¿mg/kg) in both normo- and hyperglycemic rats was more efficient in lowering the blood glucose than intraperitoneal injection (35% vs. 24% reduction) with highest effect (50% reduction) 8¿h after administration. After 10 days of treatment, the magnitude of the effect was comparable to i.g. administration of 2.5¿mg/kg of glibenclamide (38% reduction). No effect was seen on blood lipid profiles. In OGTT (oral glucose tolerance test), the extract lowered blood glucose levels by ~35%. The treatment reduced hepatic glycogen and tended to normalize the activity of gluconeogenic enzymes. Conclusion: The results demonstrate that examined plant extracts contain flavonoids with insulinotropic and antihyperglycemic effects.

KW - Former Faculty of Pharmaceutical Sciences

KW - Faculty of Health and Medical Sciences

U2 - 10.3109/13880209.2011.552187

DO - 10.3109/13880209.2011.552187

M3 - Journal article

C2 - 21619454

VL - 49

SP - 885

EP - 892

JO - Pharmaceutical Biology

JF - Pharmaceutical Biology

SN - 1388-0209

IS - 9

ER -