Pharmacognosic inverstigations on the juniperus species used for diabetes mellitus in folk medicine

Juniperus species are widely used in traditional medicine for many purposes in Anatolia. According to ethnobotanical reports which were carried out in different parts of Turkey, berries of Juniperus communis var. saxatilis, oxycedrus ssp. oxycedrus, foetidissima, and sabina have been ingested or decoctions of berries and leaves have been taken as tea to lower blood glucose levels.The aim of this study is to evaluate the antidiabetic activity profile of the berry and leaf extracts of these 4 Juniperus taxon. The ethanol extracts of berries and leaves were prepared and given to streptozotocin induced diabetic rats at 0.5 and 1 g/kg doses. Juniperus oxycedrus ssp. oxycedrus (Joso) berry and leaf extracts were the most effective extracts among all. Blood glucose levels of normoglycemic and glucose loaded rats were also reduced after administration of ethanol extracts of Joso berries and leaves. After 10 days administration of Joso extracts to diabetic rats, blood glucose levels and malondialdehyde levels in kidney and liver of rats were decreased significantly.Ethanol extracts of berries and leaves were fractionated by successive solvent-solvent extraction according to bioactivity guided fractionation techniques. n-Butanol sub-extract of berry extract (740 mg/kg) and n-hexane sub-extract of leaf extract (260 mg/kg) were found to possess high antidiabetic activity. Active sub-extracts were fractionated by column chromatography and the active principles were isolated by using different chromatography techniques. Fatty acids were found in the active fraction of ethanolic extract of Joso leaves, also shikimic acid, ferulic acid glycoside and oleuropeic acid glycoside were found in the active fraction of berry extracts. After acute and subacute administration of shikimic acid, the blood glucose levels were reduced significantly in diabetic rats.