Inhibition of protein glycation by essential oils of branchlets and fruits of Juniperus communis subsp. hemisphaerica.

Oxidative stress and protein glycation play pivotal roles in the pathophysiology of diabetes mellitus and its vascular complications. The present study aimed to investigate the anti-glycation properties of essential oils obtained from different parts of Juniperus communis subsp. hemisphaerica. The branchlets of male tree (BMT) and branchlets of female (BFT) tree, and fruits of J. communis subsp. hemisphaerica were extracted using steam distillation method. The oils were phytochemically analyzed using gas chromatography-mass spectrometry. Anti-glycation properties were evaluated using hemoglobin and insulin glycation assays. Overall, 18 volatile components were identified in the J. communis subsp. hemisphaerica oils, amounting to 82.1%, 100.0% and 96.4% of the BMT, BFT and fruit oils, respectively. Promising inhibitory activity was observed from all concentrations of the tested oils in the hemoglobin and insulin glycation assays. The inhibitory activities peaked to 89.9% (BFT oil; 200 µg mL(-1)) and 81.0% (BFT oil; 600 µg mL(-1)) in the hemoglobin and insulin glycation assays, respectively. The evidence from this study suggests that essential oils obtained from the fruits and branchlets of J. communis subsp. hemisphaerica possess anti-glycation properties. These activities may find implication for the prevention and treatment of diabetic complications.

Antioxidant activities of Juniperus foetidissima essential oils against several oxidative systems

The present study aimed to evaluate the antioxidant activity of essential oils obtained from branchlets of male and female trees as well as fruits of Juniperus foetidissima Willd., Cupressaceae, from Iran. For this purpose, essential oils of J. foetidissima were phytochemically analyzed and different concentrations of them were tested in five oxidative systems: 1) low-density lipoprotein oxidation; 2) linoleic acid peroxidation; 3) red blood cell hemolysis; 4) hemoglobin glycation; and 5) insulin glycation assays. In all employed systems, antioxidant effects were observed from the three tested oils though in varying degrees. The most promising activities of the oils were observed against hemoglobin and insulin glycation. Antioxidant activities of the oils did not appear to be dose-dependent. In addition, no consistent superiority in antioxidant effects was observed from a single oil in different assays. In view of the current results, J. foetidissima branchlet and fruit oils could be regarded as effective natural products with anti-glycation activity.