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Background and the purpose of the studyThe early stage of diabetes mellitus type 2 is associated with postprandial hyperglycemia. Hyperglycemia is believed to increase the production of free radicals and reactive oxygen species, leading to oxidative tissue damage. In an effort of identifying herbal drugs which may become useful in the prevention or mitigation of diabetes, biochemical activities of Polygonum hyrcanicum and its constituents were studied.MethodsHexane, ethylacetate and methanol extracts of P. hyrcanicum were tested for α-glucosidase inhibitory, antioxidant and radical scavenging properties. Active constituents were isolated and identified from the methanolic extract in an activity guided approach.ResultsA methanolic extract from flowering aerial parts of the plant showed notable α-glucosidase inhibitory activity (IC50 = 15 μg/ml). Thirteen phenolic compounds involving a cinnamoylphenethyl amide, two flavans, and ten flavonols and flavonol 3-O-glycosides were subsequently isolated from the extract. All constituents showed inhibitory activities while compounds 3, 8 and 11 (IC50 = 0.3, 1.0, and 0.6 μM, respectively) were the most potent ones. The methanol extract also showed antioxidant activities in DPPH (IC50 = 76 μg/ml) and FRAP assays (1.4 mmol ferrous ion equivalent/g extract). A total phenol content of 130 mg/g of the extract was determined by Folin-Ciocalteu reagent.ConclusionThis study shows that P. hyrcanicum contains phenolic compounds with in vitro activity that can be useful in the context of preventing or mitigating cellular damages linked to diabetic conditions.

The genus, Hymenocrater, belongs to the plant family Lamiaceae which contains eleven shrub species, of which H. calycinus belonges and grows wildly in Northeastern Iran. From the ethyl acetate and methanol extracts of the flowered aerial parts of Hymenocrater calycinus, four compounds were isolated using chromatographic methods and identified by spectroscopic data (MS, 1 H-and 13 C-NMR, HMQC, HMBC and 1 H-1 H COSY). The effect of rosmarinic acid, as the main component in our study was applied to Staphylococcus aureus, Escherichia coli, Candida albicans and Aspergillus niger by the broth dilution method. Isolated compounds were identified as ß-sitosterol (1), ursolic acid (2), rosmarinic acid (3) and quercetin-3-O-rutinoside (4). The results of our assay against bacteria and fungi show that, rosmarinic acid has an antifungal property against Candida albicans (MIC, 250 μg mL -1 ).

ATP-binding cassette transporter A1 (ABCA1) is a key mediator of cholesterol efflux to apoA-I in lipid-loaded macrophages, which is the first step of reverse cholesterol transport in vivo and a critical step in preventing atherosclerosis. Enhanced ABCA1 expression may inhibit foam cell formation and consequently reduce atherogenic risk. The purpose of this study was to investigate the effect of S-allylcysteine (SAC), the most abundant organosulfur compound in aged garlic extract, on the expression of ATP-binding cassette transporter A1 in human THP-1 macrophages. The human monocyte THP-1 cells were differentiated to macrophage cells in the presence of phorbol 12-myristate13-acetate (PMA). Macrophage cells were then treated with different concentrations (10, 20 and 40 mM) of SAC for 24 h. Total RNA of treated macrophages was extracted and analyzed with real-time RT-PCR. ABCA1 protein expression was also analyzed with western blotting. Results showed that SAC increased the ABCA1 mRNA (1.82-, 2.07- and 2.23-fold) and protein (1.37-, 1.55- and 2.08-fold) expression in macrophage THP-1 cells compared with control (untreated cells). Results suggested that SAC can increase ABCA1 expression in macrophages and may be beneficial in promoting reverse cholesterol efflux.

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