Redox properties of ginger extracts: Perspectives of use of Zingiber officinale Rosc. as antidiabetic agent.

In traditional medicine, several medicinal plants or their extracts have been used to treat diabetes. Zingiber officinale Roscoe, known commonly as ginger, is consumed worldwide in cookeries as a spice and flavouring agent. It has been used as the spice and medicine for thousands of years. The present study was undertaken to investigate the potential protective effect of Zingiber officinale Rosc. in a model of oxidative damage to pancreatic ß cells. The free radical scavenging activities and composition of the isolated n-hexane and ethanolic extracts were confronted with their protective, antioxidant and cytotoxic effects in INS-1E ß cells. Unlike the n-hexane extract (exerting, paradoxically, stronger antiradical capacity), both low cytotoxicity and remarkable protective effects on ß cell viability, followed by lowering oxidative stress markers were found for the ethanolic extract Zingiber officinale Rosc. The present study is the first pilot study to assess the protective potential of Zingiber officinale Rosc. in a model of cytotoxic conditions imposed by diabetes in ß cells.

[Identification of lipoxygenase expressing omega-6 dioxygenase activity by means of liquid chromatography]. / Identifikácia lipoxygenázy s omega-6 dioxygenázovou aktivitou kvapalinovou chromatografiou.

Lipoxygenases (LOX) represent a family of lipid peroxidising enzymes which catalyse the reaction of achiral polyunsaturated fatty acids by oxygen forming chiral peroxide products possessing high positional stereospecific purity. The four double bonds of arachidonic acid, the main substrate of animal LOX, present the position for a wide range of enzymatic modifications enabling eicosanoid creation, unique molecules with biological significance. In this study, lipoxygenase from rat lung cytoplasma was isolated and purified to 40-fold by combining hydrophobic and gel chromatography. The forming positional specific fatty acid hydroxyl-isomers were separated on a nonpolar system (RP-HPLC) and identified on a polar adsorbent (SP-HPLC). In the purified enzyme, dual positional specificity was demonstrated by the production of 12- and 15-HETE in the ratio of 1,0:1,38, which responds to the product spectrum of mammalian 15-LOX-1.

HPLC determination of antilipoxygenase activity of a water infusion of Ligustrum vulgare L. leaves and some of its constituents.

The aim of the study was a HPLC evaluation of the lipoxygenase activity inhibiting activity of a water infusion of Ligustrum vulgare L. leaves and selected isolates from it. The antiradical activity of the water infusion was determined using DPPH, ABTS and FRAP tests. Oleuropein and echinacoside concentrations in the water infusion were determined by HPLC. Water infusion, echinacoside and oleuropein were used for an antilipoxygenase activity assay using lipoxygenase isolated from rat lung cytosol fraction. Activity of 8-LOX, 12-LOX and 15-LOX were monitored through formation of 8-HETE, 12-HETE and 15-HETE, respectively. The water infusion exhibited the highest activity against all lipoxygenases, followed by oleuropein. Echinacoside was ineffective against LOXs in lower concentrations, while higher concentration showed similar inhibition on 8-LOX and 12-LOX. 15-LOX was affected more and the presence of echinacoside remarkably decreased its activity.