Effects of in vivo antioxidant enzyme activities of myrtle oil in normoglycaemic and alloxan diabetic rabbits

In this study we aimed to evaluate the in vivo effects of myrtle oil (myrtii oleum) on the antioxidant enzymes such as superoxide dismutase and catalase, the levels of malondialdehyde in liver tissues as an index of lipid peroxidation and nitrite-nitrate levels in normoglycaemic and alloxan-induced diabetic and MO-treated rabbits. In our previous study, we assumed that MO with a dose of 50 mg/kg, possesses a hypoglycemic activity and this activity was independent from the effects of insulin. Myrtle oil exerts its hypoglycemic activity by enhanced glycolysis, glycogenesis and decreased glycogenolysis. What is more glucose load data strongly suggest that MO treatment produces hypoglycemia mainly by reducing intestinal absorption of glucose, so MO could be an ?-glycosidase enzyme inhibitor which had a hypoglycaemic effect only on alloxan-induced diabetic rabbits on the fourth hour and on orally glucose loaded group. The major finding of this new study is that, MO may not offer any protection against oxidative stress during acute studies in normoglycemic and diabetic groups. Although the levels of superoxide dismutase and catalase enzyme activities did not change during acute studies in diabetes + MO group, there was a significant change at the end of 21 days. There is a very limited knowledge about MO and its effects on diabetes. Therefore, we tried to explain the mechanism that might underlie the protective effects of MO with this paper. © 2006 Elsevier Ireland Ltd. All rights reserved

From submarine continental accretion to arc-continent orogenic evolution: The thermal record in southern Taiwan

© 2014 Geological Society of America. Constraining the timing of initial collision is critical for understanding how long-term plate convergence is accommodated at collisional plate boundaries. Reevaluation of the age of collision from orogenic thermal evolution requires distinguishing the onset of submarine continental accretion from earlier oceanic subduction and subsequent subaerial orogenic evolution. We present new thermochronological constraints from the first age-elevation relationship transect in Taiwan and zircon and apatite fission-track ages from sediments in the western foreland. Our data reveal the onset of cooling from at least 7.1 ± 1.3 Ma, at a minimum rate of 21°C/m.y., in the submarine sedimentary wedge followed by a marked acceleration of subaerial exhumation after ca. 3.2 ± 0.6 Ma at an average rate of 1.7 km/m.y. Our data reflect the effect of margin architecture as Taiwan evolved from submarine accretion of the distal extremely thinned continental margin to crustal thickening of the proximal margin and orogenic development.Peer Reviewe