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

Flavonol glycosides and iridoids from asperula lilaciflora

A new flavonol glycoside, quercetin 3-O-[6’’’-O-3,5-dihydroxycinnamoyl-b-glucopyranosyl-(1!2)]-b-galactopyranoside (named lilacifloroside; 1) and a new iridoid 2 (named asperulogenin), were isolated from the aerial parts of Asperula lilaciflora in addition to eight known secondary metabolites, i.e.,quercetin, kaempferol, quercetin 3-O-b-glucopyranosyl-(1!2)-b-galactopyranoside, quercetin 3-O-bglucopyranosyl-(1!2)-arabinopyranoside, asperuloside, deacetylasperulosidic acid, asperulosidic acid methyl ester, and chlorogenic acid. The structures were elucidated on the basis of extensive 1D- and 2DNMR experiments as well as MS data. Compound 1 contains the rare 3,5-dihydroxycinnamoyl moiety in its structure. This work constitutes the first phytochemical study of the title plant