Abstract

The purpose of the present investigation was to determine the effects of hydromethanolic extract of saffron on changes of serum cholesterol, glucose and insulin levels in constant darkness and light conditions in healthy male rats. In this study, healthy male rats (n = 30) were divided into 3 groups of tens and kept at various light/dark conditions: Control + saffron 12:12 light/dark (LDS); constant darkness + saffron (DDS) and constant light + saffron (LLS) groups for 2 weeks. All the three groups received 50 mg/kg saffron extract through intraperitoneal injection for 2 weeks. Daily injection was repeated at 10 am. Blood samples were obtained from retro-orbital sinus before administration and on the 7 and 14th days of administration. The serum cholesterol and glucose levels were measured by the enzymatic method and insulin levels were measured using insulin kit by enzyme-linked immunosorbent assay (ELISA) method. The results showed that the serum cholesterol levels of all three groups decreased after 2 weeks of experiment and the most reduction was seen in DDS group. Comparison of serum insulin in all groups did not show any significant changes, but serum glucose level in LLS group significantly increased compared with the two other groups (P<0.05). In contrast, the levels of serum glucose significantly decreased in DDS and LDS groups compared to LLS group (P<0.05). In conclusion, these results clearly indicated that saffron extract and constant darkness have hypoglycemic and hypolipidemic effects, but constant light condition showed hyperglycemic effect on serum blood in healthy male rats.

Key words: Saffron, constant darkness, light, insulin, cholesterol, glucose, healthy male rat.