Abstract:

Objective: To study the hypolipidemic and hypoglycemic effects of total flavonoids from Malus baccata leaves (MLTF)
on STZ-induced diabetic mice. Methods: MLTF were extracted from Malus baccata leaves with 70% ethanol and its bioactive
components were quantified by HPLC. Diabetes mellitus was induced in mice by intraperitioneal injection of streptozotocin (STZ,
100 mg/kg). All mice were divided randomly into five groups, including normal control, diabetic model, metformin (250 mg/kg),
MLTF high-dose (500 mg/kg) and low-dose (300 mg/kg) groups. All mice were subjected to intragastic administration for 4
weeks. Body weight, and food and water intakes were monitored every day during the administration period, and fasting blood
glucose (FBG) was measured 3 times. We also tested the effect of MLTF on diabetic mice by using oral glucose tolerance test
(OGTT). At the end of the experiment, liver, kidney, spleen and thymus samples were removed and weighed to calculate the
tissue indexes. Blood samples were collected to evaluate blood lipid. Results: The contents of rutin, phlorizin, quercetin and
phloretin were 9.72, 51.04, 9.44 and 2.73 mg/g, respectively in MLTF. High-dose administration of MLTF could significantly
reduce the FBG and the area under the glucose tolerance curve (AUC). In contrast, low-dose MLTF could only improve the FBG
to some extent. Compared with the model group, both high-dose and low-dose MLTF could significantly decrease TG and TC
levels, and ameliorate HDL-C level. Our present study found that injured mouse organs could be repaired by low- and high-dose
administration of MLTF. Conclusion: MLTF can improve glucose and lipid abnormalities.

Key words: Malus baccata, total flavonoids, high performance liquid chromatography (HPLC), blood glucose, blood lipids