Mulberry (Morus alba L.) Leaves and Their Major Flavonol Quercetin 3-(6-Malonylglucoside) Attenuate Atherosclerotic Lesion Development in LDL Receptor-Deficient Mice

Abstract

The effects of dietary consumption of mulberry (Morus alba L.) leaves and their major flavonol glycoside, quercetin 3-(6-malonylglucoside) (Q3MG), on the development of atherosclerotic lesions, in relation to the susceptibility of plasma LDL to oxidative modification, was studied in LDL receptor-deficient (LDLR-/-) mice. Male mice aged 8 wk were randomly assigned to 4 groups (control, quercetin, Q3MG, and mulberry). The control group was fed an atherogenic-diet containing 3 g cholesterol and 15 g cocoa butter/100 g. The other experimental groups were fed the same atherogenic diet supplemented with 0.05 g quercetin/100 g for the quercetin group, 0.05 g Q3MG/100 g for the Q3MG group, and 3 g dried mulberry-leaf powder/100 g for the mulberry group. The mice were fed their respective diets for 8 wk. The susceptibility of LDL to oxidative modification was significantly decreased in the Q3MG- and mulberry-treated mice, as evidenced by the 44.3 and 42.2% prolongation of the lag phase for conjugated diene formation compared with that of the control mice. The atherosclerotic lesion area in both the Q3MG- and mulberry-treated mice was significantly reduced by 52% compared with that of the controls. However, in the quercetin group, no protective effects were observed against LDL oxidation or atherosclerotic lesion formation. In conclusion, mulberry leaves attenuated the atherosclerotic lesion development in LDLR-/- mice through enhancement of LDL resistance to oxidative modification, and these antioxidative and antiatherogenic protective effects were attributed mainly to Q3MG, the quantitatively major flavonol glycoside in mulberry leaves.

Hypoglycemic Effects of Morus alba Leaf Extract on Postprandial Glucose and Insulin Levels in Patients with Type 2 Diabetes Treated with Sulfonylurea Hypoglycemic Agents

“…Blood glucose and insulin levels are also important for preventing oxidative stress in intravascular endothelial cells, and atherosclerosis. LEM has demonstrated a suppressive effect on atherosclerotic lesions in mice [7] and the protective effect on vascular system through the decreasing of oxidative stress and anti-glycation [18][19][20], suggesting that it should form part of the dietary therapy for type 1 and 2 diabetes mellitus, and for other metabolic syndromes.…”

“…Furthermore, the appearance of polyuria and the elevation of fasting blood glucose and insulin were delayed by the daily intake of LEM in diabetic mice [5]. LEM has also been reported to have other physiological effects, including the inhibition of low-density lipoprotein oxidation in vitro [6], and the attenuation of atherosclerotic lesion development in mice [7]. We previously clarified that confections containing LEM suppressed postprandial elevations of glucose and insulin in healthy subjects [8].…”

Influence of Mulberry Leaf Extract on the Blood Glucose and Breath Hydrogen Response to Ingestion of 75 g Sucrose by Type 2 Diabetic and Control Subjects

“…In addition, mulberry extract contains compounds such as fagomine, which induces insulin secretion (17), and antioxidants that putatively reduce lipid peroxidation (5, 18,19).…”

Effect of Rutin in Buckwheat Noodle on Lipid Metabolism in Rats

“…Odbayar et al (2006) reported that dietary quercetin but not rutin reduced serum cholesterol and phospholipid levels in ICR mice, and that quercetin inhibited the expression of various kinds of mRNA related to fatty acid synthesis. On the other hand, Enkhmaa et al (2005) reported that dietary quercetin (50 mg/100 g) had no significant beneficial effects on plasma total cholesterol, LDL cholesterol and triglyceride levels of LDL receptor-deficient mice fed an atherogenic-diet containing cholesterol. In addition, it was shown that plasma cholesterol levels were not reduced by dietary quercetin (1% in diet) in mice fed a high-cholesterol diet or in Watanabe heritable hyperlipidemic rabbits (Lauridsen and Mortensen, 1999).…”