Effects of Cydonia oblonga Miller leaf and fruit flavonoids on blood lipids and anti-oxydant potential in hyperlipidemia rats.

OBJECTIVE: To study the effects of Cydonia oblonga Miller (COM) total flavonoids (TF) from leaves and fruit on the blood lipid and antioxidant potentials using hyperlipidaemic rat models. METHODS: Hyperlipidaemic rat models were created with high-lipid emulsion. Rats were distributed into normal controls, hyperlipidaemic models, and daily high (160mg/kg), medium (80mg/kg) and low (40mg/kg) TF from leaves and fruit and simvastatin (5mg/kg) groups. After four weeks, serum total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL), low-density lipoprotein cholesterol (LDL), alanine aminotransferase (ALT), aspartate aminotransferase (AST), as well as hepatic superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and malondialdehyde (MDA) were measured. RESULTS: Compared with the hyperlipidaemic model group, TF significantly reduced serum TC, TG, LDL-C (P<0.01), ALT and AST (P<0.01 or P<0.05) and increased HDL-C (P<0.05 or P<0.01). TF also reduced MDA (P<0.01 or P<0.01). CONCLUSION: COM total flavonoids can effectively regulate the metabolism of lipids, and remove oxygen free radicals. This confirms its potential value in the prevention and treatment of hyperlipidaemia.

Effect of Cydonia oblonga Mill. leaf extracts or captopril on blood pressure and related biomarkers in renal hypertensive rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Cydonia oblonga Mill. (COM) is used in traditional Uyghur medicine to treat or prevent cardiovascular disease. In a previous study COM leaf extracts were found to be active in renal hypertensive rats (RHR). The present study tests the dose-dependence of the effect of ethanol leaf extracts on hypertension and on biomarkers associated with blood pressure control, such as angiotensin-II (AII), plasma renin activity (PRA), apelin-12 (A), endothelin (ET) and nitric oxide (NO), compared to captopril. METHODS: Two-kidney one-clip (2K1C) Goldblatt model rats were divided randomly into six groups: sham, model, captopril 25 mg/kg, COM leaf extract 80, 160 and 320 mg/kg (n=10 each). Drugs were administered orally daily for eight weeks. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured before treatment and every 2 weeks. Blood and kidney samples were collected after the last treatment to measure AII, PRA, A, ET and NO. RESULTS: RHR had increased blood pressure, AII, A, PRA, ET and decreased NO. Treatment with captopril reduced blood pressure, AII, A, PRA, and ET, though not quite to normal values. COM leaf extracts significantly and dose-dependently reduced blood pressure, AII, A, RA and ET, whereas NO was increased. The highest dose of COM had the same effects as captopril. CONCLUSION: The effects of COM extracts on blood pressure and biomarkers were dose-dependent and at the highest dose similar to those of captopril. This suggests an action of COM on the renin-angiotensin system, which could explain its antihypertensive effect.

Effect of Cydonia oblonga Mill. fruit and leaf extracts on blood pressure and blood rheology in renal hypertensive rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Quince, Cydonia oblonga Mill. (COM), is used in traditional Uyghur medicine to treat or prevent cardiovascular diseases. Uyghur people have greater longevity and lower blood pressure than other central Asian populations. We therefore tested COM fruit and leaf extracts on blood pressure and rheology in renal hypertensive rats (RHR). MATERIALS AND METHODS: Two-kidney, one-clip (2K1C) renal hypertensive rats were divided randomly into eleven groups: sham, model, and model treated with daily doses of 80 and 160mg/kg aqueous or ethanol extracts of COM fruit or leaves, or 25mg/kg captopril (n=10 per group), given orally once daily for 8 weeks. Blood pressure was measured before treatment and every 2 weeks thereafter. Blood rheology was tested after 8 weeks. RESULTS: Model rats had higher blood pressure than sham 8 weeks after the procedure (systolic blood pressure 193±7 vs. 138±8mmHg, p<0.05). Those treated with captopril had decreased blood pressure within 2 weeks but that did not return to the level found in the sham group at 8 weeks (167±7, p<0.05 vs. model). With the COM extracts, the effect on blood pressure was notable after 4 weeks. At 8 weeks blood pressure was similar with captopril and with 160mg ethanol leaf extract (166±4, p<0.05 vs. model), the most effective of the extracts. Model rats had higher blood viscosity and lower erythrocyte deformability than sham. Captopril had little effect on blood rheology; whereas COM extracts reduced whole blood viscosity and improved erythrocyte deformability to levels approaching those found in sham. CONCLUSIONS: COM extracts have antihypertensive activity in renal hypertensive rats. The additional effect on rheology, compared to captopril, may convey added interest. Further studies of these effects in man appear warranted.