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.

Effect of Ocimum basilicum L. on cyclo-oxygenase isoforms and prostaglandins involved in thrombosis

ETHNOPHARMACOLOGICAL RELEVANCE

Ocimum basilicum L. (OBL) is a plant used in traditional Uyghur medicine for the treatment and prevention of cardiovascular disease. In previous studies we had found an antihypertensive and antithrombotic effect suggestive of an effect on prostaglandins, which we attempt to document here.

MATERIALS AND METHODS

6-keto-PGF1α, the metabolite of prostacyclin, and PGE2 were measured in the supernatant of human umbilical vein endothelial cells (HUVEC) and basal or LPS-stimulated mouse coeliac macrophage cultures exposed to OBL ethanol (OBL-E) extracts and petroleum ether, chloroform, ethylacetate and butanol (PE, C, EA, B) fractions. In addition, 6-keto-PGF1α and thromboxane B2 (TXB2) were measured in a rat model of thromboangiitis obliterans exposed or not to OBL.

RESULTS

Short-term exposure to OBL-E dose-dependently increased 6-keto-PGF1α from HUVEC, and long-term (24h) exposure decreased it. OBL-C and OBL-B increased 6-keto-PGF1α, whereas the other fractions tended to decrease it after 24h exposure. The extract and all fractions decreased basal and stimulated PGE2 production, but only OBL-EA and OBL-B reduced PGE2 in stimulated cultures to concentrations below the unstimulated values (P<0.05). In vivo OBL increased 6-keto-PGF1α and decreased TXB2.

CONCLUSION

OBL and its extracts increased 6-keto-PGF1α and reduced PGE2 and TXB2 production in a dose and time-related manner. This could indicate simultaneous inhibition of COX-2 and stimulation of endothelial COX-1. The butanol fraction seemed most promising in this respect.