Time‐dependent diuretic response in rats treated with Juniper berry preparations

The infusion and the essential oil of juniper berries ( Juniperus communis L .) as well as terpinen‐4‐ol were tested for diuresis response in rats. GC analysis of the oil obtained from the drug sample revealed that the ratio between the pinene fraction and terpinen‐4‐ol was 5:1. In a 1 day experiment the effect of diuresis reduction was observed and compared with the effect of vasopressin (ADH). The effect of the smallest dose of ADH (0.004 IU/100 g b.w.) intraperitoneally administered was comparable to the effect of a 10% drug infusion and 0.1% essential oil solution, while the effect of 0.4 IU/100 g b.w. of ADH was comparable to that of a 0.01% solution of terpinen‐4‐ol. During a 3 day experiment diuresis was stimulated after the second application and especially after the third application of test solutions. Among tested preparations a 10% drug infusion exerted the most considerable diuretic activity. After 72 h, i.e. three oral doses of 5 mL/100 g b.w. of drug infusion, the cumulative urine volume was 44% above the control value. The results suggest that the diuretic activity of juniper berries cannot be attributed only to the essential oil but also to hydrophilic drug constituents. Copyright © 1998 John Wiley & Sons, Ltd.