Evaluation of effects of Zingiber officinale on salivation in rats

There are some herbal plants in Iranian traditional system of medicine which are believed to be excellent remedies to alleviate the symptoms of xerostomia. The aim of the present study was to evaluate the effect of systemic administration of seven different herbal extracts on the rate of salivation in rats. The extracts of 7 herbs; Zingiber officinale Roscoe (Zingiberaceae), Citrus sinensis (L.) Osbeck (Rutaceae), Artemisia absinthium L. (Asteraceae), Cichorium intybus L. (Asteraceae), Pimpinella anisum L.(Apiaceae), Portulaca oleracea L.(Portulacaceae), Tribulus terrestris L. (Zygophyllaceae) were prepared. Nine groups of animals (including negative and positive control groups) were used and seven rats were tested in each group. After the injection of extracts, saliva volume was measured gravimetrically in four continuous seven-minute intervals. The results showed that after injection of ginger extracts salivation was significantly higher as compared to the negative control group and other herbal extracts in all of the four intervals (P<0.01). The peak action of the ginger was during the first 7-minute interval and following this, salivation decreased to some extent. The present study suggests that the extract of Zingiber offiicianle can increase the rate of salivation significantly in animal model. Further investigations on different constituents of ginger seem to be essential to identify the responsible constituent for stimulation of saliva secretion.