Enhanced maze performance and reduced oxidative stress by combined extracts of zingiber officinale and ginkgo biloba in the aged rat.

Here we assessed the effects of i.g. administration of Zingicomb (ZC), a mixture of zingiber officinale and ginkgo biloba extracts, on learning and memory, and on indicators of oxidative stress in aged rats. Effects of ZC (1 and 10 mg/kg) were investigated in 22-24 months old Wistar rats using the Morris water maze, in which they show deficient performance as compared to 3 months old rats in the undrugged state (days 1 and 2). Treatment was administered on days 3 and 4 of training, then over 7 days with training discontinued, and again on days 5 and 6 when training was resumed. Thereafter chronic treatment was maintained over 5 months. 1 mg/kg ZC improved escape learning in the water maze. The two capital indicators of oxidative stress in brain homogenates, the amount of oxidized proteins (assessed as carbonyl group containing proteins) and lipid peroxidation, were significantly reduced in ZC treated animals. Thus, ZC, which had previously been shown to improve inhibitory avoidance learning and to have anxiolytic properties in adult animals, might also facilitate spatial learning in aged animals, and reduces indices of oxidative stress in brain tissue after chronic treatment.

Dissociation between anxiolytic and hypomnestic effects for combined extracts of zingiber officinale and ginkgo biloba, as opposed to diazepam.

Previous work has shown that Zingicomb (ZC), a combination preparation of zingiber officinale and ginkgo biloba, exerts anxiolytic-like effects in the elevated plus-maze (EPM), possibly related to 5-HT antagonistic properties of its components. The first experiment of this study was performed to gauge the specificity of the anxiolytic action of ZC with respect to the mixture ratio of the single components in the combination preparation. Two different combinations of zingiber officinale and ginkgo biloba extracts (ratio of components: 1:1 or 1:2.5) were compared with the standard ratio adjusted for ZC (2.5:1). Each combination was administered intragastrically (I.G.) in five doses (0.01 to 10 mg/kg) before the rats were tested on the EPM. Zingicomb at 1 mg/kg elevated the time spent on the open arms, scanning of the open arms and excursions into the ends of the open arms, whereas the two other combinations (1:1 and 1:2.5) did not influence rats' behavior on the EPM in the entire dose range tested. With regard to the memory-disrupting effects of anxiolytics, particularly of diazepam (DZP), a second experiment was performed to compare the effects of ZC (0.5, 1, 10 mg/kg, I.G.) and DZP (1 or 5 mg/kg, I.P.) on the performance of rats in two different learning tasks. Rats were treated with DZP or ZC prior to the learning trial of a one-trial step-through inhibitory avoidance task. Retention testing 24 h later showed impaired retention for rats injected with DZP at 5 mg/kg but not for animals that had received ZC prior to training. In a further experiment, rats were treated once daily with DZP or ZC prior to the training trials in a water maze. Injections of DZP at 5 mg/kg impaired place and cue learning, whereas the treatment with ZC did not influence the navigation performance in the maze. The present results indicate that the anxiolytic-like effects of ZC are specific in that only the mixture ratio of zingiber officinale and ginkgo biloba adjusted for the phytopharmacon was active in the EPM. Furthermore, ZC did not interfere negatively with the performance on an inhibitory avoidance and a water maze task, as opposed to DZP. This finding is interesting with regard to other studies that have revealed a similar dissociation between anxiolytic and memory-disrupting effects for chemically defined 5-HT antagonists, especially for those acting at 5-HT3 receptors.

Anxiolytic-like effect of combined extracts of Zingiber officinale and Ginkgo biloba in the elevated plus-maze.

The effects of the known anxiolytic compound diazepam (DZ) on the behavior of rats in the elevated plus-maze were compared with those of zingicomb (ZC) (registered trademark of Mattern et Partner), a combination preparation of standardized extracts of Ginkgo biloba and Zingiber officinale. DZ was administered intraperitoneally (IP) in a reference dosage of 1 mg/kg 30 min before the rats were tested on the elevated plus-maze for 5 min. The treatment with DZ elevated the time spent on the open arms and excursions into the end of the open arms, increased scanning over the edge of an open arm, and decreased risk-assessment from an enclosed arm. ZC was administered intragastrically (IG) in four doses ranging between 0.5 and 100 mg/kg 60 min prior to plus-maze testing. The treatment with 0.5 mg/kg ZC elevated the time spent on the open arms and excursions into the end of the open arms; at the high dosage of 100 mg/kg, ZC led to fewer excursions to and less scanning of the open arms. Injection of 1 or 10 mg/kg ZC had no significant effect on the behavior in the maze. These data provide evidence that ZC has anxiolytic effects in the elevated plus-maze comparable to those of DZ, but that in high dosage the phytopharmacon may also have anxiogenic properties. The anxiolytic-like effects of ZC are discussed with regard to the known antiserotonergic action of ginger and Ginkgo biloba.

Blockade of lithium chloride-induced conditioned place aversion as a test for antiemetic agents: comparison of metoclopramide with combined extracts of Zingiber officinale and Ginkgo biloba.

The present study tests the hypothesis that the blockade of lithium chloride-induced conditioned place aversion might be a suitable model to assess antiemetic properties of drugs, especially in species that do not vomit, like rats. The effects of the known antiemetic compound metoclopramide were compared with those of zingicomb, a combination preparation of extracts of Ginkgo biloba and Zingiber officinale, also presumed to have antiemetic properties. Place conditioning was performed using a conventional three-compartment test procedure. On three successive conditioning trials, rats received an intraperitoneal (i.p.) injection of lithium chloride (125 mg/kg) and were placed into the compartment that they had preferred over three baseline trials. During the test, rats treated with lithium chloride (LiCl) spent less time in the treatment compartment, indicative of a conditioned place aversion (CPA). In the first experiment, metoclopramide (MCP) was administered intragastrically (IG) in doses of 2 or 10 mg/kg 60 min prior to LiCl injection. The pretreatment with 50 and 100 mg/kg zingicomb attenuated the LiCl-produced CPA, whereas a dosage of 10 mg/kg had no effect. These findings suggest that LiCl-induced CPA is a viable procedure with which to assess the antiemetic properties of metoclopramide. Furthermore, the data confirm the hypothesis that the phytopharmacon zingicomb might have antiemetic properties that are comparable to those of metoclopramide.