Long-term administration of Greek Royal Jelly improves spatial memory and influences the concentration of brain neurotransmitters in naturally aged Wistar male rats

Abstract

Ethnopharmacological relevance: Royal Jelly (RJ) is a bee-derived product that has been traditionally used in the European and Asian systems of medicine for longevity. RJ has various pharmacological activities that may prevent aging e.g., anti-inflammatory, anti-oxidative, anti-hypercholesterolemic and anti-hyperglycemic properties.

Aim of the study: To evaluate the behavioral and neurochemical effects of long-term oral, previously chemically analyzed, Greek RJ administration to aged rats.

Materials and methods: RJ powder was given to 18-month old male Wistar rats (50 and 100mg of powder/kg b.w./day) by gastric gavage for 2 months. The spatial memory was assessed in the water maze and next the level of neurotransmitters, their metabolites and utilization in the selected brain regions were estimated.

Results: The improvement of memory in rats pretreated with the smaller dose of RJ was observed compared with controls. In biochemical examination mainly the depletion of dopamine and serotonin in the prefrontal cortex along with an increase in their metabolite concentration and turnover were seen.

Conclusion: Better cognitive performance in the old animals using a non-toxic, natural food product in the view of the process of the aging of human population is noteworthy. Our results contribute towards validation of the traditional use of RJ in promoting a better quality of life in old age.

Keywords: Aged rats; Dopamine; Royal Jelly; Serotonin; Spatial memory; Water maze.