Carob (Ceratonia siliqua L.) Prevents Short-Term Memory Deficit Induced by Chronic Stress in Rats
Long-term exposure to stressful conditions could impair the normal brain structure and function, specifically the hippocampus-dependent memory. This impairment could be attributed to a decrease in brain-derived neurotrophic factor (BDNF) levels during chronic stress. Knowing that carob [Ceratonia siliqua L. (Fabaceae)] is rich in a wide variety of polyphenols with a high antioxidant value, we hypothesized that the methanolic carob extract (C. siliqua) pods will prevent stress-induced memory impairment. Hence, the methanolic extract of carob pods was investigated for its ability to enhance learning and memory as well as to protect from memory impairment in normal stressed animals. Rats were chronically stressed for 7 weeks via the intruder stress model. Carob extract was administered to animals via intraperitoneal (i.p.) route at a daily dose of 50 mg/kg. Radial arm water maze (RAWM) was utilized to test for spatial learning and memory. In addition, brain tissues were dissected to determine BDNF levels. Chronic stress (CS) impaired short-term spatial memory (number of committed errors: P < 0.05, days to criterion (DTC): P < 0.001). Animal treatment with carob pod extract prevented the short-term memory impairment induced by CS (P < 0.05), while such treatment showed no effect on memory functions of unstressed rats. Moreover, carob pod extract prevented the reduction in the hippocampal BDNF (P < 0.05) induced by chronic stress exposure. In conclusion, CS impaired short-term memory function, while methanolic extract of carob pods prevented this impairment, probably as a result of preventing reduction in BDNF levels in the hippocampus.
KeywordsCeratonia silique Carob Stress Learning Memory Hippocampus Antioxidant BDNF
Support for this work was provided from “the Deanship of Research, Jordan University of Science and Technology, Irbid, Jordan” (Grant No. 73/2008).
Compliance with Ethical Standards
The study protocol was approved by the Institutional Animal Care and Use Committee at JUST.
Conflict of Interest
The authors declare that they have no conflict of interest.
- Gooney M, Shaw K, Kelly A, O'Mara SM, Lynch MA (2002) Long-term potentiation and spatial learning are associated with increased phosphorylation of TrkB and extracellular signal-regulated kinase (ERK) in the dentate gyrus: evidence for a role for brain-derived neurotrophic factor. Behav Neurosci 116:455–463CrossRefGoogle Scholar
- Mazumder AG, Sharma P, Patial V, Singh D (2017) Ginkgo biloba L. attenuates spontaneous recurrent seizures and associated neurological conditions in lithium-pilocarpine rat model of temporal lobe epilepsy through inhibition of mammalian target of rapamycin pathway hyperactivation. J Ethnopharmacol 204:8–17CrossRefGoogle Scholar
- Shawakfeh K (2005) Pod characteristics of two Ceratonia siliqua L. varieties from Jordan. Ital J Food Sci 17:187–194Google Scholar
- Wolf OT, Atsak P, de Quervain DJ, Roozendaal B, Wingenfeld K (2016) Stress and memory: a selective review on recent developments in the understanding of stress hormone effects on memory and their clinical relevance. J Neuroendocrinol 28Google Scholar