Learning and memory improvement and neuroprotection of Gardenia jasminoides (Fructus gardenia) extract on ischemic brain injury rats

Gardenia jasminoides Ellis is a traditional Chinese medicine (TCM) that containing a variety of effective active ingredients and exhibits diverse pharmacological functions, such as anti-inflammatory, antioxidant and nerve protection.This study investigated the effect of Gardenia jasminoides extract (GJE) and Geniposide on learning and memory improvement and neuroprotection in a rat model with chronic cerebral ischemia, as well as explore the underlying mechanisms.The crude GJE was prepared using the methods of water extraction and alcohol precipitation, and refined by macroporous adsorption resin. The chronic cerebral ischemia model was simulated by permanent occlusion of bilateral common carotid arteries in rats. GJE was taken at three doses groups (150mg/kg, 100mg/kg, 50mg/kg), Geniposide group (50mg/kg), and oral administration for 30 days. Memory function was assessed using Morris water maze test. The morphological changes of hippocampus and related parts of brain in rats by Hematoxylin and Eosin (HE) staining were observed. Moreover, the levels of Acetylcholin Esterase (AchE), Nitric Oxide Synthase (NOS), Malondialdehyde (MDA), Superoxide Dismutase (SOD) in the brain tissue were quantified.GJE contained 27% gardenoside and 72% total iridoid glycoside. The chronic cerebral ischemia rat model has been proved successfully. The memory function of the rats assessed using Morris water maze test showed that GJE significantly shortened the escape latency of rats, but had no significant improvement on the number of times crossing the platform and the percentage of time spent in the target quadrant. HE staining showed that the apoptosis and necrosis of the cortex and hippocampus in the GJE group were significantly reduced. In addition, it was found that GJE could significantly improved the content of SOD, inhibited NOS and AchE activity in brain tissue, but did not show a significant reduction in the content of MDA. The effect of medium dosage of GJE was the best among these three dose groups and also better than Geniposide according to the results of all the detection index.GJE had the functions of learning and memory improvement and the neuroprotection on chronic cerebral ischemia model rats. The mechanisms were found to be strongly correlated with antioxygen free radical, reduction of NO toxicity and AChE activity, and brain neuron protective effect. GJE could be able to play a better effect on improving chronic cerebral ischemia than Geniposide.