ABSTRACT
We assessed the neuroprotective effects of quercetin-feeding at doses of 5 and 10 mg/(kg day) on Kunming mice injected daily with D-gal (50 mg/(kg day)) by behavioral tests. Quercetin-fed mice showed higher activity upon induction by new environmental stimuli, lower anxiety and higher novelty-seeking behavior in the open field tasks, and significantly improved learning and memory ability in step-through and Morris water Maze tests compared with D-gal-treated mice. We further investigated the mechanisms involved in the neuroprotective effects of quercetin on mouse brain. Quercetin significantly increased superoxide dismutase (SOD) activity and decreased the malondialdehyde (MDA) level. These results imply that quercetin can reverse oxidant impairment induced by D-gal in mouse brain. Neurotoxicity is also associated with Ca(2+) overload induced by oxidant stress. Quercetin could maintain the Ca(2+) homeostasis in the brain of D-gal-treated mice. Furthermore, we also examined the expression of growth-associated protein GAP43 mRNA in mouse brain by in situ hybridization. We found that quercetin dramatically elevated the GAP43 mRNA expression in the brain of D-gal-treated mice to regenerate normal function of neurons against the cellular injury caused by D-gal.
Subject(s)
Antioxidants/pharmacology , Brain/metabolism , Calcium/metabolism , Discrimination Learning/physiology , Malondialdehyde/metabolism , Quercetin/pharmacology , Aging/physiology , Analysis of Variance , Animals , Avoidance Learning/drug effects , Avoidance Learning/physiology , Brain/drug effects , Discrimination Learning/drug effects , Exploratory Behavior/drug effects , Exploratory Behavior/physiology , GAP-43 Protein/genetics , GAP-43 Protein/metabolism , Galactose/toxicity , Male , Mice , Mice, Inbred Strains , Neuroprotective Agents/pharmacology , Neurotoxicity Syndromes/metabolism , Neurotoxicity Syndromes/prevention & control , RNA, Messenger/analysis , Superoxide Dismutase/drug effects , Superoxide Dismutase/metabolismABSTRACT
An endophytic bacterium, designated strain Bacillus amyloliquefaciens CGMCC 5569 was isolated from Chinese medicinal Ginkgo biloba collected from Xuzhou, China. Both the filtrate and the ethyl acetate extract of strain CGMCC 5569 showed growth inhibition activity against the sapstain fungi Lasiodiplodia rubropurpurea, L. crassispora, and L. theobromae obviously (>65%) based on the comparison of the length of zones on the petri dish. From the ethyl acetate extract of the filtrate, the antifungal compounds were obtained as a series of lipopeptides, which including series of fengycin, surfactin and bacillomycin. It showed strong growth inhibition activity in vitro against the L. rubropurpurea, L. crassispora and L. theobromae by about 70.22%, 69.53% and 78.76%, respectively. The strong anti-sapstain fungus activity indicated that the endophytic B. amyloliquefaciens CGMCC 5569 and its bioactive components might provide an alternative bio-resource for the bio-control of sapstain.