title: A Review of Three Commonly Used Herbs Which Enhance Memory and New Evidences Which Show Their Combination Could Improve Memory in Young Animals.
abstract: BACKGROUND
  This review looks into the herbs Gingko biloba, Polygala tenuifolia, and Lycii fructus for their widely studied neuroprotective properties. In particular, we investigated memory enhancing effect of these herbs, and their potential synergetic effect on memory with new data. Sixmonth treated mice demonstrated shorter escape latency in water maze and shorter arrival time in a consolidated memory task. Immunochemistry showed evident increase in superoxide dismutase activities in the prefrontal cortex, implying protection against free radicals during aging. Discrete increase of catecholaminergic neurons was found in the prefrontal cortex, hippocampus, corpus striatum, and midbrain, suggesting better memory and better control on mood and behavior. Necrotic cells in the brain decreased as indicated by immunocytochemistry of lactic dehydrogenase. Terminal deoxynucleotidyl transferase dUTP nick end labeling showed no apoptotic cells in most brain areas in high dose group. Biochemistry revealed increase of dopaminergic cells in treatment groups at prefrontal cortex, and in the hippocampus and cerebellum of the high dose group. Most 6-month groups showed increase of serotonin in all three areas. For the high dose group, GABA increased in the hippocampus but not prefrontal cortex, which would help induce sleep at night. Protein kinase C increased in most groups at prefrontal cortex, hippocampus and cerebellum, signifying increase of possible signal transduction pathways for memory or other nervous activations.
  
  
  CONCLUSIONS
  Our results intimate that the interaction of the three herbs exerts beneficial effects on memory, associated cognitive function, and necrosis. Future investigations based on the present data shall aid development of clinically relevant medication.
authors.affiliation: Fujian Provincial Key Laboratory of Pien Tze Huang Natural Medicine Research and Development (R & D), Zhangzhou Pien Tze Huang Pharmaceutical CO., LTD. Zhangzhou. China.
authors.forename: Fei
authors.initials: F
authors.lastname: Hong
authors.affiliation: Fujian Provincial Key Laboratory of Pien Tze Huang Natural Medicine Research and Development (R & D), Zhangzhou Pien Tze Huang Pharmaceutical CO., LTD. Zhangzhou. China.
authors.forename: Liju
authors.initials: L
authors.lastname: Wang
authors.affiliation: School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong. China.
authors.forename: Sharon L
authors.initials: SL
authors.lastname: Wu
authors.affiliation: School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong. China.
authors.forename: H C
authors.initials: HC
authors.lastname: Tang
authors.affiliation: School of Medicine, Shenzhen University Health Science Centre, Shenzhen University, Shenzhen. China.
authors.forename: Ou
authors.initials: O
authors.lastname: Sha
authors.affiliation: School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong. China.
authors.forename: Maria S M
authors.initials: MSM
authors.lastname: Wai
authors.affiliation: School of Biomedical Sciences, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong. China.
authors.forename: David T
authors.initials: DT
authors.lastname: Yew
mesh_terms: D000818:Animals; D001921:Brain / Q000187:drug effects / Q000502:physiology; D003071:Cognition / Q000187:drug effects*; D020441:Ginkgo biloba / Q000737:chemistry; D006801:Humans; D032305:Lycium / Q000737:chemistry; D008568:Memory / Q000187:drug effects*; D018696:Neuroprotective Agents / Q000737:chemistry / Q000494:pharmacology*; D028321:Plant Preparations / Q000737:chemistry / Q000494:pharmacology*; D010946:Plants, Medicinal / Q000737:chemistry; D031801:Polygala / Q000737:chemistry; D013482:Superoxide Dismutase / Q000378:metabolism; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
chemical_list: D018696:Neuroprotective Agents; D028321:Plant Preparations; D005680:gamma-Aminobutyric Acid; D013482:Superoxide Dismutase
keywords: Gingko biloba; Lycii fructus; Polygala tenuifolia; aging; herbal interaction; memory