It is known that reactive oxygen species (ROS) have a central role in causing many types of neuronal damage such as Alzheimer's disease, Parkinson's disease, ischemia, etc. 1,2)ROS comprise a group of unstable molecules: super oxide radical (O 2 Ϫ ), hydrogen peroxide (H 2 O 2 ), hydroxyl radical (OH) and hypochlorous acid (HOCl), that are generated in all cells as a by-product of cellular metabolism during conversion of molecular oxygen (O 2 ) to water (H 2 O). Additionally, phagocytes generate oxidative bursts of ROS to combat microorganisms. Cells possess endogenous systems (superoxide dismutase, catalase, glutathione peroxide) and diet derived (vitamin C and vitamin E) anti-oxidants to prevent or limit ROS induced tissue damage. H 2 O 2 is often used to investigate the mechanism of ROS-induced cell death, 3) and the mechanism of H 2 O 2 -induced PC12 cell death has been examined. 4,5) Hydroxyl radicals form when it comes in contact with a range of transition metal ions. Oxidative stress occurs during an imbalance between ROS and anti-oxidants. Excess production of ROS may lead to cellular injury through nonspecific modification and disruption of proteins, phospholipids and nucleic acids.6) Critical sites of ROS attack are the cell membrane and the membranes of intracellular organelles. The disruptive effects of ROS involve membrane lipid per-oxidation and membrane protein modification, which may produce alterations in the membrane structure and function including fluidity, permeability, enzyme activity, ion channels, transporter and receptor proteins.7) The role of ROS has been implicated in many human degenerative diseases of aging. Various antioxidants have been found to have some preventive and therapeutic effects on these diseases induced by ROS.8) Therefore, substantial efforts have been made in recent years to identify both natural and synthetic antioxidants. Moutan Cortex Radicis (MCR), the root cortex of Paeonia suffruticosa ANDREWS, is a Chinese herbal medicine widely used as an analgesic, antispasmodic, and anti-inflammatory agent. The drug has also long been used in remedies for female diseases. MCR is reported to inhibit oxidative DNA cleavage 9) and to have a scavenging effect on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals and superoxide anion radicals generated by the xanthine-xanthine oxidase system. 10)The chemical components of MCR are known to be paeonol, paeonoside, paeonolide, paeoniflorin, benzoylpaeoniflorin, oxypaeoniflorin, benzoyl-oxy-paeoniflorin, and apiopaeonoside.PC12 cells have been widely used as an in vitro experimental model to study the effects of various neurotoxic agents, including 6-hydroxydopamine, 1-methyl-4-phenylpyridinium (MPP ϩ ), paraquat, and manganese on dopaminergic cells.11,12) PC12 cells are electrically excitable and neurosecretory (dopamine, norepinephrine, and/or acetylcholine), and contain many membrane-bound and cytosolic macromolecules associated with neurons.11)The present study was designed to investigate whether ethanol extract of MCR is capable of...

Yukmijihwang-tang (YMJ), also known as Luweidihuang-tang in China, has been widely used as a general herbal tonic for hundreds of years in many Asian countries. This study examines whether YMJ derivatives (YMJd) enhance cognitive ability in normal human subjects and discusses its potential as treatment for dementia patients with deficient cognitive ability. Subjects were divided into two groups, the placebo-treated group (n = 15) and the YMJd-treated group (n = 20). K-WAIS tests, a Korean version of an individual intelligence quotient (IQ) test, and a P300 latency assessment of event-related potential (ERP) were conducted in order to measure changes in cognitive ability before and after 6 weeks of YMJd treatment. The K-WAIS mean scores of the group treated with YMJd were significantly higher than those of the placebo group (p < 0.05), and their mean P300 latency was substantially shorter (p < 0.005). These results suggest that YMJd treatment accelerates the speed of information processing and enhances cognitive ability. YMJd treatment may help dementia patients or the elderly recover from cognition deficiencies or degeneration in clinic.

Nelumbinis Semen is a well-known traditional herbal medicine frequently used in treatment of depression in many Asian countries. In this study, its anti-depression effects in rats were investigated by comparing the test results of those treated with Nelumbinis Semen to those treated with other herbal anti-depressants, including Rehmanniae Radix Preparat, Corni Fructus, Lycii Fructus, Pinelliae Rhizoma and Hypericum Perforatum. In order to induce depression-like symptoms, the animals were placed under chronic mild stress in the form of overnight illumination for 2 consecutive days. They were treated with the respective herbal extract and forced swimming tests were conducted afterwards. The anti-depression effects of each extract were then evaluated based on a measured index, which consisted of struggling time, first latency and first rest duration. These test results show that Nelumbinis Semen provides greater anti-depression effects than the other herbal extracts. Specifically, only the rats treated with Nelumbinis Semen showed significant increases in struggling time (43.9%, p < 0.005, p = 0.0037) and in first latency time (90.2%, p < 0.05, p = 0.0116). However, the first rest duration for Nelumbinis Semen treated rats was not significantly different from the other rats. It appears that Nelumbinis Semen provides even greater anti-depression effects than Hypericum Perforatum (commonly referred to as St. John's Wort, perhaps the most widely used natural antidepressant today). The anti-depression effects of Nelumbinis Semen might be due to the modulation of the amount of neurotransmitters involved in depression.

Memory may be conceptualized into three phases of information manipulation: those processes that handle the encoding of, storage of, and drawing upon learned and witnessed facts and events, which for humans is encoded physiologically. Two general forms of memory have been classified according to their duration in time: short-term memory (STM), which is rapidly formed and can outlast training from minutes to hours, and long-term memory (LTM), which lasts from hours to days, weeks, or even years.2) The hippocampus is a brain structure that plays a critical role in learning and memory in humans and animals.3) There have been many trials to find memory enhancing or cognition enhancing agents to ameliorate dementia. 8) Other studies report that YMJ increases neurogenesis in the dentate gyrus of the hippocampus in stressed rats 9) while enhancing memory retention and cognitive activities related to memory processes. 7,8) It is also reported that YMJ reverses scopolamine-induced and p-chloroamphetamine-induced amnesia in rats. 7) In addition, our unpublished data shows that YMJ derivatives (YMJd), including Lycii fructus, enhance memory retention by protecting neuronal cells from attack by reactive oxygen species (data not shown). In our recent study, K-WAIS, the Korean version of the WAIS test, and Event-Related Potential P300 latency during auditory oddball tasks were measured to assess the effect of YMJd on cognitive abilities in normal human subjects before and after 6 weeks of YMJd treatment. We found that the K-WAIS mean scores of the group treated with YMJd were significantly higher than those of the placebo group (pϽ0.05), while their mean P300 latency was substantially shorter (pϽ0.005). These results suggest that YMJd treatment accelerates the speed of information processing and enhances cognitive ability. 10) Thus, those results suggest that YMJ and its derivatives may be useful agents for the enhancement of learning and memory. However, there have been few reported studies on accessing the mechanism of memory enhancement triggered by treatment with YMJ or YMJd. The present study is designed to evaluate the action and mechanism behind the memory-enhancing effect of the herbal extract YMJd. Our results revealed that YMJd has a significant effect on memory enhancement and the expression of genes associated not only with the prevention of neuronal degeneration but also with neuronal growth events. The herbal extract Yukmijihwang-tang (YMJ) has been widely used for centuries as an anti-aging herbal medicine in Asian countries. Among the various modified prescriptions of YMJ, YMJ derivatives (YMJd) were formulated to enhance memory retention. This study has three goals: 1) to quantitatively evaluate the memoryenhancing effect of YMJd using behavior tasks; 2) to use cDNA micro-array tools to identify candidate genes responsible for enhancing memory; and 3) to statistically evaluate the specific gene expression patterns using Real-time PCR. Memory retention abilities are addressed by the passive avoidance task with...

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