Anti-oxidant activity of acetyl-L-carnitine (ALC) and effect of green leaf odor on stress

In a previous study, it has been reported that ALC is reduced in some brain regions of the patients with chronic fatigue syndrome. To investigate the significance of ALC in brain functions, we examined effects of ALC (ú @) on the hydroxyl radical generation, (ú A) on the viability of cultured PC-12 cells exposed to oxidant stress, (ú B) on the brain lipid hydroperoxid e level of senescence-accelerated prone-8 mice (SAMP8), and (ú C) on the retention latency in passive avoidance test of SAMP8 with the deteriorated learning ability. In addition, we carried out to investigate (ú D) an effect of green leaf odor on brain amine metabolisms of rats exposed to immobilization stress. Results obtained in the present study were as follows. (i) The effect of ALC on the hydroxyl radical generation by the metal-dependent Fenton reaction was examined by the ESR spin trapping technique using 5,5-dimethyl-1-pyroline-N-oxide (DMPO) as the spin trap reagent. ALC significantly inhibited the formation of the DMPO-OH adduct produced by the reaction with the hydroxyl radical (1). (ú A) The effect of ALC on the viability of cu ltured PC-12 cells exposed to hydroxyl radicals produced by a photo-Fenton reaction agent (NP-‡ V) and UV was investigated. Application of 50 µM ALC to the cultured medium significantly increased the viability of PC-12 cells. (ú B) Brain lipid hydroperoxide levels were significantly higher for SAMP8 than for controls in 2 to 9 months of age (2,3). When the lipid hydroperoxide levels were examined in SAMP8 with repeated (every two days) intraperitoneal injections of ALC from 3 weeks of age to 4 months of age, the levels of SAMP8 treated with 400 mg/kg ALC were significantly low compared to those of saline controls (4). (ú C) When the retention latency in passive avoidance test was examined in SAMP8 treated with 400 mg/kg ALC as described in (ú B), the latency was significantly shorter for SAMP8 than for controls (4). (ú D) Brain serotonin metabolism in rats wa s increased by immobilization stress. Inhalation of green leaf odor during immobilization stress significantly restored the increased serotonin metabolism.