Semi-Continuous Fermentation of Onion Vinegar and Its Functional Properties.

For the fermentation of vinegar using onion, acetic acid bacteria and yeast strains with high fermentation ability were screened. Among them, Saccharomyces cerevisiae 1026 was selected as a starter for ethanol production and Acetobacter orientalis MAK88 was selected as a vinegar producer. When the two-stage fermentation of onion vinegar was performed at 28 °C, the titratable acidity reached 4.80% at 24 h of fermentation. When semi-continuous fermentation proceeded to charge-discharge consisting of three cycles, the acetic acid content reached 4.35% at 48 h of fermentation. At this stage, the fermentation efficiency, acetic acid productivity, and specific product formation rate were 76.71%, 17.73 g/(L·d), and 20.58 g/(g·h), respectively. The process in this study significantly reduced the fermentation time and simplified the vinegar production process. The content of total flavonoids and total polyphenols in onion vinegar were 104.36 and 455.41 µg/mL, respectively. The antioxidant activities of onion vinegar in terms of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic) acid (ABTS⁺) radical scavenging activity, and reducing power were 75.33%, 98.88%, and 1.28, respectively. The nitrite scavenging abilities of onion vinegar were 95.38 at pH 1.2. The onion vinegar produced in this study showed higher organoleptic acceptability than commercial onion vinegar.

Cinnamomum loureirii Extract Inhibits Acetylcholinesterase Activity and Ameliorates Trimethyltin-Induced Cognitive Dysfunction in Mice.

The pathogenesis of Alzheimer's disease (AD) has been linked to the deficiency of neurotransmitter acetylcholine (ACh) in the brain, and the main treatment strategy for improving AD symptoms is the inhibition of acetylcholinesterase (AChE) activity. In the present study, we aimed to identify potent AChE inhibitors from Cinnamomum loureirii extract via bioassay-guided fractionation. We demonstrated that the most potent AChE inhibitor present in the C. loureirii extract was 2,4-bis(1,1-dimethylethyl)phenol. To confirm the antiamnesic effects of the ethanol extract of C. loureirii, mice were intraperitoneally injected with the neurotoxin trimethyltin (2.5 mg/kg) to induce cognitive dysfunction, and performance in the Y-maze and passive avoidance tests was assessed. Treatment with C. loureirii extract significantly improved performance in both behavioral tests, suggesting that this extract may be neuroprotective and therefore beneficial in preventing or ameliorating the degenerative processes of AD, potentially by restoring cholinergic function.

Perilla frutescens Extract Ameliorates Acetylcholinesterase and Trimethyltin Chloride-Induced Neurotoxicity.

One of the critical features of Alzheimer's disease is cognitive dysfunction, which is, in part, due to decreases in acetylcholine (ACh). The ethanol extract of Perilla frutescens was selected for isolating the acetylcholinesterase (AChE) inhibitor based on preliminary screening. In vivo behavioral tests were performed to examine the effects of the P. frutescens extract on trimethyltin chloride-induced impairment of learning and memory in mice. A diet containing P. frutescens extract effectively reversed learning and memory impairment on the Y-maze and passive avoidance tests. To isolate the active compound from the P. frutescens extract, solvent partitioning, silica gel open column chromatography, thin-layer chromatography, and high-performance liquid chromatography were used. The AChE inhibitor was identified as rosmarinic acid.

Effect of Chaenomeles sinensis Extract on Choline Acetyltransferase Activity and Trimethyltin-Induced Learning and Memory Impairment in Mice.

The aim of this study was to search for a novel choline acetyltransferase (ChAT) activator from plants traditionally grown in Korea. An ethanol extract from Chaenomeles sinensis Koehne showed the highest ChAT-activating effect in vitro in an assay that used human neuroblastoma cells and [(14)C]acetyl-CoA. The active compound was speculated to be stearic acid methyl ester (SAME). In an in vivo experiment, C. sinensis extract and SAME improved trimethyltin (TMT)-induced deficits in learning and memory in mice as assessed by a Y-maze behavioral test and a passive avoidance test. The C. sinensis extract might attenuate the TMT-induced brain disorder. This study suggests that SAME from C. sinensis might be useful in the treatment of Alzheimer's disease.

Ligularia fischeri extract protects against oxidative-stress-induced neurotoxicity in mice and PC12 cells.

Alzheimer's disease (AD) is pathologically characterized by the presence of amyloid plaques in brain and the overproduction of amyloid beta (Aß), leading to learning and memory impairment and intense oxidative stress. In this study, the protective effect of Ligularia fischeri extract was investigated using PC12 cells. L. fischeri extract attenuated hydrogen-peroxide-induced DNA fragmentation in cells. In vivo behavioral tests were performed to examine the effects of the extract on amyloid-ß peptide1-42-induced impairment of learning and memory in mice. A diet containing the extract increased alternation behaviors in the Y-maze test and step-through latency of passive avoidance task. Moreover, we found that consumption of the extract decreased lipid peroxidation in a biochemical study of brain tissue in mice. High-performance liquid chromatography was used to identify the active compounds in the extract. These results suggest that L. fischeri extract could be protective against Aß-induced neurotoxicity, possibly due to the antioxidative capacity of its constituent, 3-O-caffeoylquinic acid.

Effects of brussels sprouts and their phytochemical components on oxidative stress-induced neuronal damages in PC12 cells and ICR mice.

In this study, the protective effects of Brussels sprouts extract and its major constituents against oxidative stress-induced damages were investigated in rat pheochromocytoma cells and Institute of Cancer Research mice. The major constituents of Brussels sprouts (3,4',5,7-tetrahydroxyflavone (kaempferol), indole-3-carbinol, and phenethyl isothiocyanate) were selectively tested. Of these, the flavonoid compound, kaempferol exhibited the highest potency in radical scavenging activity (1,1-diphenyl-2-picryl hydrazyl assay and oxygen radical absorbance capacity assay) and was most protective against oxidative stress in neuronal cell assays (measurement of intracellular oxidative stress levels and cell viability). In mice, after 4 weeks of kaempferol administration, significant protection against amyloid beta (Aß) peptide-induced neurotoxicity was also observed, as assessed through the passive avoidance test. Taken together, the results suggest that Brussels sprouts could be protective against Aß-induced neurotoxicity, possibly due to the antioxidative capacity of its major constituent, kaempferol.

2,4-Di-tert-butylphenol from sweet potato protects against oxidative stress in PC12 cells and in mice.

In this study, the protective effect of sweet potato extract against hydrogen peroxide-induced oxidative stress and cytotoxicity on the pheochromocytoma cell line (PC12) was investigated. The active component of the sweet potato extract was purified and determined to be 2,4-di-tert-butylphenol. The antioxidant capacity of 2,4-di-tert-butylphenol was measured by using 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid (ABTS) radical. To examine the effects of 2,4-di-tert-butylphenol on amyloid-beta peptide (Aß11₋42)-induced learning and memory impairment in mice, in vivo behavioral tests were performed. Administration of 2,4-di-tert-butylphenol increased alternation behavior in mice injected with Aß1₋42. These results suggest that sweet potato extract could be protective against Aß-induced neurotoxicity, possibly due to the antioxidative capacity of its constituent, 2,4-di-tert-butylphenol.

Rubus coreanus Miquel inhibits acetylcholinesterase activity and prevents cognitive impairment in a mouse model of dementia.

To find acetylcholinesterase (AChE) inhibitors for the prevention of neurological disorders, such as Alzheimer's disease, ethanol extracts of promising traditional edible Korean plants were tested. Among them, Rubus coreanus Miquel extract exhibited the most significant AChE inhibitory activity. The effect of R. coreanus extract on trimethyltin-induced memory impairment in mice was investigated using Y-maze and passive avoidance tests. Our results showed that administration of R. coreanus extract significantly improved alternation behavior and step-through latency. In addition, R. coreanus extract was sequentially fractionated, and the purified constituent was determined to be 3,4,5-trihydroxybenzoic acid.