• Natural Product Sciences
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• v.28 no.3
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• pp.138-142
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• 2022

Alzheimer's disease (AD) is the most common age-related neurodegenerative disease in industrialized countries. It is estimated that about 47 million people living with dementia and the number of cases will be tripled by 2050. However, the exact mechanism of AD is not known, and full therapy has still not been found. Various tryptophan-derived alkaloids have been reported as promising agents for the treatment of AD. In the present study, a series of tryptophan-derived alkaloids were isolated and characterized from the methanol extract of Hedera rhombea fruit. Based on the analysis of their observed and reported spectroscopic data, their structures were identified as N-[4'-hydroxy-(E)-cinnamoyl]-L-tryptophan (1), N-[3',4'-dihydroxy-(E)-cinnamoyl]-L-tryptophan (2), N-[4'-hydroxy-(E)-cinnamoyl]-L-tryptophan methyl ester (3), and N-[3',4'-dihydroxy-(E)-cinnamoyl]-L-tryptophan methyl ester (4). These compounds were screened for anti-Alzheimer activity via their inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes in vitro. As a result, compounds 3 and 4 showed moderate BChE inhibition with IC₅₀ values of 86.9 and 78.4 μM, respectively, compared to those of the positive control [berberine (IC₅₀ = 11.5 μM)]. However, all four compounds did not show significant inhibition of the AChE enzyme. This is the first time, the AChE and BChE inhibitory activities of these tryptophan-derived alkaloids were investigated and reported.

• The Korean Journal of Mycology
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• v.47 no.1
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• pp.75-81
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• 2019

The goal of this study was to characterize unrecorded wild yeasts from soils of spices plants fields and further, to elucidate its anti-demential activities and tyrosinase inhibitory activity. Piskurozyma taiwanensis R4-1 (NIBRFGC000502619), Nadsonia starkeyi-henricii R6-2 (NIBRFGC000502618), and Canadida friedrichii M12-6 (NIBRFGC000502615) isolated from soil of garlic field represented newly recorded yeast strains in Korea. Vishniacozyma peneaus I2-9 (NIBRFGC000502617) and Cryptococcus aspenensis I21-1 (NIBRFGC000502616) from soil of ginger field represented also newly recorded yeast strains, and microbiological characteristics of its fifteen yeast strains were investigated. All of these unrecorded yeasts exhibited oval-global shape and have ascospores except Canadida friedrichii M12-6. Piskurozyma taiwanensis R4-1 and Canadida friedrichii M12-6 grew well in vitamin-free medium, and Piskurozyma taiwanensis R4-1 was halotolent growing in 10% NaCl-containing yeast extract peptone dextrose (YPD) broth. After prepared cell-free of the unrecorded wild yeasts, acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activities as anti-dementia activity and tyrosinase inhibitory activity as whitening activity were determined. Cell-free extract from Canadida friedrichii M12-6 had the highest tyrosinase inhibitory activity of 14.4%.

• Journal of Microbiology and Biotechnology
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• v.32 no.9
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• pp.1154-1167
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• 2022

In this study, we investigated the anti-amnesic effect of Korean red pine (Pinus densiflora) bark extract (KRPBE) against amyloid beta_1-42 (Aβ_1-42)-induced neurotoxicity. We found that treatment with KRPBE improved the behavioral function in Aβ-induced mice, and also boosted the antioxidant system in mice by decreasing malondialdehyde (MDA) content, increasing superoxide dismutase (SOD) activities, and reducing glutathione (GSH) levels. In addition, KRPBE improved the cholinergic system by suppressing reduced acetylcholine (ACh) content while also activating acetylcholinesterase (AChE), regulating the expression of choline acetyltransferase (ChAT), postsynaptic density protein-95 (PSD-95), and synaptophysin. KRPBE also showed an ameliorating effect on cerebral mitochondrial deficit by regulating reactive oxygen species (ROS), mitochondrial membrane potential (MMP) and ATP levels. Moreover, KRPBE modulated the expression levels of neurotoxicity indicators Aβ and phosphorylated tau (p-tau) and inflammatory cytokines TNF-α, p-IκB-α, and IL-1β. Furthermore, we found that KRPBE improved the expression levels of neuronal apoptosis-related markers BAX and BCl-2 and increased the expression levels of BDNF and p-CREB. Therefore, this study suggests that KRPBE treatment has an anti-amnestic effect by modulating cholinergic system dysfunction and neuroinflammation in Aβ_1-42-induced cognitive impairment in mice.

• Korean Journal of Food Science and Technology
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• v.45 no.5
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• pp.661-665
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• 2013

The aim of this study was to investigate the anti-amnesic effect of daebo (Castanea crenata) extract on trimethyltin chloride (TMT)-induced learning and memory impairment, in vivo. The inner skin of daebo was extracted using distilled water under reflux conditions. At the end of the adaptation period, ICR mice were divided into a control group, a TMT injection group (negative control), and a sample group (C5: 5 mg/kg body weight; C10: 10 mg/kg body weight; and C20: 20 mg/kg body weight), and were tested with learning and memory tests. The ethylacetate fraction of the daebo inner skin extract was found to increase TMT-induced memory deficit in the Y-maze and passive avoidance test. Brain tissue analysis showed that the ethylacetate fraction of daebo extract lowered the acetylcholine esterase (AChE) activity and malondialdehyde (MDA) content of neuronal cells, both of which are indicative of lipid peroxidation.

• Korean Journal of Food Science and Technology
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• v.53 no.5
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• pp.553-560
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• 2021

Theanine, the major amino acid and a sweet umami component of green tea, has anti-stress effects in humans. From green tea, theanine was extracted at 80℃ for 2 h using a low temperature, high pressure extractor, and caffeine was removed using an HP-20 column with 80% ethanol. Theanine extracts were applied to produce functional jelly using three kinds of gelling agents (I, II, and III) or various concentrations of theanine extracts (10-50%). Theanine jelly was characterized with respect to its physical properties, product stability, and physiological function. Gelling agent III (tamarind gum, xanthan gum, and locust bean gum=2:3:5, w/w/w) and S3 (35% theanine extracts) jelly exhibited the optimum textural properties with lower hardness and high springiness. Among theanine jellies, S3 exhibited optimum product stability, high 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging, and acetylcholinesterase inhibitory activity. These results indicate that the anine extracts could be used as a neuroprotective source in the food industry.

• Korean Journal of Food Science and Technology
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• v.50 no.5
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• pp.517-527
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• 2018

The current study investigated in vitro anti-diabetic and neuroprotective effects of the ethyl acetate fraction in Actinidia arguta sprouts (EFAS), on $H_2O_2$ and high glucose-induced cytotoxicity in human neuroblastoma MC-IXC cells. EFAS had high total phenolic and total flavonoid contents. An assessment of 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activity of EFAS, as well as its potential for inhibiting malondialdehyde production, indicated that EFAS may possess significant antioxidant properties. EFAS exerted inhibitory effects on ${\alpha}-glucosidase$ via glycemic regulation which forms advanced glycation end products. In addition, EFAS exhibited significant acetylcholinesterase inhibitory effects. Moreover, EFAS displayed protective effects against $H_2O_2$ and high glucose-induced cell death, and inhibited the generation of reactive oxygen species in MC-IXC cells. Finally, the main physiological compound of EFAS was identified via high performance liquid chromatography as a rutin.