Akiko Ohno

NMR-based metabolomics of urine in a mouse model of Alzheimer’s disease: identification of oxidative stress biomarkers

Alzheimer’s disease (AD) is the most common cause of neurodegenerative dementia among elderly patients. A biomarker for the disease could make diagnosis easier and more accurate, and accelerate drug discovery. In this study, NMR-based metabolomics analysis in conjunction with multivariate statistics was applied to examine changes in urinary metabolites in transgenic AD mice expressing mutant tau and β-amyloid precursor protein. These mice showed significant changes in urinary metabolites throughout the progress of the disease. Levels of 3-hydroxykynurenine, homogentisate and allantoin were significantly higher compared to control mice in 4 months (prior to onset of AD symptoms) and reverted to control values by 10 months of age (early/middle stage of AD), which highlights the relevance of oxidative stress to this neurodegenerative disorder even prior the onset of dementia. The level of these changed metabolites at very early period may provide an indication of disease risk at asymptomatic stage.

Design and synthesis of estrogen receptor degradation inducer based on a protein knockdown strategy

We designed and synthesized estrogen receptor (ER) degradation inducers 5, 6, and 7, which crosslink the ER and the cellular inhibitor of apoptosis protein 1 (cIAP1). Compounds 5, 6, and 7 induced cIAP1-mediated ubiquitylation of ERα resulting in its proteasomal degradation.

Studies on Nepalese crude drugs. XXI. On the diterpenoid constituents of the aerial part of Scutellaria discolor COLEBR.

From the aerial part of Scutellaria discolor, eight new neoclerodane diterpenes (compounds 3, 4, 6, 8, 9, 10, 11 and 12) were isolated together with clerodin, dihydroclerodin-1, clerodin hemiacetal (14-hydro-15β-hydroxyclerodin), jodrellin A, scutaltisin, squalene, 24-methylenecycloartanol and a mixture of 3-epioleanolic acid and 3-epiursolic acid. The structures of new compounds were determined by spectroscopic and chemical methods as follows : 3, 15β-ethoxy-14-hydroclerodin ; 4, 15α-ethoxy-14-hydroclerodin ; 6, (6α)-19-O-acetyl-4,18 :11,16 :15,16-triepoxyneoclerodane-6,15,19-triol (6-O-deacetyl-14-hydro-15-hydroxyclerodin) ; 8, 6α-O-acetyl-2,19 :4,18 :11,16 : 15,16-tetraepoxy-14-neoclerodene-6,19-diol (19-O-deacetyljodrellin A) ; 9, 10, 11 and 12, 6α-O-acetyl-15β,19β-diO-ethyl-, 6α-O-acetyl-15α,19β-di-O-ethyl-, 6α-O-acetyl-19β-O-ethyl- and 6α,19-di-O-acetyl-2,19 : :4,18 :11,16 : 15,16-tetraepoxyneoclerodane-6,15,19-triol, respectively.

Complete NMR analysis of oxytocin in phosphate buffer

Complete NMR analysis of oxytocin (OXT) in phosphate buffer was elucidated by one‐dimensional (1D)‐ and two‐dimensional (2D)‐NMR techniques, which involve the assignment of peptide amide NH protons and carbamoyl NH2 protons. The 1H15N correlation of seven amide NH protons and three carbamoyl NH2 protons were also shown by HSQC NMR of OXT without 15N enrichment. Copyright

Intramolecular base-accelerated radical-scavenging reaction of a planar catechin derivative bearing a lysine moiety

A planar catechin derivative incorporating a lysine moiety was synthesized and showed approximately 400-fold increased radical-scavenging activity relative to naturally-occurring (+)-catechin.

Design, synthesis, and evaluation of Trolox-conjugated amyloid-β C-terminal peptides for therapeutic intervention in an in vitro model of Alzheimer's disease.

Two hallmarks of Alzheimers disease (AD) observed in the brains of patients with the disease include oxidative injury and deposition of protein aggregates comprised of amyloid-β (Aβ) variants. To inhibit these toxic processes, we synthesized antioxidant-conjugated peptides comprised of Trolox and various C-terminal motifs of Aβ variants, TxAβx-n (x=34, 36, 38, 40; n=40, 42, 43). Most of these compounds were found to exhibit anti-aggregation activities. Among them, TxAβ36-42 significantly inhibited Aβ1-42 aggregation, showed potent antioxidant activity, and protected SH-SY5Y cells from Aβ1-42-induced cytotoxicity. Thus, this method represents a promising strategy for developing multifunctional AD therapeutic agents.

Inhibition of amyloid fibril formation and cytotoxicity by caffeic acid-conjugated amyloid-β C-terminal peptides

Amyloid-β (Aβ) deposition and oxidative stress observed in the brains of patients with Alzheimers disease (AD) are important targets for therapeutic intervention. In this study, we conjugated the antioxidants caffeic acid (CA) and dihydrocaffeic acid (DHCA) to Aβ1-42 C-terminal motifs (Aβx-42: x=38, 40) to synthesize CA-Aβx-42 and DHCA-Aβx-42, respectively. Among the compounds, CA-Aβ38-42 exhibited potent inhibitory activity against Aβ1-42 aggregation and scavenged Aβ1-42-induced intracellular oxidative stress. Moreover, CA-Aβ38-42 significantly protected human neuroblastoma SH-SY5Y cells against Aβ1-42-induced cytotoxicity, with an IC50 of 4μM. These results suggest that CA-Aβ38-42 might be a potential lead for the treatment of AD.

Synthesis and radical-scavenging activity of a dimethyl catechin analogue

Catechin analogue 1 with methyl substituents ortho to the catechol hydroxyl groups was synthesized to improve the antioxidant ability of (+)-catechin. The synthetic scheme involved a solid acid catalyzed Friedel-Crafts coupling of a cinnamyl alcohol derivative to 3,5-dibenzyloxyphenol followed by hydroxylation and then cyclization through an intermediate orthoester. The antioxidative radical scavenging activity of 1 against galvinoxyl radical, an oxyl radical, was found to be 28-fold more potent than (+)-catechin.

A Metabolic Study on the Biochemical Effects of Chiral Illegal Drugs in Rats Using 1 H-NMR Spectroscopy

Considering the pharmacological effects of chiral drugs, enantiopure drugs may differ from their racemic mixture formulation in efficacy, potency, or adverse effects. Levomethorphan (LVM) and Dextromethorphan (DXM) act on the central nervous system and exhibit different pharmacological features. LVM, the l-stereoisomer of methorphan, shows many similarities to opiates such as heroin, morphine and codeine, including the potential for addiction, while the d-stereoisomer, DXM, does not have the same opioid effect. In the present study, NMR-based metabolomics were performed on the urine of rats treated with these stereoisomers, and showed significant differences in metabolic profiles. In urine within 24 h after treatment of these samples, levels of citrate, 2-oxoglutarate, creatine, and dimethylglycine were higher in LVM-treated rats than in DXM-treated rats. While urinary levels of hippurate and creatinine gradually increased over 72 h in DXM-treated rats, these metabolites were decreased in the urine by 48-72 h after treatment with LVM. The levels of these changed metabolites may provide the first evidence for different cellular responses to the metabolism of stereoisomers.