Junko Nagai

Dr. Junko Nagai

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Research Focus & Metrics

Academic Career Length

12Years (2015-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 November 2019 in Bioorganic Chemistry
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Journal Article
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KTKoichi Takao
Koichi Takao
SESaki Endo
Saki Endo
JNJunko Nagai
Junko Nagai
HKHitoshi Kamauchi
Hitoshi Kamauchi
YTYuri Takemura
Yuri Takemura
YSYoshiaki Sugita
Yoshiaki Sugita

25 December 2018 in Medicines
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Journal Article
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Hiroshi SakagamiHiroshi Sakagami
Hiroshi Sakagami
TWTaihei Watanabe
Taihei Watanabe
THTomonori Hoshino
Tomonori Hoshino
NSNaoto Suda
Naoto Suda
KMKazumasa Mori
Kazumasa Mori
YSYoshiaki Sugita
Yoshiaki Sugita
The present article reviews the research progress of three major polyphenols (tannins, flavonoids and lignin carbohydrate complexes), chromone (backbone structure of flavonoids) and herbal extracts. Chemical modified chromone derivatives showed highly specific toxicity against human oral squamous cell carcinoma cell lines, with much lower toxicity against human oral keratinocytes, as compared with various anticancer drugs. QSAR analysis suggests the possible correlation between their tumor-specificity and three-dimensional molecular shape. Condensed tannins in the tea extracts inactivated the glucosyltransferase enzymes, involved in the biofilm formation. Lignin-carbohydrate complexes (prepared by alkaline extraction and acid-precipitation) and crude alkaline extract of the leaves of Sasa species (SE, available as an over-the-counter drug) showed much higher anti-HIV activity, than tannins, flavonoids and Japanese traditional medicine (Kampo). Long-term treatment with SE and several Kampo medicines showed an anti-inflammatory and anti-oxidant effects in small size of clinical trials. Although the anti-periodontitis activity of synthetic angiotensin II blockers has been suggested in many papers, natural angiotensin II blockers has not yet been tested for their possible anti-periodontitis activity. There should be still many unknown substances that are useful for treating the oral diseases in the natural kingdom.

1 August 2017 in The Clinical Journal of Pain
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Journal Article
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JNJunko Nagai
Junko Nagai
Yoshihiro UesawaYoshihiro Uesawa
Yoshihiro Uesawa
RSRyotaro Shimamura
Ryotaro Shimamura
HKHajime Kagaya
Hajime Kagaya
Objectives: Acetaminophen and nonsteroidal anti-inflammatory drugs (NSAIDs) are antipyretic analgesics with established adverse effects (AEs); however, only a few studies have compared their AEs simultaneously. We aimed to compare the AEs of these medications to confirm the respective frequencies of both rare and major AEs. Methods: We used a high-quality database for spontaneous adverse drug event reporting in Japan. Data were extracted regarding the AEs of acetaminophen and NSAIDs to compare the tendency of the appearance of those AEs between the drugs. We also performed a principal component analysis using the AE data to assess the characteristics of major AEs. Results: Cutaneous disorders and hepatic disorders were the most common AEs induced by acetaminophen and NSAIDs, with gastrointestinal tract disorders also common with NSAID use. Principal component analysis quantitatively showed the tendencies of specific AEs, and it helped demonstrate the characteristics of AEs. Acetaminophen and NSAIDs showed different tendencies in the occurrence of AEs. Each NSAID was plotted based on the tendency of the appearance of major AEs, and AEs were classified by their likelihood of being pharmacological or idiosyncratic. Conclusions: These findings may help clinicians select an appropriate drug for patients considering their backgrounds, instead of choosing merely based on the class of the drug, for example, cyclooxygenase selectivity. This selection, based on the characteristic information on AEs occurring in clinical settings, might be more suitable for patients.

2 December 2021 in PLOS ONE
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Journal Article
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JNJunko Nagai
Junko Nagai
YIYoichi Ishikawa
Yoichi Ishikawa
Introduction: Anticholinergic adverse effects (AEs) are a problem for elderly people. This study aimed to answer the following questions. First, is an analysis of anticholinergic AEs using spontaneous adverse drug event databases possible? Second, what is the main drug suspected of inducing anticholinergic AEs in the databases? Third, do database differences yield different results?Methods: We used two databases: the US Food and Drug Administration Adverse Event Reporting System database (FAERS) and the Japanese Adverse Drug Event Report database (JADER) recorded from 2004 to 2020. We defined three types of anticholinergic AEs: central nervous system (CNS) AEs, peripheral nervous system (PNS) AEs, and a combination of these AEs. We counted the number of cases and evaluated the ratio of drug–anticholinergic AE pairs between FAERS and JADER. We computed reporting odds ratios (RORs) and assessed the drugs using Beers Criteria®.Results: Constipation was the most reported AE in FAERS. The ratio of drug–anticholinergic AE pairs was statistically significantly larger in FAERS than JADER. Overactive bladder agents were suspected drugs common to both databases. Other drugs differed between the two databases. CNS AEs were associated with antidementia drugs in FAERS and opioids in JADER. In the assessment using Beers Criteria®, signals were detected for almost all drugs. Between the two databases, a significantly higher positive correlation was observed for PNS AEs (correlation coefficient 0.85,P= 0.0001). The ROR was significantly greater in JADER.Conclusions: There are many methods to investigate AEs. This study shows that the analysis of anticholinergic AEs using spontaneous adverse drug event databases is possible. From this analysis, various suspected drugs were detected. In particular, FAERS had many cases. The differences in the results between the two databases may reflect differences in the reporting countries. Further study of the relationship between drugs and CNS AEs should be conducted.

26 August 2020 in Medicines
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Journal Article
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YSYoshiaki Sugita
Yoshiaki Sugita
KTKoichi Takao
Koichi Takao
Yoshihiro UesawaYoshihiro Uesawa
Yoshihiro Uesawa
JNJunko Nagai
Junko Nagai
YIYosuke Iijima
Yosuke Iijima
Hiroshi SakagamiHiroshi Sakagami
Hiroshi Sakagami
Since many anticancer drugs show severe adverse effects such as mucositis, peripheral neurotoxicity, and extravasation, it was crucial to explore new compounds with much reduced adverse effects. Comprehensive investigation with human malignant and nonmalignant cells demonstrated that derivatives of chromone, back-bone structure of flavonoid, showed much higher tumor specificity as compared with three major polyphenols in the natural kingdom, such as lignin-carbohydrate complex, tannin, and flavonoid. A total 291 newly synthesized compounds of 17 groups (consisting of 12 chromones, 2 esters, and 3 amides) gave a wide range of the intensity of tumor specificity, possibly reflecting the fitness for the optimal 3D structure and electric state. Among them, 7-methoxy-3-[(1E)-2-phenylethenyl]-4H-1-benzopyran-4-one (compound 22), which belongs to 3-styrylchromones, showed the highest tumor specificity. 22 induced subG1 and G2 + M cell population in human oral squamous cell carcinoma cell line, with much less keratinocyte toxicity as compared with doxorubicin and 5-FU. However, 12 active compounds selected did not necessarily induce apoptosis and mitotic arrest. This compound can be used as a lead compound to manufacture more active compound.

1 July 2021 in Bioorganic & Medicinal Chemistry
Verified
Journal Article
Closed access
KTKoichi Takao
Koichi Takao
YTYuri Takemura
Yuri Takemura
JNJunko Nagai
Junko Nagai
HKHitoshi Kamauchi
Hitoshi Kamauchi
KHKaori Hoshi
Kaori Hoshi
YSYoshiaki Sugita
Yoshiaki Sugita