Kagoshima University · Division of Agricultural Sciences, School of Agriculture, Fisheries and Veterinary Medicine · 准教授

Research keywords食品科学・機能性食品素材・機能性食品・栄養科学・心血管イベント・家政学一般・リポソーム・モデル膜・プロテオミクス・血管

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• Kajiya K, Inokuchi H, Sakakibara Y, Takamatsu H, Yamanouchi H . Preventive and inhibitory effects of Salacia on sustained contraction of vascular smooth muscle cells and characterization of th2026 · 記述言語： 英語 出版者・発行元： Biochemistry and Biophysics Reports Sustained contraction of vascular smooth muscles can abruptly restrict blood flow, leading to ischemia. While mild, prolonged contractions may cause dizziness and migraines, severe vasoconstriction (vasospasm) can result in cerebral or myocardial infarction and may be fatal. Sphingosylphosphorylcholine (SPC) is a known inducer of pathological sustained contraction that occurs independently of Ca²⁺-dependent mechanisms. Although lipid-soluble dietary compounds have been reported to inhibit SPC-induced contractions, their clinical utility is limited by poor suitability for aqueous formulations and a tendency to accumulate in membranes and adipose tissue. In this study, we sought to identify water-soluble compounds that selectively inhibit pathological sustained contraction without impairing Ca²⁺-dependent vascular contraction. We focused on Salacia , a medicinal plant extensively studied for its metabolic effects, but whose vascular actions remain poorly characterized. Extracts from both aboveground (stems and trunks) and belowground (roots) parts of Salacia , applied either before or during SPC exposure, significantly inhibited SPC-induced sustained contraction. The active compounds were identified as 3,4-dihydroxybenzoic acid (3,4-DHBA), trans -3-, trans -4-, and trans -5-caffeoylquinic acids (CQAs), ortho -hydroxybenzoic acid ( o -HBA), and para -HBA ( p -HBA). Inhibitory potency followed the order 3,4-DHBA ≈ CQA > HBA. Notably, 3,4-DHBA and CQAs readily permeated vascular endothelial cells to reach smooth muscle, and their inhibitory effects were synergistically enhanced when 3,4-DHBA was present in excess. These findings suggest that water-soluble compounds from Salacia may prevent or attenuate SPC-induced vasospasm and its associated severe vascular diseases. DOI： 10.1016/j.bbrep.2026.102530 Scopus PubMed
• 加治屋 勝子 . 地域を救う桜島大根の魅力 . 生物工学会誌103 ( 8 ) 409 - 411 2025年8月 詳細を見る 担当区分： 筆頭著者, 責任著者 記述言語： 日本語 出版者・発行元： 公益社団法人 日本生2025 · 担当区分： 筆頭著者, 責任著者 記述言語： 日本語 出版者・発行元： 公益社団法人 日本生物工学会 DOI： 10.34565/seibutsukogaku.103.8_409
• 紫外線を吸収・遮断する竹のチカラを地球の資源に2025 · クリーンテクノロジー 2025年
• Yamanouchi H., Minami Y., Kajiya K. . Evaluation and validation of angiotensin-converting enzyme inhibitory activity of moringa oleifera, quercetin, and isoquercetin: A comparative stud2025 · 担当区分： 最終著者, 責任著者 記述言語： 英語 掲載種別： 研究論文（学術雑誌） 出版者・発行元： Food Research International Moringa oleifera, known for its nutritional benefits and biological functions, such as antihypertensive effects, has cultivated in Japan. However, there is limited information available on moringa cultivated in Japan. Cardiovascular diseases, including ischemic heart disease and stroke, cause many deaths worldwide each year, with hypertension being the most significant risk factor. This study investigated the inhibitory activity of angiotensin-converting enzyme (ACE), which is one of the blood pressure elevation mechanisms, aiming to identify the active compounds in moringa leaves cultivated in Kagoshima prefecture, Japan (Kagoshima-moringa). Additionally, we evaluated the potential overestimation of the ACE inhibitory activity when measured using the fluorescence method. The ACE inhibitor compounds in the methanol-rich extract of Kagoshima-moringa were purified, and mass, aglycone, and glycoside analyses suggested isoquercetin as one of the active compounds. ACE inhibitory activity was evaluated using a fluorescent derivatization method with o-phthalaldehyde (OPA). However, the inhibitory effect of isoquercetin may have been overestimated, as the OPA fluorescence measurement indicated that isoquercetin could inhibit fluorescence readings. Therefore, the absorbance method was performed, revealing that captopril demonstrated similar inhibitory activity, whereas Kagoshima-moringa extracts showed low activity. These results indicate that the ACE inhibitory activity of flavonoids, or samples rich in flavonoids, may be overestimated when assessed by the fluorescence method using OPA. Hence, evaluating ACE inhibitor activity requires the careful selection of measurement methods; multiple activity measurement methods should be used if possible. The study underscores the importance of appropriate measurement methods for evaluating ACE inhibitory activity, guiding future research practices. DOI： 10.1016/j.foodres.2025.115768 DOI： 10.1016/j.foodres.2025.115768 Scopus

• 日本平滑筋学会若手の会開催2024 · 2024年2月
• 桜島大根由来成分による血管内皮機能改善効果の作用機序解明2020 · researchmap
• 桜島大根由来成分による血管内皮機能改善効果の作用機序解明2020 · 2020年4月 - 2025年3月
• 出前授業2018 · 錦江湾高校 2018年10月

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