Tatsuo Hayashi

Publications (4)6.26 Total impact

• Article: Dammarane-type triterpenes from the Brazilian medicinal plant Cordia multispicata.

  Masanori Kuroyanagi, Nobuo Kawahara, Setsuko Sekita, Motoyoshi Satake, Tatsuo Hayashi, Yoichi Takase, Kazuo Masuda
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  ABSTRACT: From the Brazilian medicinal plant Carucaá (Cordia multispicata), oleanane- and ursane-type triterpenoids were previously reported as anti-androgenic constituents of the plant. In this study, purification of the polar elements of the EtOAc-soluble fraction of the plant revealed nine novel dammarane-type triterpenes, named cordianols A-I (1-9) along with the known compound cordialin A (10). The structures of these new compounds were elucidated by means of spectral methods including HRFABMS, (1)H NMR, (13)C NMR, and 2D NMR (HMQC, HMBC, NOESY). Absolute configuration at C-23 of compound 7 was determined by an excitone chirality method. Some of these new compounds revealed a hemiketal structure on the A ring and a hydroxylated or epoxidated 20(22)-(E)-ene side chain and showed weak anti-androgenic activity.
  Journal of Natural Products 11/2003; 66(10):1307-12. · 3.13 Impact Factor
• Article: Phenolic constituents from Dalbergia cochinchinensis.

  Osamu Shirota, Vibha Pathak, Setsuko Sekita, Motoyoshi Satake, Yoshio Nagashima, Yutaka Hirayama, Yusuke Hakamata, Tatsuo Hayashi
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  ABSTRACT: Three new phenolic compounds (1-3), along with five known phenolics, 4'-hydroxy-2'-methoxychalcone (4), latinone (5), dalbergiphenol (6), 7-hydroxyflavanone, and dalbergin (7), have been isolated from the stems of Dalbergia cochinchinensis. The structures of 1-3 were established by spectroscopic techniques including 1D and 2D NMR methods. The inhibitory activity against testosterone 5 alpha-reductase, which causes androgen-dependent diseases, was also examined for selected compounds.
  Journal of Natural Products 09/2003; 66(8):1128-31. · 3.13 Impact Factor
• Article: Antibacterial and Antiandrogen Flavonoids from Sophora flavescens

  Masanori Kuroyanagi, Takeshi Arakawa, Yutaka Hirayama, Tatsuo Hayashi
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  ABSTRACT: Sixteen flavanones, three flavanonols, and four pterocarpans were isolated from the MeOH extract of the roots of Sophora flavescens. Twelve of these were new compounds, including eight prenylflavanones (1−8), one prenylflavanonol (9), and three novel pterocarpane derivatives (10−12). Their structures were elucidated using NMR and mass spectral methods. Some of these compounds have irregular C10 prenyl moieties at C-8 of the flavanone skeleton. These compounds exhibited significant antibacterial activities against the Gram-positive bacteria Staphylococcus aureus, Bacillus subtilis, S. epidermidis, and Propionibacterium acnes. They also exhibited antiandrogen activities.
  11/1999;
• Article: Two chalcone-prenylcoumarin Diels-Alder adducts from Brosimum rubescens

  Osamu Shirota, Setsuko Sekita, Yutaka Hirayama, Yusuke Hakamata, Tatsuo Hayashi, Takuma Yanagawa, Motoyoshi Satake
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  ABSTRACT: Two new Diels-Alder type adducts, named palodesagretin I (I) and II (II), were isolated from a Peruvian folk medicine "palo de sangre", Brosimum rubescens. The structure of these new isolates indicated them to be adducts consisting of chalcone derivs. and a prenylcoumarin produced by a Diels-Alder-type addn. reaction, with a five-membered ring-closure. Structural elucidation was based mainly on 2D-NMR analyses. [on SciFinder(R)]
  Phytochemistry. 47(7):1381-1385.