J
Johji Yamahara
Researcher at Kyoto Pharmaceutical University
Publications - 23
Citations - 785
Johji Yamahara is an academic researcher from Kyoto Pharmaceutical University. The author has contributed to research in topics: Sugar beet & Aralia elata. The author has an hindex of 11, co-authored 23 publications receiving 720 citations.
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Salacinol, potent antidiabetic principle with unique thiosugar sulfonium sulfate structure from the ayurvedic traditional medicine Salacia reticulata in Sri Lanka and India
Masayuki Yoshikawa,Toshiyuki Murakami,Hiromi Shimada,Hisashi Matsuda,Johji Yamahara,Genzoh Tanabe,Osamu Muraoka +6 more
TL;DR: In this article, a most potent natural α-glucosidase inhibitor named salacinol has been isolated from an antidiabetic Ayurvedic traditional medicine, Salacia reticulata wight, through bioassay-guided separation.
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Stomachic principles in ginger. III: An anti-ulcer principle, 6-gingesulfonic acid, and three monoacyldigalactosylglycerols, gingerglycolipids A, B, and C, from zingiberis rhizoma originating in Taiwan
Masayuki Yoshikawa,Shoko Yamaguchi,Kumiko Kunimi,Hisashi Matsuda,Yasuhiro Okuno,Johji Yamahara,Nobutoshi Murakami +6 more
TL;DR: 6-Ginesulfonic acid showed weaker pungency and more potent anti-ulcer activity than 6-gingerol and 6-shogaol and the absolute stereostructure of (+)-angelicoidenol-2-O-beta-D-glucopyranoside was clarified on the basis of its synthesis from d-borneol.
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New hypoglycemic constituents in "gymnemic acid" from Gymnema sylvestre.
Nobutoshi Murakami,Toshiyuki Murakami,Masashi Kadoya,Hisashi Matsuda,Johji Yamahara,Masayuki Yoshikawa +5 more
TL;DR: Investigation of hypoglycemic activity of major saponin constituents from "gymnemic acid" exposed not only two new saponins, but also gymnemoside b and gymnemic acid V as active principles, and an acetyl group linked 16- or 22-hydroxy group in 1 and 2 was found to migrate easily to primary 28-hydroxyl group.
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Escins-Ia, Ib, IIa, IIb, and IIIa, Bioactive Triterpene Oligoglycosides from the Seeds of Aesculus hippocastanum L.: Their Inhibitory Effects on Ethanol Absorption and Hypoglycemic Activity on Glucose Tolerance Test.
Masayuki Yoshikawa,Emiko Harada,Toshiyuki Murakami,Hisashi Matsuda,Noriko Wariishi,Johji Yamahara,Nobutoshi Murakami,Isao Kitagawa +7 more
TL;DR: Five triterpene oligoglycosides named escins-Ia, Ib, IIa, IIb, and IIIa were isolated from the seeds of Aesculus hippocastanum L. and their chemical structures were determined on the basis of chemical and physicochemical evidence.
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Elatoside e, a new hypoglycemic principle from the root cortex of aralia elata seem. : structure-related hypoglycemic activity of oleanolic acid glycosides
Masayuki Yoshikawa,Hisashi Matsuda,Emiko Harada,Toshiyuki Murakami,Noriko Wariishi,Johji Yamahara,Nobutoshi Murakami +6 more
TL;DR: A new inhibitor named elatosides E (which was shown to affect the elevation of plasma glucose level by oral sugar tolerance test in rats) was isolated from the root cortex of Aralia elata Seem together with elatoside F.