Papers - SAITO Shun

Biological activities of unique isoflavones prepared from Apios americana Medik

Kaneta H., Koda M., Saito S., Imoto M., Kawada M., Yamazaki Y., Momose I., Shindo K.

Bioscience, Biotechnology, and Biochemistry (Oxford University Press (OUP))  80 ( 4 ) 774 - 778 2016.04

Research paper (scientific journal), Joint Work, Accepted,  ISSN  0916-8451

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Four unique isoflavone aglycones (barpisoflavone A (1), 2′-hydroxygenistein (2), 5-methylgenistein (3), and gerontoisoflavone A (4)) whose structures were related to genistein were prepared from the tuber of Apios americana Medik. We examined the estrogen receptor and androgen receptor binding activities, estrogen agonistic activities, antioxidant activities, and α-glucosidase inhibitory activities of 1–4. The results obtained showed that 2 possessed potent and 1, 3, and 4 possessed moderate estrogen partial ago- nistic activities, 1 and 2 possessed moderate antioxi- dant activities, and 2 and 3 possessed moderate α-glucosidase inhibitory activities.

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Antarlides: A New Type of Androgen Receptor (AR) Antagonist that Overcomes Resistance to AR-Targeted Therapy

Saito S., Fujimaki T., Panbangred W., Igarashi Y., Imoto M.

Angewandte Chemie International Edition (Wiley)  55 ( 8 ) 2728 - 2732 2016.02

Research paper (scientific journal), Joint Work, Lead author, Accepted,  ISSN  1433-7851

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Prostate cancer is treated with androgen receptor (AR) antagonists but most patients experience disease pro- gression after long-term treatment with these compounds. Therefore, new AR antagonists are required for patient follow- up treatment. In the course of screening for a new AR antagonist, we isolated the novel compounds antarlides A–E (1–5) from Streptomyces sp. BB47. Antarlides are mutually isomeric with respect to the double bond and have a 22- membered-ring macrocyclic structure. The full stereostructure of 1 was established by chemical modifications, including methanolysis, the Trost method, acetonide formation, and the PGME method. 1–5 inhibited the binding of androgen to ARs in vitro. In addition, 2 inhibited the transcriptional activity of not only wild-type AR but also mutant ARs, which are seen in patients with acquired resistance to clinically used AR antagonists. Therefore, antarlides are a potent new generation of AR antagonists that overcome resistance.

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Novel Isoflavone Glucosides in Groundnut (Apios americana Medik) and Their Antiandrogenic Activities

Ichige M., Fukuda E., Miida S., Hattan J., Misawa N., Saito S., Fujimaki T., Imoto M, Shindo K.

Journal of Agricultural and Food Chemistry (American Chemical Society (ACS))  61 ( 9 ) 2183 - 2187 2013.03

Research paper (scientific journal), Joint Work, Accepted,  ISSN  0021-8561

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