Kyowa Hakko Kogyo Co., Ltd.

Kyowa Hakko Kogyo Kabushiki Kaisha

Kyowa Hakko Rogyo Kabushiki Kaisha

Tohru Yasuzawa

Hiroshi Sano

Hiroshi Kase

Isao Kawamoto

Yutaka Kanda

Yutaka Saito

Makoto Morimoto

Kunikatsu Shirahata

Hiromitsu Saito

Koji Yamada

Eiji Kobayashi

Yuzuru Matsuda

Shizuo Shiozaki

Satoshi Nakanishi

Kozo Asano

Keiko Ohsawa

Katsuichi Shutoh

A new compound designated KS-505 having amnesia-inhibiting activity may be prepared by fermentation of a suitable strain of Streptomyces, preferably Streptomyces argenteolus A-2 (FERM BP-2065). The compound is thought to have the structure: ##STR1##

Compound KS-505 useful for improving cerebral function

A novel DC-88A derivative represented by general formula: ##STR1## wherein ##STR2## represents ##STR3## has an excellent antitumor activity and is useful as an antitumor agent.

DC-88A derivatives

A new substance K-259-2 having a molecular formula of C.sub.21 H.sub.18 O.sub.7, a molecular weight of 382 and an elemental analysis (%) of H: 4.50, C: 65.53 and N: 0. This substance is of interest in providing a new vasodilating agent in view of its ability to dilate the blood vessel, particularly the artery, of mammals. This substance may be obtained by fermentation of a microorganism Micromonospora sp. K-259 (FERM BP 569).

Substance K-259-2 and a process for producing the same

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Sakai, Japan

Tohru Yasuzawa