Sargassum tortile

Dimeric structures are possible as exemplified by the leptosins, from a strain of Leptosphaeria (a fungus isolated from the marine alga Sargassum tortile). Some of these, e.g. leptosin A 11, may have up to 4 sulfur atoms across the diketopiperazine ring system.23 Various leptosins have antitumor and cytotoxic properties. 

The polysulfide leptosins (121-135) belong to a series of epipolythiodioxopiperazines produced by a fungal strain Leptosphaeria sp. OUPS-4, isolated from the marine alga Sargassum tortile [125, 126, 127, 128]. 

Kato, T., Kumanireng, A.A., Ichinose, I., Kitahara, Y., Kakinuma, Y., Nishihara, M., and Kato, M., Active components of Sargassum tortile effecting the settlement of swimming larvae of Coryne uchidai, Experientia, 31, 433, 1975. 

I. Kubo, T. Matsumoto and N. Ichikawa, Absolute configuration of crinitol, an acyclic diterpene insect growth inhibitor from the brown algae Sargassum tortile, Chem Lett., (1985) 249-252. 

Metab. from the mycelium of a strain of Leptosphaeria sp. attached to the marine alga Sargassum tortile. Shows potent cytotoxicity against P388 lymphocytic leukaemia cells. Pale yellow powder. Mp 190-192°. [ot] +436 (c, 0.51 in CHCI3). 

Sargassum tortile Hydroxysargaquinone (58), sargasal-1 (59), sargasal-11 (60) Cytotoxic [156]... 

Numata, A. et al. (1992) A cytotoxic principle of the brown alga Sargassum tortile and struc-... 

Numata, A., Kanbara, S., Takahashi, C., Fujiki, R., Yoneda, M., Usami, Y, and Fujita, E. (1992) A cytotoxic principle of the brown alga Sargassum tortile and structures of chromenes. Phytochemistry, 31, 1209-1213. 

Leptosin H (x=4, y = 2) Leptosphaeria sp./Sargassum tortile Takahashi et al., 1994a, 1995a... 

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