Bisindoles arcyriaflavin

Fruit bodies of wild myxomycetes often have bright colors. In 1980 Steglich et al. isolated red and yellow pigments from methanol extracts of 2 g of the red fruit bodies of Arcyria denudata [7], Structure of these pigments were elucidated by spectral data as a series of bisindole maleimides, and they were named arcyriarubin B (1), C (2), arcyriaflavin B (3), C (4), and arcyrioxepin A (5). 1, 2, and 5 were red... 

Dihydroarcyriarubin C (104), a new bisindole alkaloid, has been isolated from fruit bodies of a myxomycete Arcyria ferruginea, which was collected at Hao, Yasu-cho, Kochi Prefecture, together with two known bisindoles, arcyriarubin C (2) and arcyriaflavin C (4), and the structure of 104 was elucidated by spectral data. Arcyriaflavin C (4) was also obtained, together with arcyriaflavin B (3), from fruit bodies of Tub if era casparyi, which ( 16839) was collected at Mt. Miune, Monobe-mura, Kochi Prefecture, in November 1997. Arcyriaflavin C (4) was revealed to exhibit cell cycle inhibition activity on HeLa cells on the basis of flow cytometry studies. Fruit bodies of Fuligo Candida, which ( 23446) was collected at Motoyama-cho, Kochi Prefecture, in August 2002, were revealed to contain a relatively high quantity of cycloanthranilylproline (105). 

Arcyria pigments (bisindolylmaleimides and in-dolo[2,3-a]carbazoles). The tiny fruit bodies of the slime molds Arcyria denudata, A. nutans, and related myxomycetes contain indole pigments of the bisindol-ylmaleinimide type. Parent compounds are the red ar-cyriarubins A, B, and C. Oxidative cyclization in the 2,2 -position furnishes the pale yellow and poorly soluble arcyriaflavins A, B, and C (table I). Indolocarba-zoles of this type are also known as active principles from streptomycetes ( rebeccamycin). 

The same chromophore as is found in the arcyriaflavins occurs also in rebeccamycin (516) and in its dechloro derivative, two antitumour antibiotics isolated from Nocardia aerocoligenes 510). Also closely related to these compounds are staurosporin (517), an antibiotic from Streptomyces staurosporeus which exhibits pronounced antihypotensive activity 258), and other carbohydrate bridged bisindoles (575). Due to the small amounts of Arcyria metabolites available from the... 

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