- no.31, pp.396-403, 1989-09-17
Lampteroflavin (1), a riboflavin α-D-riboside was isolated in extraordinary small amount from the luminous mushroom, Lampteromyces japonicus (Fig 1), which was available only two weeks in a year. Extraction method was improved to utilize only alive gills under aeration instead of using the whole body (Fig 3), and the method was established as Scheme 1. It's structure has been elucidated by chromatographic and spectroscopic analyses(1). It's fluorescence spectrum was identical to the bioluminescence spectrum of the mushroom, having maximum at 524nm (Fig 2). We concluded that 1 was responsible to the bioluminescence mechanism as the light emitter, since 1 was only the fluorescent constituent in fresh gills. Previous report that illudin S (lampterol) or ergosta-4,6,8(14),22-tetraen-3-one(2) could be the emitter is thus unlikely judging from the weak fluorescent intensity and the different maximum wavelength from that of mush-room bioluminescence. Lampteroflavin (Table 1) was hydrolyzed with dil. mineral acid to give riboflavin and D-ribose. Riboflavin was identified by HPLC, ^1H NMR, UV, Fluorescence and FAB mass spectrometry. D-ribose was acetylated and then confirmed by ^1H NMR, CD and tandem mass spectrometry. Riboflavin and D-ribose was connected together with α-glycosidic linkage which was determined by ^<13>C NMR of the anomeric carbon (δ=103.2ppm)(3), NOSEY spectrum (H-1" being close to H-3" and H-5') and ^1H NMR pattern of anomeric proton. The total structure of lampteroflavin was confirmed through its chemical synthesis.