Elloxazinones A and B, New Aminophenoxazinones from Streptomyces griseus Acta 2871†

Abstract

Two new aminophenoxazinone compounds with antitumor activity, elloxazinone A and B, were isolated from the culture filtrate of Streptomyces griseus Acta 2871. Their chemical structures were determined by mass spectrometry, NMR spectroscopy and X-ray analysis. Elloxazinones A and B showed a moderate inhibition of the proliferation of human cells from gastric adenocarcinoma in vitro but a strong inhibition of hepatocellular carcinoma cells whereas elloxazinone B strongly inhibited the proliferation of human breast carcinoma cells.

Partial purification and characterisation of two actinomycete tyrosinases and their application in cross-linking reactions

“…These media were also used as liquid media screens for tyrosinase production. Optimal production of tyrosinase was found to occur in the complex medium, MPPM, a medium typically used in the production of bioactive secondary metabolites [15]. In addition, similar to other streptomycete strains [23], the addition of CuSO 4 .5H 2 O to the medium resulted in the induction of tyrosinase production in both strains, while the addition of L-methionine had a limited effect (data not shown).…”

Bezerramycins A–C, Antiproliferative Phenoxazinones from Streptomyces griseus Featuring Carboxy, Carboxamide or Nitrile Substituents

“…The latter was identified as elloxazinone B (4) by a comparison of its spectroscopic data with those published in the literature. [11] The UV spectrum and the NMR spectroscopic data of compound 1, named bezerramycin A (Figure 1), are very similar to those of the known compound elloxazinone B (4), [11] suggesting that 1 also belongs to the group of phenoxazinone antibiotics. Its empirical formula was assigned to be C 14 (Table 1).…”

“…The assignment of the protons resonating at δ H = 7.63, 9.92, 8.02 and 10.43 ppm is supported by comparison with the data for elloxazinone B. In analogy to the NMR assignments of elloxazinone B (4), [11] we attribute the chemical shifts of δ H = 7.63 and 9.92 ppm of 1 to the amide group, whereas the chemicals shifts of δ H = 8.02 and 10.43 ppm belong to the amine group. (Table 1).…”

“…WRAT-210. [12][13][14][15][16] Phenoxazinones frequently encountered in S. griseus strains include the grixazones and the elloxazinones, [11,17] all of which lack C-9 functionalization. Whereas the grixazones bear an N-acetylated cysteine moiety at C-1 through a thioether bond, the elloxazinones possess a carboxamide function in this position.…”

“…[4,9,10] Here, we report the isolation and structure elucidation of three new antiproliferative phenoxazinone antibiotics (1-3) along with the known aminophenoxazinone elloxazinone B (4). [11] In addition to the biological activities, the finding of congeners featuring carboxy, carboxamide, or rare nitrile substituents is intriguing from a biosynthetic point of view.…”