Ustilaginoidin M₁, a new bis-naphtho-γ-pyrone from the fungus Villosiclava virens

Abstract

Ustilaginoidin M1 (1), a novel bis-naphtho-γ-pyrone, was isolated from the cultures of the fungus Villosiclava virens which was the pathogen of rice false smut disease. Its structure was elucidated by spectroscopic analysis and by comparison of its physical and spectroscopic data with the literature. Compound 1 was tested for its cytotoxicity against five human cancer cell lines.

Elucidation of ustilaginoidin biosynthesis reveals a previously unrecognised class of ene-reductases

“…Likewisely, the epimerism could be possible in the dimers containing either 6 or 7 . Indeed, we observed a partial conversion (6%) from usg D ( 16 ) to its 3-epimer 20 , from usg M ( 17 ) to its 3′-epimer usg M 1 , 2 and from usg N ( 13 ) to its 3′-epimer usg P, 10 in the frozen samples of 16 , 17 , and 13 , respectively, which had been stored at −20 °C for 4 years. This suggested one alternative route to generate the 6 -containing dimers (such as 19 and 20 ) via 3-epimerism of the corresponding dimers ( e.g.…”

Detoxification of Mycotoxins through Biotransformation

“…Many other mycotoxins such as beauvericin [178,179], enniatins [180], ustiloxins [181], ustilaginoidins [182][183][184][185], sorbicillinoids [186,187] and mycotoxins from mushrooms have not been studied for their detoxification through biotransformation. Although the structures of some converted products from mycotoxins were elucidated, their toxicity to animals and humans are not clear.…”

Penicacids H–J, three new mycophenolic acid derivatives from the marine-derived fungus Rhizopus oryzae

“…As in penicacid H (1), the coupling constant of the anomeric proton (H-1 00 ) recorded in methanol-d 4 (J ¼ 7.7 Hz) suggested the b-linkage of the molecule. [35][36][37] The optical rotation of 2 was found to be [a] 20 D + 29.3 and by comparing 13 C NMR data of the sugar moiety with reported literature, 29 it was conrmed to be b-D-glucopyranose. Therefore, compound 2 was chemically conrmed to be a derivative of 7-O-(b-D-glucopyranosyl)-mycophenolic acid (penicacid H, 1), which was insignicantly named as penicacid I.…”

“…The coupling constant of anomeric proton (H-1 00 ) recorded in methanol-d 4 (J ¼ 7.7 Hz) suggested the b-linkage of the molecule. [35][36][37] The optical rotation of 1 was found to be [a] 20 D + 31.6 and by comparing 13 C NMR data of the sugar moiety with reported literature, 29 it was conrmed to be b-D-glucopyranose. To the best of our knowledge, compound 1 was only reported as a hepatic metabolite in plasma of transplant recipients on MMF treatment 38 and as a biotransformation product from MPA and glucose using Streptomyces aureofaciens.…”

“…The obtained results (Fig. 1) led to the isolation and identication of three new MPA derivatives (1-3), together with two known naphtho-g-pyrone dimers, asperpyrone A (4) [20][21][22] and dianhydroaurasperone C (5). [23][24][25][26] In this study and for the rst time, we report the isolation and structural elucidation of three MPA derivatives marked as new natural products, penicacids H-J (1-3) (Fig.…”