Structure of a New Antibiotic Oxaspirol A

Trichocladinols A–C, Cytotoxic Metabolites from a Cordyceps‐Colonizing Ascomycete Trichocladium opacum

“…The final refinement gave R 1 = 0.0547 and wR 2 = 0.1203 [I Ͼ 2σ(I)]. [24] Massarigenin A (4): The 1 H NMR, 13 C NMR, and ESIMS data were fully consistent with literature values. [6] MTT Assay: [4] In 96-well plates, 10 4 cells were introduced into each well.…”

“…The molecular formula of trichocladinol A (1; atom numbering shown and used for NMR assignments not in accord with the systematic IUPAC-consistent name) was assigned as C 13 13 C, and HMQC NMR spectroscopic data (Table 1) of 1 revealed one exchangeable proton (δ = 4.46 ppm), three methyl groups, one oxygenated methylene unit, four methines (three oxygenated), one disubstituted olefin, two sp 3 quaternary carbon atoms (one oxygenated), and one carboxy carbon atom. Interpretation of the 1 H-1 H COSY NMR spectroscopic data identified two isolated proton spin systems, C-6-C-10 (including C-12) and C-4-4-OH.…”

“…Trichocladinol C (3) is closely related to massarigenin A (4), [6] both belonging to the γ-methylidene-spirobutanolide class of metabolites, which have mainly been isolated from the basidiomycetous and ascomycetous fungi. [12][13][14][15][16][17][18][19][20][21] Biogenetically, by comparison of the biogenesis of arthropsolide A, [20] the γ-methylidene-spirobutanolides could be derived from the condensation of a tetraketide precursor and a malic acid unit followed by a series of reactions including reduction, elimination, and epoxidation. The carbon skeleton could also be derived from a polyketide chain through some unusual rearrangement reactions.…”

Functional chromatographic technique for natural product isolation

“…19,20 It is intriguing that the resin-bound p97 was able to retain both oxaspirol B ( 2 ) and C ( 1 ), but only 2 was capable of inhibiting p97 activity. This prompted us to hypothesize that structural features common to both 1 and 2 are responsible for their binding to p97 but the Michael-acceptor enone moiety present in 2 may be essential for its p97 inhibitory activity.…”

Oxaspirol B with p97 Inhibitory Activity and Other Oxaspirols from Lecythophora sp. FL1375 and FL1031, Endolichenic Fungi Inhabiting Parmotrema tinctorum and Cladonia evansii

“…19,20 Of the oxaspirols known to date, oxaspirol A ( 1 ) was the first to be encountered, and this was isolated as a weakly active antibacterial constituent from a mutant strain of the human pathogenic fungus, Rhodotorula glutinis T-110. 19 Its planar structure has been elucidated with the help of 1 H and 13 C NMR spectroscopic data and by comparison of these data with those reported for rosigenin. However, no detailed 1 H and 13 C NMR assignments of 1 have been reported.…”