Two new depsidones from the fungus Lasiodiplodia pseudotheobromae

Prenyllongnols A–D, New Prenylated Acylphloroglucinols that Fight Concanavalin A-Induced Autoimmune Hepatitis

“…The clear NOESY correlations of H-8/H-12b, H-13/H-12a, and H 3 -15/H-17a and H-18/H-17b suggested that H-13 was also on the opposite orientation with the isopentenyl group (C-7–C-11) and H 3 -15 and H-18 were located at the opposite side, which were identical with those of compound 3 . The modified Mosher’s, as a combination of chemical derivatization and the NMR spectral method, has been frequently applied to construct the absolute configuration of secondary hydroxyl in natural products and synthetic products, which was widely recognized for the accuracy and rigor of its results. − After using the modified Mosher’s method, the configuration of C-18 in 3 was identified as 18 S (Figure ) based on the amount of variation in the NMR data that were calculated using δ S –δ R . Meanwhile, it could be concluded that the relative configuration of C-14 was determined as R* on account of the NOESY correlations of H-18/H-17b and H-17a/H 3 -15 (Figure S38).…”

Δ-Keto-acid/hydroxy-lactone isomerization in some lichen depsides, depsidones and diphenyl ethers

“…If R 2′ = H (1, 5-7), then the hydrogen bonding between OH-2′ and COOH-1′ promoted the nucleophilic attack of the hydroxy group of the carboxyl on the ketone to give hydroxylactone. In contrast, with R 2′ = CH 3 (2)(3)(4), this hydroxy group is bonded with the methoxy group, and δ-keto-acid remains untransformed. Such hydrogen bonding has been widely discussed 12,15 and attested through the X-ray structure of 5-methylmellein 16 and β-collatone 9 (Fig.…”

“…Depsides, depsidones and diphenyl ethers are naturally occurring polyfunctionalized aromatic compounds produced by lichens 1,2 or, more rarely, by fungi. 3 In some depsides, the C-6 position of the B ring (more commonly referred to C-6′) is substituted by a 2-oxoalkyl chain, as shown in Fig. 1 for seven specialized metabolites selected for this study.…”

Recent advances on natural depsidones: sources, biosynthesis, structure-activity relationship, and bioactivities

“…Inflammation is a complicated defense process, which is induced by pro-inflammatory cytokines secretion by macrophages as a result of stimuli ( e.g ., infectious agent, tissue ischemia, injury, etc .) ( Zhao et al, 2021a ; Liang et al, 2022 ). Impairment of the pro-inflammation mediator secretion can lead to diverse disorders such as asthma, atherosclerosis, psoriasis, periodontal diseases, carcinogenesis, and rheumatoid arthritis ( Chen et al, 2018a ; Niu et al, 2021b ).…”