Biotransformation of β-Mangostin by an Endophytic Fungus of Garcinia mangostana to Furnish Xanthenes with an Unprecedented Heterocyclic Skeleton

Abstract

Biotransformation of β-mangostin (1) by the endophytic fungus Xylaria feejeensis GM06 afforded hexacyclic ring-fused xanthenes with an unprecedented hexacyclic heterocylic skeleton. β-Mangostin (1) was transformed to two diastereomeric pairs of enantiomers, mangostafeejin A [(−)-2a/(+)-2b)] and mangostafeejin B [(−)-3a/(+)-3b)]. The chemical structures of the transformation products were elucidated by analysis of NMR and MS data, and the structure of mangostafeejin A [(−)-2a/(+)-2b)] was confirmed by single-crystal X-ray diffraction analysis. The absolute configurations of 3a and 3b were established on the basis of calculated and measured ECD data using the ECD spectra of 2a and 2b as models. The fungal biotransformation described herein provides an effective method to convert an abundant achiral plant natural product scaffold into new chiral heterocyclic scaffolds representing expanded chemical diversity for biological activity screening.

Recent progress in biodiversity research on the Xylariales and their secondary metabolism

“…Xylaria feejeensis is biologically associated with the mangosteen fruit and was thus examined for its capability to biotransform plant metabolites to novel derivatives [58]. One of the secondary metabolites produced by said plant is the xanthone β-mangostin, which is associated with anti-inflammatory, antibacterial, antimalarial, and antimycobacterial activities.…”

Generation of Indoles with Agrochemical Significance through Biotransformation by Chaetomium globosum

“…The relative stereochemistry of 2 was established by comparing the observed coupling constants and NOE data with those of harzialactone A isolated from Trichoderma harzianum OUPS-N115. 17 Namely, its coupling constant magnitude of H-3 with H-2 and H-4 (J 2,3α = J 2,3β = J 3β,4 = 8.2 Hz and J 3β,4 = 3.3 Hz; Table 2) was closely similar to that of harzialactone A (J 2,3α = J 2,3β = J 3β , 4 = 8.3 Hz and J 3β,4 = 3.5 Hz). 18 Furthermore, NOEs of H-4 with H-3β and of H-2 with H-3α and H-5 in the NOESY spectrum of 2 (Figure 2) agreed with those of harzialactone A.…”

“…Biotransformation has advantages over conventional chemical synthesis due to its selective nature, environmental acceptability, mild conditions, and high reaction rates. 16,17 Biological assay revealed that compounds 1, 3, 5, and 6 inhibit the growth of the crop pathogenic microbes Xanthomonas oryzae pv. oryzae (Xoo) and X. oryzae pv.…”

Natural Enantiomers: Occurrence, Biogenesis and Biological Properties

“…being determined by using the helicity rule for α,β-unsaturated ketone. Compounds 493a/493b and 494a/494b, as xanthene enantiomers with an unprecedented hexacyclic heterocylic backbone, were isolated from Xylaria feejeensis GM06 in 2018 [236]. The abs.…”