Targeted isolation, identification, and antioxidant evaluation of aromatic polyketides from a plant-derived fungus Ophiobolus cirsii LZU-1509.

There are >350 species of the Ophiobolus genus, which is not yet very well-known and lacks research reports on secondary metabolites. Three new 3,4-benzofuran polyketides 1-3, a new 3,4-benzofuran polyketide racemate 4, two new pairs of polyketide enantiomers (±)-5 and (±)-7, two new acetophenone derivatives 6 and 8, and three novel 1,4-dioxane aromatic polyketides 9-11, were isolated from a fungus Ophiobolus cirsii LZU-1509 derived from an important medicinal and economic crop Anaphalis lactea. The isolation was guided by LC-MS/MS-based GNPS molecular networking analysis. The planar structures and relative configurations were mainly elucidated by NMR and HR-ESI-MS data. Their absolute configurations were determined by using X-ray diffraction analysis and via comparing computational and experimental ECD, NMR, and specific optical rotation data. 9 possesses an unreported 5/6/6/6/5 five-ring framework with a 1,4-dioxane, and 10 and 11 feature unprecedented 6/6/6/5 and 6/6/5/6 four-ring frames containing a 1,4-dioxane. The biosynthetic pathways of 9-11 were proposed. 1-11 were nontoxic in HT-1080 and HepG2 tumor cells at a concentration of 20 µM, whereas 3 and 5 exerted higher antioxidant properties in the hydrogen peroxide-stimulated model in the neuron-like PC12 cells. They could be potential antioxidant agents for neuroprotection.

Bis[2-(2-pyridylmethyl-eneamino)benzene-sulfonato]-κN,N',O;κN,N'-copper(II).

In the mononuclear title compound, [Cu(C(12)H(9)N(2)O(3)S)(2)], the copper(II) salt of 2-(2-pyridylmethyl-eneamino)benzene-sulfonic acid, the Cu(II) atom is coordinated by one O and two N atoms from a monoanion as well as by two N atoms from another monoanion in a distorted trigonal-bipyramidal environment.

Chloridotetra-kis(pyridine-4-carb-alde-hyde-κN)copper(II) chloride.

In the mol-ecular structure of the title compound, [CuCl(C(6)H(5)NO)(4)]Cl, the Cu(II) atom is coordinated by four N atoms of four pyridine-4-carboxaldehyde ligands and one chloride anion in a slightly distorted square-pyramidal coordination geometry. There is also a non-coordinating Cl(-) anion in the crystal structure. The Cu(II) atom and both Cl atoms are situated on fourfold rotation axes. A weak C-H⋯Cl inter-action is also present.

Bis[2-(2-pyridylmethyl-eneamino)benzene-sulfonato-κN,N',O]cobalt(II) dihydrate.

The title complex, [Co(C(12)H(9)N(2)O(3)S)(2)]·2H(2)O, has site symmetry 2 with the Co(II) cation located on a twofold rotation axis. Two tridentate 2-(2-pyridylmethyl-eneamino)benzene-sulfonate (paba) ligands chelate to the Co(II) cation in a distorted octa-hedral geometry. The pyridine and benzene rings in the paba ligand are oriented at a dihedral angle of 42.86 (13)°. Inter-molecular O-H⋯O and C-H⋯O hydrogen bonding is present in the crystal structure.